Taneja Aerospace and Aviation limied

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TRAINING REPORT

SUBMITTED BY

DARSHAK BHUPTANI

BRANCH

B.Tech IN AEROSPACE ENGINEERING (BTAE)

ENROLLMENT NUMBER

093574710

COLLEGE ROLL NUMBER

2009-AEP-S12

INDIAN INSTITUTE FOR AERONAUTICAL ENGINEERING

&INFORMATION TECHNOLOGY

PSC OF INDIRA GANDHI NATIONAL OPEN UNIVERSITY

S.NO 85,SHASTRI CAMPUS,NDA ROAD,SHIVANE,PUNE411023

2010-2011

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Acknowledgment

It brings me a great pleasure to be the part of Taneja Aerospace and Aviation

Limited for the training period of twenty one days.

It gave me the complete exposure to the outside world within a short period of

time, how acutually the theory is being applied pracitically.

My special thanks to Mr. Shikhar Chaturvedi, Technical Executive Managing

Director of TAAL, for taking a lot of pain to see that I can learn something new

which would not be possible to get in any books.

It is because of him only I have been able to prepare this report.

I would also thanks to all the staffs of TAAL for guiding and teaching us

something new which is practical.

I request him to be always there to guide me and show the correct path

whenever I need.

Thank you Sir once again.

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College letter/ certificate

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Company’s certificate/ company letter

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Abstract

This is the report which has been made from the exposure which I have got

from the TAAL.This includes various topics such as construction of an aerodrome,

communication system between ground and aircraft, production of P68C type

aircraft, manufacturing various types of products which has being used by DRDO,

HAL, CAE, Indian Army, ISRO, ADE etc.

For the manufacturing of these products there are various process and

procedure which has to be carried out are broadly explained with an example in

various units of TAAL.

This also include the maintaince procedure which is as per the DGCA norms

such as C-Check, painting of a commercial aircraft's.

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Contents:

1) ATC tower. 7

2) Runway. 12

3) Indian airspace. 18

4) Ground handling. 22

5) Fuel boucher. 24

6) Fire tender. 26

7) Manufacturing of aerospace components and process shops. 28

8) CNC Profiler shop. 43

9) Paint shop. 46

10) Composite shop. 50

11) Avionics laboratory. 57

12) Simulator shop. 59

13) Aircraft engines and its components. 60

14) Pnuematic system. 66

15) Presurization system. 70

16) Oxygen system. 75

17) Air conditioning system. 77

18) Aircraft Tyres. 80

19) P68C aircraft. 82

20) Introduction to UAV's. 92

21) Bell 407 helicopter. 97

22) Maintaince of A320 aircraft. 98

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ATC

Introduction: ATC means air traffic control, which plays an important role for the comunnication and

navigaion purpose in the field of aviation.

ATC was born after the first mid air collision between two planes that had occur on 7th

April

1922, over Gatewick airport, Great Britain causing the death of seven people.So the basic

function of ATC is to maintain the safe distance between the two aircraft in air as well as on

the ground and the safety of passenger and aircraft in air as well as on the ground is the

main criteria.

Brief description: ATC is important in the field of navigatioin and communiocation. Its main function is to

provide sepreesion between the two aircrafts in the air as well as on the ground in order to

avoid collision. Air traffic control is divided into three to four units which work in

coordination with each other to provide safety of an aircraft.

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ATS is air traffic surface unit which controls the movement of the aircraft on the ground

control tower is the tower which gives clearance to the aircraft for the landing and take off.

Approach tower is the tower which assign the higher flight level and ask the pilot to switch

over to the destination approach frequency.

ACU is area control unit which controls the airspace which comes before the destination of

an aircraft. So aircraft must take clearance from each ACU to approch control tower.

Position of ATC: The position of ATC in the airport should be in a such a way that a 360

0 view of the whole

airport should be available from one place.So it is at the maximum elevation from the

ground.

Area description which is under Hosur ATC: The whole air space of 5 nautical miles of radius is under the Hosur tower which includes air and

land of the airport.

This area is 3050 feet above the mean sea level.

On land, the tower controls the movement of all aircraft and other vehicals such as towing vehicle,

fuel tank,fire extinguisher vehicles etc, to and fro movements towards the runway.

Apron area is the area where the loading/unloding of the pay loads takes place before and after take

off and landing of an aircraft..

Clearance taken by the pilot before take off: If an aircraft is towed by the towing vehicle than this is known as towing in which aircraft

power is not utilized. Aircraft is towed from the hanger to the apron area or to the holding

point.

If an aircraft uses its own power for the movement on the ground is known as taxing.

For both these types of movements the pilot must take clearance from the ATS.

From the holding point the pilot must take the clearance from the ATC tower.

ATC assign a particular flight level, magnetic bearing of the destination, radial code before

giving clearance.

Note :

For HAL, radial code is BBG that is BRAVO BRAVO GOLF.

For Banglore International, radial code is BIA that is BRAVO INDIA ALPHA.

For Coimbatore airport, radial code is CCB that is CHARLIE CHARLIE BRAVO.

This is known as radio telephony language.

Information given by the controller to the pilot before take off/landing: QNH- which is Quadrateral Navigation Height. This is height of the airport from the mean

sea level. This is very important for the pilot to adjust his altimeter according to QNH as this

will give him his exact altitude from the ground.

1 mb of difference in pressure can cause an error of 30 feet.So controller has to give him

exact QNH in terms of millibar.

The time of take off and landing is the GMT and not the IST standards.

Pressure at ground level.

Temperature at ground level.

Visibility at ground level.

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Frequency used for the communication by the Hosur Tower: The frequency assigned to the Hosur tower is 129.8 Mega Hertz.

Approach tower frequency of Hosur airport is 127.7 Mega Hertz..

For the communication purpose VHF band is used whose range is from 30 to 300 Mega

hertz.

For aircraft communication frequency used is from 118 to 136.9 Mega Hertz.

Advantages of using VHF: It is used for short range of communication which is line of sight type communication.

It is more immune to noise.

It can accomodate more number of frequency which can be used for the communicaion.

Disadvantage of using VHF: It cannot be used for long range communication.

Instruments used by the Hosur tower for the communication :

Transmitter: It is a device which is used to transmit the signal from the controller to the

pilot

Receiver: It is a device which is used to receive the signal from the pilot to the controller.

Press/Push To Talk (PTT): It is used for the internal communication, commonly known as

walkie talkie.

Speakers: It is a device which is used to hear the sound of communication clearly.

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Various instruments used by the Hosur tower: Alitimeter:

It is a device which is used to measure the alitiude from the mean sea level.

This instrument sense the pressure difference between the static pressure and the outside

pressure and gives the reading in terms of altitude, as pressure decreases with increase in

altitude.

Wind monitor logger:

It is a device which gives the speed and direction of wind flow over the airfield

The units used for measuring the wind velocity is knots and the direction of wind with

refrence from the magnetic north in terms of degree measuring in anticlockwise.

Wind socks are used for the visual approach of wind which can give an

approximation of the velocity to the wind flow.

Reason for the runway to be in East West direction: Usually, the direction of flow of wind is from east to west or vice-versa throughout the year.

Aircraft usually take off and land in the direction opposite to the direction of wind, the

purpose is for the minimum usage of runway during landing and high lift co-efficient during

take off. If runway is in North South direction, then aircraft will face the cross wind which

will deviates the aircraft from its glide path.So pilot has to maintain its logitudinal axis along

the runway axis which increase the pilot efforts to maintain the magnetic bearing.Thus to

reduce the pilot effort and easy accessibility, runway is mostly in East West direction.

For bigger aircraft such as 737, A319, A320 etc cross wind of 60-70 knots only will have its

affect on the aircraft, while for the smaller aircraft 40 knots of cross wind is sufficient to

deviates the aircraft from its magnetic bearing.

But at the larger airports to handle large traffic there are both the runways present, that is

main runway and cross runway which are used simultaneously.

Rules of take off/landings: VFR known as visual flight rules:

In this type take off and landing takes place without any help from the navigational

aids.

For this type, take off and landing should take place between 20 minutes before and

after sunrise and sunset respectively.

Minimum visibilty must be 5000 meters..

Cloud height should be above 1500 feet from the ground level.

IFR known as instruments flight rules:

In this type take off and landing taks place with the help of the navigational aids.

For this type, take off and landing can take place at any time provided night landing

system is available at the airport.

With the help of ILS, take off and landing can take place even in zero visibility.

Indication over ATC: It is a light indication which indicates the type of airport it is.

If it is a combination of green and white, then it is a civilian airport.

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If it is a combination of green and yellow, then it is a water airport such as maldives,vienam.

If it is a combination of 1 green and 2 white, then it is a defence airport.

If it is a combination of green, yellow and white, then it is a Helliport.

These are known as beacons lights.

Hosur airport has a combination of green and white light over its ATC.

There is a wind direction indicator over ATC.

There is a flag which may be red or green colour depending upon the traffic.

If there is a red flag means there is movement of aircraft in the airfield and for every

movement clearance is mandatory from the ATC.

If it is green then there is no movement of aircraft and anyone can move without any

clearance from ATC.

Working of ATC: After the approval of the flight plan submitted by the pilot, ATC controller will give

clearance for the flight with a ATC transponder to every aircraft for its flight which will be

unique.

The pilot will take clearance from the ATS and will report at holding point and wait for the

threshold clearance from the ATC.

After Clearance given by ATC, aircraft take's off and control tower controller passes it to the

approach controller, who gives him higher flight level, heading, speed in tracon airspace and

ask him to switch over to destination approach frequency or ACU frequency.

Any controller can divert an aircraft from its actual flight plan depending on various factors

such as weather,turbulence, traffic etc.

Indian airspace is divided in 23 tracons and each tracon is controlled by several controllers

which gets information of an aircraft with their various parameters such as flight level flight

speed etc entering their airspace through a computer generated flight strip.

Vice-versa happens at the time of landing of an aircraft.

If an aircraft enters the indian airspace without any ATC transponder then the pilot of that

aircraft will be interogated by the controller and if fails to satisfy him with the right answer

then the controller can ask the Indian Air Force to ground that aircraft or shoot down it if it

is threat to the Indian part in terms of security.

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Runway

Introduction: Runway is the place from where an aircraft take's off and land.It should be constructed in

such a way that it can bear the sudden load without any damage.It is smoothly finished so

that an aircraft does not get any jerk.

Brief discreption: The runway is built with the high grade of concrete and tar with the addition of polybon to

the concrete and polyurea.

The runway is always free from potholes and for this bituminous material available is a non

hardening asphalt/sand mixture commnly known as ―winter mix‖.

There are various marking done over the runway according to the international standards.

The lighting over the runway for the night landing/take off is als according to the

international standards.

There are various devices such as PAPI, ILS etc.is placed beside runway for the

navigational aid to the pilot.

Runway description: The total strip length of the Hosur runway is 2.168 Km or 7111 feet.

Width of the runway is 45 meters.

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This runway is capable of handling the aircraft weighings upto 57,000 kilograms.

The runway designation is 09-27. It is in the east-west direction such that west end is

inclined at 9 degree to the north.

The centre line of the runway is white except in the cold region where it is yellow in order to

avoid confusion to the pilot from the snow colour.

The distance between the two successive centre strip is 25 meters.

Runway is sholdered for an about 20

so that there is no accumulation of water and this is

done to avoid the skiding of an aircraft in the rainy season.

Runway markings:

Taxiway:

This is the path taken by an aircraft before and after the take off and landing

respectively.

Its centre line is yellow in colour.

Holding point:

This is the point on the taxiway where an aircraft wait for the clearance to the entry

to runway provided it is clear without any obstruction.

It is the main point where the entry to runway starts.

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Threshold point:

This is the starting point of the take off.

Touch down point:

This is the point from where an aircraft can touch the runway.

The width of the srip is 3 meters while its length is 10 meters.

The strips are on both the sides of the centre line.

Aiming point:

This is the point before which an aircraft must touch the ground for a perfect landing.

If an aircraft touch after the aminig point the it can shoot the runway.

The width of the strip is 5 meters while its length is 30 meters.

The strips are on both the sides of the centre line.

Touch down zone:

This is an area between aiminig point and the touch down point. For a perfect

landing, aircraft must touch the runway only in touch down zone.

Apron area:

This is the area where loading and unloading of the payloads takes places before

evey take off and landing respectively.

Designation: Hosur runway designation is 09-27, that is 90

0 to the magnetic north and it is painted

at the start of the runway.

The two arrow indicates the direction of take off and landing.

These arrows are known as line of take off and landing.

Runway and taxiway lights: The blue coloured light on both the sides of the way is the taxiway light which indicates the

path for an aircraft for taxing process.

There are 20 blue taxi lights at Hosur airport.

Taxiway bulb is of 45 watts each and operates on single phase ac generator with constant

current regulator, CCR.

At first and last one-third of the runway there is a combination of two lights, that is yellow

and white. The middle part of the runway has light of white colour on both sides of the

runway.

If pilot uses the runway 09 then he will see the yellow and white light on both the sides of

the runway for the first part and only white light for the second part.At the last part he will

see only yellow light which indicates that he has limited length of runway remaining for the

take off.and vice -versa for the usage of runway 27 respectively.

There are five white lights on both the sides of runway from both the end to indicate

threshold point.These lights are known as Runway End Identifing Light System (REILS).

There are in all 64 lights on runway.

Runway bulbs are hallogen bulbs of 200 watts each and operates on three phase ac generator

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with constant current regulator, CCR.

All the lights are connected in series so that all the bulbs will have same current,so same

power such that they will illuminate with the same intensity.

Repair and maintanance of the runway: At the busy airport such as Mumbai, Delhi International airport, due to high traffic rate,

runway is repaired and maintained after every fifty-two take off's and fifty-two landing's.

This is because every time the aircraft hit the runway, there are chances of the damage to th

runway due to high sudden load which is due to aircraft all up weight.

Visual navigational aid avialable at TAAL airport:

Tri Colour Vasi:

In this type the three colour indications are used to show the correct glide angle for

an aircraft.

If it is amber in colour, then an aircraft is above the glide path.

If it is green in colour, the an aircraft is on the correct glide path with correct glide

angle.

If it is red in colour, then an aircraft is below the glide path with very low glide

angle.

VGSI: VGSI stands for Visual Glide Slope Indicator.

It is same as PAPI but these four lights are arranged in the square fashion with two

lights above and below.

PAPI:

P

A

P

I

s

t

a

n

d

s

f

o

r

t

h

e

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precessision approach path indicator.It is placed on the left hand

side of the approach runway because the Captain of an aircraft seat is on the left hand

side.This is placed at the threshold point.

It contains four instruments which contains lenses in it which can be seen of different

colour when observed at different angle.

When pilot is at the approach then he will see the PAPI and if he see's the innear two

red colour and outter two white colour then he is at correct glide angle of 30.

If he observes the inear three red colour and outermost as white colour, then he is

below glide angle, near about 2.20.

If he observes all the four red colour, then he is much below glide angle less then

2.20.

If he observes the inear three white colour and outermost as red colour, then he is

very little above glide angle.

If he observes all four white colour, then he is much above the glide path and above

the glide angle.

The lenses are adjusted such that they show different colours when observed at

different angles. The lenses are made up of concave and convex type. The PAPI has a

combination of four instruments namining A,B,C,D from the innear side of the

runway.

The lens in A is adjust at an angle 3057'

The lens in B is adjust at an angle 3037'

The lens in C is adjust at an angle 2059'.

The lens in D is adjust at an angle 20'.

PASI:

PASI stands for Pulsating Approach Slope Indicator.

If it is pulse rating is white light, then an aircraft is above the glide path.

If it is a steady white light, then an aircraft is on the glide path.

If it is pulse rating red light, then an aircraft is slightly below the glide path.

If it is a steady red light, then an aircraft is much below the glide path.

Tri-VGSI was replaced by VGSI and again VGSI was replaced by PAPI.Now-a-days,

ILS system is used inseted of PAPI.

The visual navigation aid available at the TAAL airport is PAPI

Signal Square:

It is the sign which are used for the visual approach by the pilot for the various

indications for the airport.

It contains four indicating symbols, they are T-shaped, dumbelled shape, aerodrome

refrence point,cross signal.

T-shaped sign is used to indicate the runway which is in use. The tail of T indicates

that an aircraft must touch down the runway parallel to the tail part from the base.

Dumbelled sign is used to indicate that aircraft should maneveure at the available

space only and it should not go in the muddy area of the airport.

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Aerodrome indicator is a sign which indicates the position of the aerodrome in terms

of latitude and longitude.So if pilot knows the latitude and longitude of the

aerodrome than he can locate and visually identify the aerodrome.

Cross sign indicates that the airport is not operational and if there is only one

diagonal line indicating that the airport is operational.

H-indicator is the indicator which is used at the time of night landing where the bulbs

present are luminated in T-fashion an indicating the runway which is used as T-sign

indicating during the day time.The bulb used are all halogens bulbs and are

connected in series so that they illuminate in with the same intensity.

This is present only at the one end of the runway and that is 09 at TAAL airport.

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Indian Airspace

Introduction: Airspace is defined as the space above the ground levvel which is used for the flying

purpose with or without it help of the controller present at the ground.This airsapce is

divided in tracons which are commonly known as zones. Each tracon is controlled by each

controller sitting in ACU using SSR and some zones are controlled using PSR also.

Brief description: Airspace forms an important part in the field of aviation.This is the space where an aircraft

that has to fly with minimumdistance in between them of 1000 feet.The air route taken by an

aircraft should be shuch that it does not intersect the other flight plan as well as it should not

cross the country airspace accidently also. In case of an international or cross country flight,

there should be proper route and it should not fly into unflying zone which may be used for

defence or R&D purpose by that country.

Airspace of the world are divided into tracons according to the country wise at an

international level with accordance with ICAO.

Each tracon is divided into two:

Controlled airspace and uncontrolled airspace.

Controlled airspace: It is defined as an airspace where flying is carried out with the help of the

ground controller.This is the airspace which is under the observation by a ground

controller for all the 24 hours.For flying in the controlled airspace, clearance from

the ground is mandatory in order to avoid collision between the two aircraft.

Uncontrolled airspace:

It is defined as an airspace where flying is carried out withot the help of the ground

controller.This is the airspace which is not under the observation by a ground

controller for all the 24 hours but ground controller can scan this airspace also. For

flying in the controlled airspace, clearance from the ground is not mandatory in order

to avoid collision between the two aircraft.

Indian Airspace: Indian airspace is divided into 23 tracons and each tracon is controlled by each ACU and

approach tower near an airport area.In India only controlled airspace is present. So flying in

India must be co-ordinated with the ground controller and without his clearance no aircraft

can be airborne and has to fly within the permissible limit of an airspace.

For the controlled airspace, the necessary equipments and informations which are necessary

are mentioned below:

PSR and SSR are very much essential in order to have aclear view of all the aircraft which is

flying under their airspace.

Flight information from the pilots such as quantity of fuel present, flight level, flight speed,

people on board etc.

Type of an aircraft, that is weather commercial, private, military, aerobatics etc.

Communication system between ground controller and an aircraft present on ground and in

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air.

Communication system between the controllers and at the time of emegency, agency which

has to be ready for the 24 hours.

Communication system between the controller and another approach controller also in case

of small airport like TAAL, small flying club.

For every flight which takes-off from the TAAL, has to take clearance from the HAL

approach and has to inform the destination approach to clear the flight level which has

assigned to that aircraft and has to give all the information about that aircraft to the approach

tower.

Flight information are the computer genrated slips which takes the current data fron the SSR

and crates a slip so that by having a look over it, controller can have a good control over the

aircraft and can communicate with it at any time.

The basic & main purpose of this is that controller does not have to waste time to the pilot

for its current position and can be a time saving system and it is used for the safe condition

of the flight.

For a stable airspace, these are required to be satisfied:

Conditions which has to be informed to the pilot:

There are various information that has to be transmitted from the controller to the pilots are:

Information regarding the weather changes

Change of servicebility of facility

Condition of an aerodrome

Controller has to identify the flight for the monitoring it and co-ordination purpose only

Pilot must not be left in doubt that they are not receiving radar services

There should be a minimum sepression of 1000 feet between two aircraft according to the

ICAO.

Alternating service:

This is the service which has to be in used in case of emergency that may be an accident or

search and rescue operation and to alert the appropriate organisation regarding this.

It has to provide the notification to the appropriate organisation depending upon the

condition.

Radar control service:

This has to be provided to an aircraft by the ground controller.

This depends upon the aircraft which may be operating IFR or VFR.

The aircraft operating at IFR, controller can be used or cannot be used for the landing part.

The aircraft operating at VFR, controller has to be used for the landing part.

Classification of an airspace: There are seven types of an airspace, they are A,B,C,D,E,F,G. In this type A is more

restricted airspace while G being least restricted airspace.

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Type A:

This is an airspace where only aircraft using IFR are allowed to fly.

It needs ATC clearance before take off and landing.

All the aircraft must be seperated from each other.

The aircraft operating VFR are not permitted to fly in A zone.

Special permissions are required for VFR for entrance in A zone.

Type B:

This is an airspace where aircraft using both IFR and VFR are allowed to fly.


All the aircraft must be seperated from each other.

The aircraft operating VFR are permitted to fly in B zone.

Type C:



All the IFR flights are seperated from all the VFR flights.

All the VFR flights are seperated from all IFR flights.

Traffic information is given to an individual aircraft only, that is VFR to VFR and

IFR to IFR.

Type D:




All the VFR flights can be passed over the IFR flights.

Traffic information of VFR is given to IFR and IFR to IFR also.

INDIAN AIRSPACE IS OF TYPE D.

Type E:




All the VFR flights can be passed over the IFR flights and vice-e-versa.

Traffic information of VFR is given to VFR and IFR and also vice-e-versa.

VFR has to have clearance from the ATC before every step of flying.

Type F:




All the VFR flights can be passed over the IFR flights and vice-e-versa.

Traffic information of VFR is given to VFR and IFR and also vice-e-versa.

VFR does not have to take clearance from the ATC before every step of flying.

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Type G:

This is an airspace where there is no need of ATC and any one can fly anywhere in

this airspace.

Instrument Flight Rules: IFR permits an aircraft for the IMC, that is instrumental metrollogical conditions.

IFR permits an aircraft to operate in IMC i which the it has to have the minimum weather

condition compared with VFR.

Procedure and training are more complex in this method and pilot has to demonstrate cross-

country flying with IFR only.

In this rule, pilot has to fly an aircraft with the help of instruments only and cannot have any

visual help as his flight level would be high enough to see anything or to get any refrence

help from the ground.

Visual flight Rules: VFR permits an aircraft to fly with the help of refrence from the ground and has to solely fly

only with the outside clues which permits the navigation, orientation and other aircraft also.

Mini weather condition for sealling and visibility for VFR are defined as a differnt types of

airspace and it depends upon the day time and night time.

Thus the cloud height and visibility is very important in all phases of height

In day time:

VFR minimum for most airspace is 3 statute milies visibility and cloud distance must be 500

feet below, 1000 feet above and 2000 feet horizontal.

The condition equal or greater than this is known as VMC, that is visual metroological

condition and can be used for both VFR and IFR.

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Ground handling

Introduction: This is very important for aviation part as this is the part where aircraft is handled with the

safety and the security of passengers and their luggages.In air pilot is incharge of the flight

but at ground there are several people which take care of ourself to whom even we dont

know.For example, airport security, the comfort level at an aircraft is also part of ground

hadling and service to the passengers in all term too.

Brief description: The comfort zone which has to be provided to the passengers at groud before he board the

plane is the main criteria of the ground handling.This includes the cabin services.

This ensures the passengers comfort, cleaning of passengers cabin, cleaning of blanckets etc.

Cattering:

This includes the unloading of unused foods and drinks and loading of the fresh food and

drinks which includes juices, tea, coffee, wine, bear, vodka etc.

Ram services:

This is the services which includes the guiding of an aircraft into or out of its parking

possition.

Towing the aircraft with the help of towing vehicle or with the help of push back tractor.

Water cart:

This is the vehicle which is used to drain the seawage from the lavatory of an aircraft and

filling with the frsh water with the help of water carriage.

Air conditioninig system:

There should be proper air conditioning at airport, bus and aircraft.

GPU:

This is an external power supply to start the engine and to charge all the batteries which are

present in the aircraft.

Luggage handling:

This is the huge system which takes care of loading and unloading of luggage in and from

the aircraft respectively.The luggage should always reach before the passenger's arrival at

the terminal.

Air cargo handling;

This includes the loading/unloading of all the cargo and moving it to its destination within

the short period of time.

Refulling and defulling:

This is the system which is used to refule or defule an aircraft before and after take off and

landing of an aircraft respectively.

Ground power:

This includes the maintainance of the passengers stairs, wheel chairs for the physically

challenged people, hydraulic mulls etc.

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De-icing and anti icing system:

This include the system which are used for the deicing the ice at the ground surface in cold

countries.

Services for the passengers:

Check in,customer calling, arrival terminal, departure services and information providing

system to the passengers at the airport is the main part of the ground handling.

Field operation services:

This is the service which inclues the dispatch of an aircraft at the scheduled timewitn co-

ordination of ATC.

Equipments used: Ground support equipments on the ram, such as push and pull back trolleys, ladder,

trolleys,catering vehicles, chock which is used to placed at the tyre of an aircraft in parked

position.

Non powered equipments:

Trolleys and bag containers, bags cards etc.

Dolly for containers and packets etc.

Powered equipments:

Refullers, trucks, buses, tractors, GPU etc.

Electrical system of an aircraft: All aircraft requires 28 V dc power while 110 V ac, 400 Hz. 3 or 4 phase of insulating wire

capable pf handling 200 A.

Clearances from an ATC: For an international flight, all the aircraft coming to India must have YKA clearance from

DGCA which stands for Young Key Alpha in order to enter the Indian airspace.

Flight plan of every flight must be approved AAI.

Slot, departure clearance will be treated as a ferry plan.

Fuel Boucher

Introduction:

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Fuel boucher is the container which is used for the storage of fuel which is used for aviation

uses.At TAAL, the feul boucher is on lease from Indian Oil Corporation limited (IOCL). It

contains Jet A1 type fuel which is used for the propulsion purpose for most of all the types

of engines. The cost of this fuel is fifty-two rupees per litre which is cheaper than the petrol.

Brief description: Fuel boucher is the container where the air turbine fuel (ATF) is stored and this is used for

both re-fuelling and de-fuelling.The aircraft which lands at TAAL airport, is de-fueled and

then only maintenance work is carried on. Once the maintenance work is completed, aircraft

is again re-fueled and it is allowed to fly.The density of the fuel used for the aviation

purpose is less than the density of the water.

Specifcation of fuel boucher: The capacity of fuel boucher is 16,000 liters.

It is internally coated with synthetic material so that it will not be in direct contact with the

container which is made up of the iron. If it comes directly in contact with the iron then

there are chances of the fuel to get contaminated due to the reaction of fuel with the metal.

There are of two methods of de-fuelling an aircraft.

Gravity and pressurize method.

Gravity method:

In this method the fuel is removed using the gravity force. In this type the fuel is not

removed completly. It is used for the general aviation type of aircraft only and cannot be

used for the larger type of aircraft.

It takes comparatively more time than the pressurize method.

Pressurize method:

In this method the fuel is removed using the pressure pump which forces the fuel to get out

of the fuel tank.This can be used for both the type of aircrafts that is general aviation and

large aircraft.

It takes less time and can be done quickly.

Procedure of refueling/defueling: Before refueling /defueling, an aircraft and the fuel boucher are grounded in order to

discharge the static electricity generated because of the circulation of fuel.

The fuel can be feed with the help of fuel pressure pump, which creates internal pressure and

force the fuel to move from the boucher to the fuel tank placed in the aircraft.

There is NRV, non return valve which prevents the flow of fuel in both the direction.

The internal pressure created should not exceed 30 kg/cm2, as it can damage the hose which

carries the fuel from the boucher to the tank.

Refulling/defulling is carried in such a way the static balance of an aircraft is maintained

and there is no change in aircraft's centre of gravity.

The fuel is stroed in the fuel tank which is placed inside the wings of the aircraft.

There is provision for the pilot to move fuel from one wing to other through the cross feed

valve.

25

Testing for the contamination: For the contamination some fuel is drained out and checked for the contamination through

the naked eyes.

There should not be any water molecule present in the fuel. For this, some fuel is drained out

and a capusle named as ―Aqua indica‖ is used to check the presence of water molecule. If

the colour of capsule changes to pink, indicating the presence of water molecules.

Some times the fuel is also sent to IOCL lab for the contamination tests.

According to the IOCL: If fuel is not used in a particular period of time then it must be circulated using pressure

pump through the whole boucher.

This will prevent the contamination of fuel from the biological growth and can be stored for

a longer period of time.

26

Fire Tender

Introduction: Fire tender is a device which mainly contains the water in the container which can be used to

extinguish the fire with the help of the pressure pump which force out the water from the

tank where it is stored.It also carries carbon dioxide, foam which also can be used to

extinguish the fire.The existence of the fire tender is a part of security department. The

security at TAAL airport is under V5 category according to DGCA of India.This depends

upon the size of the airport.At TAAL airport there are two fire tender.

Brief description: Fire tender is a device which is used to extinguish the fire which occurs due to any mishap

or any accidents.The fire can be extinguished using water, carbon dioxide,foam or a mixture

of water and carbon dioxide or a mixture of water and foam.The fire extinguisher has a

capacity to contain all these three thing at a time and has a capability to extinguish the fire

within short period of time.

Specification of fire tender: There are two fire tender available at the TAAL airport.

The capacity if first extenguisher is 5000 liters of water it can store at one time while other

has the capacity of 2000 liters of water.The small tanker is a foam tender of dry carbon

dioxide.

Each fire tender carries water, foam,100 kg of dry carbon dioxide.

The hose which is used by TAAL fire tender is 100 meter long.

As per the DGCA rules and regulations, the fire man should be at a distance of 25 meters

away from the sight of accident and has to control the fire from there only.

The foam tin which is used has a capacity of 50 kg.

Foam is a fire chemical brand which is used to control the fire.

It will produce a foam layer which will be at the bottom surface and does not allow the fire

to grow any more.

This can be used with both water and as well as dry carbon dioxide.

Procedure of the fire tender: The fire tender vehichle are placed in a such a way that at the time of accident or any mishap

it can reach the sight within a minute from that place.

So at TAAl airport the fire tender of 2000 liters capacity is placed at the side of runway

while the fire tender of 5000 liters capacity is placed with the ambulance at the taxi way at

the time of take off and landing of every aircraft which takes place at the airport.

There are two meters at the fire tender:

Engine pressure and pump pressure.

Engine pressure should be 100 psi and thus the water which is dispatched

from the tender upto 20 meter from it.

Pump pressure should be upto 15 mm of Hg. The average pump pressure is

always between 10 to 15 mm of Hg. This is used to pump out the water from

27

the tender.

There is also an input which can suck the water from the ground water source such as well,

lake etc and can store this water in the tender and then it can directed to extinguish the fire.

There are two gate valve and one main gate value.The two gate valve which are placed on

left and right hand side so that there can be two hose which can be used to extinguish fire

simultaneously.

The main gate valve is used to refill the tanker from the ground source or to drain the

whole water from the tanker through this valve.

According to the rule of the DGCA there should be every tender with foam and water are

placed at a distance of 200 to 300 meters from each other depending upon the size of runway

and the frequency of aircraft landing and take off's when they are placed along the runway

side during the take off and landing.

The gun fire is also used which can mix coarbon dioxide or foam with the water and help to

have control overt the fire easily and within the short period of time.

One tender with an officer is always on alert at the apron area where the loading and

unloading of the payload takes place.

28

Manufacturing of Aerospace components

Introduction: This is the most important and the vital section of any aircraft or a spacecraft as it has to take

all the desired load as well as it must enough strength to withstand it.So the main creteria for

the construction point of view is high strength to weight ratio. There are materials which can

provide very high strength but add a lot of dead weight, resulting less capacity to carry the

pay load.

Brief description: The manufacturing of aircraft parts and its components is very important from the structure

point of view.The main criteria of this section is to maintain the dead weight as low as

possible and to gain the maximum strength from it.There are variety of materials available

but the proper selection from it is more important from economic, manufacturing and the

requirement point of view.So it depends upon the manufactures and their descission with the

customers regarding the materials which has to be used from various considerations.

Commonly used material and alloys are: Aluminum alloy

Copper Alloy

Stainless Steel Alloy

Titanium

Composite material

Nickel Alloy

Magnesium Alloy

Common aerospace materials include stainless steel, titanium and copper/brass

alloys. They are designed to be strong and resistant to corrosion, as well as maintain

their integrity in any temperature. These steel alloys are available in sheets, wire, bars,

plate and other standard forms. They can also be custom forged, whereby they are

melted and pressed into a specified shape.

Manufacturing of aerospace materials: Sheet metal fabrication plays an important role in manufacturing aircraft parts like

Bulkheads, stringers, Stiffeners, Ribs, Skins etc. Even the casings & boxes for Avionics,

Electrical & Instruments are fabricated from sheet metal. The strength to weight ratio is

of prime importance.

Aluminum alloy has the best strength to weight ratio due to which more than 75%of the

aircraft body is made of aluminum alloy and aluminum alloy sheets & extrusions are

generally used for making these parts. The grade of alloy may vary depending on its end

use on the assembly. Titanium alloy & stainless steel sheet is also used to form the parts

operating in heat zone at high temperature

Process operation:

While making any sheet metal part some or all the following operations are performed

depending on size, shape & complicacy of the part.

29

Marking – First of all the size of the material/ sheet required for making the part as per

drawing is marked by a marker or scriber. Lead pencils should NEVER be used

on aluminum sheets, since it develops corrosion over a period of time.

Shearing - The blanks are cut to the marked size with the help of shear

Nibbling tool – It is a hand operated tool for shearing aluminum sheets up to 1.6 mm

thickness. It is good for cutting straight or curved shape as well as for

cutting holes, trimming & matching.

Aviation Snips – Left hand & right hand cutting snips with 90 deg. handle w.r.t. blade is

used for cutting the material in tight space where material can not be

turned.

Hand operated slitting shear – It has long handle for applying leverage while cutting the

steel sheets upto 5mm thickness.

CNC shearing machine- The CNC machine is used for shearing the Aluminium sheets upto

6mm thickness, steel sheets upto 5mm thickness & stainless steel

sheets upto 2.5 mm thickness.

Routing— The blank is routed on routing machine to cut to the exact shape & contour of

the part. Two type of routing machines are available in our sheet metal shop.

a) Manual router

Parts having simple cutouts, contours can be routed on manual

router with the help of Drilling Routing Template (DRT) made of steel sheet. DRT is

30

clamped to the sheet to be routed with C clamp. Keeping DRT as reference the

operator moves the DRT in the guide way provided on the routing table & cuts the

sheet as per DRT

b) CNC Routing machine

For routing the sheet on CNC machine, the sheet is kept on the wooden bed & is

clamped by using stoppers made of hylam wood. The operator cut the sheet as per

the program fed in the computer.Parts up to 5mm thickness 7 lengths up to 4meter

having intricate shape & contour can be routed on the CNC router.

nForming – The parts are formed to achieve the specified shape/ contour as per drawing on a

form block. The blank obtained from CNC router or manual router is formed

into desired shape by using form block tool (FBT) . These tools are made of

Hylam wood or metal. Hylam wood normally preferred over metal due to its

light weight as well as easy rework ability. The blank is placed over the FBT

with top plate on it & is clamped with locking pins. The blank along with FBT

is then pressed either in brake press or hydraulic press or rubber pad press

31

Joggling- Joggling operation is performed to make the space to accommodate the part to be

fitted in same level on assembly. A typical joggled part to accommodate another part

is shown . The joggle can be formed with wooden tool in Al. sheets up to 1.5mm

where as in sheets above 1.5mm & extrusions joggle can be formed in metallic dies

with the help of hydraulic press.

Rolling— A sheet is rolled between the rollers to the required contour of specified radius.

sheets upto 2mm thickness & part width upto 400mm can be rolled in hand roller

shown in fig. Steel sheets up to 2.5 mm thickness and Al.sheets up to 5 mm & width

upto 3 meter can be rolled in manual rolling machine . This is used for rolling the

skins of 1/2U & SBS assembly of VSSC. Steel 7 aluminium sheets upto 10 mm

thickness can be rolled in power operated rolling machine available in sheet metal

shop. This is mainly used for rolling the skins of SONC assembly.

32

Shrinking – It is the process of thickening of the metal by pulling it into itself mechanically

with a hammer & a padded dolly. For example, imagine a car hit by a mile

stone or a tree on the road. The dent formed in the body of the car due to this hit

causes stretching of metal in the center of the dent by shrinking the metal on the

periphery of the dent. Pounding of the metal between hammer & a steel dolly tends

to thin the metal, hence a soft wooden block & hammer only should be used for this

purpose.

Stretching—

Stretching the metal is the process opposite to shrinking. It is the process of pulling

the metal apart by pulling the metal away from its center point or by pounding on the

metal with a hammer on one side while holding a dolly on other side. This flattens

the metal in the area being worked, forcing it to move outward in to the surrounding

the metal. More stretching the metal will tear it when it becomes too thin to have any

strength. The part is stretched to form a smooth groove or curve of specified

dimension by flowing the material manually or by a machine. A part formed by

stretching & shrinking.

Dressing—

The part is dressed to remove the wrinkles, waviness, unevenness from a formed part

before and after solutionising. It must be noted that after solutionising the part must

be hand dressed within 2 hrs. otherwise it will start attaining its original hardness &

it becomes difficult to hand dress. Alternately it should be stored in cold storage to

form it later. Hand dressing is done by using plastic or wooden mallet & clamping

the part on bench vice or otherwise by any other clamping method.

Trimming—

Trimming is carried out to remove the excess material and finish to exact size as per

drawing. Material can be removed using electrically operated dual hacksaw blade &

later finished by filing.

Deburing—

Deburring is carried out to remove sharp edges, corners form a finished part with the

help of deburring tools or with polish paper.

33

Tools used for the operations are:

Shears-

Different type of shears, snippers used in a sheet metal shop is shown in Fig.1. these

can be used to cut thin sheets. However the thick sheets and the extrusions can be cut

accurately In a manually operated shear or CNC operated shearing machine.

Router –

For cutting a blank to exact shape and contour , routers are used. These can be

manually operated or CNC operated Machine.

Bending tools—

The blanks from thin sheets can be bend to any angle or shape on wooden or steel

blocks or steel mandrels with the help of wooden / plastic mallets. The parts made of

thick sheets or extrusions can be accurately bend in bending machine with bending

tool of correct size & shape. A CNC bending machine whereas manual bending

machine.

Blocks—

These are the blocks made of wood / hylam in exact shape & contour as per the

requirement and a part can be formed on these form blocks with the help of hammer.

A typical form block for a leading edge is shown in fig.6. Similarly a form block

used on a stretch forming machine.

Templates—

These are made of steel and are used to check the contour & shape of the part formed

on a form block or bend on the bending machine.

Hydraulic Press—

The parts from thick sheets, extrusions can be formed with the help of metallic dies

or forming tools in Hydraulic press or rubber pad press .

Joggling tool/ dies—

The joggles to accommodate the overlapping parts in same level are formed in thin

sheets with joggling tools using wooden/ plastic mallet. The joggle in thick sheet &

extrusions are formed in male –female matching metallic joggling dies with the help

of bend press or hydraulic press.

Scnz.

34

Rolling Machine—The three roller rolling machine is used to roll the sheet to desired shape

or radius.These could be manually operated or power operated.

Mallets—The wooden/ plastic mallets are used to form / dress the part to accurate shape &

contour.

Deburring tools—Deburring tools / files are used for removing the sharp edges, corners &

finishing the part.

Press forming tools –

For bending /forming the extrusions of various cross section in hydraulic press, press

forming tools are used.

English wheel—

It is used to form the grooves, curves In the panels. It gets its name from the two

steel wheels between which metal is formed. The wheels – one above & one below

are rolled against each with a piece of sheet metal in between, under a pre adjusted

pressure setting. The wheels roll as the sheet is moved back & forth.

Stretching & Shrinking machine—

A hand operated stretching & shrinking machine whereas a part being formed on

pneumatically operated machine.

Fluting Pliers & Hand Seamers—

Fluitng pliers are used to straighten ribs, flanges & to form curved stringers. The

jaws form the metal in such a way that ―shrinks‖ a small section of a flange.

A coordinate measuring machine (CMM): It is a device for measuring the physical geometrical characteristics of an object. This

machine may be manually controlled by an operator or it may be computer controlled.

Measurements are defined by a probe attached to the third moving axis of this machine.

Probes may be mechanical, optical, laser, or white light, among others.

35

Heat treatment & anticorrosive treatment processes: The sheet metal component has to undergo heat treatment process during the process of

forming as well as after forming.

The heat treatments are carried out mainly for the two metals and their alloys, they are steel

and alluminium.

Annealing –

The blank of sheet should be annealed before forming / bending to make it soft so

that it can be formed / bend easily without any defect or cracks.

Thick sheets & extrusions should be annealed in between the stages to remove the

work hardening otherwise the part may crack during forming / bending.

The holding temperature is 4100

C for one hour in air circulation oven.adjhl

Solutionising—After forming & dressing the part, it is solutionised to regain its original

hardness which was removed during annealing.This is carried at the holding

temperature of 5000 C for 30 miniutes, it depends upon the thickness of the

sheet.

Ageing—The solutionised & finished components are artificially aged to retain its hardness

for long time. However materials like D16 , D19 gets aged naturally over the

period and does not need any artificial ageing.The holding temperature for this is

1600 Cfor nearly 12 hours to 18 hours which depends upon the customers needs.

Protective coating— Fully completed & aged parts are protected with anti corrosive

treatment. Aluminium alloy parts are Anodized where as steel parts are Cad plated &

stainless steel parts are passivated. Additionally all parts are further coated with

etch / epoxy primer or any other primer before painting.

36

For steel:

There are two types of hardening process is being carried out.

First one is carried out in muffle furnance at 8100 C and in the second type tempering is

carried out t 6300 C which depends upon the thickness, duration is decided.

After solutionising, Al alloy is placed in a cold storage as between the 6 days agening has to

be done. The holding temperature is just below the -150 C for 15 hours just to make it hard.

Precepitation:

It is an artificial form of hardening.

Natural hardening:

It is the hardness which has achived by cooling an alloy at the room temperature.

After heat treatment it comes to the chemical shop:

In this shop there are three process which is carried out for alluminium alloy, they are:

Anodizing

Alodine

Chemical milling

And for steel:

Cadmium plating is done by electro deposition

Process shop

There are many operations which are carried upon a single job in order to achive the requirement.

There are various process which is done in sequence stated as below.

Vapour degreasing:

Chemical used: Trichloro etheylene

Temperature: 750 to 87

0 C

Duration: 2 to 3 minutes.

Uses: For removing oil, grease, dust, forign particles etc.

Chemical alkaline defreasing bath:

Chemical used: Sodium carbonate and Trisodium phosphate

Temperature: Room temperature


Uses: For removing oil, grease, dust, forign particles etc.

Swill water bath:

Chemical used: Pure water, only H+

and O- ions



37

Total dissolved solids: 1000 ppm

Size: 1600 x 600 x 650 mm

Uses: For removing all the past chemicals and that should not pass to

other bath tubs and should not pollute the chemicals.

Alkaline pickling bath:

Chemical used: Sodium carbonate- 20 to 30 g/l



Size: 1600 x 600 x 650 mm

Uses: For mild etching

Swill water bath:


and O- ions




Size: 1600 x 600 x 650 mm



De-oxidation bath:

Chemical used: Nitric acid- 20%



Size: 1600 x 600 x 650 mm

Uses: To remove the oxide layer which has formed due to various

heating process.

Swill water bath:


and O- ions




Size: 1600 x 600 x 650 mm



Anodising Bath II:

Chemical used: Chromic acid-30 to 50 g/l


0 C.

Duration: For one hour

Size: 1600 x 600 x 650 mm

Uses: Electro plating is carried out here.

Here cathode is stainless steel while the job is anode.

Main purpose is to make anti corrosion and electrical

resistance.

38

Swill water bath:


and O- ions




Size: 1600 x 600 x 650 mm



Hot water sealing:

Due to some process, porous will be created so to just fill up all the porous and make the job

porous free, this treatment is carried out.

Water bath:


and O- ions


0 C

pH level: 5.5 to 6


Size: 2800 x 1600 x 500 mm



Common Heat Treatments:

Softening:

Softening is done to reduce strength or hardness, remove residual stresses, improve

toughness, restore ductility, refine grain size or change the electromagnetic properties

of the steel.Restoring ductility or removing residual stresses is a necessary operation

when a large amount of cold working is to be performed, such as in a cold-rolling

operation or wiredrawing.Anneling— full Process, spheroid zing, normalizing and

tempering— austempering, martempering are the principal ways by which steel is

softened.

Hardening:

Hardening of steels is done to increase the strength and wear properties. One of the

pre-requisites for hardening is sufficient carbon and alloy content. If there is

sufficient Carbon content then the steel can be directly hardened. Otherwise the

surface of the part has to be Carbon enriched using some diffusion treatment

hardening techniques.

39

Material Modification:

Heat treatment is used to modify properties of materials in addition to hardening and

softening. These processes modify the behavior of the steels in a beneficial manner to

maximize service life, e.g., stress relieving, or strength properties, e.g., cryogenic

treatment, or some other desirable properties, e.g., spring aging.

Welding:

There are three types of welding carried out at TAAL factory, they are:

Arc welding

Gas welding

Thermit welding

and Resistance welding.

Arc welding:

In arc welding, a metaalic rod is used as a filler element and an electric current is

used as a source of power with the help of transformer.

TIG welding:

TIG stands for the Tungsten Arc Welding. In this type of welding tungsten rod is

used as an electrode and as per the requirement filler rod is selected. A gas sheild is

created in this type of welding with the help of argon which helps the contact of the

atmoshpheric air to be in direct contact with the job during the operation.

This is used for very less thickness material and especially for non-ferrous elements

can be welded easily and succesfully using this welding.

Al alloys, Mg alloy, Cu alloy and non-ferrous alloys can be welded together with this

welding.

The filler rods usually ised for this type of weldings are

Al alloy 4043

Al alloy 5356

Al alloy 5056

ST steel 347

Carbon CM steel 4130.

Gas Tungsten Arc Welding (GTAW) is frequently referred to as TIG welding. TIG welding is a

commonly used high quality welding process. TIG welding has become a popular choice of welding

processes when high quality, precision welding is required.

In TIG welding an arc is formed between a nonconsumable tungsten electrode and the metal being

welded. Gas is fed through the torch to shield the electrode and molten weld pool. If filler wire is

used, it is added to the weld pool separately.

40

TIG Welding Benefits

lding Gases

Argon

Argon + Hydrogen

Argon/Helium

Helium is generally added to increase heat input (increase welding speed or weld penetration).

Hydrogen will result in cleaner looking welds and also increase heat input, however, Hydrogen may

promote porosity or hydrogen cracking.

Requires greater welder dexterity than MIG or stick welding

Lower deposition rates

More costly for welding thick sections

Resistance welding:

In this type of welding, a resistance is created and the materials whcih has to be

welded together are heated such that by applying proper amount of pressure, they are

welded together.

Spot welding:

In this type of welding with the help of high electric current, the two materials are

welded with each other such that there are spots created.

The current supplied is 350 to 1220 Amp.

The voltage and frequency applied is 415 and 50 Hz. respectively

41

Seam welding:

In this type of welding with the help of high electrical curren, the two materials are

welded with each other such that there are no spots can be visible and such type of

welding are known as seam welding.

The current supplied is 350 to 650 Amp.

The voltage and frequency applied is 415 and 50 Hz. respectively

The machine which is used for both sopt and seam welding is known as ―Mechelonic Engineers‖

Products of TAAL for HAL:

TAAl is preparing the bombs which are being heat treated and the spot welded with the help

of Mechelonic Engineers machine. This is the bomb wich has a volume capacity of 350

litres which carries the fuel in it and it is droped over the target and that is exploded with the

fire.

For this TIG welding is done and compressed air is used to check for any leakages and if

there are any leakages, then it is again welded.

The mock Up helicopter for the next month airshow, representing the HAL is being prepared

by the TAAL using composites and the panels which are made up of alluminium and welded

together.

Jigs which are used as a stand for holding various components are also joined together with

various welding processes.

NDT Shop:

NDT stands for the non destructive test which is carried out for every job after it has been

manufactured in order to check the presence of any crack in it. If there is a presence of any

crack, then a job is rejected otherwise it is accepted without any distortion present in it.

Procedure:

For this process, liquid fluorecent paint is painted and then it is dried for some 2 to 3

minutes and it is washed under forced water so that all the paint is removed from its surface.

After the washing process, it is dried in the hot oven for near about 15 to 20 minutes and

42

then a chemical known as a developer is spread over the whole body and observed under UV

rays.

If there is any crack formation in it then that area will glow with the fluorecent colour

depending upon the depth of the crack and finally it is sent back to the manufacturing unit

for a replacement.

Purpose of the washing is to remove the excess penetrant from the part which is under UV

lighting (Dark Enclosure and special UV lighting).

Intensity of light is 275 micro watt/cm2.

Water bath:

Size: 3 x 1 x 0.9 m

Duration: 90 seconds.


0 C.

Maximum pressure: 25 psi.

Drying oven:

The job is dried in this oven with the help of forced air circulation.

For drying the parts, after the water wash and before applying a developer over it.

Size: 3 x 1 x 0.9 m

Duration: 15 minutes.


0 C.

Dry Developer tank:

Specifications: ZP4B

Developing time: 10 minutes.

43

CNC Profiler Shop

Introduction: CNC profiler shop is the shop where the milling operations are done with the help of CNC

machine.CNC stands for ―Computer Numerical Control‖ in which a computer is used to do

or perform the operations using programming language.The tolerance for the job done with

the help of CNC machine is only 0.3 mm.

Brief description: Milling machine is the machine which is used to do various types of operation on a single

job using variable tool.In this machine the tool is stationary while the job is rotated with

three degree of freedom, that is on X-axis, Y-axis and Z-axis respectively.

In CNC milling machine a programing language is used to control the machine which in

turns control the operation of the job.There is a programmer which reseta the machine using

suitable progrme for a particular operation such as chiping, drilling, boring metal removing,

levelling, smooth finishing, curving etc.

The base of this machine is the hydraulic base so that each movement of its part is done

hydraullics only.

The software which is used for this CNC milling machine is the ―Power mill‖ which is

generated to operate in three dimenssional.

Proceedure: The design for the job is prepared by the designer using catia V5 software, and a job sheet is

prepared which gives various types of commands has to use and which tool has to be used

for a particular operation with appropriate diagram in 3-D view.

Then the operator is given the raw material, which he removes the extra material from it

using a rough milling cutter as per the instruction stated in the job sheet.

For example:

The job has to be done is a bracket which is used for the joining purpose.

Format of the each program for a particular operation:

Tool type Flat drill

Tool diameter 16 mm

Programe name S1M1 16 flat R

Feed 600 mm/min

Speed 2000 rpm

Depth of the cut 1 mm

Cycle time 0.3 minitues

Wall stock 0.3

Bottom stock 0.5

Total length 70 mm

44

The operators which operates this machines must be skilled person and they must be expert

in controlling the CNC machines.he must be able to underastand all the terms related to this

machine and must satisfies all the condition which are necessary for a good profile job

without any error.

The chances of the fatal accidents should be minimum and there should be continuous flow

of the job production so that the final outcome of the company should be good.

Explanation of the job sheet: The tool type indicates the type of tool is eused for the operation.

What is the tool dimenssion of the tool used for a particular operation.

The name of the programe.

Feed indicates how much maximum the tool can remove the excess material from the job.

Speed indicates the speed at which the tool is rotating in rpm.

Depth of cut indicates how deep the cut for each stroke should be maintain.

Wall stock indicates the tolerance at the wall of the job

Bottom stock indicates the tolerance at the bottom of the job

Total length indicates the full length of the job.

This is one part of the operation and depending upon the type of job there may be various

types of operation which has to be performed over it and for each operation such type of

table is prepared by the programmer and a designer.

Step 1: S1M1 R means setting one milling 1, and R stands for the rough finishing.

That is using a 16 flat , flat is cutter which is used to remove the excess material from

the job using a tool whose diameter is 16 mm and it is a flat tool.

Step 2: S2M2 R Bull nose.

Bull nose is the name of the tool which is used for small curving operations.

Here R also stands for the rough finishing.

It will have a corner radius which is used for the curving the edge for the job.

This is used for the finishing the edge of the job.

Step 3: S3M3 F flat 12

Flat means a flat tool is used whose diameter is of 12 mm.

Here F stands for the finishing process where all the surface of the job are finished

using the same tool.

Machines available at TAAL:

There are four CNC milling machine available at TAAL manufacturing unit, that is CNC

profiler shop.

These machine are BMN 45, BMV 60, BMV 80 and a horizontal milling machines.

The first three machines are the same vertical machines only they differ with eachother is in

their dimenssion and their power consumption.

BMV 45 Consumes the power of 45 KW. The maximum size of job it can accomodate is of

width 450 mm and length 800 mm.





45

Horizontal milling machine consume more power than every machine so one has to be sure

that no other machine is being operated when the horizontal milling machine is being used

for the operation. The job size which can be accomodate in it is of 2000 mm in width and

4000 mm in length. Operation are very similar to the vertical milling machine.In this

machine job is stationary and tool is in motion.

Type of coolents:

At the time of any operation coolent is used to reduce the heat which is generated through

the friction between the tool and the job.

The coolent used is castrol coolent which protects the tool from wear and increase the life of

the tool with better finishing of the job.

Inspection tools: There are various types of tools which are used for the inspection of a job after its

operation . The simple type of equipment is DTI which is nothing but the direct touch

indicator. In this type the needle is very sensitive to the uneven dimenssions. The needle is

touched at a particular surface of the job and then the job is rotated and moved through out

the section. If there is unevenness in the dimenssion, then the needle will not be in preset

value and will indicate the deflection.

Touch ball is a similar type of tool, where if light glows then it is correct and if it does not

then it is under dimenssion.

Adapters: These are the used to hold the tool and then they are placed in the milling machine.

There are many more types of tools and machineries which are used for various types of

operations denpending upon the type of the job and the customers requirements.

46

Paint Shop

Introduction: Aircraft painting is also an important part of aircraft manufacture.This has to be done very

carefully so that the dead weight must be maintain within the permissible limit.The

thickness of the paint should be not more than 25 microns. If this thickness is increased then

the dead load of an aircraft increases so that instead of 6 passenger, an aircraft can carry only

4 passenger in case of P68C type of an aircraft.

Brief description: Polyunithene paint is used in aircraft painting.To make piant suitable for painting 100ml

primer, 100ml hardner and 25ml thinner has to be mixed in paint which have to be applied

on aircraft surface. As primer mixing require half an hour.

Two types of primer are usually used

1). Epoxy primer, and

2). Etch primer

Primer ratio should be of 1:1.After primer mixing,it should be kept for 10min. for

cooling.Then the mixture is brought in viscosity cup.Viscosity cup is a device used to

measure viscosity.As the thickness and thin of mixture can be checked through it.

If paint comes out from the hole of viscosity cup within 17-23 seconds then the paint or

mixture is ok and there is no need to add anything in it.If paint takes 25 sec. in coming down

from hole then the amount of thinner is added in it,depending upon the quantity of paint. On

iodizing we use Epoxy primer(brown plate) and in anodizing we use Etch primer(white-grey

plate).

Primer cooling time is 8 hours. And after cooling paint can be done on the required area or

surface.

Test for primer:- Primer is a layer which is put on surface before doing paint.Usually there are three

types of tests carried out on paint,they are:

Scribber tape test: In this test small part of surface is to be made in form of grids by the means of scribber. Then a

layer of primer is applied on it and after that it should be covered by tape. At the time of removle of

tape,If some part sticks on it then it means that the primer has less sticking or gripping capacity.

Water tape test: In this test a piece of cotton dipped in water should be kept on small part for 24 hours. Then rub it

25 times,if primer removes then it is not good and having less gripping capacity.

Amigy test:

This test is usually done to check weather the quantity of fuel is good or not. This test is also used to

check weather the mixing is correct or not.

While doing paint, first check the room temperature. It should be 15-35 C. Secondly check

humidity which is to be 35-75. If humidity is greater than it then paint flows. Bearing

47

pressure should be 42-45 psi.

In every part we have to give 23-25 microns thickness of paint.

Procedure that must be followed during an aircraft painting: The paint that has to be used must not be polluted as well as by using the it should

not pollute the enviorment.

The paint should have enough surface tension so that it is grabed by the surface and

does not peel off the surface under extreme conditions.

The paint should also be anti corrosive.

Before painting an aircraft following should be done:

1).Inspection of aircraft: inspection of aircraft includes following points-

Finding out dents and deants,

Inspect for corrossion parts,

Loose rivets,

Inspected in flight control surfaces,

aircraft's windows,doors,de-iceing boots,propellers,etc.

2).Paint stripping:

This is done chemically or by scotch bright.

3).Over spray protection:

Before painting, windows should be covered,seams should be covered with

alluminium tapes,landing gears are covered with plastics or glass.

4).Primer:

3 layers of primer should be done.Two layers of epoxy primer and one layer of

anticorrossion primer.

5).Base coat:

After primer go for base coat, three coats of PPG aerospace paint.

6).Design and number application details:

Deicing boots,

Flight control balances.

There are 20 steps for painting:-

1).Initial inspection

2).Removal of flight controls as per manufacture specification,removed checked balanced

3).Strip to metal and non-metallic surfaces

4).Inprocess inspection:After airframe stripping,it is done to find out hidden corrossion.

5).Corrossion control:All external surface corrossion from airframe is removed.

6).Metal perfection:Imperfection on airframe is corrected if necessary.

48

7).Fiber glass and plastic perfection:All fiber glass and plastic are machined sanded,filler

prime with epoxy primer and hand sanded.

8).Skin seans: skin seans are cleared and inspected.

9).Resist area of control surfaces are thoroghly cleared.

10).wet sanding; all the surfaces are wet sanded, including landing gears.

11).wet cleaning: airframe is cleand with

12).Final cleaning; airframe is chemically cleand with two seperate

13).All alluminium components are wash prime with acid component. Wash primer to 0.2-

0.3mm thickness and allowed to dry for 1 hour.

14).Chromit prime:All surfaces are primed with low viscous chromit primer with 0.9-6mm.

15).Top coat:All surfaces are painted using state of art berves commercial state equipments

and acrylic urithene paint with double coating on all surfaces.

16).Design:Two trim tabs are tempted to essure symmetric and smooth flowing of transition.

17).Registration no. Is coordinating colour are applied with as per customer requirment.

18).Anti-slip compound:A new anti-slip compound are applied to the wing walk and other

areas.

19).Ressembling:flight controls, cowling fastners and excess panel used are reinstalled

with steel.

20).Final step: Before aircraft leaves final inspection is done in order to check the quality

of paint and work done over it.

The photo is of the painting work carried out at Airworks CMRO of Boeing 737-400.

49

50

Composite Shop

Introduction: The aircraft body is made up of an alluminium alloy and the skin is made up of alluminium

sheets.But nowadays, there is great demand for the high power to weight ratio or more

aerodynamically, high lift to weight ratio. The dead weight of an aircraft must be minimum

so steel was replaced by an alluminium and now alluminium has being replaced by the

composites.

Brief description: For less weight and high strength is the main criteria for an aircraft body so composites are

used. The section which are made up of composites have high strength to weight ratio.So the

power developed for the same amount of fuel consumtion is much higher for the composite

then the alluminium alloy.

There are some parts which cannot be made up of alloys even alluminium alloys can be

used.Thus the composite are used which give the same strength with less weight.

These are the fabric which is made up of fibres which are in thread forms. Then these fibres

are club with each other as per the requirement and the various process such as heating,

pressurizing, vacuuming etc are being carried out and a tough solid body with high strength

and less weight.

There are various chemicals are used as such as resiens, tools for various jobs, various types

of machine such as an autoclave vacuum pressure etc.

Materials used for the composites: There are various types of materials used the composite types which depends upon the job

size and its requirement.The most commonly material used are kevlar fibre, carbon fibre,

glass fibre, ox-core or honeycomb fibre, peel ply, protective layer etc.

Arrangement of these fibres: There are many hybrids are developed using the above stated material. Most commonly used

hybrid is the glass fibre and the carbon fibre.

These fibres are arranged such a way that there are always perpendicular to each other.

If they are arranged parallel to each other than the required strength from the material will

not be obtained.

When they are joined together to make a complete section, their arrangment also plays an

importanat role for the total strength of it. Mostly, the strips of the hybrid fibre are arranged

perpendicular to each other, which results in high strength.

Layers of glass fibres and carbon fibres are integrated with the help of reseins and the

hardners as per the customers needs.

Wet lay shop: This is the first part of the composite shop.

Wet lay process is a process to make the tools using hardners and reseins and a fabric for the

outer covering jobs.

51

Thermo forming and curing: Thermo forming and a curing is a process of making the scale down model which is made

for the wind tunnel test and the effect of various factors which can occur at that altitude is

studied with the help of wind tunnel test and results obtained from it.

This is also used for mock up type. Mock up means a full scale model of an aircraft. For

example TAAL is preparing a mock up helicopter for the airshow which is going to be

conducted next month is fully made using composite materials. It resemble the original

model but it cannot be airborne.

If someone likes the mockup then he can place an order and then the whole production of

original aircraft takes place. The model is placed at airshow for growing the bussiness with

less marketing expenditure as the company cannot spend money for constructing an aircraft

to be placed in airshow.

These types of mock up are known as LUH, that is Light Utility Helicopter.

Dry bagging and cutting: This is the second part of the composite shop.

In this shop there is an important machine known as an industrial autoclaves where the job is

inserted and depending upon the requirement, various operations are carrided out.

Industrial autoclave: Industrial autoclaves are pressur vessels used to process parts and materials which require

exposure to elevated pressure and temperature. The manufacture of high-performance

components from advanced composites often requires autoclave processing.

Industrial autoclaves used in the aerospace industry. The autoclave on left is gas-fired; the

machine on right is electrically heated. At full pressure, the force acting against the door of

the grey machine is over one thousand tons. Both machines use rotating lockring doors; the

larger one is hydraulically turned, the smaller is pneumatic.

Dimenssions and its specifications: Maximum diameter is 1500 mm.

Maximum length is 3000 mm.

Working pressure is upto 10 bars.

Working temperatue is upto 25000 C.

Thermocouples are 12 J

Vacuum connections are 12.

52

Operates at 415 V, 3-phase ac current.

When it is used the whole company has to be shut down as it consumes the power of

230 KW.

Principle of operation: An autoclave applies both heat and pressure to the workload placed inside of it. Typically,

there are two classes of autoclave. Those pressurized with steam process workloads which

can withstand exposure to water, while circulating heated gas provides greater flexibility and

control of the heating atmosphere.

Processing by autoclave is far more costly than oven heating and is therefore generally used

only when isostatic pressure must be applied to a workload of comparatively complex shape.

For smaller flat parts, heated presses offer much shorter cycle times. In other applications,

the pressure is not required by the process but is integral with the use of steam, since steam

temperature is directly related to steam pressure. Rubber vulcanizing exemplifies this

category of autoclaving.

Design and construction of pressure vessel: Pressure vessel design involves Barlow's formula, used to calculate the required wall

thickness. However, the design of a complex pressure containment system involves much

more than the application of this formula. For almost all pressure vessels, the ASME code

stipulates the requirements for design and testing. Prior to delivery, the pressure vessel is

hydrostatically tested at 130% of its rated pressure under the supervision of an ASME code

inspector. It is filled with water, and a small pump raises the pressure to the necessary test

value, at which it is held for a specified time (30 minutes according to the ASME code). The

inspector checks for leaks as well as evidence of flaws or inadequacies in the welding..

Materials: The selection of the materials from which the autoclave is fabricated turns entirely upon the

application. For steam autoclaves, carbon steel is used, but a corrosion allowance is added to

the calculated thickness. This accommodates the rusting that occurs with repeated cycles of

exposure to steam, water, and air. Implicit in this is the need to monitor the loss of metal

and decommission the vessel when excessive thickness loss has occurred.

For temperatures of up to 650°F (343°C), no adjustment needs to be made in calculating

vessel wall thickness. Above this temperature, the allowable strees is derated. Above 750°F

(399°C), high-temperature alloys are used. The rated temperature, which is stamped on the

vessel's data plate, applies to the vessel wall itself, not to the gas circulating in the autoclave.

This is relevant when internal insulation is used to circulate air or gas at a temperature

beyond the rating of the vessel.

Doors

Of the entire machine, the costliest (depending on the size of the autoclave) and most

important single piece of hardware is the fast-opening door. It must be of full diameter to

53

allow access to the working space, seal tightly against rated pressure at the highest shell

temperature, operate readily and quickly, and comply with the same safety code that governs

the rest of the pressure vessel. Of all safety-related concerns, the most critical are those

which relate to the door's operation.

Heating:

Modulating gas burner firing into tubular heat exchanger: Introducing heat into the working chamber can be done in a variety of ways. For most

autoclaves, and particularly those used to process composite parts or perform adhesive

bonding of metal structures, the easiest and least costly initially is electricheat. Resistance

heaters are compact and reliable and can be placed conveniently in the circulating air duct.

Since the thermal mass of these heaters is small, control of chamber temperature is precise

and additional heaters can usually be installed at a later date without excessive bother. These

heaters are essentially 100% efficient and can be fitted for any voltage, single or three phase.

Installing more capacity than is required extends the life of the heaters by allowing them to

run at lower surface temperatures and provides greater assurance of attaining required heat-

up rates. Increasing the heating capacity generally costs little in initial price. It is unsafe to

automatically assume that every autoclave manufacturer uses high quality tubular Incoloy-

sheathed rods, individually replaceable and properly supported. In the interest of economy,

some expect the customer to accept nichrome wires strung on ceramic insulators.

Cooling: Cool-down at the end of the process cycle requires a means of extracting heat from the

autoclave. The necessity of controlled cool-down will itself depend upon the work being

processed. With some composite materials in thick lay-ups, slow cooling prevents internal

microcracking of the resin matrix resulting from thermally-induced stresses.

The cooling method used will depend upon the highest temperature reached before cool-

down and the degree of precision that must be maintained as the chamber temperature ramps

down. For low temperatures and cool-down rates that can be allowed to vary significantly or

54

simply cool-down at any rate results from a fixed flow of coolent water circulated through a

coil in the airstream will be effective and inexpensive. A serpentine finned coil placed at the

circulating fan input or adjacent to the heater array serves this purpose using plant water as a

coolant.

Circulation:

External motor drive on small autoclave, shaft seal, during construction.

Unless the autoclave uses steam injection, the circulation fan carries the burden of assuring

temperature uniformity throughout the working chamber. Since the heat flows from the

source, whether electric resistance, steam coil, or firing tube, into the circulating air stream

and then into the workload, the greater the airflow turbulence, the better the heat transfer,

particularly with workloads that are heavy and dense.

The fan drive must be sized for the conditions creating the greatest load on the fan, i.e.,

lowest temperature and highest pressure, even though this combination of conditions rarely

occurs. Ideally, this means backward-incline fans; these are more efficient than radial

impeller and forward-curve types.

The purpose of circulating the air or inert gas through the autoclave is to assure effective

heat transfer and temperature uniformity. Vigorous circulation and careful attention to where

the airflow actually goes are the best ways of accomplishing this. As a rough rule of thumb,

do not consider less than 300 feet per minute average air speed through the empty

workspace of the autoclave. More than this will make heat transfer more effective.

The aircraft industry has specifications relating directly to temperature uniformity. Even if

the application is non-aerospace, one of these specifications may be worth adopting to

assure process quality and reliability.

Insulation:

55

Internal fibreglass insulation (pipe & tank board) applied by mechanical retainer, rated at

450°F (232°C).

The substantial mass of the pressure vessel provides assurance of pressure containment, but

it represents an equally massive heat sink which must be heated and cooled cyclically as the

autoclave runs. Steam autoclaves are necessarily insulated on the exterior, making this heat

loss unavoidable. Autoclaves using air or another gas employ thermal insulation on the

interior, and this incurs a one-time penalty in the cost of the pressure vessel and a slight

operating cost resulting from the somewhat greater internal volume to be pressurized.

The insulation, which is protected behind a metal shell, is sized to keep the heat loss within

an acceptable range and to keep the temperature of the outside surface of the vessel below

that which would affect worker safety. Generally, this is 120°F (49°C), with 140°F (60°C)

sometimes allowed on fittings and plumbing. Depending upon company policy on energy

conservation, this temperature may be set even lower.

Pressurization: The choice of pressurizing agent is driven by the process. Air may be acceptable for

autoclaves operating at comparatively low temperatures, but it may be wholly unacceptable

beyond that. The flammability of the materials often used in composite parts increases under

pressure, as the partial pressure of oxygen rises. Thus, nitrogen or carbon dioxide may be

used for pressurization.

Vacuum: Parts processed in an autoclave are often vacuum bagged to enable the pressure to operate

isostatically on the workpieces. In simplest form, the workload is fully contained inside a

loosely-fitting bag made of resilient plastic capable of withstanding the temperatures

involved. When vacuum is drawn, the bag is compressed by atmospheric pressure and

compacts the components inside. Between the parts and the bag, an absorbent material

provides a channel for the evacuation of the air and wicks up the excess resin squeezed out

during curing.

Controls and instrumentation: While much of the operation of a simple autoclave can remain manual, temperature control

is virtually always automated, as this is easily done at low cost. The value of the products

processed in most autoclaves justifies a high degree of automation. The hardware and

software available for industrial process automation makes fully automatic operation of an

autoclave affordable and reliable. It is realistic to design and implement such automation

without the services of an outside vendor in many cases.

Temperature: As with the other parameters, the required precision of temperature control depends upon

the process specification. The autoclave should exceed this capability by a margin sufficient

to preclude all chances of inadequate or excessive temperatures in the workload. Too hot and

the parts can be damaged or undergo thermal excursion; too cold and the full structural

properties may not be realized. Equally vital is the avoidance of variation in temperature

throughout the working volume of the autoclave. Aerospace specifications include

maximum allowable variation as well as how to test for uniformity.

56

Pressure: Control of pressure presents the fewest challenges. Given a source of air or gas of sufficient

pressure and flow capacity, the autoclave control system opens the pressurization valve and

shuts it once the internal pressure has reached the setpoint. Depressurization occurs when

the dump valve is opened. On large autoclaves, a silencer or muffler may be needed. The

valves are on/off rather than modulating, for cost reasons.

As the temperature rises, the gas expands, driving the pressure upward. A trim valve releases

the excess, maintaining the setpoint.

Vacuum: Often the least controlled factor in an autoclave, the vacuum may or may not require

modulation. In some instances, it is not automated at all and involves little more than a

connection to the plant vacuum system, a few manual valves, and a gauge. At the other

extreme, the vacuum control system may be considerably more complex than that of the air

temperature.

Safety assurance: Safety is always a concern with autoclaves. The ASME code is extremely conservative; as a

result, pressure vessels are among the safest, least risky types of machine in use today.

A conservatively designed autoclave has multiple safety valves which are each sized to be

able to cope with the greatest available airflow into the vessel plus not less than 30%. The

valves are mounted on a manifold that allows multiple pressure vessel outlets to feed

multiple safety valves, each one of which can handle the entire air dump by itself, even if

one pressure vessel outlet is accidentally blocked by debris from an internal failure. The

added cost of the redundant safety valves is approximately one tenth of one percent of the

machine price.

57

Avionics laboratory

Introduction: Avionics of an aircraft contains the the radar system, communication system, instruments

and the electrical system of the whole aircraft. The study of these systems and its installation

comes under the avionics laboratory.

Brief description: This is an important section of an aircraft design. This deals with the study of different types

of aircraft systems and their installation at the right place with proper electrical power

supply without disturbing the centre of gravity of an aircraft. For this purpose the drawings

of installations are made such that they show various minute details of the power supply that

has to be supplied to it with proper wiring and appropriate place with an ease to operate by

the crew.

Procedure: The main and the basic steps involves study of the aircraft wiring drawing. Then appropriate

place is selected from which the power can be supplied to it with proper grounding.

The excat place is selected so that the pilot can easy access it and it does not disturbed any

other instrument with its position and its power consumption.

These drawing are made in the avionics lab because if they give order to the foreign

companies then they will charge from 10,,000 to 50,000 USD $.So these drawigns and their

installation are done within the companies thruogh their engineers.

For interconnections, cables with proper insulations are required. It depends upon the size

that is its length of the wire and the diameter of the wire depending upon the type of an

instrument and its installation place.

Then, the drawings and the necessories accesories are compared with the aircraft

drawing and the final decesions is taken with proper study only.

Electrical systems of an aircraft: For every instrumnets and systems present in the aircraft, eletrical power is essential for

their operations and the amount ofthe power varies with the system.

So every system requires electrical power of different magnitude and this has to be

controlled as per the requirement.The electrical power is supplied to each and every parts

and components of an aircraft of various sections such as hydraullic system, engines, oxgen

system, pneumatic system, air conditioning system, pressurization system, aircraft system,

aircraft computer, aircraft lightinig, landing gear system, control surfaces of an aircraft,

pressure indicators at every part and components, fuel pump etc.

Flight instruments: These are the instruments which are used by the pilots for the navigation purpose and

without this flying a aircraft is very difficult.

The various flight instruments are air speed indicator, vertical speed indicator commonly

known as rate of climb/descent indicator, pitot static type, gyros whcih are used for the

heading that can be magnetic heading, radial heading is also used.Radio is very important

for the communication purpose with the ground controller as well as cabin crew and

interpilots also.

58

Instruments used in avionics lab:

Air data testor:

This is the instrument where various instruments are tested before its installation in

an aircraft whose basic is air related data.

It is used to check the correctness of the alitmeter, air speed indicator, vertical speed

indicator etc. For this purpose static pressure will be the atmoshperic pressure while

the dynamic pressure is created in the testor ad it is given to the instrument.So with

its basic principle of working it will show the data.If this data coinside with the air

testor instrument data then that instrument is in working condition.

COM testor:

This testor have the transmitter, receiver, loud speaker and the convertor. This is

basically done for the communication test. That is to check weather the flight

instrument is able to transmit and receive the signals and is the communication

possible with that instrument is checked.

COM/NAV and multiple test:

This is an instrument which is used to check the working condition of the

navigational instrument.The main part of this testor is the simulator which is used to

create the artificial bearing signals at a particular inclination. This data is set by the

operator and if the instrument shows the same bearing which is selected then that

instrument is in working condition.

Example of this test is ADF, which receives the signal from the simulator and

converts it into the bearing bearing which shows the deflection.

These all test are mandatary to check all the flight instruments which are being installed at

pilot desk pannel before its installation.

59

Simulator Shop

Introduction:

Simulator is a device which is used by the pilots for flying practice at the ground level only.

There are two types of simulator available, they are stationary and the movable simulator.

This creates a great feel to the pilot that he is flying an aircraft and can practise the

emergency conditions which can be used at real time of emergency.

Brief description:

Simulaor are of two types, one which is stationary where the position of the pilot will be

locked in a such a way that only pilot seat will be in motion. While in the movable simulator

the whole simoulator is able to move such that a pilot will feel that he is actually flying an

aircraft at that flight level.

Construction:

The outer body of a simulator is made up of composites and wood such that it will resembels

that particular aircraft only and it is controlled using hydraullic and pnuematic systems to

gain various effects.

There will be hi-fi type of loud speakers which will give the pilot a feel that he is flying.

There will be a good quality of projector which will give a view of various events such as

landing, take off, crusing and also manuevering type also.

The instruments used in simulator cockpits are original instruments for which various static

and dynamic pressure is supplied to it depending upon the pilots control by a computer.

Uses from economic point of view:

This is the cheapest way to teach the pilots for the emergency conditions. The cost of a civil

aircraft is basically 200 to 400 crores while the cost of one simulator of one type may cost

upto 2 crore only.So by using simulator he can learn many things which he cannot learn

using an original aircraft.

Product of TAAL:

Currently, TAAL is manufacturing a simulator of MIG 21, for CAE.

CAE is the Canadian Aviation Electronics which has its base at Banglore International

Airport Limited.

60

Aircraft engines and its components

Introduction: Aircraft engines are the basic and forms the main parrt for the propulsion purpose of an

aircrat.There are various types of engines which are used for the propulsion of an

aircraft.The basic type is piston type engine.The efficiency of the propeller engine is very

high compare to all other various types of engines available.

Brief description: The basic type of engine which is used for the propulsion is ―Piston type‖.In this type the

reciprocating motion of the piston in the cylindrical block is converted into the circular

motion of the propeller which is mounted on the crank shaft.

The modified version of this engine is the ―Turbo jet engines‖. In this type combustion of

fuel takes place at constant pressure and only air is taken in during the suction stroke of it

and it is compressed adiabatically.The working of this type of engine is based on the disel

cycle.

The combination of the propeller and the turbo jet has given rise to the new engine known as

―Turboprop engine ‖ in which the main thrust is developed by the proulsive device and its

efficiency lies between the propeller engine and jet engines.

The next generation engine is the ―Turbo-fan engine‖. In this type of engine there is a fan

ahead of the jet engine which increases the amount of air taken in by the engine.There is

new term involved know as bypass ratio. Bypass ratio is defined as the total amount of air

taken by engine which flow above the hard core jet engine to the amount of air flowing

through the hard core jet engine. For a civilian aircraft the bypass rartio is 6.The efficiency

of this type of engine is considerable and it is widely used for the commercial purpose for its

low fuel consumption with high payload carring capacity.

The high speed engine is ―RAM jet engine‖. In this type the engine is brought to the

minimum speed which is necessary for its motion by an auxillary means and the air which is

taken in by the ramjet is compressed as it will be in high speed without the compressor and

can be used for missile, rocket, statellite which is launched from a particular altitude.

The engines which are used only for the helicopters are ―Turbo shaft‖.In this type of engine

a gas turbine engine is used which burns the fuel in the pressence of the compressed air at

constant temperature such that expassion work is extracted from the turbine is used to rotate

the turbine. The crank shaft is mounted on the some turbine shaft so that rotation of this

turbine, makes the shaft also to rotate. With the help of the gear mechanism this rotation in

horizontal plane is converted into the vertical plane which rotates the blades of the

helicopter which gives rise to the lift with a particular balde angle and at a particular pitch.

Reason for the loud noise: When aircraft engine is working, there is emission of the loud noise which is high enough

to cause the noise pollution.

This is because when the exhaust gas leaves the nozzle from the aircraft engine there is a

61

huge temperature differnce between the engine and the ambient temperature which gives rise

to the loud nosie.The engine temperature is near about 20000

C while the atmospheric

temperature at an alititude of 11Km from the ground surface is -56.50C.

Position: Most of the time the engines are placed below the wing to get more stability and easy access

of fuel to the engines as they are stored in the wings.For general aviation purposes the

engine can be placed at the nose, wings while for commercial use there can be an

arrangment for three engines, one at the tail and two at the wings or just at the wings.

There are some chatered planes where the engines are placed at the rear section of an aircraft

symmetry about the tail.

Components of engines:

For propeller type:

The basic components are propeller, piston, cylindrical block,crank shaft,gear

mechanism, spark ignition system, inlet/outlet manifold,crank case, carburator etc.

This type of engines are used for the general aviation such as P68C.

For turbo jet type:

The basic components are turbine, axial compressor, diffuser, converging-diverging

nozzle, cooling system, fuel injector, nozzle.

This type of engines are used for the fighter aircraft where the speed is the main

criteria.

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For turbo fan: The basic components are fan, turbine, axial compressor, diffuser, converging-

diverging nozzle, cooling system, fuel injector, nozzle.

This type of engines are used for civil aviation where fuel consumption is the main

criteria with high payload carring capacity.

For ramjet:

The basic components are turbine, diffuser, converging-diverging nozzle, cooling

system, fuel injector, nozzle.

This type of engines are used for super/hyper sonic speed such as missile.

Method of fuel injector: For the propeller type the fuel is injected with the help of mixture which mixes the fuel and

air. Carburator is incharge for the correct air to fuel ratio and it varries it according to the

required perfomance from the engine.If high power is required then the fuel/air mixture

must be rich mixture while during crusing the mixture should be lean in order to get the

maximum efficiency from the engine with minimum fuel consumption.

For the jet engines only fuel is injected through the injector at the constant pressure in the

chamber where the air is compressed adiabatically.Due to high pressure,the temperature is

near to the ignition temperature and the fuel andd it burns.The fuel is passed through the

CDN (converging diverging nozzle) for the complete combustion of it. When it is passed

through CDN, the fuel gets burns but there are some fuel atoms which are not burnt.So when

again they are passed through CDN, their speed decreases as it passes through the

divergent and thus pressure increases with decrease in velocity. This results in increase in the

temperature which can be used for the combustion of the remaning part of the fuel and this

is how the complete combustion of the fuel is achieved.

The fuel can be supplied to the engine from the fuel tank by the two methods:

Gravity Feed and pressure feed.

Gravity feed:

In this type fuel is passed to the engine with the help of gravity where the fuel tank

are placed at the higher level.If they are placed at the same level or below the engine

then the gravity will have no effect.

Pressure feed:

In this type fuel is passed to the engine with the help of the pressure pump and fuel

tank can be placed at same or low level. The fuel can be sucked and consumed by the

engine from the remote areas of the fuel tank which is not possible in the gravity

feed type.

Engine cowling: Engine cowling is the part which forms the outer covering known as the hosue of the whole

engine assembly and it gives the aerodynamic shape to the engine for the better flow

movement of air around the engine which reduces the drag considerably.

These cowlings are also used for the thrust reversal purpose which is used as the braking

system of an aircraft also.In this type when they are extended the direction of the exhaust is

in the same direction of the flight which result in the opposed velocity which is used to

reduce the aircraft speed at the ground.

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This also increase more drag as it disturbs the flow aerodynamically which helps to reduce

the speed of an aircraft in case of any emergency or landing at the short runway.

Adjustable cowling flaps: These are the flaps which are used to increase the rate of heat transfer from the engine to the

outer atmosphere.These flaps are opened when there is requirement of high power such as

during take off, the heat generated in the engine is very high and thus for cooling the engine

they are operated which increase the surface area of the fin resulting in the high rate of heat

transfer through the method of conduction.

Uses of the air sucked by the engine: The main use of the sucked air by the engine is the complete combustion of fuel and

producing the required thrust for the proplusion.

In turbo-fan type the air which is sucked is passed over the turbojet engine for the cooling

purpose which can be done through the convection method of cooling.

This air is also used for the air conditioning system which works on the air cooling cycle.

This air is also used for the pressurisation system where the pressure in the aircraft is equal

to the pressure at the 8000 feet and to maintain a constant differential pressure during

ascenting and descenting between the aircraft pressure and the ambient pressure which can

be withstand by the aircraft structure.

The sucked air which is compressed in the compressor of an engine is used for the

pnuematic system in the case of recharging the whole system.

The air from the engine is blowed over the external part of the wing in order to delay the

flow seperation and the stagnation point from the surface.

Aircraft engine control: Aircraft engine control provides a means to control the various engine components and

monitoring the aircraft power plant through the various indicators and the basic controls.

The basic controls are:

The master switches:

1) Battery master 2) Alternate master

These both the masters provides the electrical power to all the engine components

Throttle:

This is used to set up the mass flow rate of air flowing through the engine.Higher is

the mass flow rate, higher is the combustion resulting more power and more

thrust.So it is used to power up the engine.

Pitch control:

It is used to adjust the constant speed units and it also controls the pitch of the

propeller which is used for the intake of air and making it to pass moro through the

hard core engine

It is also used to control the rpm of the engine using variable pitch.

Mixture control:

It is used to set the amount of fuel to intake airflow.At high altitude the amount of

oxygen present in the air is low so in order to maintain the mixutre stiochemically

correct, the amount of the fuel flow should also be low.This process is known as

leaning.

Techometer:

It is a gauge used to measure the engine speed in rpm.

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Manifold pressure gauge:

It is used to measure the intake manifold pressure.

Oil temperature gauge:

It indicates the oil temperature.

Oil pressure gauge:

It indicates the oil pressure.

Exhaust gas temperature gauge:

It indicates the temperature of the exhaust gas at the nozzle.

It is also used to indicate the air fuel mixture.

Cylinder head temperature gauge:

It indicates the temperature of the each cylinder.

It is also used to indicate the air fuel mixture.

Carburator heat controller:

It is used to control the application of heat to the carburator venturi area to remove or

to prevent the formation of ice in the throat area of the carburator.

Alternate air:

It is used to bypass the air to feed the injected engine.

Fuel regulator:

Fuel primer pump:

It is a manual pump which is used to add small amount of fuel in a cylinder of an

engine to assist in starting a cold engine.

Fuel quantitiy gauge:

It is used to indicate the quantity of the fuel available in the identified fuel tank and it

is per fuel tank in the cockpit.

Fuel select valve:

It is the valve which is used to select the fuel tank from which the fuel has to be

supplied to the engine.

Fuel pump:

Fuel pressure gauge: It is used to indicate the supply fuel pressure to the carburator.

Fuel boost pump switch:

It is used to control the auxillary/electrical means to provide the fuel to the

engine in case of any emergency or in case of any accident.

Cylinder head temperature: CHT is used to indicate the temperature of each cylinder of an aircraft engine.

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Only for turboprop: If an aircraft is fitted with the turboprop engine then there are extra controls which are very

important from the performance of an engine point of view.

The propeller blades are made up of titanium alloy.

Propeller controller: It is used to set the dersired propeller speed by the pilot at a particular pitch.

The blades are tilted at an angle of 130 towards the hub.

This is done to increase the total mass air flow rate through the core engine

resulting high propulssive efficency.

For variable pitch:

Hydraullic pump is used to move the propeller in and out of the hub for

variable pitch adjustment.

Cross feed: Is is procedure which is used to transport the fuel from one tank placed in one wing to the

other tank placed in other wing through the cross feed valve.

This is done in case of emergency such as fuel shortage in one wing or to supply the remaing

amount of fuel in case of engine failure.It is also done to maintain the static balance of an

aircraft in air or in ground too.

Cross feed valve control is at placed in the cockpit at the top instrumental panel.

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Pneumatic System

Introduction: This is the system where the main working fluid is the compressed air and it can over take

all the hydraullic system in case of any failure. This is also known as vacuum system of an

aircraft.

This system is used for the movement of the control surface and various other movements

such as door opening, landing gear operation etc.

Brief description: In every aircraft there are many parallel systems are present which can take over each other

in case of any emergency. In Airbus aircraft's there are three hydraullic systems which are

connected in parallel with each other and a manual operation is always available while in

Boeing aircraft's there are two hydraullic systems which are connected in parallel with each

other and a manual operation is always available. If all the hydraullic system fails, then there

is a system which can be used instead of it and it is known as pneumatic system

The basic difference between these two system is that in hydraullic system, working fluid

used is incompressible oil while the fluid used in pneumatic system is compressed air.

Sources of compressed air: There are three sources of bleed air: each operating engine, the APU (when on the ground),

and the external Air Cart. Bleed air supplies the following pneumatic systems: the engine

starter, air conditioning and pressurization systems, anti-ice (wings, tail, engines, and urinal

ejectors), and windshield defogging.

The bleed air manifold acts as a storage and distribution system. A main manifold extends

within the wing‘s leading edge with branch ducts distributing air to various pneumatic

systems throughout the airplane.

The engine bleed air manifold reroutes bleed air from the main manifold to the engine

systems for engine starting and air inlet scoop/oil cooler scoop anti-icing. It also routes

bleed air from the engine compressor to main manifold and engine systems.

BLEED AIR REGULATORS Four engine bleed air regulators connect the engine bleed air manifold to the main manifold.

Each regulator is solenoid controlled, pneumatically actuated, and failsafe closed (closes in

event of ESS DC failure). They are each individually controlled by it‘s own 3-position

switch, located on the overhead anti-icing control panel.

OFF closes bleed air regulator.

ON allows the regulator to modulate output; set to keep main manifold pressure at

approximately 45 psi.

OVERRIDE is non-regulating setting; positions regulator to full open.

BLEED AIR PRESSURE GAUGE

The bleed air pressure gauge is either located above the CP‘s upper circuit breaker panel on

the H-Model, or behind the Nav Station on the E-Model. This gauge indicates the pressure

(in psi) in the bleed air manifold. When the flight station air conditioner is operating, the

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gauge indicates 6 psi lower than the actual manifold pressure.

BLEED AIR LEAK CHECK

APU: 35 psi minimum. Leak check from 30 psi to 15 psi in no less than 8.5 seconds.

Engine: 70 psi minimum. Leak check from 65 psi to 35 psi in no less than 10 seconds.

BLEED AIR DIVIDER VALVE

The bleed air divider valve divides the bleed air manifold in half to facilitate control of the

system; closing the valve isolates the system so that one air conditioning unit can continue to

operate in case of bleed air duct failure.

A two-position switch (ESS DC) controls the motor-driven bleed air divider valve. The

valve is motored closed with CLOSED selected and motored open with NORMAL selected.

Since it is motor-driven, the valve freezes in last energized position when power is lost.

BLEED AIR ISOLATION VALVE

Two wing bleed air isolation valves separate each wing‘s manifold from the rest of the main

bleed air manifold; used as backup to the bleed air divider valve. The valves are closed

electrically (ESS DC), but must be opened manually with handles located on each side of

the cargo compartment, forward of the wing beam.

BLEED AIR SYSTEM MALFUNCTIONS

Bleed air leaks can be quite hazardous, with 600° F air potentially starting a fire, and

damaging aircraft structure, equipment, electrical wiring, and/or fuel tank sealant. There are

two types of bleed air system failure: uncontrollable loss of bleed air (bleed air leak) and

failure of an engine bleed air regulator.

BLEED AIR REGULATOR FAILURE

Should the bleed air regulator fail, you will not be able to open the valve for engine start.

Some FE‘s will ‗tap‘ on the valve with a mallet or some other tool Often, that will correct a

stuck valve. A manual wrench on the valve allows the bleed air regulator to be opened to

start the engine on the ground in case of emergency (departing a hostile field) when the

regulator has failed closed. However, when manually opened in this fashion the regulator

cannot be closed in flight; potential complications if bleed air malfunctions encountered in

flight.

BLEED AIR LEAK

Discussion: Sim instructors at the schoolhouse say this malfunction is one that many crews

tend to rush through and miss steps on. When procedures call for closure of engine bleed air

valves, the FE needs to look for a rise in torque to confirm that they actually close. Bleed

air isolation valves will be closed at the discretion of the flight crew.

Other symptoms may include: illumination of fire lights, erratic operation of electrical

equipment, wing overheat, and loss of bleed air as indicated by low manifold pressure. If

bleed air is being lost from the system, the engineer will proceed as follows:

1. ENGINE BLEED AIR switches on the affected wing - OFF

2. BLEED AIR DIVIDER VALVE - CLOSED

If an uncontrolled loss of bleed air cannot be isolated, place all engine bleed air valve

switches to OFF and land as soon as possible.

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CAUTION:

If an engine bleed air valve cannot be closed (regulator closure is determined by

observing torque increase on affected engine) and the bleed air system is leaking,

it may be necessary to shut down the engine.

CAUTION:

Do not open the APU bleed air valve after landing. If an uncontrolled loss of bleed

air is experienced, operation of APU bleed air could repressurize the area(s) where

the failure occurred.

NOTE:

When all Bleed Air switches are OFF, air flow to both air conditioner units is lost,

thus depressurizing the aircraft.

Bleed air overheats associated with the anti-icing system. While that is indicative

of a b leed air leak, we‘ll discuss those EPs in the anti/de-icing section of the

study guide.

SUMMARY OF BLEED AIR LIMITATIONS

Bleed Air Output

APU Output

Engine Output

Bleed Air Check

APU

Engine

Min: 35 psi

Min: (unregulated) 70

psi

Regulated: 45 psi. If

individual regulator

pressures are not

within approximately

3 psi of each other,

place the bleed

switches to either

OFF or OVRD for

takeoff

30.15 psi in no less

than 8.5 seconds

65..35 psi in no less

than 10 seconds

Pneumatics Panel

General

The pneumatic system can be supplied by engines, APU or a ground source. The manifold is

normally split by the isolation valve. With the isolation valve switch in AUTO, the isolation

valve will only open when an engine bleed air or pack switch is selected OFF.

Air for engine starting, air conditioning packs, wing anti-ice and the hydraulic

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reserviorscomes from their respective ducts. Air for pressurisation of the water tank and

the aspirated TAT probe come from the left pneumatic duct. External air for engine

starting feeds into the right pneumatic duct. Ground conditioned air feeds directly into the

mix manifold.

The minimum pneumatic duct pressure (with anti-ice off) for normal operation is 18psi.

If engine bleed air temperature or pressure exceed limits, the BLEED TRIP OFF light will

illuminate and the bleed valve will close. You may use the TRIP RESET switch after a short

cooling period. If the BLEED TRIP OFF light does not extinguish, it may be due to an

overpressure condition.

Bleed trip off's are most common on full thrust, bleeds off, take-off's. The reason is

excessive leakage past the closed hi stage valve butterfly which leads to a pressure build up

at the downstream port on the overpressure switch within the hi stage regulator. The simple

in-flight fix is to reduce duct pressure by selecting CLB-2 and/or using engine and/or wing

anti-ice.

WING-BODY OVERHEAT :

This indicates a leak in the corresponding bleed air duct. This is particularly serious

if the leak is in the left hand side, as this includes the ducting to the APU. The wing-

body overheat circuits may be tested by pressing the OVHT TEST switch;

both wing-body overheat lights should illuminate after a minimum of 5 seconds. This

test is part of the daily inspection.

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Pressurization System

Introduction: Pressurization means maintaning the cabin pressure above tha ambient atmoshpherich

pressure.As there is rise in an altitude, there is a decrease in the pressure level. So it is very

difficult for the passengers and the crew of an aircraft to sustain in such a low atmospheric

pressure.There will be some disorder known as Hypoxia which can occur to the passenger,

in order to avoid this and for the comfort level the cabin must be pressurised which has

given to rise in pressurization system.

Brief description: The human body is habitual to the mean sea level conditions, that is one atmoshpheric

pressure. The value is 101325 Pa. So if the pressure level decrease below this then there are

chances of some complications and in order to avoid this pressurization is very much

essential.

But if the cabin pressure is set at the mean sea level pressure, than at an altitude of 36,000

feet the cabin differnetial pressure willbe near about 50 psi which is very high from the

structure point of view. So in order to avoid this cabin pressure is set such that the

differential pressure betweent the cabin and the anmbient atmoshpheric must not more than

7 psi.

Upto 8000 feet, there is no need for the pressurized cabin. So the cabin pressure is always

set at the pressure equal to the pressure at 8000 feet to reduce the differntial pressure and to

maintain it within the permissible limit.

During ascent and descent, the pressurize system sets the cabin pressure such that a

differential pressure is maintained within the safe range.

PRESSURIZATION SYSTEM The Herk gets its cabin pressure from bleed air ducted through the flight station and cargo

compartment air conditioners. It consists basically of a pressure controller (that controls the

outflow valve), various pressure gages, a safety valve, and emergency depressurization door.

CABIN PRESSURE CONTROLLER The cabin pressure controller is located on the overhead air conditioning and pressurization

panel. It has 3 functional modes: rate of climb control, maintain cabin altitude, maintain

maximum pressure differential.

The rate of cabin pressure change (rate of climb control) can be regulated at a minimum of

30-200 fpm and a maximum of 1600-2900 fpm. It will maintain the selected rate of climb

until reaching the desired cabin altitude. The controller can maintain a cabin altitude

automatically from –1000 to +10,000 feet (constant pressure or isobaric control). It will

maintain that selected cabin altitude automatically until a maximum differential pressure is

reached (15.16 mm of Hg). After the maximum differential is reached, the cabin altitude

will rise directly as aircraft altitude increases. The MX T.O. (21 GS) states that the

differential pressure is limited to 15.18 mm Hg by the pressure controller, but why that is

different than the Dash-1‘s 15.16 mm Hg is unknown.

In event of loss of electrical control power to the pressurization system, automatic control of

pressurization continues as selected on the pressure controller. Normal ops can continue.

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Only manual control of pressurization has been lost.

OUTFLOW VALVE The outflow valve is located on the right side of the side of the airplane at the aft end of the

flight station. It regulates outflow of air from inside the airplane to control pressurization.

The valve is controlled by the pressure controller (pneumatically) or by manual

pressurization in case the pressure controller fails, or if pressurization outside of normal

range is desired. Manual pressure control provides an alternate means of regulating

pressurization in case the pressure controller fails, or if pressurization outside of normal

range is desired. The gage limit of the outflow valve is (-1.2 to 15.8 mm Hg).

SAFETY VALVE The safety valve is located on the aft cargo door (the ―barbecue grill‖), and is electrically

and pneumatically controlled. It is pneumatically opened for a non-pressurized condition or

emergency depressurization. It is normally closed when the aircraft is pressurized. It‘ll

open a automatically to relieve excessive positive (15.9 mm of Hg) or negative

(-0.76 mm of Hg) differential pressure.

EMERGENCY DEPRESSURIZATION SYSTEM The emergency depressurization switch is a guarded toggle switch located beneath the

differential pressure gauge. This is the electrical (BATT DC) method of depressurizing the

airplane for emergency conditions. When the switch is positioned from Normal to

Emergency Depressurization the shut-off valves for the air conditioning units & the under-

floor heat are closed and both outflow & safety valves are opened. The aircraft may be later

repressurized by placing switch back to Normal.

The emergency depressurization handle is a yellow a T-handle directly above pilot‘s head.

This is a mechanical means in which to depressurize the airplane. Pulling downward on the

T-Handle releases a depressurization panel in the center overhead escape hatch. This of

course will ‗create a hole‘ big enough to quickly depressurize the airplane. Now while this

panel may be reinserted to repressurize, it is widely considered to be a difficult task to

accomplish while airborne. Therefore the emergency depressurization switch should be the

primary means for quickly depressurizing the aircraft.

SUMMARY

PRESSURIZATION

LIMITATIONS

Outflow Valve

Safety Valve relieves

pressure at

Pressure Controller

(in AUTO)

Cabin Altitude Select

Knob

Jettison Crew

Entrance Door

Taxi/Takeoff

While Pressurized

-1.2‖ Hg (min); 15.8‖ Hg (max)

-.76‖ Hg and 15.9‖ Hg

15.16‖ Hg

Do not force below -1000‘ or above

10,000‘. To do so may damage the

pressure controller.

Cabin Pressure should be no greater than

3.1‖ Hg

Do Not Pressurize

Do not attempt to lock or unlock any

window, door, or hatch (first depressurize

and turn air-conditioning master switch to

AUX VENT.)

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PRESSURIZATION EMERGENCIES

EMERGENCY OPERATION OF CABIN PRESSURIZATION

PRESSURE INCREASE:

A cabin pressure increase only occurs when an outflow valve is malfunctioning in a

closed or nearly closed position. If the outflow cannot be controlled by automatic or

manual means, cabin pressure may increase at an excessive rate; it will have to be

reduced by other means:

Immediately shut off engine bleed air, one at a time, until the rate of pressure

increase is at a safe value. Control pressure by using engine bleed air to vary the

amount of conditioned air as necessary. If further control is needed, consider using

only one air-conditioner during descent to expedite depressurization.

PRESSURE DECREASE:

Several things may cause a decrease in or loss of pressurization. If you cannot

control the loss, don oxygen masks immediately and begin a descent if required.

Maintain an altitude at which oxygen is not required. Check for an excessive cabin

leakage at doors, windows, hatches, and the safety valve.

WARNING:

Never attempt to lock or unlock windows, doors, or hatches while the airplane is

pressurized. The FE will depressurize the airplane, and then place air conditioner

master to AUX VENT.

Check the bleed air system for excessive external leakage by completing bleed air

check procedures. As discussed before, the bleed down should be from 65 to 35 psi

in no less than 10 seconds.

EMERGENCY DESCENT

WITHOUT STRUCTURAL DAMAGE:

A rapid descent with gear and flaps up should be flown. Set throttles to FLIGHT

IDLE and descend at maximum speeds. When flying in excess of VH Avoid

moderate and severe turbulence.

WITH STRUCTURAL DAMAGE:

Unless there are indications that changing the airplane configuration will cause

further damage, carry out a rapid descent with the gear and flaps down. Reduce

speed, lower the flaps to 100% and extend the gear, set throttles to FLIGHT IDLE,

and maintain 145 KIAS in the descent.

WINDSHIELD AND WINDOW FAILURE If an windshield or other window failure occurs, reduce the cabin pressure to 10 inches Hg

or less when:

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An inner or outer pane of any cargo compartment window cracks.

Either or both panes of any flight deck window crack (positive pressure is maintained in

this case to counteract ram air pressure on flight deck windows).

Reduce cabin pressure to zero if both panes of any cargo compartment window crack.

IN-FLIGHT DOOR WARNING

Question : you pass through an area of turbulent air. Suddenly the master door warning light

illuminates. The loadmaster calls and informs you that he sees a red light illuminated next to

the crew entrance door. You have four passengers on board the aircraft.

Answer: In-flight Door Warning

When the master door warning light or an individual door warning light illuminates, notify crew

and passengers, check ADS RAMP & DOOR switch OFF, and proceed as follows:

WARNING:

Upon notification of door warning light, all crew members will immediately fasten

their safety belts. The LM will ensure that the passengers fasten their safety belts

also.

WARNING:

Personnel will not go near the crew entrance door until it has been determined that

it‘s safe to do so.

1. Oxygen- ―As required‖ (P)

The pilot will direct all crewmembers to don their oxygen/quick-don masks and to select

100% on their regulators.

WARNING

If the airplane is still pressurized, the pilot will direct anyone on the flight deck without

seats or oxygen to remain there until the cause of the unsafe indication is determined.

2. Pressurization- ―Depressurizing‖ (E)

3. Descent- ―As required‖ (P)

NOTE

If range is an important and all passengers have supplemental oxygen, the pilot may elect

to have the crew go on oxygen, the airplane depressurized, and the door inspection made

at altitude.

4. Air conditioning master switch- ―AUX VENT‖ (E)

5. Doors- ―Checked‖ (E)

WARNING

The airplane shall be completely depressurized before making a door check. The

engineer will check the door, and must wear a restraint harness or parachute. If it can‘t be

determined what caused the door light to illuminate, the flight may be continued with

partial pressurization at the discretion of the pilot (below the point where the light

illuminates and with all personnel secured with safety belts). If the doors are fully secure

74

and the trouble is determined to be a faulty door warning switch, the airplane may be

fully pressurized. If flight profile permits, it is desirable to not have any pressure on an

outward-opening door, such as the crew entrance door or cargo ramp, unless door-

warning system is fully operational.

6. Master door warning light switch- ―OFF‖ (E)

Related Question: What if the door open light illuminated as you were climbing through an

intermediate altitude, say 13,000 feet. Let‘s say you ask for and receive clearance to

descend to 9,000 so you can depressurize and inspect the door. But as you begin your

descent and the FE starts depressurizing, the door warning light suddenly goes out. Could

you elect to level off at that altitude and just continue with partial pressurization?

Answer: No. The point of this question is that you must inspect the door before making any

decision to continue with partial pressurization. And in order to do the door inspection, the

airplane must be completely depressurized. A good answer would be to continue the descent

below 10,000 feet, so you and your passengers can come off oxygen. Then, finish

depressurizing and have the FE inspect the door. His findings will determine the correct

course of action. Read carefully:

The door is not secure.

This happens occasionally with the crew entrance door, when the latch mechanism

gets out of adjustment and the door doesn‘t fully close. As pressurization increases,

the door bows outward until it breaks contact with the warning switch. There is no

choice in this case. Do not pressurize the airplane—even partially—and continue to

your destination below 10,000 feet, if practical.

The door is secure, and the door warning switch looks good.

This is an example where the FE can‘t determine what caused the light to illuminate.

Under these conditions, you could elect to restore partial pressurization (below where

the light came on). All personnel must remain seated with their belts fastened,

however.

The door is secure, but the door warning switch is faulty.

If the warning switch itself is confirmed bad, then you can continue with full

pressurization.

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Oxygen System

Introduction: Aircraft flies at a flight level of 360.As the density of air decreases with increase in flight

level, the amount of oxygen also decreases.Thus at such a high altitude, there is a need of

oxygen at that altitude for the process of respiration for passengers and crew of an aircraft.

Brief description: As aircraft flies at such a high alititude, desity of air descreses incredibly.Thus the mass of

air available is also very less which in turn contains less amount of oxygen present in it.Thus

there must be an auxillary system for the oxygen in every aircraft which flies at a high

altitude.

OXYGEN SYSTEM The liquid oxygen (LOX) system provides a 25-liter oxygen supply for aircrew/personnel

usage for a minimum of 96 man-hours. The system converts LOX to gaseous oxygen, and

delivers that gas to the regulators at 300 psi. The regulators in turn dilute the oxygen as

required according to cabin altitude in NORMAL, or 100% oxygen if selected.

LOX CONVERTER The LOX converter is located inside the nose wheel well on the right side; it is the device

that converts LOX to gaseous oxygen. A LOX filler valve located on right side of fuselage

nose, providing means to service the system. There is also a LOX vent located to the right

and above the nose wheel well that relieves the pressure accumulated in the converter. This

vent is not labeled on many aircraft and since the LOX could be vented at any time, never

enters the nose wheel well from the right side.

OXYGEN REGULATORS The aircraft has 10 diluter-demand automatic pressure breathing regulators; six are on the

flight deck and four in the cargo compartment.

SIX ON THE FLIGHT DECK

Pilot‘s and copilot‘s side shelf.

Rear of overhead control panel (flight engineer‘s).

Navigator‘s control panel.

One at each end of the crew bunk.

FOUR IN THE CARGO COMPARTMENT

Two on forward right side.

One aft of each paratroop door.

PRE-FLIGHT OXYGEN Prio to the Before Starting Engines Checklist, check out the O2 system in accordance with

Section 4 of the Dash One. At the end of the check, leave the diluter lever in 100% oxygen

and the supply lever ON; now it‘s ready for use in case of emergencies.

For unpressurized flight other than HALO-type missions involving oxygen pre- breathing,

(and not involving smoke and fumes elimination), diluter lever should be set to

NORMAL oxygen unless symptoms of hypoxia are experienced. HALO/HAHO missions

require use of 100% oxygen.

76

LOX INDICATOR The LOX indicator on the lower right side of CP‘s instrument panel indicates liters of

oxygen in converter (up to 25 liters). An oxygen low-level warning light, adjacent to

quantity indicator, illuminates when 2.5 liters or less is remaining. Oxygen is usable all the

way down to 0 liters remaining. The minimum oxygen for flight is enough to complete the

flight with the crew on oxygen from the ETP (but no less than 5 liters or 300 psi).

WALK-AROUND BOTTLES The 4 portable oxygen bottles facilitate movement of personnel within the airplane when

oxygen is needed (say during door open light illuminated during flight above 10,000‘ MSL).

They are also a last-ditch oxygen backup in case of emergency where oxygen is needed, but

for some reason aircraft oxygen is unusable.

The A-21 regulator used in the C-130 supplies 100% oxygen regardless of setting. The

portable oxygen bottle duration varies according to how hard the user is breathing, but can

easily get fully depleted in about 4 minutes.

The location of the walk-around bottle are: left of the pilot, right of the CP, the right side of

forward bulkhead in cargo compartment, and aft of the right wheel well. A recharge hose is

at each portable oxygen bottle location to refill bottles. A user can breathe continuously

from a portable oxygen bottle while it is simultaneously being refilled via the recharge hose.

77

Air Conditioning System

Introduction: Air conditioning system is very important for the comfort level of passenger and crew of an

aircraft respectively.As the aircrfat fly at an altitude of 36,000 feet that is 11 km from the

mean sea level MSL, the temperature at that level is -56.50

C or 216.66 0K or -69.7

0F. It is

very difficult to sustain such an extreme condition so air conditioning system is very

essential in every aircraft from the comfort point of view.

Brief description: In this system the cabin temperature is maintained at a constant temperature of near about

180 to 23

0 C respectively inspite of variable atmoshpheric temperatures depending upon the

altitude..

The process of maintaining the favourable temperature within the cabin with the help of

some system or a device is known as air conditioning system and with the help of this

system there will be always a positive differential temperature between the cabin and the

ambient temperature.

AIR CONDITIONING SYSTEM: The aircraft has two independently operated altitude compensating air conditioning units,

plus under-floor heating, that provide climate control and supply air with which to pressurize

the aircraft. The flight deck air conditioner is located under flight deck; output 70 pounds

per minute (ppm) at sea level (33 ppm at 35,000 feet). (NOTE: E-Model only produces 35

ppm at sea level). The cargo compartment air conditioner is located in the forward

unpressurized portion of the right wheel well. The output is the same for both E & H model

Herk; 70 ppm at sea level (33 ppm at 35,000). The under-floor heating unit provides an

additional 34 ppm at 35,000 feet.

OPERATION OF AIR CONDITIONING The airflow regulator for each unit controls bleed air from the bleed air manifold to each

unit. A two-stage refrigeration unit is used to cool the 600° F bleed air. The first stage cools

bleed air by passing through a heat exchanger (manifold tubing exposed to ambient outside

air; no actual air exchange takes place). The second stage uses a portion of cooled air and

super cools the air by turning a turbine. (The air expends energy to turn the turbine, and

rapidly expands, and thus is super cooled).

Temperature control is done electrically by opening temperature valves to mix hot bleed air,

first stage cool air, and second stage super cooled air to achieve the desired temperature.

Water separation is used to remove about 80% of moisture from air for crew comfort and to

reduce fogging.

UNDER FLOOR HEATING Hot bleed air is routed between the cargo floor and aircraft skin to keep the floor warm at

approximately 80° F. Bleed air is routed via a shutoff valve (upstream, and therefore

independent of cargo compartment air conditioning) and through a motor-driven under-floor

temperature control valve to automatically maintain the proper temperature. A recirculating

fan is used to direct hot air from the top of the airplane and blow it back to the floor. The

fan will come on whenever the under-floor heat is selected (regardless of fan switch

position) or when independently selected with fan switch (with under-floor off). Running

the fan in hot weather conditions helps cool SKE R/T, and cuts down on some SKE

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malfunctions.

AIR CONDITIONING CONTROLS The air-conditioning controls are located on the overhead panel next to APU control panel.

AIR CONDITIONING MASTER SWITCH

The Air Conditioning Master Switch is a 5-position rotary switch:

AUX VENT:

Turns on both air conditioning units and under-floor heating off; ram air ventilates

airplane. Safety valve and outflow valve open.

OFF: Both air-conditioning units and under-floor heating off. Safety valve closed, outflow

valve open.

NO PRESS:

Both air-conditioning units on (if selected on their respective shutoff switches),

under-floor heating as selected. No pressurization. Outflow valve and safety valve

open.

AUTO PRESS:

Both air-conditioning units on (if selected), under-floor heating as selected. Desired

pressure automatically controlled. Safety valve closed, outflow valve and safety

valve open.

MAN PRESS:

Both air-conditioning units on (if selected), under-floor heating as selected. Allows

for manual control of pressurization. Safety valve closed, outflow valve manually

modulated via electrical circuitry.

TEMPERATURE CONTROL SWITCHES

Temperature control switches allow separate automatic or manual temperature control of the

flight deck and cargo compartment units. Each unit has a 4-position toggle switch: AUTO,

COOL, WARM, and OFF (COOL & WARM will spring load back to OFF). In AUTO, the

temperature is as selected by the rheostat switch adjacent to it. When positioned to COOL

or WARM, switches directly position the temperature control valves toward cooler or

warmer positions. The Manual switch must be held for about 35 seconds for the valve to

move from extreme hot to extreme cold position. The switch must be held for about 4

minutes for valve to go from extreme cold to extreme hot.

In event of loss of electrical control power to the air conditioning system, the temperature

setting cannot be changed because the temperature control valves remain in last energized

position.

SHUTOFF SWITCHES

Two shutoff switches enable either air conditioning system to be shut down individually. If

OFF, the airflow regulator stops bleed airflow regardless of setting of air conditioning

master switch.

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FLIGHT DECK DIVERTER SWITCH

The H-Model‘s large flight deck air conditioner is often more than the flight deck crew

needs. A Flight station airflow control (a 4-position rotary switch) allows and controls how

much, if any, air from the flight station air conditioner is diverted to cargo compartment via

a 5-inch diameter duct.

Flight

Station

Cargo

Compartment

MIN: Diverter valve full open 30.00% 70.00%

NORMAL: Diverter partially open 60.00% 40.00%

INTMED: Diverter partially open 80.00% 20.00%

MAX: Diverter valve closed 100.00% 0.00%

Flight station airflow switch may be used to provide some airflow from the cargo

compartment to the flight station when the flight station air conditioner is inoperative.

UNDERFLOOR HEATING SWITCH

Under floor heating switch: ON/OFF toggle that turns on under floor heating and

recirculation fan. Under floor heating fan switch: ON/OFF toggle, turns on cargo

compartment recirculation fan only.

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Aircraft Tires

Introduction: Aircraft tires, tubeless or tube type, provide a cushion of air that helps absorb the shocks and

roughness of landings and takeoffs: they support the weight of the aircraft while on the

ground and provide the necessary traction for braking and stopping aircraft on landing.

Thus, aircraft tires must be carefully maintained to meet the rigorous demands of their basic

job to accept a variety of static and dynamic stresses dependably--in a wide range of

operating conditions.

Brief description:

Aircraft Tire Construction: Dissect an aircraft tire and you'll find that it's one of the strongest and toughest

pneumatic tires made. It must withstand high speeds and very heavy static and

dynamic loads. For example, the main gear tires of a four-engine jet transport are

required to withstand landing speeds up to 250 mph, as well as static and dynamic

loads as high as 22 and 33 tons respectively..

Tread: It is made of rubber compound for toughness and durability, the tread is patterned in

accordance with aircraft operational requirements. The circumferential ribbed pattern

is widely used today because it provides good traction under widely varying runway

conditions.

Tread Reinforcement: One or more layers of reinforced nylon cord fabric strengthens the tread for high

speed operation. Used mainly for high speed tires.

Breakers: Not always used, these extra layers of reinforcing nylon cord fabric are placed under

the tread rubber to protect casing plies and strengthen tread area. They are considered

an integral part of the carcass construction.

Casing Plies/Cord Body: Diagonal layers of rubber-coated nylon cord fabric (running at opposite angles to one

another) provide the strength of a tire. Completely encompassing the tire body, the

carcass plies are folded around the wire beads and back against the tire sidewalls (the

"ply turnups").

Beads: Made of steel wires embedded in rubber and wrapped in fabric, the beads anchor the

carcass plies and provide firm mounting surfaces on the wheel.

Flippers: These layers of fabric and rubber insulate the carcass from the bead wires and

improve the durability of the tire.

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Chafers: Layers of fabric and rubber that protect the carcass from damage during mounting

and demounting. They insulate the carcass from brake heat and provide a good seal

against movement during dynamic operations.

Bead Toe: The inner bead edge closest to the tire center line.

Bead Heel: The outer bead edge which fits against the wheel flange.

Inner liner: They are on tubeless tires, this inner layer of less permeable rubber acts as a built-in

tube; it prevents air from seeping through casing plies. For tube type tires, a thinner

rubber liner is used to prevent tube chafing against the inside ply.

Tread Reinforcing Ply: Rubber compound cushion between tread and casing plies, provides toughness and

durability. It adds protection against cutting and bruising throughout the life of the

tread.

Sidewall: Sidewalls are primarily covers over the sides of the cord body to protect the cords

from injury and exposure. Little strength is imparted to the cord body by the

sidewalls. A special sidewall construction, the "chine tire," is a nose wheel tire

designed with built-in deflector to divert runway water to the side, thus reducing

water spray in the area of rear mounted jet engines.

Apex Strip: The apex strip is additional rubber formed around the bead to give a conture for

anchoring the ply turnups.

82

P68C Aitcraft

Introduction: Vulcanair the owner of the Partenavia Type Certificates and all its rights is constantly

updating its successful P68 design. The Vulcanair P68C Series is a six seater, twin engine,

high wing, fixed landing gear airplane presenting numerous improvements such as a modern

cockpit, new adjustable seats, standard pilot door, sturdier main gear and brakes.

The P68C is the sensible alternative to many single engine and light twin aircraft in today‘s

General Aviation market.

In P68C, P stands for Partenavia type, 68 stands for the year 1968 in which it was designed

for the first time and C stands for the series of the design.

Brief description: The design of this aircraft is based on very basic theory of aircraft structures and design.

Wing span 12.00 m or 39.37 ft

Wing area 18.60 m2 or 200.23 ft

2

Overall length 9.55 m or 31.33 ft

Overall height 3.40 m or 11.15 ft.

It is the standard 2+4 seat P68C airplane .

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Main Characteristics of an aircraft:

Weights and Loadings

Maximum Ramp Weight

2100 kg 4630 lbs

Maximum Take-Off Weight

2084 kg 4594 lbs

Maximum Landing Weight

1980 kg 4365 lbs

Typical. Std. Empty Weight 1420 kg 3130 lbs

Maximum Zero-Fuel Weight 1890 kg 4167 lbs

Typical Max Useful Load 680 kg 1499 lbs

Maximum Fuel Load (usable) 523 Lt 138 US Gal

Powerplant Engine Manufacturer and their components:

Engine Designation: IO-360-A1V6 installed on P68C

where I indicates the injector type,

O indicates the opposed arrangment of the cylinder,

360 indicates the piston displacement in the cylinder,

A indicates the crank case design,

1 indicates the power rating,

V indicates the accessories type present in it, and

6 indicates the counter weight of the crank shaft in the form of

fly wheel

Number of the powerplant:

P68C is the twin engine aircraft.

So there are two similar engine placed under the wings of an aircraft.

Engine Type :

4-cylinder, 361 inch, 3 horizontal, direct drive, air cooled, fuel injected.

Engine components: For every cylinder there are two spark plug for the ignition system of the engine, so for one

whole engine there are eight spark plug and thus for the whole aircraft there is sixteen spark

plug in all.

The oil for the lubrication is poured from the upper surface of the wing.

There are fuel pump and booster pump also to increase the rate of fuel injection.

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The fuel used for the propulsion purpose is gasoline with the the grade of 100 LL i.e low

lead.

If the carburetor is present then the model specification will start directly with O and not

with I.

There are two magneto to reduce the vibrations which occurs due to the rapid movement of

the piston within the crankcase.

Dip stick is used to check the level of oil present in the engine.

Oil cooling system is placed in the front side of the engine so that it can get the cool ram air

directly from the atmoshphere.

Fuel sensors are used to check various parameters such as fuel level in the tank,fuel

temperature, amount of fuel injected per stroke etc.

Governor is one of the important equipment for the propeller which is used to control the

rpm of the propeller which in turn controls the thrust of an aircraft.

Oil filters are used to filter the oil which is used for the lubrication purpose.When oil is

changed at that time oil filters are also changed.

There are in all three ram air intake by the system, one for fin cooling system to the core

engine, other for the oil cooling system and the last one is the main system through which

air is induced in each cylinder of the engine.

Power generated by this engine is 200 shp (Aspirated),

Propeller Manuf./Design Hartzell, 2 blades FC 7666A model

Propeller Type: Constant speed, full feathering, non reversible, hydraulically operated

variable pitch

Dimensions of the other parts:

Doors :

Entrance door width 0.820 m or 2.690 ft

Cargo door size 0.802 x 0.835 m or 2.631 x 2.739 ft

Service door width 0.540 m or 1.772 ft

Main optional equipment available:

Pneumatic de-icing

Propeller de-icing

Air conditioning

Twin bladed propellers

85

Tinted windshields

DME and ADF

Performance: The performance data has been averaged from actual flight tests, with the aircraft and

engines in good condition and using average piloting techniques.

Max Range Cruise Speed (@ 75%, ISA, FL 80) 301 km/h

Rate of Climb (2 Engines MTOW)

Single Engine Rate of Climb (MTOW s.l.)

6 m/s 1100 fpm

1 m/s 200 fpm

Stall Speed, 35 deg Flaps, MTOW 106 km/h

Max Altitudes 5920 m

SE Service Ceiling 1520 m

Range, FL 100, 55% Pwr. (incl. 45’ Res.) 2960 km

Take-Off distance over 50 ft, MOTOW, ISA 400 m

Take-Off Ground Run 240 m

Landing Distance over 50 ft, MLW 600 m

Landing Ground Run 200 m

Max endurance, FL 100,65% Pwr, ISA >10 h

Load Factor + 3.74g to – 1.50 g

Control surfaces: It has all the primary control surface that is aileron for the roll movement, elevator for the

pitch movement and the rudder for the yaw movement.

Actually, it does not have elvator, instead it has stabilator which acts as both stabilizer as

well as elevator and it is of variable incidence type.

The secondary control surfaces are trim tabs, spring tabs and fixed tabs.

Trim tabs which is present on the rudder, is a movable type and it is used to reduce the pilot

efforts.

Spring tabs which are at the tails, moves accordingly with the flow and adjust the fine yaw

movement.

The fixed tabs which are placed at the ailerons adjust the fine roll movements on both the

wings.

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Structure:

Materials Choice:

Aluminium construction of the P68C Series aircraft presents following advantages:

weight, compared to a similar structure made of aircraft certified composite

materials, aging and fatigue qualities of aluminium structure together with the ease of

repair.

Whole aircraft body is made up of the alluminium sheets for the high strength and to

reduce the dead weight of the aircraft considerably.

As alluminium has high strength to weight ratio, alluminium sheets are used.

Alluminium can withstand the the sonic vibrations.

Aircraft skin is made up of the composite material from the OX-core,which is in the

honeycomb structure and it is sandwhich between the alluminium sheets, this is done

to reduce the skin friction drag.

There are static discharger which are placed at the trailing edge of the wings and also

at rudder. The function of this discharger is to discharge the static electricity

generated in the aircraft due to the circulation of the charge particles around the body

which is the result of the airflow over whole body.

The fuel tank is of wet type, in which the whole wing volume acts as a fuel tank.

There are six drain points from which fuel can be drained and can be checked for any

contamination before every flight.

The aileron used in this aircraft is of combination type of the ailerons which are

stated as:

Differential and frise aileron.

In differential aileron the upward displacement is more than the downward movement.

While in the frise type both the displacement are of equal magnitude, but when the leading

edge of aileron comes down then it goes below the wing level causing more drag due to the

flow disturbance.

So there are stops which are used to adjust the movement of the aileron from its mean

position depending upon the requirement.

Landing gear: The geometry of the landing gear is tricycle, with the fixed type.

Center of gravity of an aircraft is always near the wing so landing gear are installed at an

angle 60

to 200 from the C.G. Of an aircraft.

In the tricycle combination each gear makes an angle of 600

with the other two, while it

makes an angle between 600 to 90

0 from the ground surface.

The tyre is tubed tyre which is filled with the nitrogen gas.

87

The brake system contains the disc brake with the hydraulic supply to actuate it..

The landing gear can take the pressure upto 50 psi at all up weight.

There are three jacking points available at the root of the landing gear to lift the aircraft on

ground using hydraulic jacks for the maintainance purposes.

Antennas: There are various types of antennas which are used for various instrument which sends and

receive the signal through the antennas only.

There are three antennas placed over the fuselage.

The middle antenna is the ELT antenna, which activates only when the force more tha =n or

equal to the 5g acts on it.

It is used to locate the aircraft in case of any accident or if an aircraft is lost in heavy dense

forest.It sends the signals upto 100 Km of radius in omni direction in VHF band.

There are two types of ELT's:

Fixed type and portable type.

Fixed type:

In this type ELT is fixed at the upper part of the aircraft so that damage to it would be

minimum in case of any accident.

Portable type:

In this type it is placed on board in the hand baggage place which is above the

passengers seat. It is used if an aircraft is floating on the water then it is thrown out

so that as soon as it comes in contact with the water it gets activated and sends signal

in three frequency.

First frequency is used for the civil aircraft, that is in VHF band- 121.5 MHz.

Second frequency is used for the militry aircraft,that is in VHF band-243MHz

Third frequency is used for the civil aircraft, that is in UHF band-406.25MHz

406.25 MHz is trasmitted to the satellite and then it is received by the ground

station which is located at the ISRO banglore which recives the aircraft type,

aircraft number location, aircraft owner address etc for the whole India.

GPS:

GPS antenna is located above the cockpit so that the excat location of an aircraft can be

found using the GPS system in terms of the longitude and the latitude.

88

ATC transponder: ATC transponder is located below the cockpit so that it can reply to the interrogation asked

by the SSR through MODE B and MODE C.MODE A is used for the altitude. It gives

various information to the ground controller regarding the flight data as well as

identification.

Using PSR only position of an aircraft can be located. This is done by sending the signal and

getting it reflected back from the aircraft body, the time required to travel the total distance

is nothing but the time interval between the transmission and receving the signal and thus

the distance is calculated using the below formula and an aircraft is located on the PSR.

R= CT/2

where R is the distance of an aircraft from the station.

C is the velocity of the EM waves, that is 3,00,000 Km/hr

T is the time taken by an EM waves to travel.

DME: Master beacons is located below the fuselage before the ATC transponder pointing towards

the nose of an aircraft.

It gives the slant range for an aircraft that how far it is fron the runway.

1 DME is equal to the 1 nautical mile and 1 nautical mile is equal to 1.85 Km.

VOR and localiser antenna: VOR and localiser antenna are placed at the top of the tail..

VOR frequency band is from 108 to 118 MHz.

Localiser frequency band is from 108 to 112 MHz.

Identification of localiser and VOR frequency:

For localiser, the frequency after the decimal must be odd tenth of the cycle

while for the VOR, the frequency after the decimal must be even tenth cycle..

Example: 108.12 MHz. is for the localiser and 108.24 is for the VOR.

ADF: ADF antenna is placed below the fuselage of an aircraft before the DME.

ADF stands for the automatic direction finder which gives the relative bearing of an aircraft.

Relative bearing = Magnetic bearing – Aircraft bearing

It gives the relative bearing to the station. For the working of ADF there should be NDB at

ground station.

Marker beacons: They are placed below the fuselage before the ADF. They are used by the pilots to get the

fair idea how far they are from the runway using three various colour identification.

Glide slope and the weather radar are placed in the radom.

89

ILS: It contains of the three parts:

Localiser:

It is used by an aircraft to allign with the centre line of the runway.

It gives the lateral guidence to the pilot.

Glide slope:

It is used to give the vertical guidance to the pilot.

It is used to maintain the correct glide angle.

Marker beacons :

It is used to give a fair idea about its position to the pilot from the runway.

If the outer most beacon lits then he is very far from the runway.

If the middle beacon lits the he is near to the runway.

If the innear most beacon lits then he is very near to the runway.

Advantages of VOR over ADF: VOR gives signal in 360

0 so pilot can reach the bearing station from any side, while using

ADF pilot can approach the bearing station only from one path.

ADF works from 100 Hz to 1050 Hz, that from low frequency to medium frequency.

To get the ADF signals there should be NDB at the ground station.

Instrument used for the various flight parameters:

Altimeter:

This instrument is used to measure the altitude of an aircraft from the ground level.

This work on the principle of pitot and static pressure. This presure diference is

converted into the height from the ground level.

Air speed indicator:

This is an instrument which is used to determine the speed of an aircraft.

This works on the simple pitot static tube to measure the velocity of the airflow over

the aircraft body which in turn is the aircraft speed.

Vertical speed indicator:

This is an instrument which is used to determine the rate of climb or rate of descent.

This works on the principle where the pressure diffence is calculated for a different

altitude and the time required for it, which gives the rate of change of altitude.

Cylinder head temperature:

This is used to indicate the maximum temperature in the engine cylinder head.

90

Fuel indicator:

This is used to indicate the fuel remaining in the tank.

Cabin temperature:

This is used to indicate the cabin temperature which is also used to set the air

conditioning temperature.

Airtificial horizon: This is used to indicate the the aircraft position with respect to the ground.

It is half blue and half is brown in colour which indicates the sky and ground

respectively.

If horizon indicates the brown colour then aircraft nose is moving towards the ground

and if it is blue then aircraft nose is moving upward.

RMP indicator:

This is used to indicate the revolution per minute of engine.

Localiser:

This is used to allign the aircraft along the runway.

Radio:

This is used for the communication purpose between the pilot and the ground as well

as with the other pilot flying in the same airspace.

These are the some instruments which are used in the cockpit of a P68C aircraft.

Lights of an aircraft:

On tail:

The light which is in the horizontal plane is known as an anti collision light which

illuminates white colour.

The light which is in the vertical plane is known as a navigational light.

On port wing:

The light which is present on the port wing is red light.

On star board wing:

The light which is present on the star board wing is green light.

These lights are used to indicates that an aircraft is flying in the airspace during the

night time.

At the nose gear:

The light which is present on the nose gear is known as landing lights which is used

for the landing during the night time.

There is a stall strip on the leading edge on the star board side in order to assign the

warning alarm in the cockpit that the aircraft is stalling. This is present on the root

side in order to get back the control of the aircraft as soon as possible. If wing tips get

stall first then it is very difficult to get back the control of the aircraft.

91

Economy : The economy of the aircraft is the result of the low operating costs and of the low

maintenance costs which are a direct result of the aircraft construction simplicity and low

fuel consumption and replacement costs of its power plants.

Maintenance costs are reduced to the minimum, thanks to

rugged maintenance free, leaf spring fixed undercarriage,

lack of complicated systems,

unsurpassed accessibility of servicing points.

The high wing configuration enables the engine intakes and propeller tips to be kept

well clear of the ground thereby reducing dust ingestion and stone denting to the minimum

and extending engine and propeller service lives to the maximum.

Conclusion:

The P68C aircraft results to be an easy and extremely safe machine with excellent

performance and low operating cost compared to its competitors.

It is the sensible alternative to many single engine and light twin aircraft in today‘s General

Aviation market.

The P68C can truly be considered an ―all round performer‖ which can be used both for

leisure or business and easily adapts to a broad range of today‘s pilot flying needs.

92

Introduction to UAV's

Introduction: UAV stands for unmaned aerial vehicles.These are the vehicles which fly without the pilot

and controlled by the ground controller who is at the ground control station known as

GCS.They are also known as ―DRAWN‖. These are the small aircraft which are used for

Reasearch and Defence prpose by the DRDO, survelliance purpose, aerial photography etc.

Brief description: UAV are the unmaned vehicle which is used for the defence as well as civil purpose.It is also

an aircraft which uses IC engine for its propulsion system. These are very useful where the

propogation of human is not possible, for example in case of any mishap these UAV's are

used for the scearch operation or in case where the temperature of the atmoshphere is very

high which is impossible for human to survive and work, UAV's can be used.For aerial

photography in the areas of the danger where pilot's cannot be used, there also UAV's are

used.If these UAV are destroyed or get damage then there will be no human loss.All the

UAV's have a 60

of freedom for its movement.

Types of UAV's:

There are three types of UAV's classified as:

Fixed wing type

Rotary wing type

Balloon type

Fixed wing type:

These are the most common type of UAV whcih can serve various applications.

Maximum range is 5926 Km.

These are also called as large UAV's

The UAV's whose range is 1500 Km, is specifically known as medium UAV.

The UAV's whose range is just 12 Km, is specifically known as a small UAV, which

is used for the traffic survelliance and by the air police.

These small UAV's are very stable compared to the above two.

These UAV's can fly upto an altitude of 6000 meters from the ground level.

Specifications of fixed wing type UAV's:

In India there are three types of UAV's:

Nishant UAV by DRDO

Rustom UAV by DRDO

Laksh UAV by DRDO.

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Rustom and Laksh UAV's are distinguished by its shape, size and endurance.

Nishant UAV:

It can carry 2 GPS system,2 powerful optical camera's as its payload.

It has two tail, one static and other movable.

The lenght of its fuselage is 18 meter.

It is a programmed UAV which is controlled by a controller from the GCS.

It can cover an approximate area of 50 km2.

It can be used for the survillence purpose for 18 hours in one stretch.

It's maximum take off weight is 5 kg.

Uses of Nishant UAV:

It is used for the wild life conservsation.

It is used for detecting the weather changes in a particular area.

It is used for the border survelliance.

It is used for the survelliance in big organisation whose campus is large

enough for the human survelliance.

The main use of Laksh UAV is that it is meant for the practing purpose targeting from the

ground to air.

Rotary wing type:

This type of UAV have a several advantages of the manueveurabilityand hovering.

They are very unstable so it is very difficult to control it and thus rewuires

applications of reliables control loss.

Balloon type:

This type of UAV are used for the weather changes calculation specifically known as

airship.

These are used where there is an international sports event is organisized.

Components of UAV's:

UAV platform:

It contains airframe.

It can be of any configuration like aircraft.

It should be aerodynamically designed regarding its shape.

Its dead weight should be as low as possible so that it can carry maximum payload.

Propulsion system:

It depends upon the type of the mission and the requirement of the need.

It mainly uses IC engine for it propulsion system.

Flight control system: It is the most important parameter as using this only one can have its control over the

UAV.If the flight control fails then there are no chances of regaining it flight control

back and the UAV is out of control.

Different types of sensors are used for the control surface, gyroscope etc.

Navigational and avoidance systems are also used for the safe flight of the UAV.

94

Payload:

Camera or an optical sensing system is used by the ground controller to locate the

target.

Other payload can be optical cameras, GPS, sensors, radar system etc.

GCS:

GCS stands for the ground control station.

There are avionics flight display available at GCS so that the controller can control

the UAV with the reference of the readings which are being displayed on the screen

of the system.

There is a navigational aid system to control the UAV from the station only.

The position of a UAV can be calculated from the ground station using position

monitoring system.

The system will also have a joystick for the control of pitch, roll and yaw movement

of a UAV.

It also has a system to get various types of the data such as photo, video, of flight

data also at every instant and the data includining the position of its control surface

too from a UAV.

Current applications:

All UAV's are reffered as D3.

D3 means Dull

Dirty

and Dangerous.

Autopilot system of UAV's: It is a micro pilot, MP2028G is the part of the main computer system.

It uses air pressure, gyroscope, GPS to sense for the inertia, speed, altitude etc.

Uses are: Crowd monitoring

Aerial recognissance

Air traffic and security watch

Air to air missile

Battel field managment

Air to ground missile

Crop management

Ground to air missile

Disaster and damage estimation

Fire fighting

Fishery protection

Life raft deployment

Litering on parks and beaches

Marine and mountain search and rescue

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Minerals, oil and gas exploitation

Oil and gas pipe lines

Pollution control of air sampling

Search and rescue operations

Water ways and shiping

Wide area monitoring.

Components of UAV's:

Core:

This is the main autopilot board and all other parts which are installed on the UAV.

AGL:

This is placed above the ground level.

This is ultra sonic altimeter placed at a level of 4.88 meter above the ground level.

It is mandatory for the autonomous take off's and landing.

Micro pilot servo: It is used to send the signal to the control surface which is used to control the pitch,

roll and yaw movement in all the three axis of the rotation.

Micro pilot ANT:

This is the GPS antenna which connects to the main core.

It is mounted on the base of 10 x 10 sq. cm. area board.

Radio modems and micro pilot com board:

It connects the GCS system and the communications to the autopilot via com boards.

Installation: Autopilots components are connected to the GCS system on a single board.

Servos of elevator, throttle, flap, aileron are connected with the GCS system on a single

board which is connected to the com board.

Modes of controlling a UAV:

Stability aqumation system (SAS):

It controls the rolling, pitching, and yawing motion of a UAV.

It is important to engage SAS before operating any other mode.

AP mode:

AP stands dor the autopilot mode.

Autopilot maintains a particular flight parameter and adjust itself with respect to the

atmoshpheric weather conditions.

ATT mode:

In this mode autopilot will maintain a particular flight level or more

specifically, it will maintain the desired altitude.

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Wing leveller mode:

In this mode,the autopilot will maintain the level of wing through out its

flight in order to maintain the lateral as well as longitudinal stability of the

UAV

Turn co-ordinate mode:

In this mode, the autopilot co ordinate a perfect balance between both the

aillerons and a rudder of a UAV for a particular angle of bannking.

Navigation mode:

Same as an aircraft, that is VOR beacons and ILS.

Command mode (CMD):

This mode is very important as this will only give command to ATT mode to

maintain a particular altitude, speed and various other flight parameters.

There are three CMD mode:

Heading hold mode: It will maintain that particular heading.

Altitude hold mode: It will maintain that particular altitude.

Speed hold mode: It will maintain that particular speed.

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Bell 407

Introduction: This is a hellicopter which is manufactured by Bell company which has an engine of turbo

shaft type which is manufactured by Roll's Royce's engine.This is of rotary type of an

aircraft where the main lift generating device is the blades which are of aerofoil shape. It is

of 2+4 TYPE helicopter, means it can carry 2 pilots and 4 passengers.The mechanism of this

is helicopter is very simple and it can be flown only with one pilot too.

Brief description: The helicopter is of rotary type of an aircraft where the lift is generated by the propellers

blades of it which are rotated at very high speed. As a result of this there is a pressure

difference is created between the two surface and it gets its lift.There are two rotars which

are very essential for all the three movements, that is pitch, yaw and roll movement.

The capacity of this helicopter is 413 ponds

The instruments used are the same as that used for an aircraft's system.

The additional instrument is to set the blade angle and its pitch with the engine rpm with the

additional setting of the blade rotation with it.

For the take off and landing part, the engine as well as all the blades are rotated at full rpm.

If the throttle is set at the F mode then all the controlls of pitch movements and the blade

angle setting is done automatically that is the ECU (engine control units) controls the rpm of

an engine.

The rotation of the rear rotar is always rotated in clockwise direction in order to give a net

positive torque so that the cabin is in a stable position.

The speed of helicopter is decided by only using the pitch and the blade angle of all the

propellers.

There is a tube which measures the outside temperature and inside there will be air

conditioning system.

There is an oil instrument pannel which indicates the main engine rpm and the oil pressure

and its temperature.

The front rotar is rotated in anti clockwise direction while the rear rotar rotates in anti

clockwise direction.

There is an anti collision light at the tail.

The important parameter is the ratio of tail rotar to the main rotar which is 4.

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Maintanace of Airbus A320

Introduction: This is an aircraft which is designed and manufactured by the Airbus Engineers in European

companies. The engine which is used in this type is of Turbofan type which have low bsfc

and high efficeiency.The capacity of this aircraft is to carry 210 passengers as it may vary

asper the type of class which is accomodate.This is the capacity of VT-KFX aircraft.

Maximum take-off weight is 77.8 tons. This is an aircraft which is fully computerised.

Brief description: For an aircraft there are various checks which has to be carried out at regular intervals after

the completion of flying hours.There are four types of checks through which an aircraft must

have to pass thruogh it after prescribed flying hours.

The checks are A,B,C,D.

A is carried after every 500 hours of flying.

B is carried after every 1000 hours of flying.

C is carried after every 6000 hours of flying.

D is carried after every 12,000 hours of flying.

In D checks there is replacement of all the aircraft's parts.

For Boeing 737-400 there are almost 2 to 3 millions parts while for A380 there are nearly 8

to 9 millions of parts which are used for the construction of an aircraft.

Inspection of an every aircraft is carried affter every 100 hours of flying.

There are some special inspection which can be carried out at any time and it is independent

of its flying hours.

At TAAL campus there is also another private organisation known as ―Airworks‖ which has

set up its MRO facilities here for Class C check.

So basically comercial aircraft comes at Airworks for the class C check.

Information regarding A320:

Aircraft structure:

The structure is made up of an alluminium alloy which has high strength to weight ratio.

The pressurization is very important for this type of an aircraft which flies at a very high

altitude.If the cabin pressure is set at the mean sea level pressure, than at an alititude of

36000 feet the differential pressure between the cabin pressure and ambient pressure will be

50 psi,which is very high from structure point of view.

If a body has to withstand this diffrentail pressure then the thickness of the body must be

increased so there is increase in dead weight which results in less payload capacity.

In order to increase the payload capacity, the cabin pressure is set at the pressure at 8000 feet

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which gives the differential pressure of only 7 psi, if an aircraaft flying at 36000 feet.

Engine: The engine is made by Roll's Royce company which is of turbofan type.

In this type of an aircraft, there are two engines which are placed under both the wings.

The bypass ratio is 5:1, this means if 5 kg of air moving through the fan above the jet

engine than only 1 kg is passing through the jet engine.

The blade of the fan is made up of titanium alloy which cost around 12 lakhs rupees each.So

if there is a bird hit then the maintainance cost goes high.

If the bird passes through the hard core engine then the whole assembly gets damage and it

is very difficult for an engineer to do maintainance work, which indirectly increase the

maintainance cost.

For high compression ratio, the thickness of the blade placed in the turbine and compressor

section increases, which increase difficulties level of maintainance.

The fan, jet engine, axial compressor, turbine are placed on the same shaft.

80 to 85% of the thrust is mainly due to the fan which bypass it over the jet engine.

The tip is made up of rubber material which vibrates during the motion and does not allow

the ice formation at higher altitude.

The leading edge of engine has anti iceing system in order to maintain the aerodynamical

flow of air through the engine.

The cowling is made in order to cover the whole assembly and to give proper aerodynamic

shape.

The bleed air from the engine compressor is used for the pnuematic system while the ram air

is used for the air conditioning system.

At the time of thrust reversal, the second part of the cowling slides back and there is an

arrangement where the alluminum surface becomes perpendicular to the direction of the

flow of air through the engine and thus the direction of thrust is reversed.

The converging diverging type of nozzle is used to increase the velocity of air passing

through it.

Actually, the velocity of air is very less but as the mass of air intaken is high, which gives

high momentum and this is nothing but the thrust which is received after some time which is

taken by an air to flow through the engine.

There is oil pressure gauge, temperature gauge, fuel pressure gauge,fuel temperature gauge,

turbine pressure gague, turbine temperature gauge, compressure pressure gauge, turbine

temperature gauge etc are pressent on such type of an engine.

The nozzle of a jet engines is inside the duct of the whole assembly. Because of this the

flames comming out from the nozzle will guide and heat up the cool air comming through

the bypass which reduces the nosie pollution.

The engine is mounted on five main parts which are connected to the main wing. This will

take the complete load of the whole engine assembly.Two at back and front while only one

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in the middle. So servicing to this middle point is very difficult.

Control surface: Like a conventional aircraft it has rudder, ailerons, elevator, flaps, trim tabs.Its horizontal tail

is of variable incidence type and such type of combination of elevator and stabalizor is

known as stabilator.

There are seven hing movements for the flap extension from the wing.

There are only three settings available for the flap angle setting, that is 1,2,and 3.

Setting 1 means, flap angle is 100.

Setting 2 means, flap angle is 150 to 20

0.

Setting 3 means, flap angle is 300.

There is leading edge flaps for more lift co-efficient.

There are slots and slats through which the bleed engine air is blown over the wing in order

to delay the separation of flow from its surface.

There are anti-icing valve which will heat up the leading edges and will not allow the

formation of ice over the leading edge. This will maintain the aerodynamic shape of it.

There are three flaps extension from the main wing and only one extension of aileron from it

Fuelling of an aircraft: This is carried only by pressurze system. The feul has to be filled from the lower surface of

wing. It has an integral type of fuel tank within it. In this type of an aircraft, fuel cannot be

filled from the upper surface of the wing as it can be done in boeing type aircraft.

For this purpose, jet A1 type of fuel is used at 50 psi or a pressure of 3.5 bar for refulling an

aircraft.For de-fulleing an aircraft, the maximum pressure is 11 psi or 0.8 bar.

Cargo section: There are two cargo section available at the rear and the front.

The capacity of the rear cargo compartment is 20 tons while the capacity of front cargo is 15

tons.

There are two doors for the rear section and only one for the front section.

All these doors can be operated through hydraullics, pneumatic or manually.

Hydraullic system of an aircraft: There are three types of hydraullic system present in this type of aircraft. They are green,

yellow and blue system. If one fails then there is other one who can take over the charge.

But if it also fails then the third one will come into picture. And if all the three fails then

there is always option for a hand pump.

Green system does not have any separate electrical pump.

Yellow system works at 3000 psi and has an individual electrical pump, which takes over the

charge from green in case if it fails.

Blue system also works at 3000 psi and has an individual electrical pump, which takes over

the charge from yellow in case if it fails.

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Landing gear system: For the extension and retraction of the landing gears, hydraullic preeure is used which is

3000 psi.

Free fall actuators are used which will give a free falling of landing gear assembly only if

there is a jerk of near about 150 to 200 psi.

Antennas: There are in all 11 to 12 antennas which are used for communication, navigation,

identification, search and rescue operations.

External lights of an aircraft: On the port wing there will be red light.

On the star board, there will be green light,

These both lights illuminates at angle of 1400.

On the tail, there will be white light which is known as navigational lights.

This light illuminates at an angle of 1100.

There is anti collision lights at the top and bottom of the fuselage which has an high

intensity and its visibility is upto 3 km and it is red in colour.

All these lights will blink twice for an airbus while only once for boeing aircraft's

For small aircrafts like ATR, one wing light will be stationary and other wing light will be

blinking.

Braking system of an aircraft: In aircraft brake system, only disc brakes are used. In this system there will be odd numbers

of stators and even numbers of rotars.

So there will be 1 rotars in between two stators.

At the time of application, it will leave and catch the tire which will give rise to the friction

which resists its forward motion.

This is done to avoid over heating and to reduce the wear and twar of the system.

Date post:	19-Jan-2015
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