Radar for Dummies Final Draft

WARNING THIS IS NOT A GENUINE FOR DUMMIES EDITION Or PUBLICATION



Featuring:

John Dow1 as “Super Pilot E.E” (Extremely Experienced) Flew almost any thing with wings except Mosquitoes, Flies, Butterflies, and Birds

John Dow 2 as “Super Engineer E.K” (Extremely Knowledgeable) Always wanted to be a Pilot, but Dad and Mom said no (or failed the medical)

Radar Beam and its Energy level legend as “Beam Width”

Angle 4 Angle 3 Angle 2 Angle 1

Thunderstorm as “CB “(the Bad Guy)

Tip1 And Tip2 as “Windshield” after meeting the Bad Guy CB

H2+ O-

H2O as “Water” in liquid and/or solid state

Radar Switch as “ SYSOFF”

Radar Switch as “ SYSON”

Tilt Control as “Manual Tilt”

ECP as “Range”

This is not e genuine For Dummies EDITION Or PUBLICATION, 2

A330 as “SUPERTOY “ flown by Super Pilot E.E who thinks he is handling it very smoothly and very precisely

Flight Computers s “FMGECSECELACPRIMS” flying the SUPERTOY while Super Pilot EE thinks he is handling….

MCDU as “FMS2” used by Super Pilot EE to do everything he cannot do anymore such as navigating , calculating trajectories estimates, and fuel consumption

The scene as “the Sky” where Super Pilot flies SUPERTOY ,convinced that he is handling…But forgot that he was created without wings

Rockwell Collins as ” WXR-2100”

Honeywell as ”RDR 4 B”

Skull as “the result in flying through Radar Shadows”


Featuring: ..................................................................2 Introduction:...............................................................6

Airplanes, thunderstorms, and some tips... .....................................................6 Tip 1.......................................................................................................................6 Tip 2 ......................................................................................................................6 Tip 3 ......................................................................................................................7

First thing first, a little bit of theory ..................................7 How can Radar detect the clouds? ....................................................................7

The radar antenna tilt ......................................................................................8 How thick is the slice? ...................................................................................10

Lets look at the beam (again) ...........................................................................11 Beam width Cross Section Diameter versus Distance ............................11

Tilt Angle, Cloud top ...........................................................................................11 Tilt up .................................................................................................................11 Tilt down ............................................................................................................11

By the way, what is The Gain? ..........................................................................12 The Clouds ............................................................... 13

Where is the water in liquid form in the cloud? ..........................................13 For the Radar, what type of look the cloud has?.........................................13

For the Display how the clouds will look like? ..........................................15 Clouds and reflectivity .......................................................................................15 Reference Thunderstorm ..................................................................................17 What and where is the Bright Band?..............................................................18

Bright Band associated with Thunderstorms ...........................................18 Bright Band associated with Stratiform Clouds ......................................18

Among other stuff Shadows, and attenuations............................................19 Mountains Shadowing......................................................................................19 Cloud shadowing caused by attenuation .....................................................20

The last but not least, the earth curvature .................................................21 Radar Radiation and Children............................................................................22

Let’s apply the Theory to use the WX Radar......................... 23 Tilt Angle, Cloud top, Relative Cloud Height .................................................23

Tilt up .................................................................................................................23 Tilt down ............................................................................................................23

Relative Cloud Height .........................................................................................23 Example: .............................................................................................................23 Let’s acquire a Target.....................................................................................24 Step1...................................................................................................................24 Step2 ..................................................................................................................25 Step3 ..................................................................................................................25

Now that we have a target, what is next? ....................................................26 Which way to go?.............................................................................................26 The Avoidance Procedure ..............................................................................26 ATC Communication .........................................................................................26


Actions to be taken if a revised air traffic control Clearance cannot be obtained .................................................................................................................27

Storms, Shapes any few things to remember ......................... 28 Normal Storm .......................................................................................................28 Storm with specific shapes ...............................................................................28

Avoid any target with a dry intrusion .........................................................29 Avoid any target with a hook or bow shape...............................................29 Avoid any target with protruding "fingers." .............................................30 Avoid any target with an asymmetric colouring and shapes. .................30 Avoid any target with an "arrow shape."....................................................31 Avoid any target with scalloped edges. ......................................................31

Turbulence Mode: ....................................................... 32 Settings to remember................................................... 33 Did we talk about lightning? ............................................ 34 What is This? ........................................................... 35 What is that? ........................................................... 36


Introduction:

Airplanes, thunderstorms, and some tips...

“Thunderstorms are made of unacceptable environmental hazards to aviation." In other words avoid thunderstorms while flying your plane.

To achieve this, use the following tips.

Tip 1

Open your eyes and look out of the window if there are any unusually shaped things with strong flashing lights.

There is

Nothing

I did tip1 it did not work

Tip 2

Look in the weather radar.

There is Nothing

I did tip2 it did not work


Tip 3

Switch the Radar ON and learn how to use it.

First thing first, a little bit of theory

How can Radar detect the clouds? It echoes on WATER in LIQUID state i.e., it Only detects wet precipitations, such as Rainfall, Wet hail, Wet turbulence depending on droplets Size Number and Composition

He is trying to fool me? Liquid or Ice, it is the same molecule… H2O

When water is in its liquid state, the poles of the water molecules (H2+ O-) are able to change orientation, responding to the Radar pulses, thus able to align, and reflect a significant amount of radar energy. Whereas iced water molecules are locked in a random spatial orientation, unable, to change, to respond, to and to reflect radar energy.

If you don’t trust me, remember your micro wave oven, the water boils very quickly, whereas it takes ages to heat up the frozen food, your wife prepared for you before you sent her and the kids for the 2 months summer vacation

COOL the weather Radar is a Wet precipitation detector.

.


How does a Weather Radar Beam look like?

Angle 4 Angle 3 Angle 2 Angle 1

It is cone shaped, with different levels of energy from the center to the edge of the beam. Energy Distribution:

98.4% 99.9% 91.3% 60%

Angle 1+2 is often referred as the weather detection beam width, and/or as the beam width of the antenna.

Angle 1+2 value depends upon the antenna radius: • A 30-inch antenna gives 3.0 degrees, • A 24-inch antenna gives 4.5 degrees • A 12-inch it gives 8.0 degrees.

Angle 3+ 4, forming the outer edge of the cone that will unfortunately produce the unwanted ground clutter.

The radar antenna tilt


So the Radar Tilt is NOT slaved to the Aircraft Pitch…

This is correct; in fact the CENTER of the beam is referenced and maintained to the EARTH’S HORIZON, using ADIRS inputs

So this is why we set manually the Tilt to 4 for Takeoff Climb Descent

Yes it is to display Weather ahead and to detect Wet Wind Shear along your Flight Path

The Radar beam slices the sky, like Darth Vader with its Laser Saber


How thick is the slice?

Well, it is dependant upon the tilt angle and the range selected on the ECP

An angle of 1 degree intercepts a height of 1000 ft at 10 NM. 4000ft at 40 NM 16000 ft at 160 NM

Or = (Distance in NM + “00”) x 3.5

And If you like formulas, get that:

Beam Width (in Degrees) = 70 X Wavelength /Antenna

While the following formula can be used to calculate the approximate beam width (Cross Section) at any range: Beam width (in feet) = Distance in NM X 350

When the Tilt is at Zero it is the center of the beam that is at zero, so I have to consider the beam width.


Lets look at the beam (again)

Beam width Cross Section Diameter versus Distance Distance from Aircraft Diameter of Beam Cross-Section 10 NM 3500 Feet .58 Nautical Miles 20 NM 6900 Feet 1.15 Nautical Miles 40 NM 13800 Feet 2.31 Nautical Miles 80 NM 27700 Feet 4.61 Nautical Miles 160 NM 55400 Feet 9.23 Nautical Miles 320 NM 110800 Feet 18.5 Nautical Miles

Tilt Angle, Cloud top

Tilt up Cloud Top Elevation Angle = tilt angle - ½ beam width

Tilt down Cloud Top Elevation Angle = tilt angle + ½ beam width


By the way, what is The Gain?

The Gain IS NOT amplifying the TX and/or the RX signals, sensitivity, output, input…

The term Antenna Gain describes how much the energy leaving the antenna is focused into a particular direction, ANTENNA GAIN = FOCUSED INTENSITY AVERAGE INTENSITY

So it is like when I am doing the walk around at night, I have to focus my torch light, in order to see better the cockpit Oxygen and the APU fire extinguisher

Absolutely, but remember Manual Gain SHOULD be used for thunderstorm and/or terrain analyses. When the analyse is completed return it to AUTO


The Clouds

Where is the water in liquid form in the cloud?

Where is the water in liquid form?

The water in liquid form is usually below the ISO 0˚C

For the Radar, what type of look the cloud has? This is how a Radar with an electronically scanned

antenna would see the cloud. However with today’s technology the Radar sees only slices of it.


And replaces precipitation fall rate by its corresponding colors

It is obvious that the cloud is bigger than what the Radar sees

Then the Video Integration Processor (Image processor) applies the following rule


For the Display how the clouds will look like?

Finally the Radar Display will show you the 2D horizontal slice of the cloud

Clouds and reflectivity Is the Radar energy totally reflected back by the rain drops?

No, because, as you can imagine each raindrop “scatters” some of the incoming signal into random directions. Some of this “scattered” energy will be returned to the radar. However most of it will simply be lost.


Furthermore, the reflectivity will vary within the cloud. This is due to the water/ice distribution

The bottom of the CB below the freezing level and is composed entirely of water, thus providing the Best reflectivity. DO NOT FLY BELOW the STORMS

The mid part of the storm is composed of a combination of super-cooled water and ice crystals. Reflectivity begins to diminish .

The top of the storm is entirely composed of ice crystals It is almost invisible to radar.

Turbulence Bow Wave is often present above growing storms top, DO NOT OVERFLY STORMS unless you are at least 10000 ft above it


Reference Thunderstorm

In order to be able to calibrate weather radar systems, the industry needed to have a reference thunderstorm. After years of studies, and thunderstorm-size evaluation, they decided that the following storm model would be appropriate:

A sphere with a 3NM Radius, filled with liquid water drops having the same dimension.

Hold on, such a sphere will not fill the Radar Beam beyond 80 NM.

Yes, this is why storms would tend to be green at longer ranges but steadily grow in intensity until they turn red when close to the aircraft, by the way the industry calls it “beam filling”

And this is why you should learn to “calibrate” the Radar, and what follows will help you big time


What and where is the Bright Band?

In fact there are two Bright Bands, one associated with Thunderstorms, and one associated with Stratiform clouds

Bright Band associated with Thunderstorms It is the volume within the bottom of a storm where the beam must be directed in order to achieve a calibrated radar display, remember: where is the water in liquid state?

Bright Band associated with Stratiform Clouds “Bright Band” associated with stratiform rain occurs at or within 3,000 feet below the freezing level. In this region, ice crystals begin to melt and are coated with a layer of water this result in very strong radar returns. This will cause the entire weather picture to turn red (red out) due to the fact that the stratiform rain clouds always cover a large area.


Among other stuff Shadows, and attenuations

Mountains Shadowing

As the Beam cannot go through the mountain there is a black area extending beyond it, we call it mountain shadow, if you have the EGPWS use the PIC mode with the same range to confirm it, or use your chart, and/or have a look at the MORA. But remember that CITIES don’t have shadows

Also, have a look at mountain shadow orientation versus the wind; remember if the wind is at 90˚, with instability (look at your SIGMET chart)… Then look out for standing mountain waves, they can extend for several 100s NM, watch for pitch increase/decrease with IAS increase/decrease, look out for Lenticular and Rotor clouds…


Cloud shadowing caused by attenuation

Some POWERFULL Thunderstorms have a precipitation rate so high that the Radar pulse looses a lot of its strength as it travels through the core of the storm, to the point where a lot of the radar energy is lost; as a result a black area takes plan just behind the thunderstorm.

In any case NEVER FLY THROUGH such Shadow

Regardless of its origin, i.e., mountain or thunderstorm, a Radar shadow is a very serious matter and is to be treated with respect, furthermore as far as cloud shadow is concerned NEVER FLY IN IT


The last but not least, the earth curvature Due to the Earth curvature, the earth surface falls away by approximately 65000 ft at 320 NM (ECP max Range) So, if you are cruising at35000 feet, the earth’s surface is actually 100,000 feet below the aircraft at 320 NM distance.

This is why weather detection at high ranges is not possible, the radar beam will always be above the clouds and massive ground clutter will occur


Radar Radiation and Children

I need to use SYSOFF because I want to have Boys

I need to use SYSON because I want to have Girls

The Maximum Permissible Exposure Level (MPEL) area is illustrated below, and as long as you are outside the area you are protected for Max Exposure, please note that the Cockpit is not in the area, Baby’s sex is more a mother nature story than a Radar Radiation Story.

You can get further details reading FAA Advisory Circular 20-68B This is not e genuine For Dummies EDITION Or PUBLICATION, 22

Let’s apply the Theory to use the WX Radar

Tilt Angle, Cloud top, Relative Cloud Height We need to remember that the top of a cloud it is most likely be made of ice particles; therefore we need to set manual GAIN to MAX in order to compensate for reflectivity loss.

Tilt up Cloud Top Elevation Angle = tilt angle - ½ beam width

Tilt down Cloud Top Elevation Angle = tilt angle + ½ beam width

Relative Cloud Height To compute the Relative Cloud Height, we will use 1 in 60 rule, Relative Cloud Height= Cloud Top Elevation Angle X Range X 6080 60

Example:

Tilt Angle = 3.5˚ Up Beam Width = 8˚ Range= 45 NM Aircraft Flight Level 350 Cloud Top Elevation Angle =3.5˚- 4˚ =-.5˚ Relative Cloud Height = -.5˚ X 45 X 6080 =- 2280 Feet 60 Cloud top = 35000 - 2280 = 32720 Feet


Let’s acquire a Target Considering that the bright band is located between 8000 to 15000 feet, this is where we should target the thunderstorms cells in order to calibrate our radar, scanning the sky in front of us looking for the optimum tilt angle. The bright band is 7000 wide within a thunderstorm 35000 high at 80 NM the beam covers 27700 feet (see table page 10) which is ideal.

Step1 Let’s compute the Tilt angle needed to scan the bright band, considering that we are cruising at FL380 the bright band top will be 23000 feet below, and the bright band bottom will be 31000 feet below. Tilt angle top = bright band top X 60 Range X 6080 Tilt angle bottom = bright band bottom X 60 Range X 6080 Tilt angle top = 23000X60 = 5˚ Tilt angle Bottom = 31000X60 = 6.8˚ 45X6080 45X6080 Lower the tilt angle to the above value accepting ground clutter, bearing in mind that the terrain elevation below the airplane, will interfere. In order to assess it we can use the MORA value displayed on the ND, if it is the case than we will need to use to tilt angle equal to the Top of the Bright Band.


Step2 Adjust the tilt angle upwards until you start to loose the weather target strength, because you are partially scanning the bright band

Step3 Lower the tilt in order to re-maximize the weather target while accepting only ground clutter close to but ahead of the weather target, when this is done you have optimized the tilt.


Now that we have a target, what is next? Next is to avoid it, by flying laterally at least 20 NM away from the active cell, unless we are Cruising a minimum 10000 Feet above it (a simple glance at the tropopause height versus the aircraft Flight level would give you a quick answer)

Which way to go? The best side is the upwind side, since the storm blocks the wind which in terms creates turbulent air downwind

The Avoidance Procedure Using the Offset function of the FMS we can evaluate precisely the lateral deviation required to avoid the weather. Furthermore, it is recommended to use offset function to parallel the Track thus to be at the correct FL versus Quadrant, whereas using heading could put you in the incorrect FL.

ATC Communication As per ICAO Procedure, a rapid response may be obtained by stating "WEATHER DEVIATION REQUIRED" to indicate that priority is desired on the frequency, please note that the pilot still retain the option of initiating the communications using the urgency call "PAN PAN PAN PAN PAN PAN " to alert all listening parties to a special handling condition, which may receive ATC priority for issuance of a clearance or assistance. When communication is established, the pilot shall notify ATC and request clearance to deviate from track, and, when possible, the extent of the deviation expected.


Actions to be taken if a revised air traffic control Clearance cannot be obtained 1) Establish communication with and alert nearby aircraft by

broadcasting, at suitable intervals: flight identification, flight level, aircraft position (including the ATS route designator or the track code) and intentions (including the magnitude of the deviation expected) on the frequency in use, as well as on frequency 121.5 MHz (or, as a backup, the VHF inter-pilot air-to-air frequency 123.45).

2) Watch for conflicting traffic both visually and by reference to ACAS;

3) Turn on all aircraft exterior lights 4) When the aircraft is approximately 19 km (10NM) from track, initiate

a level change based on the following criteria:

Route centre line track

Deviations > 19 km (10 NM)

Level change

EAST 000-179 magnetic

LEFT RIGHT DESCEND 300 ft CLIMB 300 ft

WEST 180-359 magnetic

LEFT RIGHT CLIMB 300 ft DESCEND 300 ft

5) Continue to attempt to contact ATC to obtain a clearance.

6) When returning to track, be at its assigned flight level, when the aircraft is within approximately 19 km (10NM) of centre line.


Storms, Shapes any few things to remember

Normal Storm

Storm with specific shapes


Avoid any target with a dry intrusion

(Dryer air being sucked into the thunderstorm) giving it a V or U shape. There are several reasons for this. Severe thunderstorms have dry air mixing in the middle altitudes which can create an intrusion. Hail rising and descending in a thunderstorm would also appear as a missing area cut-out from the storm.

Avoid any target with a hook or bow shape.

Hook shapes are indicative of rotations taking place within severe thunderstorms. This is a strong clue to ground weather observers that hail and tornadoes are possible.


Avoid any target with protruding "fingers."

Like a hook, a finger shows strong possibilities for tornadoes and hail.

Avoid any target with an asymmetric colouring and shapes.

Remember, severe storms created by wind-shear aloft will tilt to one side. This gives shapes and colourings that are not even or concentric.


Avoid any target with an "arrow shape."

Again, this is indicative of a storm with tilt and the possibility of severe hazardous weather.

Avoid any target with scalloped edges.

Scalloped edges show turbulent motions taking place within the cloud. There is a good chance for hail here also.


Avoid any target with changing shapes. Rapidly growing shapes show rapid motions taking place within the cloud. Turbulence will almost always take place under these conditions.

Avoid any target storm with a few VIP (Colour) Level

1 dots showing nearby. Hail falls many times outside of the thunderstorm. Checking the winds at altitude and correlating it to the side of the storm that hail will fall should help identify that potential hazard.

Turbulence Mode: This mode is used to display area of turbulence within the cloud cells, if any it will be coloured in magenta. On the Radar control panel select TURB on the EFC select 40 NM as the range, adjust the tilt for the new range. Red and Magenta targets should be avoided.


If a higher range is selected, turbulence will be displayed on the first 40 NM, then only weather will be shown beyond 40 NM

Settings to remember • Always Keep a range on one ND higher than the other ND to see

what is coming next

• 80 NM is the Range to use for weather detection • 40 NM is the Range for Turbulence mode

• If Strato-cumulus and Thunderstorm are embedded, than use the

Manual Gain to get ride of the RED OUT generated by the stratiform clouds, by increasing slowly the Gain until the storm cells appears.


Did we talk about lightning? Lightning is associated with thunderstorms, for which the weather Radar has to be used (It has also to be switched “ON” for identification by military Radars) It is ironic, but sometime, that very same Weather Radar will attract lightning. When lightning is observed, it is wise to get the UNRELIABLE AIRSPEED CHECK LIST, simply because in some cases the Radom can be damaged! Although most Airliners are designed to sustain lightning strikes, lightning strikes are hazardous. But before it strikes, here is what you will experience:

1. Static on the VHF 2. A strong Ozone Odor (O3 is always present in highly ionized

environment) 3. A beautiful Electric Bleu static discharge on the wind screen 4. A very high increasing pitch tone on the VFH

And when the pitch is at its highest LIGHTNING STRIKES. As you did not leave the area at the first signs, and consequently got strike by lightning, log it and fill an ASR.


What is This?

This is a picture taken by a First Officer during a flight in the Far East; we can see a part of the Typhoon they found themselves into simply because the Radar was fully dimmed on both NDs And someone did not look at the Sigmet This is not e genuine For Dummies EDITION Or PUBLICATION, 35

What is that?

Happy Landing

No it is not cosmic radiation No it is not a Radar defect No it is not a Display defect No it is not a Laser Beam No it is not a UFO It is a Radar Jamming exercise conducted by the military at your expenses.

HAPPY LANDING


Date post:	12-Mar-2015
Category:	Documents
Upload:	titiyou
View:	636 times
Download:	1 times

Radar for Dummies Final Draft

Documents