LECTURE 2 COMPOSITION OF AIRCRAFT WEIGHT MASS (WEIGHT) &
BALANCE 1 MBC 3204 - SIR ARIFF AMC
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WEIGHT DEFINITION Weight is the force that results from the
acceleration by gravity on the mass of an object. W = mg In modern
scientific usage, weight and mass are fundamentally different
quantities. Mass is an intrinsic property of matter, whereas weight
is a force that results from the action of gravity on matter: it
measures how strongly the force of gravity pulls on that matter. 2
MBC 3204 - SIR ARIFF AMC
Slide 3
Continue.. MBC 3204 - SIR ARIFF AMC 3 However, in most
practical everyday situations the word "weight" is used when,
strictly, "mass" is meant. For example, most people would say that
an object "weighs one kilogram", even though the kilogram is a unit
of mass. weight will give us more stability
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MBC 3204 - SIR ARIFF AMC 4 Therefore in our discussion later,
please KNOW that WEIGHT is a MASS of aircraft.
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Continue.. MBC 3204 - SIR ARIFF AMC 5 The lift generated by the
airfoils of the aircraft must be able to overcome the weight. Why?
Less weight will give us better performance More weight will give
us more stability Excessive weight will cause the aircraft
crash.
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TIME TO THINK!! MBC 3204 - SIR ARIFF AMC 6 Do you agree with
all the facts given?? Give any examples to proves this fact. You
may relate it with anything in your life. Not necessarily related
with aviation. THINK OUT OF THE BOX!
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WEIGHT CONTROL MBC 3204 - SIR ARIFF AMC 7 When an aircraft is
designed, it is made as light as the required structural strength
will allow, and the wings or rotors are designed to support the
maximum allowable weight. Weight is a critical factor for an
aircraft. Excessive weight reduces the efficiency of an aircraft
and the safety margin available if an emergency condition should
arise.
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MBC 3204 - SIR ARIFF AMC 8 COMPOSITION OF AIRCRAFT WEIGHT
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OVERVIEW MBC 3204 - SIR ARIFF AMC 9 All aircraft have a
specified maximum mass. This limit must be respected, whether the
aircraft is a micro-light or a Boeing 747 or an Airbus A380.
Attempting to fly an overloaded/overweight aircraft can cause
various effects (Performance and stability control)
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MBC 3204 - SIR ARIFF AMC 10 To ensure aircraft can fly safely,
limitation are set by the design engineer. Maximum Take-Off Weight
(MTOW): The maximum permissible weight to conduct a takeoff.
Maximum Landing Weight (MLW): The maximum permissible weight to
conduct a landing. Maximum Zero Fuel Weight (MZFW): The maximum
weight of an aircraft which its structural limits would allow.
Slide 11
MBC 3204 - SIR ARIFF AMC 11 Maximum Takeoff Weight (MTOW) MTOW
of an aircraft is the maximum weight at which the pilot of the
aircraft is allowed to attempt to take off. It is the heaviest
weight which should be limited in order to ensure the aircraft can
fly safely during take-off. At its MTOW an aircraft complies with
all the structural and performance requirements. The MTOW of an
aircraft is fixed.
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Continue.. MBC 3204 - SIR ARIFF AMC 12 It does not vary with
altitude or air temperature or the length of the runway to be used
for takeoff or landing. MTOW is usually specified in units of
kilograms or pounds. What is the difference between kilogram (kg)
and pound (lb)??
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Maximum Landing Weight (MLW) MBC 3204 - SIR ARIFF AMC 13 The
maximum permissible weight to conduct a landing. What will happen
if the aircraft weight during landing is greater than MLW? What is
the possibility?
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MBC 3204 - SIR ARIFF AMC 14 The Zero Fuel Weight (ZFW) of an
airplane is the total weight of the airplane and all its contents,
minus the total weight of the fuel on board. When an airplane is
being loaded with crew, passengers, baggage and freight it is most
important to ensure that the Zero Fuel Weight does not exceed the
Maximum Zero Fuel Weight. Designers of airplanes can optimize the
MTOW and prevent overloading in the fuselage by specifying a MZFW.
This is usually done for large airplanes. Most small airplanes do
not have a MZFW specified among their limitations. Maximum
Zero-Fuel Weight (MZFW)
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Example.. MBC 3204 - SIR ARIFF AMC 15 For example, if an
airplane is flying at a weight of 5,000 lb and the weight of fuel
on board is 500 lb, the Zero Fuel Weight is 4,500 lb. Some time
later, after 100 lb of fuel has been consumed by the engines, the
total weight of the airplane is 4,900 lb and the weight of fuel is
400 lb. What is the Zero Fuel Weight?
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All Up Weight (AUW) The total weight of the aircraft including
of all items at any specific time. During take off All up weight
(AUW) must not exceed the Maximum Take Off Weight (MTOW) For
Take-Off: AUW/TOW MTOW 16 MBC 3204 - SIR ARIFF AMC
Slide 17
Continue.. MBC 3204 - SIR ARIFF AMC 17 During landing All up
weight (AUW) must not exceed the Maximum Landing Weight (MLW) For
Landing: AUW/LW MLW Total ZFW also must not exceed the Maximum Zero
Fuel Weight (MZFW). ZFW MZFW
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IMPORTANT MBC 3204 - SIR ARIFF AMC 18 For Take-Off: AUW/TOW
MTOW For Landing: AUW/LW MLW
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All Up Weight (AUW) Where, PAYLOAD = Passengers & Cargo
FUEL = Flight Fuel + Reserve Fuel DOW = Dry Operating Weight DOW
also known as Aircraft Prepared for Service (APS) AUW = DOW +
PAYLOAD + FUEL 19 MBC 3204 - SIR ARIFF AMC
Slide 20
Dry Operating Weight (DOW) @ APS Basic Weight + Crew &
Baggage Basic Weight It consists of Empty Weight + Basic Equipment
Weight. Empty Weight Weight of airframe, engines and standard
structures. Basic Equipment Weight Weight of common installations
inside the airplane. 20 MBC 3204 - SIR ARIFF AMC
Slide 21
Payload The weight of all persons and items of load carried in
an aircraft for which a fare or charge is being paid. PAYLOAD =
Passengers + Cargo 21 MBC 3204 - SIR ARIFF AMC
Slide 22
22 Fuel FUEL = Flight Fuel + Reserve Fuel Flight Fuel = It is
the weight of the fuel required for and burnt during a flight. With
the given flight distance and mean airspeed, Flight Fuel can be
calculated as follows: Flight Fuel = Fuel Flow Flight Time Where,
Flight time= Distance / Mean Airspeed
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All Up Weight (AUW) However, AUW is not same during Take-off
and landing. Why? During TAKE-OFF: AUW during Take-Off=DOW +
PAYLOAD + (Flight Fuel + Reserve Fuel) During LANDING: AUW during
Landing =DOW + PAYLOAD + Reserve Fuel Note that, as a flight
progresses, flight fuel is consumed and finished. 23 MBC 3204 - SIR
ARIFF AMC