7.16 Aircraft Weight & Balance

Question 2

Why are the weight and balance of an aircraft important?

Answer 2

They are crucial for safety and efficiency in operation.

An aircraft without good balance can exhibit poor manoeuvrability, making it difficult to fly.

Question 3

What is the impact of an aircraft’s weight on its construction and operation?

Answer 3

Weight affects the design, materials used, and performance characteristics of the aircraft.

Question 4

Why must weight be evenly distributed in an aircraft?

Answer 4

To conform to specified centre of gravity limits for safe flight.

Question 5

What does ‘Maximum Weight’ refer to in aviation?

Answer 5

‘Maximum Weight’ refers to the maximum allowable weight of an aircraft, which includes:
* Maximum Takeoff Weight (MTOW)
* Maximum Landing Weight (MLW)
* Maximum Zero Fuel Weight (MZFW)

Question 6

What are the two vital elements in weight and balance considerations of an aircraft?

Answer 6

Weight and Centre of Gravity (CG).

Question 7

What can be determined using the datum line?

Answer 7

The location of various weights and their moments in relation to the aircraft’s CG.

Question 8

Define Mean Aerodynamic Chord (MAC).

Answer 8

MAC is a reference used to determine the centre of gravity location of an aircraft in relation to its aerodynamic properties.

Question 9

What is the significance of environmental weight limits for an aircraft?

Answer 9

Environmental weight limits influence both aircraft structure and performance.

Question 10

What information does a Type Certificate Data Sheet contain?

Answer 10

It contains the specifications and weight and balance report related to aircraft weighing procedures.

Question 11

What factors determine the maximum allowable weight of an aircraft?

Answer 11

Surface area, wing shape, and lift generated at safe airspeed.

Question 12

What is the consequence of improper loading of an aircraft?

Answer 12

It reduces efficiency, affecting manoeuvrability, rate of climb, speed, and fuel consumption.

Question 13

What happens if an aircraft is nose heavy?

Answer 13

Higher forces are needed at the tail to maintain level flight, increasing drag and fuel consumption.

Question 14

What is meant by ‘Centre of Gravity’ (CG)?

Answer 14

The point where the total weight of the aircraft is assumed to be concentrated.

Question 15

What is the difference between permanent and temporary ballast?

Answer 15

Permanent ballast is installed and not removable; temporary ballast is for specific flight conditions.

Question 16

What happens if an aircraft is overloaded?

Answer 16

It can lead to longer take-off runs, reduced climb rates, lower service ceilings, and decreased manoeuvrability.

Question 17

What is the arm in relation to an aircraft’s weight and balance?

Answer 17

The horizontal distance from the datum to a specific part of the aircraft, measured in inches.

Question 18

What is a moment in terms of aircraft weight and balance?

Answer 18

A moment is the product of weight multiplied by its arm, indicating torque values.

Question 19

What does a positive moment indicate?

Answer 19

Weight being added aft of the datum or weight being removed forward of the datum.

Question 20

What is the relationship between CG and aircraft stability?

Answer 20

The CG must be slightly ahead of the centre of lift to ensure longitudinal stability.

Question 21

What should the flight crew consider regarding aircraft weight and performance?

Answer 21

They must check performance charts to ensure safe operation under current weight conditions.

Question 22

What are the consequences of losing an aircraft’s weight and balance report?

Answer 22

The aircraft must be weighed again, and a new report generated.

Question 23

Fill in the blank: The horizontal distance from the datum is called the _______.

Answer 23

Arm.

Question 24

True or False: An aircraft’s CG can be located outside the specified limits for safe flight.

Answer 24

False.

Question 25

What is the Centre of Gravity (CG) in an aircraft?

Answer 25

The point along an aircraft's longitudinal axis at which an aircraft's weight is said to be concentrated.

Question 26

How does the position of the CG affect longitudinal stability?

Answer 26

Longitudinal stability is maintained by ensuring the CG is slightly ahead of the centre of lift.

Question 27

What happens if the CG is too far aft?

Answer 27

The aircraft becomes unstable and difficult to recover in the event of a stall or spin.

Question 28

What is the effect of a forward CG on the aircraft's performance?

Answer 28

Increased tail load is required, causing higher drag and potentially insufficient elevator authority.

Question 29

What is the consequence of a laterally unbalanced condition in an aircraft?

Answer 29

It can cause adverse effects, requiring correction with aileron trim tabs.

Question 30

What is the significance of the datum in CG calculations?

Answer 30

The datum is a predetermined reference point from which CG is measured.

Question 31

Fill in the blank: The CG is calculated by dividing the total moment by the total _______.

Answer 31

weight.

Question 32

What is the Mean Aerodynamic Chord (MAC)?

Answer 32

The chord drawn through the geographic centre of the plan area of the wing.

Question 33

True or False: The allowable CG range is expressed in percentages of the MAC.

Answer 33

True.

Question 34

What are the two critical weights for aircraft operations?

Answer 34

* Maximum Take-off Weight (MTW) * Maximum Landing Weight (MLW)

Question 35

What is the maximum zero fuel weight?

Answer 35

The approved maximum weight of an aircraft without fuel, including the aircraft and all carried items.

Question 36

What is the standard mean weight for male passengers on larger aircraft?

Answer 36

84.6 kilograms (186.5 pounds).

Question 37

What document contains detailed specifications for an aircraft's type design?

Answer 37

Type Certificate Data Sheet (TCDS).

Question 38

What is the purpose of the TCDS?

Answer 38

It provides weight and balance information and specifications required for type certification.

Question 39

What must be included when determining the actual mass of passengers?

Answer 39

Passengers' personal belongings and hand baggage.

Question 40

What is the minimum mass for hand baggage according to regulations?

Answer 40

6 kilograms (13 pounds).

Question 41

How is the CG expressed in relation to the MAC?

Answer 41

As a percentage of the Mean Aerodynamic Chord (MAC).

Question 42

What is the impact of fuel scheduling in swept wing aircraft?

Answer 42

It is critical due to fuel imbalances affecting the CG position.

Question 43

How is the CG determined in a beam with weights?

Answer 43

By measuring the arm of each weight, calculating moments, and dividing total moments by total weight.

Question 44

What is the maximum ramp or taxi weight?

Answer 44

The maximum weight approved for ground manoeuvres, including start, taxi, and engine run-up fuel.

Question 45

What happens if an aircraft operates with a CG outside of its range?

Answer 45

Operation is prohibited.

Question 46

What is the first step in preparing an aircraft for weighing?

Answer 46

Follow the conditions detailed in the Aircraft Maintenance Manual Chapter 8

Question 47

What environment is ideal for weighing an aircraft?

Answer 47

Inside a closed hangar on a level floor

Question 48

What must be done to the aircraft before weighing to ensure accurate results?

Answer 48

Allow the aircraft to acclimatise for several hours

Question 49

What is the significance of taking multiple readings at each reaction point?

Answer 49

To obtain a reliable average figure

Question 50

What position must the aircraft be in to obtain consistent results during weighing?

Answer 50

In the rigged or jigged position with the longitudinal axis parallel to the floor

Question 51

True or False: Some small aircraft may experience a negative load on the tail when in the rigged position.

Answer 51

True

Question 52

What should be done if a small aircraft has a negative load on the tail?

Answer 52

Use a spring balance anchored to the ground to measure the negative reaction

Question 53

What must be included when determining an aircraft’s empty weight?

Answer 53

Only the weight of residual (unusable) fuel

Question 54

Fill in the blank: The aircraft must be weighed with _______ to ensure only residual fuel is accounted for.

Answer 54

no fuel in the aircraft tanks or fuel lines

Question 55

What is the purpose of a hydrometer in the context of aircraft weighing?

Answer 55

To determine the weight of each gallon of fuel

Question 56

What must be checked regarding the engine oil before weighing an aircraft certified since 1978?

Answer 56

The engine oil level must be checked, and the oil system must be serviced if it is less than full

Question 57

What fluids must be filled or drained according to manufacturer instructions before weighing?

Answer 57

Hydraulic reservoirs must be filled; drinking water and lavatory tanks must be drained

Question 58

How should the aircraft be positioned when weighing?

Answer 58

In its level flight attitude

Question 59

What tools can be used to ensure the aircraft is level during weighing?

Answer 59

Plumb line, spirit level, built-in levelling indicator

Question 60

What is the purpose of stress plates during jacking?

Answer 60

To prevent damage under the jack pads

Question 61

What is the Aircraft On-board Weight and Balance System (OBWBS)?

Answer 61

A system that incorporates electronic load cells to weigh the aircraft while on the ground

Question 62

What must be adhered to when calculating a weight and balance record?

Answer 62

Certain procedures to ensure the report's accuracy

Question 63

List three sources of information for weight and balance changes.

Answer 63

* Type Certificate Data Sheet (TCDS) * Aircraft Operation Manual (AOM) * Aircraft Maintenance Manual (AMM)

Question 64

True or False: Minor equipment changes do not require a weight and balance check.

Answer 64

True

Question 65

What happens when major parts or equipment are added or removed from an aircraft?

Answer 65

A weighing procedure must be conducted

Question 66

What must always reflect the aircraft's status?

Answer 66

The aircraft’s permanent weight and balance records

Question 67

What is the recommended environment for weighing an aircraft?

Answer 67

Inside a closed hangar or on firm, level ground with minimal wind ## Footnote The aircraft should be positioned several hours before weighing to achieve an even temperature.

Question 68

What must be inspected and calibrated before weighing an aircraft?

Answer 68

All precision measurement equipment ## Footnote Errors in measurement equipment can adversely affect the aircraft.

Question 69

List the necessary equipment for weighing an aircraft.

Answer 69

* Scales * Hoisting equipment * Jacks * Levelling equipment * Blocks, chocks, or sandbags * Straightedge, spirit level, plumb bobs, chalk line, measuring tape

Question 70

What are the three types of scales typically used to weigh an aircraft?

Answer 70

* Beam scales * Platform scales (mechanical & electronic) * Load cells (electronic)

Question 71

Describe how beam scales function.

Answer 71

A bar rises when weight is applied; a sliding weight is adjusted until centered ## Footnote Used for very small and light aircraft.

Question 72

How does a mechanical platform scale work?

Answer 72

It uses springs that compress when weight is applied, causing a wheel to display the weight ## Footnote Limited to small and light aircraft due to accuracy.

Question 73

What is the preferred method for weighing large aircraft?

Answer 73

Electronic platform scale ## Footnote The aircraft is towed or rolled onto the scales and requires chocks to prevent movement.

Question 74

Explain the function of load cells in aircraft weighing.

Answer 74

They sense weight changes and generate electrical signals to display weight ## Footnote Each load cell is connected to a display unit.

Question 75

What is the advantage of using load cells on jacks for weighing?

Answer 75

Allows the engineer to level the aircraft easily ## Footnote Adjusting the jacks can achieve a flight-level attitude.

Question 76

How is a spirit level used in aircraft weighing?

Answer 76

It indicates level condition by centering a bubble between two lines ## Footnote Commonly placed in the nose or main landing gear bay of the aircraft.

Question 77

What is the purpose of a plumb bob in the weighing process?

Answer 77

To provide a reference for the aircraft's attitude by hanging vertically ## Footnote Used in conjunction with a spirit level.

Question 78

What should be done with the readings after weighing an aircraft?

Answer 78

They must be compared with the weight and centre of gravity schedule and TCDS ## Footnote TCDS provides essential weight and balance information.

Question 79

What happens if the weight check readings are outside the TCDS limits?

Answer 79

The aircraft must be checked again for compliance with the Weight and Centre of Gravity Schedule ## Footnote Discrepancies must be rectified before re-weighing.

Question 80

Fill in the blank: An aircraft must be in a _______ attitude when weighed.

Answer 80

[flight level]

Question 81

True or False: It is acceptable to weigh an aircraft in windy and moist conditions.

Answer 81

False