I85PREP
⌘ K
EASA ATPL021 aircraft general knowledge foundations study materials
EASA ATPL021 aircraft general knowledge foundations study resources

EASA ATPL021 aircraft general knowledge foundations practice questions

One question at a time. Build your EASA ATPL021 aircraft general knowledge foundations understanding.

First 50 of 190 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Airframe, controls and landing gear

A structure designed so that, after the failure of a single principal structural member, the remaining structure can carry the limit load without catastrophic failure, is described as:

  1. Safe-life
  2. Damage-tolerant
  3. Fail-safe Correct answer.
  4. Stiffness-critical

Explanation

A fail-safe structure has multiple or redundant load paths so that after the failure of one principal member, the remaining structure still carries limit load until the damage is detected and repaired.

Question 2Airframe, controls and landing gear

The limit load of an aircraft structure is defined as:

  1. The load at which the structure fails completely
  2. The maximum load expected in normal service operation Correct answer.
  3. The limit load multiplied by the safety factor
  4. The load that produces 50% permanent deformation

Explanation

Limit load is the maximum load anticipated in normal operation; the structure must withstand it without detrimental permanent deformation. Ultimate load (limit x 1.5 safety factor) is the load it must carry for at least 3 seconds without failure.

Question 3Airframe, controls and landing gear

In a semi-monocoque fuselage construction, the primary purpose of the longerons and stringers is to:

  1. Carry torsional loads only
  2. Provide the aerodynamic skin shape only
  3. Carry pressurisation hoop stress
  4. Carry bending and longitudinal (axial) loads Correct answer.

Explanation

In a semi-monocoque structure the stringers and longerons carry the longitudinal bending and axial loads, the frames maintain shape, and the skin carries shear and pressurisation hoop loads.

Question 4Airframe, controls and landing gear

Aircraft fatigue life is most directly affected by:

  1. Steady cruise loads only
  2. The number and magnitude of cyclic (fluctuating) loads Correct answer.
  3. The static ultimate load applied once
  4. Outside air temperature during cruise

Explanation

Fatigue is the progressive cracking caused by repeated cyclic loading well below the static strength; both the number of cycles and their amplitude determine fatigue life. Pressurisation cycles are a major contributor for the fuselage.

Question 5Airframe, controls and landing gear

An anti-skid braking system protects against a locked wheel by:

  1. Increasing brake pressure continuously until the wheel stops
  2. Applying full brake pressure only on the upwind wheel
  3. Disabling the brakes above 100 kt
  4. Sensing impending wheel lock from wheel-speed deceleration and momentarily releasing brake pressure Correct answer.

Explanation

Anti-skid (anti-lock) systems monitor wheel-speed deceleration; when a wheel is about to skid (decelerating too rapidly relative to ground speed), pressure to that brake is momentarily released to restore rotation, maximising braking near the optimum slip ratio.

Question 6Airframe, controls and landing gear

A fusible plug fitted in a wheel hub is designed to:

  1. Indicate tyre pressure electronically
  2. Lock the wheel during parking
  3. Melt and deflate the tyre if the wheel/brake overheats, preventing a burst Correct answer.
  4. Detect a skidding wheel

Explanation

Thermal (fusible) plugs are made of a low-melting-point alloy; if brake heat raises the wheel temperature excessively, the plug melts and releases tyre pressure in a controlled way, preventing an explosive tyre burst.

Question 7Airframe, controls and landing gear

During landing gear extension, the device that ensures the doors and the gear leg operate in the correct order is a:

  1. Pressure relief valve
  2. Sequence valve Correct answer.
  3. Shuttle valve
  4. Thermal relief valve

Explanation

A sequence valve allows hydraulic flow to the next actuator only after the previous operation is complete, ensuring, for example, that gear doors open before the leg extends and close afterwards in the correct order.

Question 8Airframe, controls and landing gear

The oleo-pneumatic shock strut absorbs landing loads by:

  1. Compressing a steel coil spring only
  2. Deforming a rubber block
  3. Forcing oil through a metering orifice while compressing a gas (nitrogen) charge Correct answer.
  4. Bleeding air through the tyre valve

Explanation

An oleo-pneumatic strut forces hydraulic oil through a metering orifice to damp the impact (converting energy to heat) while compressing a nitrogen gas charge that acts as the spring; this combination both absorbs and dissipates landing energy.

Question 9Airframe, controls and landing gear

On a conventional aircraft, the primary flight controls are the:

  1. Flaps, slats and spoilers
  2. Trim tabs and servo tabs
  3. Speedbrakes and air brakes
  4. Ailerons, elevator and rudder Correct answer.

Explanation

Primary flight controls control the aircraft about its three axes: ailerons (roll), elevator (pitch) and rudder (yaw). Secondary controls (flaps, slats, spoilers, trim, speedbrakes) augment or assist these.

Question 10Airframe, controls and landing gear

In a fly-by-wire flight control system, pilot inputs are:

  1. Converted to electrical signals processed by flight control computers that command the surface actuators Correct answer.
  2. Transmitted by steel cables directly to the surfaces
  3. Sent pneumatically to bellows at each surface
  4. Used only as a backup to the autopilot

Explanation

In fly-by-wire, sidestick/control-column movements become electrical signals that flight control computers process (applying flight-envelope protections and control laws) before commanding the hydraulic or electric surface actuators.

Question 11Airframe, controls and landing gear

A control surface mass balance is fitted primarily to:

  1. Move the surface centre of gravity forward to prevent flutter Correct answer.
  2. Reduce the control surface weight
  3. Increase the surface area
  4. Provide aerodynamic trim

Explanation

Mass balancing places weight ahead of the hinge line to move the surface centre of gravity forward (toward or onto the hinge), preventing inertial coupling with structural bending that can cause flutter.

Question 12Airframe, controls and landing gear

Spoilers used as ground spoilers (lift dumpers) on landing act to:

  1. Increase lift to allow a smoother touchdown
  2. Provide reverse thrust
  3. Destroy lift so that weight transfers to the wheels, improving braking effectiveness Correct answer.
  4. Steer the nosewheel

Explanation

On touchdown, ground spoilers deploy to dump (spoil) the wing lift, transferring aircraft weight onto the wheels; this increases the normal force on the tyres so the wheel brakes can develop much more retarding force.

Question 13Airframe, controls and landing gear

Trailing-edge flaps are extended primarily to:

  1. Increase the wing camber and lift coefficient, lowering the stall speed for take-off and landing Correct answer.
  2. Reduce drag at high speed
  3. Provide roll control
  4. Increase the maximum operating Mach number

Explanation

Extending flaps increases wing camber (and, on Fowler flaps, area), raising the maximum lift coefficient and lowering the stall speed; this allows slower, steeper approaches and shorter take-off/landing distances at the cost of extra drag.

Question 14Airframe, controls and landing gear

A trimmable horizontal stabiliser (THS) provides pitch trim by:

  1. Moving a small tab on the elevator only
  2. Varying the incidence angle of the whole horizontal stabiliser Correct answer.
  3. Deflecting the rudder
  4. Changing the wing flap setting

Explanation

A THS trims the aircraft in pitch by changing the incidence of the entire horizontal stabiliser, providing a powerful, low-drag means of trimming across a wide speed and centre-of-gravity range, with the elevator used for manoeuvring.

Question 15Airframe, controls and landing gear

Nosewheel steering on a large transport aircraft is normally accomplished by:

  1. Differential engine thrust only
  2. The rudder aerodynamic force on the ground
  3. Castoring of the nosewheel only
  4. Hydraulic actuators commanded by a tiller and/or the rudder pedals Correct answer.

Explanation

Nosewheel steering uses hydraulic steering actuators commanded by a hand tiller for large angles (taxi turns) and the rudder pedals for small angles (take-off/landing); differential braking and thrust assist but are not the primary steering means.

Question 16Airframe, controls and landing gear

A multi-disc carbon brake assembly on a transport aircraft generates braking force by:

  1. Magnetic eddy currents
  2. Reversing wheel rotation electrically
  3. Inflating a bladder against the tyre
  4. Pressing rotating discs (rotors) against stationary discs (stators) to convert kinetic energy into heat by friction Correct answer.

Explanation

Hydraulic pistons clamp a stack of alternating rotating discs (keyed to the wheel) and stationary discs (keyed to the axle); friction between them converts the aircraft's kinetic energy into heat, decelerating the wheel. Carbon brakes tolerate very high temperatures and save weight.

Question 17Airframe, controls and landing gear

Aluminium alloys are widely used in airframe construction primarily because they offer:

  1. The highest possible operating temperature of any material
  2. Immunity to fatigue cracking
  3. A good strength-to-weight ratio, are relatively easy to form and resist corrosion when treated Correct answer.
  4. The lowest cost of any structural material

Explanation

Aluminium alloys provide a favourable strength-to-weight ratio, are readily formed and machined, and resist corrosion when alloyed, anodised or clad; this combination made them the traditional primary airframe material before the growth of composites.

Question 18Airframe, controls and landing gear

Composite materials such as carbon-fibre-reinforced plastic are increasingly used in airframes because they:

  1. Conduct electricity better than aluminium
  2. Offer high strength and stiffness at low weight, with no metal-type fatigue corrosion, but need special lightning protection and inspection Correct answer.
  3. Are completely immune to all damage
  4. Are cheaper and easier to repair than aluminium in every case

Explanation

Carbon composites give very high strength and stiffness for low weight and do not corrode or fatigue like metals, but they conduct electricity poorly (needing embedded mesh for lightning protection) and can hide internal delamination, requiring specialised inspection and repair.

Question 19Airframe, controls and landing gear

A damage-tolerant structure relies on which principle to remain safe in service?

  1. Replacing parts at fixed intervals regardless of condition
  2. Assuming cracks may exist and using scheduled inspections to find and act on them before they grow critical Correct answer.
  3. Building every part so strong that cracks never start
  4. Operating below limit load at all times

Explanation

Damage tolerance accepts that flaws and cracks can exist; the structure is designed so cracks grow slowly and remain detectable, and a programme of scheduled inspections ensures damage is found and repaired before it reaches a critical size.

Question 20Airframe, controls and landing gear

The angle of attack vane (or probe) provides information that is critical for the operation of the:

  1. Stall warning and protection system Correct answer.
  2. Cabin pressurisation controller
  3. Fuel quantity indicating system
  4. Engine oil cooler

Explanation

Angle-of-attack sensors feed the stall warning and stall protection systems (e.g. stick shaker, alpha protections in fly-by-wire); the wing stalls at a critical angle of attack, so AoA is the key parameter for stall protection.

Question 21Airframe, controls and landing gear

A stick shaker fitted to the control column is part of the:

  1. Autopilot disconnect system
  2. Trim runaway protection
  3. Landing gear warning
  4. Stall warning system, vibrating the column to warn of an approaching stall Correct answer.

Explanation

The stick shaker is a stall warning device that vibrates the control column as the aircraft approaches the stall angle of attack, giving the crew a clear tactile and aural warning before the aerodynamic stall, often coupled with a stick pusher on some types.

Question 22Airframe, controls and landing gear

Leading-edge slats deploy to delay the stall by:

  1. Reducing the wing area
  2. Increasing the wing sweep
  3. Acting as air brakes
  4. Re-energising the boundary layer and allowing the wing to reach a higher angle of attack before stalling Correct answer.

Explanation

Slats form a slot that directs high-energy air over the upper wing surface, re-energising the boundary layer; this delays flow separation, raising the maximum lift coefficient and the stalling angle of attack for take-off and landing.

Question 23Airframe, controls and landing gear

On a fly-by-wire aircraft, the term 'control law' refers to:

  1. A legal regulation on who may fly the aircraft
  2. The maximum number of flight hours per pilot
  3. The set of computer rules that translate pilot inputs into surface commands, including flight-envelope protections in the normal law Correct answer.
  4. The procedure for filing a flight plan

Explanation

Control laws are the algorithms by which the flight control computers convert sidestick/column inputs into surface deflections; in normal law they typically provide load-factor demand and envelope protections (against overspeed, stall, excessive bank/pitch), reverting to alternate or direct laws after certain failures.

Question 24Airframe, controls and landing gear

A landing gear ground/air sensing (squat) switch on the main gear is used to:

  1. Measure tyre pressure
  2. Steer the nosewheel
  3. Charge the brake accumulator
  4. Tell aircraft systems whether the aircraft is on the ground or airborne so that functions like ground spoilers and pressurisation logic operate correctly Correct answer.

Explanation

The squat (weight-on-wheels) switch senses oleo compression to give a ground/air signal; many systems use it, for example to arm ground spoilers and thrust reverse on the ground, inhibit certain warnings, and control pressurisation and configuration logic.

Question 25Hydraulic, pneumatic and electrical power

In a hydraulic system, the component that converts hydraulic pressure into linear mechanical motion to move a flight control or landing gear is the:

  1. Accumulator
  2. Actuator (jack) Correct answer.
  3. Reservoir
  4. Filter

Explanation

An actuator (hydraulic jack) converts fluid pressure into linear (or rotary) mechanical movement, driving services such as flight controls, landing gear and flaps.

Question 26Hydraulic, pneumatic and electrical power

The main purpose of a hydraulic accumulator is to:

  1. Cool the hydraulic fluid
  2. Remove air from the fluid
  3. Store fluid under pressure, dampen pressure surges and provide an emergency reserve Correct answer.
  4. Indicate fluid quantity in the reservoir

Explanation

An accumulator stores hydraulic fluid under pressure (against a gas charge, typically nitrogen), dampens pressure pulsations and surges from the pump, and can supply a short-term emergency reserve of pressurised fluid.

Question 27Hydraulic, pneumatic and electrical power

Which type of hydraulic fluid is most commonly used in large transport aircraft because of its fire resistance?

  1. Mineral-based (red)
  2. Vegetable-based (blue)
  3. Phosphate-ester synthetic (e.g. Skydrol) Correct answer.
  4. Silicone-based

Explanation

Large transport aircraft use phosphate-ester synthetic fluids (such as Skydrol) chiefly for their fire resistance and high-temperature stability. They are corrosive to paint and skin, so handling precautions are required.

Question 28Hydraulic, pneumatic and electrical power

The main source of bleed air for air conditioning and pressurisation on a typical jet transport (non-bleedless design) is:

  1. Ram air inlets only
  2. Compressor stages of the engines (and the APU on the ground) Correct answer.
  3. Electric compressors driven by the generators
  4. The exhaust gas of the engines

Explanation

On a conventional jet, hot high-pressure air is tapped (bled) from engine compressor stages, regulated, and supplied to the air conditioning packs and pressurisation; the APU provides bleed air on the ground or as a backup. The B787 is the notable bleedless exception using electric compressors.

Question 29Hydraulic, pneumatic and electrical power

In an air-cycle machine (ACM) air conditioning pack, cooling of the bleed air is achieved primarily by:

  1. Expansion of the air through a cooling turbine that extracts work Correct answer.
  2. A vapour-cycle refrigerant compressor
  3. Spraying water into the duct
  4. Passing the air over dry ice

Explanation

An air-cycle machine cools by expanding compressed bleed air through a turbine; the turbine extracts work (driving the ACM compressor) and the expansion drops the air temperature, with heat exchangers and a water separator completing the process.

Question 30Hydraulic, pneumatic and electrical power

Cabin pressurisation is controlled by regulating the:

  1. Outflow valve, which varies the rate at which air leaves the cabin Correct answer.
  2. Bleed-air inflow rate only
  3. Number of air conditioning packs running
  4. Ram air inlet door position

Explanation

Inflow from the packs is roughly constant, so cabin pressure is controlled by the outflow valve, which modulates how fast air leaves the cabin; opening it lowers cabin pressure and closing it raises it.

Question 31Hydraulic, pneumatic and electrical power

The maximum cabin differential pressure on a transport aircraft is limited primarily to:

  1. Protect the fuselage structure from overstress Correct answer.
  2. Keep the cabin altitude at sea level
  3. Reduce engine bleed demand to zero
  4. Prevent the outflow valve from freezing

Explanation

Maximum differential pressure is set by the fuselage structural strength; the pressure relief/safety valves and the cabin pressure controller limit differential pressure to protect the structure from overstress and fatigue.

Question 32Hydraulic, pneumatic and electrical power

The primary source of electrical power generation on a large jet transport is the:

  1. Aircraft battery
  2. Static inverter
  3. Ram air turbine
  4. Engine-driven AC generators Correct answer.

Explanation

Each engine drives an AC generator (often through a constant speed drive forming an integrated drive generator, IDG) which is the main source of electrical power in flight; batteries, the APU generator, RAT and external power are backups or supplements.

Question 33Hydraulic, pneumatic and electrical power

Aircraft AC electrical systems are typically operated at a nominal frequency of:

  1. 50 Hz
  2. 60 Hz
  3. 400 Hz Correct answer.
  4. 1,000 Hz

Explanation

Aircraft constant-frequency AC systems use 400 Hz, which allows transformers and motors to be much smaller and lighter than at 50/60 Hz, an important weight saving on aircraft.

Question 34Hydraulic, pneumatic and electrical power

A constant speed drive (CSD) between the engine and an AC generator is used to:

  1. Convert AC to DC
  2. Increase the generator voltage to 400 V
  3. Provide emergency battery charging
  4. Maintain a constant generator input speed (hence constant frequency) despite varying engine speed Correct answer.

Explanation

A CSD is a hydromechanical transmission that holds the generator drive speed constant as engine RPM varies, so the AC output stays at a constant 400 Hz; combined with the generator it forms an integrated drive generator (IDG).

Question 35Hydraulic, pneumatic and electrical power

A transformer rectifier unit (TRU) in an aircraft electrical system:

  1. Converts DC to AC for instruments
  2. Converts AC to regulated DC for the DC busbars and battery charging Correct answer.
  3. Steps 400 Hz up to 800 Hz
  4. Provides constant frequency to the generators

Explanation

A TRU transforms (steps down) the 115 V AC and rectifies it to 28 V DC to supply the DC busbars and charge the battery; it is the main link between the AC and DC systems.

Question 36Hydraulic, pneumatic and electrical power

A nickel-cadmium (Ni-Cd) aircraft battery, compared with a lead-acid battery, is generally characterised by:

  1. A high discharge-rate capability and risk of thermal runaway if overheated Correct answer.
  2. Lower cost and lower current output
  3. Inability to be recharged
  4. A nominal cell voltage of 2.0 V

Explanation

Ni-Cd batteries can deliver very high currents (good for engine/APU start) and maintain voltage under load, but excessive temperature or overcharging can cause thermal runaway, so temperature monitoring is provided. Each Ni-Cd cell is nominally about 1.2 V.

Question 37Hydraulic, pneumatic and electrical power

A circuit breaker in an aircraft electrical circuit is designed to:

  1. Step the voltage down
  2. Convert AC to DC
  3. Maintain constant frequency
  4. Automatically open the circuit to protect the wiring from excessive current Correct answer.

Explanation

A circuit breaker protects the wiring (and equipment) by tripping (opening) when current exceeds a rated value, preventing overheating and fire; it can be reset after the fault is cleared, unlike a fuse.

Question 38Hydraulic, pneumatic and electrical power

A semiconductor diode in an electrical circuit primarily acts to:

  1. Store electrical charge
  2. Amplify a signal
  3. Generate AC voltage
  4. Allow current to flow in one direction only Correct answer.

Explanation

A diode conducts current in the forward direction and blocks it in the reverse direction; this rectifying property is the basis of converting AC to DC and of circuit protection against reverse current.

Question 39Hydraulic, pneumatic and electrical power

The ram air turbine (RAT) provides emergency electrical and/or hydraulic power by:

  1. Burning APU fuel
  2. Drawing power from the main battery
  3. Being driven by the airflow when deployed into the slipstream Correct answer.
  4. Tapping engine bleed air

Explanation

The RAT is a small propeller/turbine deployed into the airflow that uses the aircraft's forward speed to drive an emergency generator and/or hydraulic pump after loss of normal power sources.

Question 40Hydraulic, pneumatic and electrical power

Static dischargers (static wicks) fitted to trailing edges of control surfaces serve to:

  1. Discharge accumulated static charge to atmosphere to reduce radio interference Correct answer.
  2. Drain fuel vapour
  3. Heat the surface against icing
  4. Provide lightning grounding to the runway

Explanation

Static dischargers bleed off the static electricity (precipitation static) that builds on the airframe in flight, releasing it into the atmosphere at points away from antennas to reduce interference with radio and navigation equipment.

Question 41Hydraulic, pneumatic and electrical power

A hydraulic system thermal relief valve is provided to:

  1. Filter contaminants from the fluid
  2. Maintain reservoir level
  3. Release pressure that builds up when trapped fluid expands due to heat Correct answer.
  4. Cool the actuators

Explanation

When fluid is trapped between closed valves and warms up, it expands and pressure rises; a thermal relief valve opens to relieve this excess pressure back to the reservoir, protecting the lines and components.

Question 42Hydraulic, pneumatic and electrical power

An engine-driven hydraulic pump on a large transport is most commonly a:

  1. Fixed-displacement gear pump only
  2. Hand pump
  3. Centrifugal pump
  4. Variable-displacement (pressure-compensated) piston pump Correct answer.

Explanation

Engine-driven pumps on transport aircraft are usually variable-displacement axial-piston pumps that are pressure-compensated, automatically reducing flow as system pressure is reached to maintain constant pressure efficiently.

Question 43Hydraulic, pneumatic and electrical power

The negative pressure relief valve in a pressurised fuselage prevents:

  1. The cabin pressure exceeding the maximum differential
  2. Loss of bleed air
  3. External (ambient) pressure exceeding cabin pressure, which could collapse the structure inward Correct answer.
  4. Outflow valve sticking

Explanation

If outside pressure ever exceeds cabin pressure (e.g. a rapid descent with a blocked inflow), the negative (inward) pressure relief valve opens to admit air and prevent the fuselage from being crushed inward; the positive relief valves protect against excess differential pressure.

Question 44Hydraulic, pneumatic and electrical power

Bonding and earthing straps between airframe components are fitted primarily to:

  1. Increase structural strength
  2. Reduce aerodynamic drag
  3. Carry hydraulic fluid
  4. Provide a low-resistance electrical path so static charge and fault/lightning currents can flow safely and equipment grounds are common Correct answer.

Explanation

Bonding straps electrically connect separate metal parts (e.g. control surfaces to structure) to give a low-resistance path that equalises potential, allows static and lightning/fault currents to dissipate safely, and provides a common earth/ground for electrical equipment.

Question 45Hydraulic, pneumatic and electrical power

A static inverter in the aircraft electrical system is used to:

  1. Convert AC into DC for the battery
  2. Maintain constant generator frequency
  3. Charge the hydraulic accumulator
  4. Convert DC into AC, typically for essential AC loads in an emergency Correct answer.

Explanation

A static inverter is a solid-state device that converts battery/DC power into AC (e.g. 115 V 400 Hz) to supply essential AC instruments and equipment when normal AC generation is lost.

Question 46Hydraulic, pneumatic and electrical power

Load shedding in an aircraft electrical system refers to:

  1. Increasing all loads to use spare capacity
  2. Disconnecting non-essential loads to protect the remaining supply when generating capacity is reduced Correct answer.
  3. Transferring fuel between tanks
  4. Reducing cabin pressure

Explanation

When electrical generating capacity is reduced (e.g. loss of a generator), the system automatically or manually sheds non-essential loads (galleys, some lighting) to ensure that essential and emergency services remain powered within the available capacity.

Question 47Fuel, icing, fire and oxygen concepts

A pneumatic (bleed-air) thermal anti-ice system protects the wing leading edge by:

  1. Inflating rubber boots to crack the ice
  2. Ducting hot engine bleed air through the leading-edge skin to keep it above freezing Correct answer.
  3. Spraying glycol from porous panels
  4. Passing electrical current through the skin

Explanation

Thermal anti-ice ducts hot bleed air (piccolo tubes) along the inside of the leading-edge skin to keep its surface above freezing, preventing ice formation. It is an anti-ice (continuous) system rather than a de-ice (cyclic) system.

Question 48Fuel, icing, fire and oxygen concepts

Pneumatic de-icing boots on a turboprop wing leading edge remove ice by:

  1. Heating the leading edge continuously
  2. Coating the surface with a hydrophobic film
  3. Cyclically inflating and deflating to crack and shed accreted ice Correct answer.
  4. Vibrating the skin ultrasonically

Explanation

De-icing boots are inflated and deflated in a cycle; the expansion cracks the accumulated ice and the airflow sheds it. They are a de-ice (allow ice to form, then remove it) rather than anti-ice system.

Question 49Fuel, icing, fire and oxygen concepts

On a high-wing-loaded jet transport, fuel is normally consumed first from which tanks to relieve wing-bending moment?

  1. The centre (fuselage) tank, keeping wing tanks full as long as possible Correct answer.
  2. The wing tip tanks, then inboard
  3. All tanks simultaneously at equal rate
  4. The trim tank in the tail first

Explanation

Fuel in the wings provides downward bending relief in flight, so the centre/fuselage tank is generally used first while the wing tanks are kept full as long as possible to reduce wing-bending stress and improve fatigue life.

Question 50Fuel, icing, fire and oxygen concepts

A fuel jettison (dump) system is fitted to allow an aircraft to:

  1. Increase range by lightening the aircraft
  2. Reduce weight to maximum landing weight after a high-weight take-off for an immediate return Correct answer.
  3. Cool the engines on the ground
  4. Transfer fuel to balance the aircraft

Explanation

Fuel jettison reduces the aircraft from a high take-off weight down to or near the maximum landing weight so it can land safely soon after departure (e.g. an emergency return) without overstressing the structure.