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AAK ATPL (Kazakhstan) practice questions

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Question 1Air Law

Under the Chicago Convention, what is the fundamental principle regarding airspace above a State's territory?

  1. Each State has complete and exclusive sovereignty over its airspace. Correct answer.
  2. The airspace above the high seas belongs to the nearest coastal State.
  3. ICAO holds sovereignty over the airspace of all member States.
  4. States may exercise sovereignty only up to 10,000 feet above their territory.

Explanation

Article 1 of the Chicago Convention recognises the complete and exclusive sovereignty of each State over the airspace above its territory. This principle underlies bilateral air service agreements and national permission for overflight. It applies to the whole of the territorial airspace, not merely to a limited altitude band.

Question 2Air Law

Two aircraft are converging at approximately the same altitude. One is on the right of the other. Which aircraft has the right of way?

  1. The aircraft on the right gives way to the aircraft on the left.
  2. The aircraft on the left gives way to the aircraft on the right. Correct answer.
  3. The faster aircraft has the right of way.
  4. The higher aircraft has the right of way.

Explanation

Annex 2 provides that when two aircraft converge at approximately the same level, the aircraft on the right has the right of way. The aircraft on the left must therefore give way. Speed and altitude do not determine priority in this situation.

Question 3Air Law

Under ICAO Annex 1, what is the minimum age for the issue of an airline transport pilot licence (ATPL)?

  1. 18 years
  2. 20 years
  3. 23 years
  4. 21 years Correct answer.

Explanation

Annex 1 sets 21 years as the minimum age for the issue of an ATPL. A private pilot licence may be issued at 18 years, and a commercial pilot licence also at 18 years. The higher age for the ATPL reflects the experience and responsibility associated with airline transport operations.

Question 4Air Law

Which VHF frequency is designated for aeronautical emergency communications?

  1. 118.0 MHz
  2. 120.5 MHz
  3. 121.5 MHz Correct answer.
  4. 123.45 MHz

Explanation

121.5 MHz is the internationally designated VHF emergency frequency for civil aviation. It is used for distress and urgency communications and for emergency locator transmitters. The corresponding military UHF emergency frequency is 243.0 MHz.

Question 5Air Law

Which SSR transponder code is selected to indicate an emergency?

  1. 7000
  2. 7500
  3. 7700 Correct answer.
  4. 7600

Explanation

Code 7700 is the standard SSR code used to indicate a general emergency. Code 7600 indicates radio communication failure, and code 7500 indicates unlawful interference. Code 7000 is used in some regions to indicate VFR flight without a specific ATC-assigned code.

Question 6Air Law

Under ICAO Annex 13, which State is responsible for initiating an accident investigation?

  1. The State of the Operator
  2. The State of Registry
  3. The State of Occurrence Correct answer.
  4. The State of Manufacture

Explanation

The State of Occurrence is responsible for instituting the investigation and for conducting it in accordance with Annex 13. Other States with a special interest, such as the State of Registry, State of the Operator and State of Manufacture, may participate and appoint accredited representatives. The objective is to prevent future accidents rather than to apportion blame.

Question 7Air Law

Under ICAO Annex 6, who has final authority for the operation and safety of an aircraft during flight?

  1. The pilot in command Correct answer.
  2. The operator's duty manager
  3. The air traffic controller
  4. The State of Registry

Explanation

Annex 6 gives the pilot in command final authority for the operation and safety of the aircraft during flight time. This authority includes the discretion to deviate from rules when necessary in an emergency. Other parties have operational or regulatory roles but do not hold this final authority.

Question 8Air Law

An aircraft's Certificate of Airworthiness is normally issued by which authority?

  1. The State of Manufacture
  2. ICAO
  3. The State of the Operator
  4. The State of Registry Correct answer.

Explanation

Annex 8 requires that a Certificate of Airworthiness be issued by the State of Registry on the basis of satisfactory evidence that the aircraft complies with its airworthiness requirements. The State of Registry may accept a certificate issued by another State in certain circumstances. ICAO itself does not issue certificates of airworthiness.

Question 9Air Law

Which ATS service is responsible for notifying appropriate organisations when an aircraft is in need of search and rescue aid?

  1. Flight information service
  2. Advisory service
  3. Alerting service Correct answer.
  4. Aerodrome control service

Explanation

Under Annex 11, the alerting service notifies the appropriate search and rescue organisations and assists those organisations as required. Flight information service supplies information useful for safe flight but does not coordinate search and rescue. Advisory and aerodrome control services have different functions.

Question 10Air Law

What is the primary purpose of a runway end safety area (RESA)?

  1. To reduce damage to aircraft that undershoot or overrun the runway. Correct answer.
  2. To provide a level platform for the ILS localiser antenna array.
  3. To provide a clear, obstacle-free area for taxiing aircraft near the apron.
  4. To mark the beginning of the take-off run available for departing aircraft.

Explanation

Annex 14 requires a runway end safety area beyond the end of the runway strip to reduce the risk of damage to aircraft that undershoot or overrun the runway. It is intended to provide a defined area in which an aircraft can be brought to a stop with reduced consequences. It does not serve taxiing, marking or navigation-aid purposes.

Question 11Air Law

A NOTAM is issued to give notice of which type of information?

  1. Annual renewal of an aircraft certificate of airworthiness.
  2. Monthly summary of airport landing fees and charges.
  3. Temporary information essential to flight safety. Correct answer.
  4. Permanent publication of aeronautical charts and procedures.

Explanation

A NOTAM is a notice distributed by telecommunication containing information about the establishment, condition or change of an aeronautical facility, service, procedure or hazard, the timely knowledge of which is essential to flight operations. NOTAMs typically address temporary or short-notice matters. Permanent information is normally published in the Aeronautical Information Publication.

Question 12Air Law

In aerodrome security terminology under Annex 17, what is a security restricted area?

  1. An area reserved exclusively for air traffic control staff.
  2. An area where only aircraft maintenance is carried out.
  3. A public area of the terminal accessible to all persons.
  4. An area to which access is controlled for security reasons. Correct answer.

Explanation

A security restricted area is an area of an aerodrome to which access is controlled in order to maintain security. It may include airside areas, baggage areas and other zones subject to screening or access control. The definition is broader than a maintenance area or an air traffic control facility.

Question 13Air Law

Under ICAO Annex 18, who is primarily responsible for the correct classification, packing, marking and labelling of dangerous goods?

  1. The pilot in command
  2. The shipper Correct answer.
  3. The consignee
  4. The aircraft operator

Explanation

Annex 18 places the primary responsibility for the correct classification, packing, marking and labelling of dangerous goods on the shipper. The operator must ensure that dangerous goods are accepted only in accordance with the Technical Instructions and that personnel are trained. The pilot in command and consignee do not prepare the shipment.

Question 14Air Law

Under the Tokyo Convention 1963, which State has primary jurisdiction over an offence committed on board an aircraft in flight?

  1. The State of the operator's principal place of business
  2. The State over which the aircraft is flying
  3. The State where the aircraft next lands
  4. The State of registry of the aircraft Correct answer.

Explanation

The Tokyo Convention 1963 recognises the jurisdiction of the State of Registry over offences committed on board an aircraft in flight. Other States may exercise jurisdiction in specified circumstances, but the State of Registry has the primary competence. The Convention also deals with the powers of the aircraft commander.

Question 15Air Law

What does the third freedom of the air permit an airline to do?

  1. Set down traffic taken on in the airline's own State in another State. Correct answer.
  2. Overfly another State without landing or making a stop.
  3. Pick up passengers in another State and carry them to a third State.
  4. Carry traffic between two points that are both within another State.

Explanation

The third freedom of the air allows an airline to put down, in another State, passengers, mail and cargo taken on in its own State. The fourth freedom is the corresponding right to pick up traffic in another State for carriage back to the home State. The fifth freedom permits carriage between two foreign States on a service originating in the home State.

Question 16Air Law

Under ICAO Annex 7, what must be displayed on an aircraft to identify its nationality and registration?

  1. The airline's name and the flight number
  2. The nationality mark and the registration mark Correct answer.
  3. The aircraft type and serial number
  4. The certificate of airworthiness number

Explanation

Annex 7 requires aircraft to display a nationality mark or common mark together with a registration mark. For example, aircraft registered in Kazakhstan carry the nationality mark UP. Airline names, flight numbers and certificate numbers are not the nationality and registration marks.

Question 17Air Law

Which international convention introduced a two-tier system of liability for death or injury to passengers, with a strict liability limit that cannot be exceeded unless the carrier is negligent?

  1. The Montreal Convention 1999 Correct answer.
  2. The Warsaw Convention 1929
  3. The Rome Convention 1952
  4. The Chicago Convention 1944

Explanation

The Montreal Convention 1999 modernised the Warsaw system and introduced a two-tier liability regime for passenger death or injury. The first tier imposes strict liability up to a specified SDR limit, and the second tier allows additional damages where the carrier is proved negligent or otherwise at fault. The Warsaw Convention established an earlier presumption of liability but not the modern two-tier structure.

Question 18Air Law

Under the Hague Convention 1970, which act constitutes the offence of unlawful seizure of aircraft?

  1. Unlawfully seizing control of an aircraft by threat or use of force Correct answer.
  2. Damaging air navigation facilities used in international aviation
  3. Committing an act of violence on board that endangers the safety of the aircraft
  4. Communicating false information that endangers an aircraft in flight

Explanation

The Hague Convention 1970 defines unlawful seizure as unlawfully, by force or threat of force or any other form of intimidation, seizing or exercising control of an aircraft. It is the principal international instrument against hijacking. Acts of violence on board are addressed primarily by the Tokyo Convention, while sabotage and false information are covered by the Montreal Convention 1971.

Question 19Air Law

Under Article 5 of the Chicago Convention, what is the position on non-scheduled flights by aircraft of other contracting States?

  1. Such flights are permitted without prior permission, subject to the right of the State to require landing. Correct answer.
  2. Such flights are governed only by the national law of the operator's State.
  3. Such flights are prohibited from crossing another State's territory in all circumstances.
  4. Prior permission is always required before such a flight may cross another State's territory.

Explanation

Article 5 allows aircraft engaged in non-scheduled international air services to fly into or over the territory of another contracting State without prior permission, subject to the observance of the Convention and the right of the State to require landing. The State may also impose regulations for the safety of navigation. Scheduled services are governed separately, principally through Article 6.

Question 20Air Law

In Class C controlled airspace, what separation is provided between IFR flights and VFR flights?

  1. No separation is provided, and both receive traffic information only.
  2. Separation is provided only during the hours of darkness.
  3. IFR flights are separated from all flights; VFR flights receive traffic information. Correct answer.
  4. VFR flights are separated from IFR flights but not from other VFR flights.

Explanation

In Class C airspace, IFR flights are separated from all other IFR and VFR flights. VFR flights are separated from IFR flights and receive traffic information regarding other VFR flights. Class G, by contrast, provides no separation to IFR or VFR flights.

Question 21Aircraft General Knowledge (airframe, systems, powerplant, emergency equipment, instrumentation)

In a semi-monocoque fuselage, which structural members run lengthwise and carry the primary bending loads?

  1. Wing spars
  2. Bulkheads
  3. Longerons Correct answer.
  4. Ribs

Explanation

Longerons are the longitudinal members of a semi-monocoque fuselage and take the main bending loads, with the skin carrying shear. Bulkheads are transverse frames that maintain shape and carry concentrated loads. Spars and ribs belong to the wing and tail structures rather than the fuselage primary bending path.

Question 22Aircraft General Knowledge (airframe, systems, powerplant, emergency equipment, instrumentation)

What is the primary function of a hydraulic accumulator in an aircraft system?

  1. Stores fluid under pressure to damp surges Correct answer.
  2. Cools the returning fluid before it enters the reservoir
  3. Drives the engine-driven pump
  4. Filters contaminants from the fluid

Explanation

An accumulator contains a gas charge separated from the hydraulic fluid, so it absorbs pressure pulses from pump delivery and actuator movement and stores energy for short peak demands. This smooths system operation and can provide limited emergency flow. Filtration, cooling and pump drive are performed by other components.

Question 23Aircraft General Knowledge (airframe, systems, powerplant, emergency equipment, instrumentation)

What is the purpose of the torque link (scissors) fitted to an oleo-pneumatic landing gear strut?

  1. It locks the gear in the down position
  2. It absorbs side loads transmitted to the fuselage
  3. It keeps the wheel aligned by preventing strut rotation Correct answer.
  4. It meters the flow of hydraulic fluid during strut compression

Explanation

The torque link connects the upper and lower strut sections and prevents the lower leg, and therefore the wheel, from rotating about the strut axis. It transmits torque between the two halves while still allowing the strut to extend and compress. It carries no vertical shock load itself.

Question 24Aircraft General Knowledge (airframe, systems, powerplant, emergency equipment, instrumentation)

How does an anti-skid braking system maintain effective braking on a slippery runway?

  1. It keeps the brakes applied after touchdown
  2. It increases brake pressure when the wheel slows down
  3. It automatically retracts the gear after take-off
  4. It releases brake pressure when a wheel is about to skid Correct answer.

Explanation

Wheel speed sensors detect a rapid fall in wheel rotation, and the control unit commands a pressure release valve to reduce braking at that wheel. Braking is then reapplied near the optimum slip level, which preserves cornering grip and stops the tyre from locking. Maximum deceleration occurs at a small amount of slip, not at full lock.

Question 25Aircraft General Knowledge (airframe, systems, powerplant, emergency equipment, instrumentation)

What is controlled by the cabin outflow valve in a pressurised aircraft?

  1. It controls the temperature of air supplied by the packs
  2. It closes automatically whenever the engines are running
  3. It regulates the bleed air entering the air-conditioning packs
  4. It regulates the air leaving the cabin to control pressure Correct answer.

Explanation

The cabin is pressurised by a continuous supply of conditioned air, and pressure is set by how fast that air is allowed to escape. The outflow valve modulates the discharge overboard, thereby controlling cabin altitude and rate of change. Inflow is controlled by the pack and bleed valves, not by the outflow valve.

Question 26Aircraft General Knowledge (airframe, systems, powerplant, emergency equipment, instrumentation)

Which flight instrument is connected to the static source only and displays the rate of climb or descent?

  1. Airspeed indicator
  2. Turn coordinator
  3. Altimeter
  4. Vertical speed indicator Correct answer.

Explanation

The vertical speed indicator is fed only by static pressure and responds to the rate at which that pressure changes, which is calibrated as feet per minute of climb or descent. It does not use pitot pressure at all. The altimeter also uses static pressure only, but it displays height rather than rate.

Question 27Aircraft General Knowledge (airframe, systems, powerplant, emergency equipment, instrumentation)

By what principle does a Halon 1301 fire extinguisher suppress a fire?

  1. It smothers the fire with dry powder
  2. It chemically interrupts the combustion reaction Correct answer.
  3. It displaces oxygen with carbon dioxide
  4. It cools the fire by absorbing heat

Explanation

Halon 1301 breaks the chain reaction of combustion at a chemical level, which stops the flame even at low concentration. It is effective in confined spaces such as engine nacelles and cargo holds and leaves no residue. Cooling and oxygen displacement are secondary effects and are not the primary mechanism.

Question 28Aircraft General Knowledge (airframe, systems, powerplant, emergency equipment, instrumentation)

What is the function of the pressure relief valve in an aircraft hydraulic system?

  1. It isolates a failed subsystem automatically
  2. It limits maximum system pressure by bypassing fluid Correct answer.
  3. It maintains a constant output pressure from the pump
  4. It indicates low pressure in the cockpit

Explanation

The relief valve opens at a preset pressure above normal operating pressure and returns fluid to the return line or reservoir, protecting lines, seals and components from overpressure. It is a safety device, not a regulator, so it stays closed in normal operation. Pressure regulation is performed by the pump's own compensator or by the system pressure regulator.

Question 29Aircraft General Knowledge (airframe, systems, powerplant, emergency equipment, instrumentation)

What is the purpose of a shimmy damper on a nose landing gear?

  1. It centres the nose wheel automatically after the aircraft takes off
  2. It locks the nose wheel during retraction
  3. It increases steering authority at low speed
  4. It damps oscillations of the nose wheel about its steering axis Correct answer.

Explanation

Shimmy is a rapid self-excited oscillation of the nose wheel about its steering axis, and the damper adds hydraulic or friction resistance to suppress it. Without damping, the oscillation could damage the gear and tyres during taxi and landing roll. Centring and locking are separate functions of the centring cam and the downlock.

Question 30Aircraft General Knowledge (airframe, systems, powerplant, emergency equipment, instrumentation)

How does the air cycle machine in a bleed-air air-conditioning system produce cold air?

  1. It mixes fresh and recirculated cabin air
  2. It compresses bleed air to raise its temperature
  3. It removes water from the cabin recirculation flow
  4. It cools air by expanding it while driving a compressor Correct answer.

Explanation

Bleed air is first compressed and cooled, then passed through the expansion turbine of the air cycle machine, where it does work on the turbine shaft and leaves at a much lower temperature. The shaft drives the compressor section of the same machine. Water separators remove moisture downstream, but they do not produce the cooling.

Question 31Aircraft General Knowledge (airframe, systems, powerplant, emergency equipment, instrumentation)

Why is fuel used as a coolant in many turbine-powered aircraft?

  1. It prevents the fuel from freezing during long flights at high altitude
  2. It improves the calorific value of the fuel
  3. It lubricates the engine oil seals
  4. It absorbs heat from oil and hydraulics before being burned Correct answer.

Explanation

Fuel is available in large quantity and is ultimately consumed, so it makes an efficient heat sink. Fuel/oil and fuel/hydraulic heat exchangers transfer heat into the fuel, which then cools the engine oil and other systems before being burned. This saves weight compared with dedicated air-cooled heat exchangers.

Question 32Aircraft General Knowledge (airframe, systems, powerplant, emergency equipment, instrumentation)

What is the purpose of the constant-speed drive or integrated drive generator on an aircraft AC generator?

  1. It converts alternating current into direct current for the battery bus
  2. It protects the generator from overcurrent damage
  3. It keeps generator frequency constant as engine speed varies Correct answer.
  4. It disconnects the generator in the event of an overvoltage

Explanation

AC frequency is proportional to generator shaft speed, which would otherwise vary with engine rpm. The constant-speed drive uses a hydraulic or mechanical unit to hold the generator at a fixed speed so that 400 Hz is produced over the engine's operating range. Protection and rectification are performed by other components.

Question 33Aircraft General Knowledge (airframe, systems, powerplant, emergency equipment, instrumentation)

How does a thermal anti-icing system protect the wing leading edges?

  1. It uses electrical heater mats on the leading edges
  2. It sprays glycol onto the protected surfaces
  3. It uses hot bleed air to heat the wing leading edges Correct answer.
  4. It inflates rubber boots fitted along the wing leading edges

Explanation

Hot compressor bleed air is ducted through piccolo tubes inside the leading edge and exhausts through holes to heat the skin above freezing. This prevents ice from forming rather than removing it after formation. Boots, glycol and electrical mats are different anti-icing or de-icing methods.

Question 34Aircraft General Knowledge (airframe, systems, powerplant, emergency equipment, instrumentation)

How does a chemical oxygen generator supply oxygen to passengers?

  1. It stores oxygen as a compressed gas in a cylinder
  2. It generates oxygen by electrolysis of water
  3. It produces oxygen by a chemical reaction when activated Correct answer.
  4. It supplies filtered cabin air to the mask

Explanation

A chemical generator contains a sodium chlorate candle that, once ignited by a firing pin, decomposes to release oxygen for roughly 12 to 15 minutes. It is used in passenger service units because it needs no plumbing or storage of high-pressure gas. Compressed gas cylinders and liquid oxygen systems are separate arrangements.

Question 35Aircraft General Knowledge (airframe, systems, powerplant, emergency equipment, instrumentation)

Why do turbofan engines open variable bleed valves at low engine speeds?

  1. They supply cabin air during cruise
  2. They supply cooling air to the turbine blades at take-off
  3. They increase the engine pressure ratio at high power settings
  4. They prevent compressor stall by relieving pressure at low speed Correct answer.

Explanation

At low rotational speed the front compressor stages can deliver more air than the rear stages can accept, raising the risk of stall. Bleed valves release some air into the bypass duct to match the stages and keep the airflow stable. They close as speed increases and are not used for cabin supply or turbine cooling.

Question 36Aircraft General Knowledge (airframe, systems, powerplant, emergency equipment, instrumentation)

What does feathering a propeller achieve after an engine failure?

  1. It reduces propeller noise during the climb
  2. It aligns the blades with the airflow to reduce drag Correct answer.
  3. It holds the propeller at a constant speed
  4. It increases thrust at low airspeed

Explanation

Feathering rotates the blades to a very coarse angle so that they present minimum area to the relative airflow. This virtually eliminates windmilling drag and reduces load on the failed engine. Constant-speed operation is the normal governing function, not feathering.

Question 37Aircraft General Knowledge (airframe, systems, powerplant, emergency equipment, instrumentation)

Position error of the airspeed indicator is caused by what?

  1. Blockage of the static port by ice or a foreign object
  2. Incorrect pressure sensed at the pitot and static ports Correct answer.
  3. Compressibility effects at high altitude and high Mach number
  4. Mechanical lag in the instrument mechanism

Explanation

Position error, also called pressure error, arises because the airflow around the fuselage and wing distorts the pressure actually sensed at the pitot and static ports compared with the true free-stream values. It is determined in flight test and corrected by calibration tables. Compressibility, lag and blockage are separate error sources.

Question 38Aircraft General Knowledge (airframe, systems, powerplant, emergency equipment, instrumentation)

What does rigidity in space mean for a spinning gyroscope rotor?

  1. It precesses whenever the aircraft turns
  2. It aligns itself with the local vertical at all times
  3. It follows the yaw rate of the aircraft
  4. It tends to remain fixed in direction in inertial space Correct answer.

Explanation

A rotor spinning at high speed has angular momentum, so its spin axis tends to maintain its direction in space unless a torque is applied. This property is used in attitude and heading reference instruments. Precession occurs only when an external torque acts on the gyro.

Question 39Aircraft General Knowledge (airframe, systems, powerplant, emergency equipment, instrumentation)

A stall warning system using a vane on the fuselage side activates when what condition occurs?

  1. Flap position goes beyond a set angle
  2. Angle of attack exceeds a set value Correct answer.
  3. Airspeed falls below a fixed value
  4. Rate of descent exceeds a set value

Explanation

A stall occurs at a critical angle of attack regardless of speed, weight or configuration, so a vane that aligns with the local airflow senses the angle directly. The warning is triggered as the angle approaches the critical value, giving the pilot time to reduce it. Speed-based warnings cannot account for weight and load factor.

Question 40Aircraft General Knowledge (airframe, systems, powerplant, emergency equipment, instrumentation)

Why is the cabin rate of climb normally limited to about 500 ft/min?

  1. To limit the bleed-air demand on the engines
  2. To prevent the outflow valve from freezing at high altitude in cold soak
  3. To avoid discomfort from pressure changes in the ears and sinuses Correct answer.
  4. To protect the pressure hull from fatigue cracking

Explanation

The pressure change rate that the human ear and sinuses can tolerate comfortably is limited, so the cabin pressure controller restricts the rate of change of cabin altitude. This is why cabin altitude climbs and descends more slowly than aircraft altitude. Structural fatigue and valve icing are not controlled by this rate limit.

Question 41Aircraft General Knowledge (airframe, systems, powerplant, emergency equipment, instrumentation)

In a typical turbofan, which parameter is used as the primary thrust indicator and which as the limiting parameter at take-off?

  1. N2 as the indicator, oil pressure as the limit
  2. N1 as the limit, EGT as the thrust indicator
  3. EGT as the indicator, N1 as the limit
  4. N1 as the thrust indicator, EGT as the limit Correct answer.

Explanation

Fan speed N1 correlates closely with thrust, so take-off thrust is set by reference to N1. Exhaust gas temperature is monitored as the limiting parameter because it reflects turbine entry temperature and structural limits. N2 and oil pressure are not thrust-setting parameters.

Question 42Aircraft General Knowledge (airframe, systems, powerplant, emergency equipment, instrumentation)

What is the main effect of air entrained in an aircraft hydraulic system?

  1. Spongy operation and pump cavitation Correct answer.
  2. A reduced boiling point of the hydraulic fluid at altitude
  3. A rise in steady system pressure
  4. Increased viscosity of the fluid

Explanation

Gas bubbles are compressible, so actuator response becomes spongy and delayed, and the pump can cavitate, causing noise, vibration and overheating. Entrained air also promotes foaming in the reservoir. Systems are therefore bled and kept under a positive head of pressure.

Question 43Aircraft General Knowledge (airframe, systems, powerplant, emergency equipment, instrumentation)

What is the function of bus tie breakers in a multi-generator aircraft electrical system?

  1. Convert AC to DC for the essential bus
  2. Allow a bus to be supplied by another generator if one fails Correct answer.
  3. Prevent the generators from running in parallel in flight
  4. Discharge the battery during an engine start

Explanation

Bus tie breakers connect or separate the main AC buses so that a generator feeding one bus can supply another bus whose own generator has failed. They also allow the system to be split into isolated channels when required. They do not perform rectification or battery discharge.

Question 44Aircraft General Knowledge (airframe, systems, powerplant, emergency equipment, instrumentation)

How is fail-safe structural design applied to a transport aircraft?

  1. The structure is designed so that cracks cannot form under any load
  2. The structure is certified only for a limited number of flight cycles
  3. The structure is replaced after a fixed number of flight hours
  4. The structure can sustain loads with a failed element until damage is found Correct answer.

Explanation

Fail-safe or damage-tolerant design provides multiple load paths and crack-arrest features so that a crack or failed element does not cause immediate loss of the structure. Inspection programmes then detect the damage before it becomes critical. Safe-life design, by contrast, retires components after a calculated life.

Question 45Mass and Balance

Dry operating mass is defined as the basic empty mass plus which of the following items?

  1. Basic empty mass plus the usable fuel on board
  2. Crew, passengers, passenger baggage and the traffic load carried on the sector
  3. Basic empty mass plus the traffic load
  4. Crew, crew baggage, cabin service equipment and potable water Correct answer.

Explanation

Dry operating mass is the basic empty mass plus everything needed to operate the flight that is not traffic load or fuel: crew, crew baggage, catering, removable passenger service equipment and potable water. Traffic load and usable fuel are added afterwards to obtain the operating mass and the take-off mass.

Question 46Mass and Balance

An aircraft has a total mass of 62 000 kg and a total moment about the datum of 1 178 000 kg·m. Where is its centre of gravity located?

  1. 0.053 m aft of the datum
  2. 19.0 m forward of the datum
  3. 19.0 m aft of the datum Correct answer.
  4. 1.90 m aft of the datum

Explanation

Centre of gravity position is the total moment divided by the total mass: 1 178 000 ÷ 62 000 = 19.0 m. Moments taken about the datum are positive aft of it, so the CG lies 19.0 m aft of the datum.

Question 47Mass and Balance

An aircraft of mass 8 000 kg has its centre of gravity at 12.0 m aft of the datum. A load of 800 kg is then placed at a station 17.0 m aft of the datum. What is the new centre of gravity position?

  1. 12.05 m aft of the datum
  2. 12.50 m aft of the datum
  3. 12.45 m aft of the datum Correct answer.
  4. 13.00 m aft of the datum

Explanation

Take moments about the datum: (8 000 × 12.0) + (800 × 17.0) = 96 000 + 13 600 = 109 600 kg·m, and the new mass is 8 800 kg, so the CG is 109 600 ÷ 8 800 = 12.45 m. Equivalently the CG shifts aft by load × arm change ÷ new mass = 800 × 5.0 ÷ 8 800 = 0.45 m.

Question 48Mass and Balance

During cruise, fuel is burned from a tank whose centre of gravity lies aft of the aircraft centre of gravity. Assuming no other mass changes, what happens to the aircraft centre of gravity?

  1. It stays unchanged until the tank is completely empty
  2. It moves forward Correct answer.
  3. It stays unchanged, because the fuel is part of the aircraft mass
  4. It moves aft, because fuel mass is lost from behind the CG

Explanation

Removing mass from a point aft of the CG removes more aft moment than the average, so the remaining CG moves forward. The shift is proportional to (mass removed × distance from CG to the tank) ÷ (original mass − mass removed).

Question 49Mass and Balance

An aircraft has a mean aerodynamic chord of 4.0 m, and the leading edge of the MAC is 15.0 m aft of the datum. A centre of gravity at 16.4 m aft of the datum corresponds to which position?

  1. 9 % MAC
  2. 65 % MAC
  3. 35 % MAC Correct answer.
  4. 41 % MAC

Explanation

The distance from the LEMAC to the CG is 16.4 − 15.0 = 1.4 m, and as a fraction of the 4.0 m MAC this is 1.4 ÷ 4.0 = 0.35, i.e. 35 % MAC. In general, %MAC = (CG arm − LEMAC arm) ÷ MAC length × 100.

Question 50Mass and Balance

A cargo hold floor is limited to a maximum floor loading of 600 kg/m² and a maximum running load of 400 kg/m. An item of 1 200 kg with a floor contact area of 3.0 m² and a length of 1.5 m along the fuselage is loaded. Which statement is correct?

  1. The running load limit only is exceeded Correct answer.
  2. Neither limit is exceeded
  3. Both limits are exceeded
  4. The floor loading limit only is exceeded

Explanation

Floor loading is 1 200 ÷ 3.0 = 400 kg/m², which is below the 600 kg/m² limit. Running load is 1 200 ÷ 1.5 = 800 kg/m, which exceeds the 400 kg/m limit, so the item must be spread over a longer length or split into smaller items.