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Question 1. Which design philosophy assumes that a component will be replaced before it reaches its fatigue limit? A) Fail‑safe B) Damage tolerance C) Safe‑life D) Redundant Answer: C Explanation: Safe‑life design requires components to be removed from service before fatigue cracks can initiate, ensuring they never reach failure. Question 2. In a fail‑safe structure, the failure of a single element is tolerated because: A) The element is made of a higher‑strength alloy. B) Redundant load paths share the load. C) The structure is inspected more frequently. D) The element is replaced after each flight. Answer: B Explanation: Fail‑safe design provides alternative load paths, allowing the structure to continue carrying loads after a local failure. Question 3. Damage‑tolerance philosophy primarily relies on which of the following to maintain safety? A) Scheduled part replacement B) Real‑time crack detection and monitoring C) Over‑design of all structural members D) Use of only composite materials Answer: B Explanation: Damage tolerance assumes that cracks may exist but are detectable by non‑destructive inspection before they become critical. Question 4. Which stress is produced when a wing experiences upward bending due to lift?
A) Shear stress in the spar caps B) Torsional stress in the ribs C) Compression in the upper skin D) Tension in the lower skin Answer: D Explanation: Upward bending puts the lower surface of the wing in tension and the upper surface in compression. Question 5. The primary advantage of using titanium alloys in airframe construction is: A) Low cost B) High fatigue strength with low density C) Easy welding D) Excellent corrosion resistance in seawater Answer: B Explanation: Titanium offers a high strength‑to‑weight ratio and good fatigue resistance, making it ideal for critical high‑stress components. Question 6. What is the main purpose of a stringer in a semi‑monocoque fuselage? A) To provide the primary load‑bearing skin B) To reinforce the skin against buckling C) To house wiring bundles D) To attach the landing gear Answer: B Explanation: Stringers stiffen the thin skin, preventing local buckling under compressive loads. Question 7. In a monocoque fuselage, the load‑bearing structure is primarily: A) The internal frames only B) The outer skin alone C) The combination of frames, stringers, and skin
Explanation: Airbus commonly uses blue hydraulic fluid for the green system and green fluid for the blue system to avoid confusion. Question 11. Skydrol, a phosphate‑ester hydraulic fluid, is preferred over mineral oil because: A) It is less expensive. B) It has a higher boiling point and better fire resistance. C) It is compatible with all seals. D) It does not require filtration. Answer: B Explanation: Skydrol’s high flash point and fire‑resistant properties make it safer for high‑temperature hydraulic systems. Question 12. In an aircraft hydraulic system, the accumulator’s main function is to: A) Store hydraulic fluid for later use. B) Provide a source of pressurized fluid to smooth pressure fluctuations. C) Filter contaminants from the fluid. D) Act as a backup pump. Answer: B Explanation: The accumulator absorbs pressure spikes and releases fluid to maintain steady system pressure during transient demands. Question 13. Which component provides the primary power source for a hydraulic system on a turbofan with no engine‑driven pump? A) Electric motor‑driven pump B) Ram air turbine (RAT) C) APU‑driven pump D) Manual hand pump Answer: C Explanation: On many turbofan aircraft, the APU supplies hydraulic power when the engines are not running.
Question 14. A priority valve in a hydraulic system ensures that: A) All actuators receive equal flow. B) Critical systems receive flow before secondary ones. C) The system pressure never exceeds 3000 psi. D) The fluid temperature stays below 100 °C. Answer: B Explanation: Priority valves route hydraulic fluid to essential functions (e.g., flight controls) before less critical actuators. Question 15. The purpose of a fire‑shut‑off valve on a hydraulic line is to: A) Prevent hydraulic fluid from reaching a fire. B) Increase system pressure during fire. C) Release hydraulic fluid to extinguish fire. D) Divert fluid to an alternate pump. Answer: A Explanation: Closing the valve isolates the hydraulic circuit from a source of fire, preventing fluid from feeding the fire. Question 16. A Power Transfer Unit (PTU) in a dual‑hydraulic system is used to: A) Transfer hydraulic fluid between the two systems. B) Transfer mechanical power from one pump to the other when pressure differs. C) Convert hydraulic power to electrical power. D) Provide emergency manual control of the brakes. Answer: B Explanation: The PTU mechanically couples the two hydraulic systems, allowing one pump to drive the other when one system loses pressure. Question 17. The main advantage of a tricycle landing‑gear arrangement over a tailwheel configuration is:
D) Are self‑lubricating. Answer: B Explanation: Carbon discs dissipate heat more efficiently and are lighter, improving braking performance and reducing unsprung mass. Question 21. An anti‑skid system on an aircraft brake system works by: A) Preventing wheel spin through a hydraulic lock. B) Modulating brake pressure to maintain optimal wheel deceleration. C) Applying the brakes only after touchdown. D) Using a mechanical clutch to disengage brakes. Answer: B Explanation: The anti‑skid system senses wheel speed and reduces brake pressure when a wheel is about to lock, maintaining traction. Question 22. The hydro‑planing speed (Vₕ) for a tire can be approximated by the formula Vₕ = 9 × √P, where P is the tire pressure in kPa. If a tire is inflated to 220 kPa, what is the approximate hydro‑planing speed in knots? A) 30 kt B) 42 kt C) 133 kt D) 150 kt Answer: C Explanation: √220 ≈ 14.8; 9 × 14.8 ≈ 133 kt, which is the estimated hydro‑planing speed. Question 23. Ailerons are primarily used to control: A) Pitch B) Yaw C) Roll D) Altitude Answer: C
Explanation: Deflecting ailerons creates differential lift on the wings, inducing roll about the longitudinal axis. Question 24. The function of a balance tab on a control surface is to: A) Provide primary aerodynamic force. B) Reduce pilot control forces by moving opposite to the main surface. C) Increase the surface’s structural strength. D) Act as a backup in case of hydraulic loss. Answer: B Explanation: A balance tab moves opposite to the main surface, creating an aerodynamic moment that assists the pilot, reducing required force. Question 25. A leading‑edge slat improves aircraft performance by: A) Increasing the wing’s camber at high speeds. B) Delaying flow separation, thus raising the maximum lift coefficient. C) Reducing drag at cruise. D) Acting as a primary flight control. Answer: B Explanation: Slats create a slot that energizes the boundary layer, allowing higher angles of attack before stall. Question 26. Spoilers on a wing are used to: A) Increase lift during climb. B) Reduce lift and increase drag, aiding descent and roll control. C) Provide primary roll control. D) Act as a backup for ailerons. Answer: B Explanation: Deploying spoilers disrupts airflow, decreasing lift and increasing drag, useful for descent and speed reduction.
C) Heating of cabin air using electric heaters. D) Moisture removal only. Answer: B Explanation: The ACM uses a turbine‑driven compressor and expansion turbine to cool air through a reverse Brayton (air‑cycle) process. Question 31. The outflow valve in a pressurised cabin system controls: A) The rate at which cabin air is heated. B) The cabin pressure by regulating air outflow. C) The supply of fresh air from the ground. D) The operation of the oxygen masks. Answer: B Explanation: By opening and closing, the outflow valve maintains the desired cabin altitude by controlling the amount of air leaving the cabin. Question 32. An “explosive decompression” scenario is most likely to occur when: A) A small leak in a window allows gradual pressure loss. B) A structural failure creates a large opening in the fuselage at high altitude. C) The outflow valve is stuck open. D) The cabin pressurisation system is turned off. Answer: B Explanation: Explosive decompression involves a sudden, massive pressure drop due to a large breach, causing rapid loss of cabin pressure. Question 33. The purpose of a fuel surge tank is to: A) Store extra fuel for long‑range flights. B) Prevent fuel starvation during high‑G maneuvers by providing a small volume of fuel near the pump inlet. C) Separate water from fuel. D) Act as a pressure regulator.
Answer: B Explanation: A surge tank ensures a continuous fuel supply to the pump even when the main tank fuel moves away due to manoeuvre‑induced forces. Question 34. In a typical transport aircraft, the centre tank is usually pressurised to: A) The same pressure as the wing tanks. B) Slightly higher than wing tanks to aid fuel feed. C) Lower than wing tanks to prevent over‑pressurisation. D) It is not pressurised; it is vented to ambient. Answer: B Explanation: The centre tank is often slightly pressurised to assist fuel flow toward the engines, especially during climb. Question 35. A fuel quantity indication system (FQI) that uses capacitance probes determines fuel level by: A) Measuring the change in electrical resistance. B) Detecting variations in dielectric constant between fuel and air. C) Weighing the fuel tank. D) Using ultrasonic waves. Answer: B Explanation: Capacitance probes sense the change in dielectric constant as the fuel level changes, providing an electronic fuel quantity reading. Question 36. The main hazard associated with handling Skydrol hydraulic fluid is: A) Its high flammability. B) Its corrosive effect on skin and eyes. C) Its tendency to freeze at low temperatures. D) Its strong odor causing respiratory irritation. Answer: B
Question 40. Halon fire‑extinguishing agents are favored in aircraft fire loops because: A) They are non‑toxic and leave no residue. B) They are inexpensive and widely available. C) They are water‑based and cool the fire. D) They react chemically with metal to prevent re‑ignition. Answer: A Explanation: Halon extinguishes fire by interrupting the chemical reaction and leaves minimal residue, which is important for aircraft systems. Question 41. The purpose of a water separator in an air‑conditioning pack is to: A) Remove moisture from cabin air before it enters the cabin. B) Extract water from the fuel system. C) Provide drinking water for the crew. D) Cool the bleed air by condensation. Answer: A Explanation: The water separator condenses and removes moisture from the bleed‑air stream, preventing cabin humidity and ice formation. Question 42. In a pneumatic system, an “IP” bleed valve refers to: A) Intermediate pressure, typically 30–40 psi. B) Inlet pressure from the APU. C) Internal pressure for the hydraulic system. D) Ignition pressure for the engine. Answer: A Explanation: IP (Intermediate Pressure) bleed air is reduced from the HP stage and used for pneumatic systems like air‑conditioning and anti‑icing. Question 43. The primary function of the anti‑skid valve in a brake system is to: A) Prevent brake fluid from boiling.
B) Modulate hydraulic pressure to avoid wheel lock‑up. C) Release brake pressure when the aircraft is on the ground. D) Supply extra pressure during emergency braking. Answer: B Explanation: The anti‑skid valve senses wheel speed and reduces brake pressure when a wheel is about to lock, maintaining traction. Question 44. A “cross‑feed” valve in a fuel system allows: A) Fuel to be transferred from one wing tank to the other. B) Fuel to be pumped from the centre tank to the wing tanks. C) An engine to draw fuel from the opposite side tank. D) Fuel to be dumped overboard. Answer: C Explanation: Cross‑feed enables an engine to receive fuel from the opposite wing tank, providing redundancy in case of a tank failure. Question 45. The purpose of a “fuel jettison” system is to: A) Transfer fuel from the wing tanks to the centre tank. B) Reduce aircraft weight quickly for emergency descent. C) Increase fuel pressure for high‑altitude operation. D) Remove water from the fuel. Answer: B Explanation: Fuel dumping expels fuel to lower the aircraft’s weight, allowing a safe emergency landing within performance limits. Question 46. In a typical hydraulic system, the term “constant‑pressure” refers to: A) A system that maintains pressure regardless of flow demand using a pump and accumulator. B) A system that only provides pressure when a valve is opened. C) A system that varies pressure with aircraft speed. D) A system that uses only electric pumps.
Explanation: Magnesium’s low density makes it attractive for weight‑critical components, despite its lower strength and corrosion concerns. Question 50. In a pressurised aircraft, the “safety valve” is set to open at: A) Cabin altitude of 8 000 ft. B) A pressure differential that would cause the fuselage to exceed its design limit. C) The same setting as the outflow valve. D) 0 psi differential. Answer: B Explanation: The safety valve protects the structure by venting excess pressure before the fuselage reaches its maximum allowable stress. Question 51. The main advantage of using carbon‑fiber‑reinforced polymer (CFRP) for wing skins is: A) Lower cost than aluminum. B) Higher stiffness‑to‑weight ratio and fatigue resistance. C) Easier repair in the field. D) Compatibility with all adhesives. Answer: B Explanation: CFRP provides excellent stiffness and fatigue characteristics while being lighter than metal structures. Question 52. The “flap‑lever” in a transport aircraft is typically linked to: A) The aileron control system. B) The hydraulic system via a mechanical actuator. C) The electrical fly‑by‑wire control computer only. D) The engine thrust levers. Answer: B Explanation: Flaps are generally actuated by hydraulic power, with the lever commanding valve positions that control hydraulic flow.
Question 53. A “trailing‑edge flap” primarily increases: A) Maximum cruise speed. B) Lift coefficient at a given angle of attack. C) Wing structural rigidity. D) Fuel consumption during climb. Answer: B Explanation: Deploying trailing‑edge flaps changes the wing camber, raising the lift coefficient and allowing slower flight without stalling. Question 54. The “alpha‑max” angle of attack is: A) The angle at which maximum lift is produced before stall. B) The angle at which the aircraft’s nose‑up trim limit is reached. C) The maximum allowable pitch angle in normal law. D) The angle at which the landing gear retracts. Answer: A Explanation: Alpha‑max is the highest angle of attack that yields maximum lift before aerodynamic stall occurs. Question 55. In a pneumatic anti‑icing system, the “heat‑exchanger” is used to: A) Cool the bleed air before it reaches the wing. B) Transfer heat from engine oil to the bleed air. C) Reduce bleed‑air temperature to prevent overheating of anti‑icing ducts. D) Remove moisture from the air. Answer: C Explanation: The heat‑exchanger cools high‑temperature bleed air to a level suitable for anti‑icing ducts, preventing damage from excessive heat. Question 56. The “ram air turbine” (RAT) provides: A) Primary hydraulic pressure during normal operation. B) Emergency electrical and hydraulic power when all other sources fail.
Explanation: Modern hydraulic systems include particle counters that alert crew/mechanics to contamination levels exceeding limits. Question 60. The “pitot‑static” system provides which of the following parameters? A) Cabin pressure and temperature. B) Airspeed, altitude, and vertical speed. C) Engine thrust and fuel flow. D) Hydraulic pressure and temperature. Answer: B Explanation: Pitot tubes measure dynamic pressure (airspeed), while static ports provide static pressure for altitude and vertical speed. Question 61. The “anti‑ice” system for a propeller typically uses: A) Electrical heating elements embedded in the blades. B) Hot air from the engine’s exhaust. C) Pneumatic boots that expand. D) A glycol spray system. Answer: A Explanation: Propeller anti‑ice on many turboprops uses electric heating elements to prevent ice accumulation on the blades. Question 62. A “flap‑actuator” that uses an electro‑hydraulic drive is advantageous because: A) It eliminates the need for hydraulic fluid. B) It provides faster response and precise positioning. C) It can operate without electrical power. D) It reduces aircraft weight significantly. Answer: B Explanation: Electro‑hydraulic actuators combine the power of hydraulics with the precision of electrical control, offering quick and accurate flap movement.
Question 63. The “zero‑fuel‑weight” (ZFW) of an aircraft is defined as: A) The weight of the aircraft when all fuel is burned. B) The maximum permissible weight of the aircraft without any payload. C) The total aircraft weight minus the usable fuel weight. D) The weight of the aircraft with a full fuel load. Answer: C Explanation: ZFW = Operating Empty Weight + Payload + Reserved Fuel; it excludes usable fuel, representing the weight the aircraft can carry before adding fuel. Question 64. In a “dual‑hydraulic” aircraft, the two hydraulic systems are typically colour‑coded as: A) Red and Yellow B) Blue and Green C) Black and White D) Orange and Purple Answer: B Explanation: Airbus and many other manufacturers use blue and green colour coding to differentiate the two independent hydraulic circuits. Question 65. The “hydraulic pressure relief valve” is set to open at a pressure that is: A) Slightly above normal operating pressure to protect components from over‑pressure. B) Below normal operating pressure to maintain constant flow. C) At the same pressure as the accumulator pre‑charge. D) Only when the system is shut down. Answer: A Explanation: The relief valve vents excess pressure to prevent damage when pressure exceeds the design limit. Question 66. The function of a “fuel‑boost pump” is to: A) Transfer fuel from the wing tanks to the centre tank. B) Increase pressure to feed fuel to the engines when the main pump is insufficient.
