Practical Practice Exam Questions And

FAA Mechanic Powerplant Oral & Practical Practice Exam Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the purpose of the turbocharger on an aircraft reciprocating

engine?

• To reduce exhaust noise
• To increase engine RPM
• To maintain sea-level pressure at higher altitudes
• To improve fuel efficiency at ground level

Rationale: Turbochargers compress the intake air to compensate for

reduced air density at high altitudes, maintaining engine performance.

• Which type of ignition system is typically used on a reciprocating aircraft

engine? 1 / 4

• Glow plug ignition
• Magneto ignition
• Diesel ignition
• Capacitor discharge ignition

Rationale: Magnetos generate their own electricity and do not require

external power, making them reliable for aircraft use.

• What is the primary purpose of an aircraft engine propeller governor?
• To reduce engine noise
• To prevent propeller blade damage
• To maintain a constant engine RPM
• To control engine fuel mixture

Rationale: The governor adjusts propeller blade pitch to keep RPM

constant under varying loads.

• Which factor primarily determines the maximum allowable manifold

pressure for a turbocharged engine?

• Ambient temperature
• Engine structural limits
• Fuel octane rating
• Propeller pitch

Rationale: Engine design and component limits dictate the maximum

manifold pressure to prevent damage. 2 / 4

• Which of the following is a primary function of the exhaust system in a

reciprocating engine?

• Cooling the intake air
• Filtering fuel impurities
• Removing combustion gases and reducing back pressure
• Increasing mixture density

Rationale: The exhaust system safely expels combustion gases while

minimizing back pressure that could reduce engine efficiency.

• What is the purpose of a carburetor heat control?
• To increase fuel efficiency
• To prevent or remove carburetor ice
• To reduce engine temperature
• To increase manifold pressure

Rationale: Carburetor heat uses warm air to prevent ice from forming in

the carburetor venturi.

• What is the primary role of an aircraft engine oil system?
• Reduce fuel consumption
• Increase combustion efficiency
• Lubricate, cool, and clean engine components
• Control ignition timing

Rationale: Engine oil reduces friction, dissipates heat, and carries away

contaminants. 3 / 4

• What is the effect of detonation in a reciprocating engine?
• Reduced fuel consumption
• High-temperature, uncontrolled combustion that can damage the

engine

• Smoother engine operation
• Improved power output

Rationale: Detonation occurs when fuel-air mixture explodes prematurely,

causing shock waves and potential engine damage.

• What is the main advantage of a constant-speed propeller?
• Simpler design
• Lighter weight
• Maintains optimal engine RPM for varying flight conditions
• Reduces fuel consumption at all speeds

Rationale: Constant-speed propellers adjust blade pitch to keep engine

RPM steady, maximizing efficiency and performance.

• Which component prevents reverse rotation of a turboprop engine?
• Propeller governor
• Free-turbine coupling
• Reduction gearbox
• Magneto system

Rationale: A free-turbine coupling allows the propeller to stop or rotate

backward without damaging the engine.

• / 4