A&P POWERPLANT ORAL EXAM PREP
2026/2027 | AVIATION MECHANIC
QUESTIONS, ANSWERS, TEST BANK & FAA
POWERPLANT EXAM REVIEW | INSTANT
DOWNLOAD PDF
SECTION I: RECIPROCATING ENGINES
1. What are two main causes of a cylinder having low compression?
A) Fuel contamination and oil dilution
B) Piston rings not seating or broken, and valves not seating or burned
C) Carbon deposits and lead fouling
D) Excessive oil consumption and fuel leaks
Correct Answer: B
Rationale: A compression test is a standard diagnostic procedure. Low
compression in a cylinder points to either piston rings not sealing properly or
valves that are not seating correctly. A "wet" compression test can help
differentiate between ring and valve problems .
2. What is the purpose of the induction system in a reciprocating engine?
A) To exhaust combustion gases
B) To deliver air and fuel to the cylinders
C) To cool the engine
D) To lubricate moving parts
Correct Answer: B
,Rationale: The induction system is the pathway for the fuel-air mixture from the
carburetor or fuel injection system to the cylinders. Its design and proper
functioning are critical for engine performance and efficiency .
3. What type of cooling is used on most aircraft reciprocating engines?
A) Liquid cooling
B) Air cooling
C) Oil cooling
D) Electric cooling
Correct Answer: B
Rationale: Most aircraft reciprocating engines are air-cooled, using fins on
cylinders and cylinder heads to increase surface area for heat dissipation. Liquid
cooling is less common in general aviation due to weight and complexity .
4. What is the purpose of cylinder baffles on air-cooled engines?
A) To reduce engine noise
B) To direct cooling air around the cylinders
C) To improve fuel economy
D) To increase engine power
Correct Answer: B
Rationale: Cylinder baffles direct the flow of cooling air around the cylinders to
ensure even cooling and maximize heat dissipation. They prevent air from
bypassing the cylinders, which is critical for preventing cylinder overheating .
5. What is the purpose of the oil filter in a reciprocating engine?
A) To add oil to the system
B) To remove contaminants from the engine oil
,C) To cool the oil
D) To pressurize the oil
Correct Answer: B
Rationale: The oil filter removes contaminants and wear particles from the engine
oil, preventing them from causing damage to engine components. It is a critical
component of the lubrication system .
6. What is the purpose of the oil cooler?
A) To heat the oil
B) To cool the oil
C) To filter the oil
D) To pressurize the oil
Correct Answer: B
Rationale: The oil cooler is a heat exchanger that transfers heat from the engine
oil to the outside air, maintaining the oil at an optimal operating temperature.
Proper oil temperature is critical for engine health and lubrication .
7. What is the purpose of cowl flaps?
A) To control engine temperature by regulating airflow through the engine
compartment
B) To reduce drag
C) To improve aerodynamics
D) To increase engine power
Correct Answer: A
Rationale: Cowl flaps are adjustable panels at the bottom of the engine cowling
that control engine temperature by regulating the amount of cooling air flowing
through the engine compartment .
, 8. A turbine engine operator reports that the engine surges when the throttle is
advanced rapidly. The maintenance manual states that the fuel control unit
includes an acceleration limiter. What is the function of this device?
A) It limits the maximum engine speed to prevent overspeed
B) It schedules fuel flow to prevent compressor stall during rapid throttle
movement
C) It regulates the rate of turbine cooling air flow
D) It adjusts the idle speed
Correct Answer: B
Rationale: An acceleration limiter prevents compressor stall or surge when the
throttle is advanced quickly by scheduling fuel flow to ensure the combustion
process can keep up with the rapid increase in air flow .
9. How are gas turbine engine tachometers calibrated?
A) In revolutions per minute (RPM)
B) In percent RPM
C) In feet per minute
D) In miles per hour
Correct Answer: B
Rationale: Turbine engine tachometers are calibrated in percent RPM rather than
absolute RPM because the engine's operating range is expressed as a percentage
of its maximum rated RPM. This standardization allows pilots to monitor engine
performance accurately across different engine models .
10. On a turbine engine, what is the engine pressure ratio (EPR) and what does it
indicate?
2026/2027 | AVIATION MECHANIC
QUESTIONS, ANSWERS, TEST BANK & FAA
POWERPLANT EXAM REVIEW | INSTANT
DOWNLOAD PDF
SECTION I: RECIPROCATING ENGINES
1. What are two main causes of a cylinder having low compression?
A) Fuel contamination and oil dilution
B) Piston rings not seating or broken, and valves not seating or burned
C) Carbon deposits and lead fouling
D) Excessive oil consumption and fuel leaks
Correct Answer: B
Rationale: A compression test is a standard diagnostic procedure. Low
compression in a cylinder points to either piston rings not sealing properly or
valves that are not seating correctly. A "wet" compression test can help
differentiate between ring and valve problems .
2. What is the purpose of the induction system in a reciprocating engine?
A) To exhaust combustion gases
B) To deliver air and fuel to the cylinders
C) To cool the engine
D) To lubricate moving parts
Correct Answer: B
,Rationale: The induction system is the pathway for the fuel-air mixture from the
carburetor or fuel injection system to the cylinders. Its design and proper
functioning are critical for engine performance and efficiency .
3. What type of cooling is used on most aircraft reciprocating engines?
A) Liquid cooling
B) Air cooling
C) Oil cooling
D) Electric cooling
Correct Answer: B
Rationale: Most aircraft reciprocating engines are air-cooled, using fins on
cylinders and cylinder heads to increase surface area for heat dissipation. Liquid
cooling is less common in general aviation due to weight and complexity .
4. What is the purpose of cylinder baffles on air-cooled engines?
A) To reduce engine noise
B) To direct cooling air around the cylinders
C) To improve fuel economy
D) To increase engine power
Correct Answer: B
Rationale: Cylinder baffles direct the flow of cooling air around the cylinders to
ensure even cooling and maximize heat dissipation. They prevent air from
bypassing the cylinders, which is critical for preventing cylinder overheating .
5. What is the purpose of the oil filter in a reciprocating engine?
A) To add oil to the system
B) To remove contaminants from the engine oil
,C) To cool the oil
D) To pressurize the oil
Correct Answer: B
Rationale: The oil filter removes contaminants and wear particles from the engine
oil, preventing them from causing damage to engine components. It is a critical
component of the lubrication system .
6. What is the purpose of the oil cooler?
A) To heat the oil
B) To cool the oil
C) To filter the oil
D) To pressurize the oil
Correct Answer: B
Rationale: The oil cooler is a heat exchanger that transfers heat from the engine
oil to the outside air, maintaining the oil at an optimal operating temperature.
Proper oil temperature is critical for engine health and lubrication .
7. What is the purpose of cowl flaps?
A) To control engine temperature by regulating airflow through the engine
compartment
B) To reduce drag
C) To improve aerodynamics
D) To increase engine power
Correct Answer: A
Rationale: Cowl flaps are adjustable panels at the bottom of the engine cowling
that control engine temperature by regulating the amount of cooling air flowing
through the engine compartment .
, 8. A turbine engine operator reports that the engine surges when the throttle is
advanced rapidly. The maintenance manual states that the fuel control unit
includes an acceleration limiter. What is the function of this device?
A) It limits the maximum engine speed to prevent overspeed
B) It schedules fuel flow to prevent compressor stall during rapid throttle
movement
C) It regulates the rate of turbine cooling air flow
D) It adjusts the idle speed
Correct Answer: B
Rationale: An acceleration limiter prevents compressor stall or surge when the
throttle is advanced quickly by scheduling fuel flow to ensure the combustion
process can keep up with the rapid increase in air flow .
9. How are gas turbine engine tachometers calibrated?
A) In revolutions per minute (RPM)
B) In percent RPM
C) In feet per minute
D) In miles per hour
Correct Answer: B
Rationale: Turbine engine tachometers are calibrated in percent RPM rather than
absolute RPM because the engine's operating range is expressed as a percentage
of its maximum rated RPM. This standardization allows pilots to monitor engine
performance accurately across different engine models .
10. On a turbine engine, what is the engine pressure ratio (EPR) and what does it
indicate?
