Powerplant Theory and Maintenance Flashcards
7 cards from real AMT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Powerplant Theory and Maintenance flashcards as text
What is the purpose of the intercooler in a turbocharged reciprocating engine?
Answer: To reduce the temperature of compressed induction air
An intercooler reduces the temperature of induction air after compression by the turbocharger, increasing air density for better fuel-air mixture.
A reciprocating engine is said to be 'detonating' when:
Answer: The fuel-air mixture explodes instantaneously rather than burning progressively
Detonation occurs when the fuel-air mixture explodes instantaneously instead of burning progressively, causing severe pressure spikes and potential engine damage.
Which turbine engine component is most susceptible to thermal fatigue and oxidation?
Answer: High-pressure turbine blades
High-pressure turbine blades operate at the highest temperatures in the engine and are therefore most susceptible to thermal fatigue and oxidation.
When performing a differential compression test on a reciprocating engine cylinder, a reading of 72/80 psi is obtained. What does this indicate?
Answer: The cylinder is serviceable; the leakage is within acceptable limits
A 72/80 reading (90% efficiency) is within the typically accepted limit of 75–80% of regulated pressure, indicating the cylinder is serviceable.
In a gas turbine engine, the primary function of the diffuser section is to:
Answer: Convert air velocity into static pressure
The diffuser section converts high-velocity compressor discharge air into high-static-pressure, lower-velocity airflow before combustion.
Which type of oil system is commonly used in dry-sump aircraft engines?
Answer: A pressure pump and scavenge pump transfer oil to and from an external tank
Dry-sump systems use a pressure pump to deliver oil and one or more scavenge pumps to return it to an external oil tank, keeping the crankcase free of oil.
What is the role of the fuel control unit (FCU) on a turbine engine?
Answer: To meter fuel flow based on power lever position and engine parameters
The FCU meters the correct quantity of fuel to the combustion chamber based on power lever position, engine speed, and inlet conditions.