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
Which statement about pre-ignition in a reciprocating engine is correct?
Answer: Pre-ignition occurs before the spark plug fires and can cause engine damage
Pre-ignition occurs when the fuel-air charge ignites before the spark plug fires, often due to a hot spot, and can cause severe engine damage.
The compressor pressure ratio of a turbine engine is defined as:
Answer: Compressor outlet total pressure divided by compressor inlet total pressure
Compressor pressure ratio is the ratio of total air pressure at the compressor outlet to total air pressure at the compressor inlet, indicating compression efficiency.
A reciprocating engine has excessive blow-by past the piston rings. Which instrument indication would you expect?
Answer: Increased oil consumption and crankcase pressure
Blow-by allows combustion gases to pass the piston rings into the crankcase, causing increased crankcase pressure and oil consumption.
During turbine engine ground run-up, a 'hung start' is characterized by:
Answer: RPM stabilizing below idle with exhaust temperature continuing to rise
A hung start occurs when the engine lights off but RPM stabilizes at a sub-idle value while EGT continues to rise, risking a hot start.
What does the term 'specific fuel consumption' (SFC) describe in turbine engines?
Answer: The pounds of fuel burned per hour per pound of thrust produced
Specific fuel consumption (SFC) is the ratio of fuel flow (lb/hr) to thrust produced (lb), measuring how efficiently an engine converts fuel into thrust.
Which ignition system component stores energy and releases it as a high-intensity spark during engine starting in a gas turbine?
Answer: Capacitor-discharge exciter box
The capacitor-discharge exciter box stores electrical energy and releases it as a high-voltage, high-energy spark to the igniters during turbine engine starting.
Which of the following best describes 'compressor stall' in a gas turbine engine?
Answer: Airflow through a compressor stage separates from the blade surfaces, causing flow disruption
Compressor stall occurs when the angle of attack on compressor blades becomes excessive, causing boundary layer separation and disrupted airflow.