Powerplant Systems & Maintenance Flashcards
7 cards from real Airframe Mechanic Certification 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 Systems & Maintenance flashcards as text
What is the primary purpose of an engine's magneto impulse coupling?
Answer: Retard ignition timing during starting to prevent kickback
Impulse couplings retard and then rapidly release to produce a hot spark at low engine RPM during starting, preventing kickback.
When inspecting a turbine engine's compressor blades, a nick that exceeds allowable limits requires:
Answer: Repair per the manufacturer's structural repair manual
Damage exceeding allowable limits must be repaired per the manufacturer's structural repair manual or the engine must be removed.
In a reciprocating engine, detonation differs from pre-ignition in that detonation:
Answer: Results from fuel-air mixture auto-igniting after normal spark ignition
Detonation is explosive auto-ignition of the end charge after normal spark ignition, whereas pre-ignition occurs before the spark plug fires.
Which statement about turbine engine oil systems is correct?
Answer: Most turbine engines use a dry sump oil system
Turbine engines use a dry sump system where oil is stored in a separate tank rather than the engine sump.
A fuel control unit (FCU) on a turbine engine primarily schedules fuel flow based on:
Answer: Compressor inlet temperature and pressure, throttle position, and RPM
The FCU uses multiple inputs including compressor inlet conditions, throttle position, and RPM to schedule the correct fuel flow.
When performing a compression check on a reciprocating engine cylinder, a reading of 72/80 indicates:
Answer: The cylinder is serviceable per most manufacturer limits
A differential compression ratio of 72/80 (90%) is typically within the acceptable range of 60/80 or greater per most manufacturers.
What does EGT (Exhaust Gas Temperature) measure in a turbine engine?
Answer: Temperature of exhaust gases at a specified turbine stage
EGT measures the temperature of exhaust gases at a specified point aft of the turbine section, used as an indicator of engine health and limits.