PLT115: Aircraft Engine
What code PLT115 covers, why the FAA tests it, and how to study Aircraft Engine before your checkride.
Recall aircraft engine - detonation/backfiring/after firing, cause/characteristics
What this means for your checkride
Detonation is the uncontrolled explosion of the fuel-air charge instead of a smooth burn, caused by too-low-grade fuel, an over-lean mixture, or excessive heat. It spikes cylinder pressure and temperature and can quickly damage the engine.
Detonation causes real engine damage, so the FAA tests its causes and the fixes: a richer mixture, lower power, and the correct fuel grade.
Pilots confuse detonation with preignition. Detonation is an abnormal burn after normal ignition; preignition is ignition before the spark, often from a hot spot.
Where to study it
A code on your test report is an area of deficiency. An authorized instructor must review it with you and endorse that review before you take the practical test, and the examiner may revisit it during the oral. Study it until you can explain it out loud, not just recognize the answer.