Powerplant Systems and Components
Turbine and piston fundamentals
For turbine engines, know the sections (intake, compressor, combustion, turbine, exhaust), the meaning of bypass ratio, EPR and N1/N2, and how each parameter is sensed. Understand fuel systems (boost pumps, HP pump, fuel control unit or FADEC, fuel/oil heat exchanger), lubrication (dry-sump, oil tank, scavenge, chip detectors), ignition (exciter, igniter plugs, starting sequence), starting (starter, start valve, light-up, hung start, hot start) and thrust reversal (cascade, bucket, hot-stream). For piston engines, know the four-stroke cycle, carburettor icing versus fuel injection, magneto checks and the reason for dual ignition.
Traps
Questions confuse hung start (rpm stagnates, temperature moderate) with hot start (temperature rises rapidly, often due to excess fuel). They confuse N1 (fan/LP compressor, primary thrust parameter on high-bypass) with N2 (HP compressor). They test the purpose of the fuel/oil heat exchanger (oil cooling and fuel heating, anti-icing of fuel) and the meaning of FADEC redundancy (dual channels, active/standby).
Worked example
A start shows rising EGT with slow N2. Reason: excess fuel with insufficient airflow - a hot start. Action: abort the start, motor the engine to clear fuel, investigate. Choose the option that aborts and motors, never the option that continues to idle.
Rule of thumb
For any abnormal parameter, ask what is being measured, what drives it, and what protects it. If the option ignores the protective action, it is wrong.