Aircraft General Knowledge
Airframe, powerplant and systems
You must understand the layout and purpose of the primary and secondary flight controls, the hydraulic, electrical, fuel, pneumatic and ice-protection systems, and the limitations that follow from them. For piston engines know the four-stroke cycle, mixture control, carburettor icing, detonation and pre-ignition; for turbines know N1/N2, EPR, EGT and the meaning of take-off and continuous limits. System questions often turn on redundancy: which bus feeds which pump, what happens when a generator fails, and what is lost with a hydraulic failure.
Instruments
Pitot-static instruments (ASI, altimeter, VSI) depend on static pressure; gyroscopic instruments depend on rigidity and precession. Know the errors: position error, instrument error, compressibility, density error, and the effects of a blocked pitot or static source. A blocked pitot tube with the static port open makes the ASI behave like an altimeter; a blocked static source makes the ASI under-read in a climb and over-read in a descent, while the altimeter freezes at the trapped pressure.
Worked example
If the static source blocks at 5,000 ft during a climb, the altimeter remains near 5,000 ft and the VSI reads zero. Treat the aircraft as having unreliable pressure information: use the alternate static source, and cross-check attitude and GPS altitude.
Rule of thumb
Pitot blocked - ASI becomes an altimeter. Static blocked - ASI becomes a poor climb/descent indicator and the altimeter is frozen.