Aircraft General Knowledge
Airframes, Systems, and Powerplants
This domain covers aircraft structure, flight controls, landing gear, hydraulic, electrical, and fuel systems, plus engine operation and instruments. For the PPA, you need a basic understanding of how these systems work and common failure modes.
Instruments
Study the pitot-static system: airspeed indicator, altimeter, vertical speed indicator. Understand how blockages affect readings. Also, gyroscopic instruments: attitude indicator, heading indicator, turn coordinator. Know their power sources and errors.
Traps
Questions often present scenarios: "What happens if the pitot tube is blocked?" The airspeed indicator acts like an altimeter. Or "What is the source of power for the turn coordinator?" It is electrically driven. Also, know the difference between indicated, calibrated, true, and ground speed.
Worked Example
If the static port is blocked, the altimeter will freeze at the altitude where the blockage occurred, and the airspeed indicator will over-read at higher altitudes. This is a classic exam question.
Rule of Thumb
For pitot-static: "Pitot blocked: airspeed behaves like altimeter; static blocked: airspeed behaves like a reverse altimeter." For gyros: attitude and heading indicators are usually vacuum-driven; turn coordinator is electric.