Aircraft General Knowledge
Aircraft General Knowledge tests how the airframe, systems, powerplant and instruments work together, and how their failures present to the crew.
Airframe and flight controls
- Semi-monocoque construction uses skin, stringers, frames and spars; fail-safe and damage-tolerance design requires inspection for cracks and corrosion.
- Primary controls are ailerons, elevator and rudder; secondary controls include flaps, slats, spoilers and trim. Trim reduces control force, not stall speed.
Systems
- Hydraulics: reservoir, engine-driven pump, accumulator, relief valve, selector valve and actuators. A leak can cause loss of a system; check quantity and pressure.
- Electrical: DC bus bars, generators or alternators, battery and circuit breakers. Know what is essential and what is shed.
- Pneumatics: bleed air for pressurization, anti-ice and engine starting; know valve positions and limits.
- Fuel: tanks, boost pumps, crossfeed and vents; observe imbalance limits.
Powerplant and instruments
- Turbine engine: N1/N2, EGT, fuel flow, oil pressure and temperature. EGT indicates turbine temperature; exceedance damages the hot section.
- Pitot-static: ASI, altimeter and VSI. A blocked pitot affects the ASI; a blocked static affects ASI, altimeter and VSI.
- Gyroscopic: attitude indicator, heading indicator and turn coordinator; suction or electrically driven.
Worked example
An aircraft climbs with its pitot tube blocked by ice. The ASI behaves like an altimeter: in a climb, trapped pressure causes indicated speed to increase; in a descent it decreases. The altimeter and VSI remain normal if static pressure is clear. Use attitude and power, and select pitot heat.
Traps
- Treating EGT as cylinder head temperature on a turbine.
- Assuming a standby battery powers all avionics.
- Ignoring static leak effects on all three pitot-static instruments.