Aircraft General Knowledge
AGK tests how the airframe, engine, systems and instruments work and how their failure shows in the cockpit. The PPL level is practical: know what a gauge is telling you and what to do when it is not.
Airframe and controls
The primary controls are ailerons (roll), elevator (pitch) and rudder (yaw); flaps increase lift and drag; trim relieves control force. Mass balancing prevents flutter. Control locks must be removed before flight.
Engine and propeller
A four-stroke piston engine produces power on the power stroke; the mixture control sets fuel/air ratio; the carburettor can ice at 0–20°C with high humidity. Magnetos are independent ignition sources; a mag check drop of about 50–150 rpm is normal, but a dead mag or excessive drop is not. A fixed-pitch propeller converts rpm into thrust.
Systems and instruments
Pitot pressure drives the ASI; static pressure drives the altimeter, VSI and ASI. A blocked static source makes the ASI behave like an altimeter and the VSI freeze. Gyroscopic instruments depend on vacuum or electricity.
Worked example
A 28 V system has a 70 A alternator (1,960 W). Continuous loads are avionics 12 A, nav lights 6 A, strobes 4 A, pitot heat 10 A and fuel pump 5 A = 37 A. A 25 A landing light raises this to 62 A, leaving 8 A. If the battery is charging at 10 A, demand is 72 A and exceeds the alternator, so shed a non-essential load.
Traps
Treating a gauge as a direct measurement; forgetting carb ice on a warm humid day; ignoring a magneto drop; assuming the alternator charges a flat battery in flight.