Aircraft General Knowledge: Airframe, Powerplant and Systems
What you must know
AGK questions cover the airframe structure, flight controls, landing gear, powerplant, fuel, electrical, hydraulic, pneumatic, ice and rain protection, and instruments. Understand the piston engine cycle, carburettor versus fuel injection, mixture leaning with altitude, magneto ignition and the purpose of the dual system, constant-speed propeller operation, and the function of the alternator and battery. Know the pitot-static system and the instruments driven by it - airspeed indicator, altimeter, vertical speed indicator - and the gyroscopic instruments: attitude indicator, heading indicator and turn coordinator, including their power sources and failure indications.
Traps in questions
- Confusing which instruments are suction-driven (gyroscopic) versus electrically driven.
- Blocked pitot tube: the ASI behaves like an altimeter. Blocked static: the ASI reads high in climb and low in descent.
- Carburettor icing occurs at outside air temperatures well above freezing, especially in humid conditions at low power.
- Magnetos are independent of the electrical system; the engine keeps running with the alternator failed.
Worked rule of thumb
Use the "three sources" check: pitot pressure, static pressure, gyroscope. For every instrument question, name the source first, then predict the indication. Example: with a blocked static port, in a climb the ASI over-reads because trapped static pressure stays higher than ambient.
Study approach
Draw the pitot-static lines and label each instrument. Then draw the electrical system and mark what fails when the alternator drops offline.