Aircraft General Knowledge
AGK questions test systems knowledge: airframe, powerplant, fuel, oil, electrical, pitot-static, and flight instruments. Understand the four-stroke cycle (induction, compression, combustion, exhaust), the function of the carburettor and the risk of carburettor icing, and the purpose of mixture control with altitude. Know the pitot-static system: the pitot tube feeds the airspeed indicator; the static port feeds the altimeter, vertical speed indicator and airspeed indicator. Blocked pitot or static sources produce characteristic errors that examiners love.
Traps: candidates confuse the instruments fed by pitot versus static pressure, and misidentify the effect of a blocked static port (the ASI behaves like an altimeter). Others forget that carburettor icing can occur at outside air temperatures well above freezing, especially in humid conditions, and that applying carburettor heat enriches the mixture and can cause a temporary power drop. Also know the difference between indicated, calibrated and true airspeed.
Worked example: in descent with a blocked static port, the altimeter sticks, the VSI reads zero, and the ASI over-reads as altitude increases (because trapped static pressure is higher than ambient). Rule of thumb: pitot blockage affects the ASI only; static blockage affects all three pressure instruments. Know the magneto check: a drop within limits on either magneto, with the engine running smoothly, is normal; excessive drop or rough running indicates a problem.