Aircraft General Knowledge: Airframes, Systems and Powerplants
Airframe and systems essentials
You must be able to describe the primary structure (fuselage, wings, empennage, landing gear) and how loads are carried: tension, compression, shear, bending and torsion. Know the flight control surfaces and their secondary effects - aileron drag and adverse yaw, elevator effectiveness with speed, rudder and yaw coupling. Systems questions cover hydraulic, pneumatic, electrical, fuel, and ice protection: know what happens when a pump fails, how a bus tie works, and why fuel is managed by tank sequencing rather than simply total quantity.
Powerplants
For piston engines, understand the four-stroke cycle, mixture and carburettor icing, detonation versus pre-ignition, and the purpose of magneto checks. For turboprops and jets, know the compressor–combustion–turbine sequence, the meaning of EGT/ITT and N1/N2, and why limiting parameters are expressed as maximum continuous or take-off limits. A frequent trap is confusing detonation (uncontrolled explosive combustion after ignition) with pre-ignition (ignition before the spark). Another is assuming that a higher power setting always means a richer mixture - mixture is set according to altitude and temperature.
Worked example / rule of thumb
Carburettor icing rule of thumb: the risk is highest with moderate temperature and high humidity, and carburettor heat should be applied before the ice becomes severe, because heat needs a functioning engine to work. For systems, use the "source–distribution–user" chain: identify the source, the distribution path, and the user, then ask what fails when the middle link breaks.
Study strategy
Draw each system as a simple block diagram once; that diagram answers most system questions.