Aircraft General Knowledge: Airframe, Systems, Electrics, Powerplant and Emergency Equipment
What the exam tests
This domain tests airframe structures, flight controls, hydraulic and pneumatic systems, electrical generation and distribution, fuel systems, pressurisation, ice and rain protection, fire detection and extinguishing, and emergency equipment. Questions often ask what happens after a system failure and which actions are immediate.
Core systems
- Primary controls are ailerons, elevator and rudder; trim, flaps and slats are secondary or auxiliary.
- Hydraulic systems store pressure in accumulators and may have engine-driven and electric pumps; loss of pressure increases control forces or makes some services unavailable.
- Electrical buses are arranged so essential loads can be fed from the battery or standby alternator/generator after a failure.
- Fuel systems must prevent unporting, manage imbalance and provide usable fuel; fuel gauges are not a substitute for fuel planning.
- Pressurisation uses bleed air and outflow valves; rapid decompression requires oxygen masks and emergency descent.
- Fire detection warns of overheat or fire; extinguishing agents must be used only on the affected zone.
Worked example
A single alternator fails in flight. The battery bus continues to supply essential instruments, radios and one fuel pump, but battery endurance is limited. The pilot reduces non-essential electrical load, checks the standby source, avoids unnecessary radio transmission, and plans to land at the nearest suitable aerodrome. Continuing IFR into IMC without a reliable charging source is not acceptable.
Traps
Do not assume a battery will last indefinitely. Do not reset a tripped circuit breaker repeatedly without knowing the cause. Do not confuse a fire warning with a smoke warning, and do not delay an emergency descent after a rapid decompression.