Aircraft General Knowledge - Airframe, Systems, Electrics, Powerplant and Emergency Equipment
What this domain tests
Airframe, systems, electrics, powerplant and emergency equipment questions test how a transport aeroplane is built and how it fails. Expect semi-monocoque structures, hydraulics, pressurisation, electrical distribution, gas-turbine parameters, and the location and operation of emergency equipment.
Core rules
- Structure: stressed skin, stringers and frames carry bending and shear; a semi-monocoque fuselage uses the skin for part of the load. Redundancy comes from multiple spars and crack-stopping features.
- Hydraulics: engine-driven pumps plus electric backup; a pressure-loss checklist normally gives gravity gear extension and alternate braking.
- Electrics: AC generators feed the main buses through generator control units; the battery bus keeps essential instruments alive. A TRU converts AC to DC.
- Pressurisation: cabin altitude and differential pressure are controlled by outflow valves; masks deploy automatically at about 14,000 ft cabin altitude.
- Powerplant: N1 (fan/LP spool) and N2 (HP spool) speeds, EGT and fuel flow are the primary indications; starting is limited by EGT and starter duty cycle.
Worked example
Both generators trip in cruise. The battery bus supplies standby instruments and the radio for a limited time, but the battery is not a long-term source. The correct action is to reduce electrical load, attempt a generator reset once, and plan to land before battery endurance expires.
Traps
Do not assume all hydraulic systems are identical; check which system drives which service. In fire drills the order is often throttle, fuel, ignition, extinguisher, but the checklist wording matters. Emergency equipment locations are asked literally: know which exits have slides and where the portable oxygen bottles are stowed.