Aircraft General Knowledge – Airframe, Systems, Electrics, Powerplant
Airframe questions test structures, loads, fatigue, corrosion, flight controls and landing gear. The exam favours applied understanding: why a semi-monocoque wing carries bending, how load factors affect stress, and what inspection finds.
Structure and loads
A semi-monocoque fuselage uses skin, stringers, frames and bulkheads; the skin carries shear and part of the bending, stringers carry bending, frames hold shape. Limit load is the maximum expected in service; ultimate load is 1.5 × limit, and structure must not fail below ultimate. Cabin pressurization adds cyclic stress, so fatigue inspections focus on joints, cutouts and pressure bulkheads.
Flight controls and gear
Ailerons control roll, elevator pitch, rudder yaw; trim reduces control force. Flaps increase lift and drag for take-off and landing. Landing gear absorbs landing loads; shimmy dampers and torque links matter. Hydraulic systems actuate gear, brakes and some controls; check pressure and fluid loss indications.
Worked example
A wing spar carries a 60 kN bending load over an effective area of 0.03 m². Stress = force/area = 60,000 N / 0.03 m² = 2.0 MPa. If the allowable is 3.0 MPa, the margin is positive; if the load factor doubles in a 2 g manoeuvre, stress becomes 4.0 MPa and exceeds allowable.
Traps
Confusing limit and ultimate load; assuming composite structure has no fatigue; missing corrosion types such as exfoliation and galvanic corrosion; using gross area instead of effective area.