Aeroplane Aerodynamics, Structures and Systems
Core concepts
Combine aerodynamics with aircraft hardware. Cover high-lift devices (flaps, slats, spoilers), flight controls (ailerons, elevators, rudder, trim, fly-by-wire), hydraulic and pneumatic power, air conditioning and pressurisation, fuel, ice and rain protection, landing gear, and the electrical and avionics architecture. Understand structural design philosophy: fail-safe, safe-life, damage tolerance, and the purpose of structural inspections.
Traps to watch
- Spoilers versus speedbrakes: both dump lift, but their primary function and deployment differ; spoilers also assist roll control on some types.
- Pressurisation: the outflow valve controls cabin pressure; the safety valve protects against overpressure. Do not confuse them.
- Hydraulic system colour coding and redundancy: know which system powers which service.
- Fail-safe versus safe-life: fail-safe structures tolerate damage until inspection; safe-life components are retired at a fixed life.
- Fly-by-wire: normal, alternate and direct laws have different levels of protection; questions test which protections remain.
Worked example
On a typical twin-jet, loss of one hydraulic system may leave certain services inoperative; the remaining systems provide redundancy. In a fly-by-wire aircraft, degradation to alternate law typically removes some envelope protections (such as certain pitch protections) while retaining basic control - the aircraft remains controllable but with reduced protection.
Rule of thumb
For systems questions, ask "what is the source of power, what is the redundancy, and what is the failure effect?" That triad structures almost every answer.