ATPL Aero & Systems study guide
ATPL Aero & Systems · Work through your exam, one topic at a time.
Aircraft General Knowledge - Airframes, Systems and Powerplants is the technical systems paper in the EASA ATPL (Aeroplane) theoretical knowledge set. It is aimed at candidates working toward a commercial pilot licence or ATPL, whether in a modular course or an integrated programme, and it also underpins the type-specific ground school that follows. The ATPL Aero & Systems study guide has 10 sections and about 3,562 words.
01Airframe Structure, Loads and Structural Limitations
An airframe is a load path. Every question about structure reduces to asking which member carries which load and what limits that member.
361 words, about 2 min02Hydraulic Systems and Hydromechanics
Hydraulic systems transmit force by pressure acting on area: F = p × A. Because liquids are effectively incompressible, pressure is uniform throughout a connected static system, so a small piston moving a long distance can move a large piston a short distance with the same work.
391 words, about 2 min03Pneumatic, Air-Conditioning and Pressurisation Systems
Transport aircraft bleed air from the engine compressor (HP and LP stages, with a pressure-regulating and shut-off valve), from the APU, or from a ground cart. Bleed air is hot and at high pressure, so it passes through a pre-cooler (fan air) and then the air-conditioning pack.
374 words, about 2 min04Electrical Systems, Generation and Distribution
Aircraft use 28 V DC (small aircraft) or 115 V AC 400 Hz (transports), with 235 V AC on some large types. AC is generated by integrated drive generators (IDG) or variable frequency generators; the IDG holds constant output frequency despite engine speed variation.
377 words, about 2 min05Flight Controls, Fly-by-Wire and Autopilot Actuation
Primary controls are elevator, aileron and rudder (pitch, roll, yaw); secondary are flaps, slats, spoilers and trim. Control surfaces are actuated by cables and pulleys, push-pull rods, or hydraulically powered actuators.
341 words, about 2 min06Landing Gear, Wheels, Tyres and Brakes
Landing gear absorbs landing and taxi loads through shock absorbers (oleo struts) that convert kinetic energy into heat. A gas (nitrogen) spring supports the aircraft and oil metering dissipates energy.
339 words, about 2 min07Fuel Systems, Tanks and Fuel Management
Fuel is carried in integral tanks (the wing structure sealed to form a tank), bladder tanks or rigid tanks. Integral tanks save weight but require sealing and inspection.
357 words, about 2 min08Ice and Rain Protection, Fire and Smoke Protection
Ice protection is either anti-icing (preventing ice) or de-icing (removing ice). Thermal anti-icing uses bleed air through piccolo tubes in the wing leading edge and engine intakes; electrical heating is used for pitot tubes, static ports, TKS weeping wings and propeller blades.
364 words, about 2 min09Piston Engines, Propellers and Engine Control
A piston engine operates on induction, compression, power and exhaust strokes. Power depends on volumetric efficiency, mixture and ignition timing.
312 words, about 2 min10Gas Turbine Engines, Thrust, Performance and Monitoring
A turbojet or turbofan operates on the Brayton cycle: intake, compression, combustion, exhaust. Thrust is produced by accelerating a mass of air: F = ṁ × (Vj − V0), plus a pressure term at the nozzle.
346 words, about 2 min