Showing content mapped to EASA Part-66. Change authority in the header.
Turbine engine principles
The gas turbine works on the Brayton cycle: suck, squeeze, burn, blow. Thrust comes from accelerating a mass of air rearwards (F = m × (Vj − Va)). Engine types: turbojet, turbofan (high bypass on transport aircraft), turboprop and turboshaft. Key sections: intake, compressor, combustion, turbine, exhaust.
Engine indicating systems
Parameters displayed to the crew: N1 and N2 (or N3), EPR, EGT/ITT, fuel flow, oil pressure/temperature/quantity and vibration. Speed is sensed by tachometer probes or phonic wheels, temperature by chromel-alumel thermocouples in parallel, and vibration by accelerometers. Understanding sensor types and their signal characteristics is central to B2 troubleshooting.
Engine control — FADEC
FADEC (Full Authority Digital Engine Control) uses dual-channel EECs with independent sensors and a dedicated alternator (PMA) for power. It schedules fuel flow, variable stator vanes, bleed valves, ignition and thrust reverse, provides overspeed protection and reports faults for maintenance. Thrust lever position becomes an electrical demand rather than a mechanical linkage.
Starting & ignition
Air-turbine starters use bleed air from the APU, ground cart or cross-bleed. The start sequence monitors N2 rise, fuel introduction, light-up and EGT; faults include hung start, hot start and wet start. Ignition uses high-energy exciters and igniter plugs — treat as a high-voltage hazard and observe the discharge delay before disconnecting.
Monitoring and interfaces
Engine data feeds EICAS/ECAM, the FMS for performance, and maintenance systems (ACMS/CMC) for trend monitoring. Trend analysis of EGT margin, fuel flow and vibration is used to predict deterioration and plan removals. Thrust-reverser control and indication involve interlocks with weight-on-wheels and throttle position.