Showing content mapped to EASA Part-66. Change authority in the header.
Fundamentals & performance
Thrust = mass flow × (jet velocity − aircraft velocity), plus a pressure term. Thrust falls with altitude (density) and rises in cold air. Flat rating protects the engine by holding thrust constant up to a corner-point temperature. Propulsive efficiency improves with a higher bypass ratio; specific fuel consumption (SFC) is fuel used per unit thrust per hour.
Intake, compressors and combustion
The intake must deliver clean, distortion-free subsonic air to the compressor. Axial compressors use rotating blades and stator vanes; each stage adds a small pressure rise. Surge/stall is prevented by variable inlet guide vanes, variable stator vanes, bleed valves and multi-spool design. Combustion chambers (can, cannular, annular) burn fuel at roughly constant pressure with primary, secondary and dilution airflow.
Turbines and exhaust
Turbines extract energy to drive compressors and accessories. Blades use directionally solidified or single-crystal alloys, internal cooling passages and thermal barrier coatings. Fixings are typically fir-tree roots with defined creep and tip-clearance limits. The exhaust system provides propelling nozzle, and may include mixers, noise attenuation and thrust reversers (cascade, bucket or cold stream).
Fuel and control systems
Fuel path: LP pump, fuel/oil heat exchanger, filter, HP pump, fuel control unit or FADEC-controlled metering valve, flow meter, spray nozzles. Hydromechanical units are largely superseded by FADEC. Protections include overspeed limiting, acceleration/deceleration scheduling and flameout protection.
Oil, air and ignition systems
Oil systems are self-contained pressure, scavenge and breather circuits with synthetic oil, coolers, filters, magnetic chip detectors and SOAP sampling. Internal air systems provide cooling, sealing and bearing-load balance; external bleed feeds anti-ice, air conditioning and starting. Ignition uses high-energy exciters with two igniters — used for start, relight and continuous ignition in bad weather.
Maintenance & inspection
Practices include borescope inspection, compressor water wash, blade blend limits from the engine manual, trend monitoring of EGT margin and vibration, engine change and QEC build, ground running and safety zones (intake hazard and exhaust danger areas). Life-limited parts are controlled by cycle count.