Module 15 Gas Turbine Engine case studies
Module 15 Gas Turbine Engine · Put your knowledge to work in context.
Module 15, Gas Turbine Engine, is one of the knowledge modules in the EASA Part-66 aircraft maintenance licence syllabus. It is aimed at candidates working toward a turbine-engine rating or a Category B1/B2/B3 licence, and at certifying staff who need to show they understand how a gas turbine engine and its systems actually function before they sign anything off. The module moves from fundamentals - thermodynamics, thrust, engine layouts and station numbering - through the compressor, combustion section, turbine, exhaust and thrust reversers, then into the supporting systems: bearings, seals and lubrication, fuel metering and FADEC, air systems, starting and ignition, and indication and monitoring. Questions are multiple choice and tend to test understanding rather than recall of a single number: why a compressor surges, what a bleed valve does to surge margin, why EGT is the limiting parameter. The Module 15 Gas Turbine Engine case studies are 5 cases and about 3,412 words.
1Surge During High-Altitude Acceleration with Anti-Ice and ECS Bleed
A super-midsize twinjet cruises at FL410, Mach 0.80, OAT −56 °C. Both engines are high-bypass turbofans with FADEC-controlled variable stator vanes (VSVs) and one handling-bleed valve per engine.
750 words, about 4 min2Suction Feed and Cavitation after Boost Pump Failure at FL410
During an ETOPS sector at FL410, the left fuel boost pump low-pressure light illuminates. The crew leaves the pump off; engine 1 continues to run on suction feed.
689 words, about 3 min3EGT Margin Loss and Active Clearance Control Feedback Failure
A 180-minute ETOPS twinjet engine has 14,200 cycles. Over the last 600 cycles, takeoff EGT margin - redline minus peak takeoff EGT at flat-rated thrust - fell from 42 °C to 11 °C.
636 words, about 3 min4Reverser Unlocked Warning during Initial Climb
During initial climb at 3,000 ft in rain and 2 °C, the left engine REV UNLOCK amber message appears with a master caution. The left engine N1 is stable, there is no yaw or vibration, and the right engine is normal.
692 words, about 3 min5Hung Start of a Cold-Soaked Engine at a Mountain Airport
At a mountain airport, OAT −18 °C, a twinjet has been cold-soaked overnight. The crew starts the right engine.
645 words, about 3 min