Module 15 Gas Turbine Engine

It is a multiple-choice examination, delivered as part of the Part-66 knowledge modules. The number of questions, the time allowed and the pass mark are set by the licensing authority, which publishes the current figures on its website. Confirm the details for your authority and category before you book.

It is usually considered one of the heavier modules because it is systems-dense: compressor aerodynamics, turbine cooling and fuel control all reward genuine understanding. Candidates with hands-on engine experience find it manageable; those learning purely from notes often struggle with the 'why' questions rather than the 'what' questions.

Retakes are normally permitted, but the rules on waiting periods, the number of attempts and how results are recorded vary by authority. The official body publishes the current policy, so check its site rather than assuming a fixed number of attempts or a fixed interval between sittings.

Most candidates need several weeks of part-time study rather than a few days. Work through the syllabus in order, spend extra time on compressor stall/surge and fuel metering, then move to timed question practice. Track which domains you get wrong repeatedly and revisit those chapters instead of re-reading everything.

Start with fundamentals, because station numbering and the thrust equation underpin everything else. Then work through the gas path in order - inlet and compressor, combustion, turbine, exhaust - before the supporting systems: lubrication, fuel, air, starting and ignition, then indication and monitoring. That sequence makes later chapters feel like revision.

Confusing pressure and velocity changes through a compressor stage, muddling surge with stall, and not knowing which parameter limits a given rating. Another frequent weakness is fuel system architecture - what the FADEC commands versus what the hydro-mechanical unit actually meters. Learn the function of each component, not just its name.

No. The exam tests principles and system function, not the pressure ratio of a particular engine. Understand trends - what happens to EGT, thrust and surge margin as conditions change - rather than memorising numbers that differ between engine types. Use a generic turbine engine textbook as your backbone.

Each knowledge module is examined separately, and the results contribute to the experience and knowledge requirements for the licence you are applying for. The authority sets how results are combined and how long they remain valid, so consult its published requirements for your specific category.

No. This is independent study material written for candidates preparing for the module. It is not affiliated with, endorsed by, or connected to any licensing authority or training organisation. Always treat the official syllabus and the authority's published examination details as the authoritative reference.