Aircraft Maintenance Engineering (B1.1): Core Knowledge and Exam Strategy
What the B1.1 licence actually covers
The B1.1 category is a mechanical licence for turbine-engine aeroplanes. Candidates must be comfortable across airframe systems, gas-turbine engines, electrical and avionic interfaces at a mechanical level, and the regulatory framework that governs release to service. The syllabus is built from the EASA Part-66 module set, so revision should be organised by module rather than by aircraft type: mathematics and physics underpin Module 1–2, materials and hardware Module 6, maintenance practices Module 7, human factors Module 9, legislation Module 10, aerodynamics Module 8, and the airframe/engine/system modules 11–17.
Concepts you must genuinely understand
Questions rarely ask for a definition in isolation. Expect them to combine a physical principle with a maintenance consequence. Know the difference between limits and tolerances, between inspection and check, and between maintenance and repair. Understand torque versus tension, the purpose of a lockwire or self-locking nut, galvanic corrosion between dissimilar metals, and why a magnetic particle inspection only finds surface and near-surface defects in ferromagnetic material. In engines, be secure on the Brayton cycle, compressor surge and stall, turbine blade creep, and EGT as an indicator of condition rather than of thrust directly.
Traps that catch candidates
- Unit confusion: mixing inches and millimetres, or psi and bar, in a calculation.
- Regulatory absolutes: words like always or never in an answer are usually wrong; airworthiness codes allow approved alternatives.
- Confusing roles: the certifying staff releases the aircraft; the approved organisation holds the approval.
- Sign conventions in stress, bending moment and electrical questions.
Rule of thumb
If a question gives data, write the formula and units before substituting. If it gives a scenario, ask who is permitted to sign, and against which approved data? That single question resolves a large share of legislation and maintenance-practice items.
Worked example
A bolt is torqued to 40 N·m with a wrench 0.25 m long. Required force at the handle: F = T / d = 40 / 0.25 = 160 N. Note the unit and the lever arm measured from the fastener centre, not from the end of the wrench.