Categories, Subcategories and Scope
Selecting among A1-A4, B1.1-B1.4, B2, B2L, B3, L1C-L5 and C before applying a module matrix or experience route.
How to prepare for UK Part-66 basic-knowledge examinations
Fix the intended A, B1, B2, B2L, B3, L or C route; use the regulatory module matrix and knowledge levels; then rehearse the exact MCQ and essay components that apply to each selected module.
Core concepts
Concept 1
Category A covers limited authorised line-maintenance tasks, while B1 is the mechanical route divided by aeroplane or helicopter and turbine or piston powerplant.
Exam cue: Choose aircraft class, powerplant and intended certification privilege before choosing modules.
Concept 2
B2 covers avionics on all aircraft; B2L excludes Group 1 aircraft and is built from one or more system ratings; B3 is limited to piston-engine non-pressurised aeroplanes at or below 2,000 kg MTOM.
Exam cue: For B2L, identify the exact system ratings rather than treating it as a smaller universal B2.
Concept 3
Category L covers defined light-aircraft, sailplane, balloon and airship subcategories, while Category C is the base-maintenance certification category for aeroplanes and helicopters.
Exam cue: Separate basic licence category, aircraft rating, organisation authorisation and task competence.
Risk pitfalls and guardrails
Using B1.1 and B1.3 interchangeably because both involve turbine engines.
Guardrail: Do not mix Category A, B1, B2/B2L, B3 or Category L module variants, or treat the aggregate 601-item study allocation as an official CAA examination total.
Assuming B2L applies to Group 1 aircraft.
Guardrail: Do not mix Category A, B1, B2/B2L, B3 or Category L module variants, or treat the aggregate 601-item study allocation as an official CAA examination total.
Treating an unendorsed basic category as authority to certify every aircraft type.
Guardrail: Do not mix Category A, B1, B2/B2L, B3 or Category L module variants, or treat the aggregate 601-item study allocation as an official CAA examination total.
Memory anchors
A
Limited authorised line maintenance and simple defect rectification personally performed.
B1
Mechanical route divided by aircraft kind and turbine or piston powerplant.
B2 / B2L
B2 is the full avionics route; B2L is non-Group-1 and system-rating limited.
B3 / L
B3 covers defined light piston aeroplanes; L covers specified light-aircraft and lighter-than-air subcategories.
C
Category C supports release following base maintenance on aeroplanes and helicopters.
Checkpoint rule
Do the check-up only after you can summarize each concept in one sentence and identify one dangerous pitfall from memory.
Knowledge Check (after reading)
Short check-up to confirm understanding of this module.
Check-up Questions
Which Part-66 subcategory applies to turbine aeroplanes on the Category A route?
A mechanic wants the B1 route for piston helicopters. Which subcategory matches?
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
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