Category L Airframe Modules
Modules 4L-7L across wood, metal tube and fabric, composite, metal and general light-aircraft structures or systems.
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
Modules 4L, 5L and 6L are construction-specific and appear only where the selected L subcategory requires the material.
Exam cue: Map the selected L subcategory to its exact material modules.
Concept 2
Module 7L brings together general airframe, controls, landing gear, systems, instruments, maintenance and inspection knowledge.
Exam cue: Identify load path, damage type, inspection method and approved repair limit.
Concept 3
L1C and L2C omit wood and metal modules, while L1 and L2 include all three construction routes.
Exam cue: Treat environmental conditions as part of composite, wood, fabric and corrosion control.
Risk pitfalls and guardrails
Adding 4L or 6L to a composite-only route without checking the matrix.
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.
Using one material's repair process on another.
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.
Ignoring moisture, temperature or contamination during inspection and repair.
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
4L
Wood, metal tube and fabric construction and repair.
5L
Composite material, damage, inspection and repair.
6L
Metal structure, corrosion, damage and repair.
7L
General airframe, controls, systems and maintenance.
C Suffix
L1C and L2C are composite-only subcategories.
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
What wood defect is especially concerning where moisture has entered a glued joint?
Why must aircraft timber grain direction be considered in a repair?
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
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