Part-66L Information
UK continuing airworthiness regulation requires BGA inspectors to hold a UK Part-66 licence with the correct category to certify a release to service for Part-21 sailplanes, powered sailplanes, TMGs and aeroplanes. A UK Part 66 licence is valid for 5 years from the date of issue.
This information is published to support BGA inspectors and those planning to become BGA inspectors. Feedback is welcome and in particular with reference to study resources.
The regulation
To apply for a Part66L licence, the applicant is required to:
- demonstrate by examination a level of knowledge in the appropriate subject modules in accordance with UK Regulation (EU) No 1321/2014. The examinations can be conducted by specifically authorised invigilators, and
- provide practical maintenance experience on operating aircraft in a form acceptable to the CAA and signed by an appropriate signatory.
See below for practical guidance.
Examination learning objectives
The numbers, eg 1L, refer to the module in the Part66L requirements. The learning objectives take the reader to a link to source CAA information.
Note that not all of the following modules are required to qualify for a Part66L. The minimum requirement for Part66L Composite Sailplanes is a pass in 1L, 2L, 3L, 5L, 7L and 12L. For all un-powered sailplanes, a pass is required in 1L, 2L, 3L, 4L, 5L, 6L, 7L and 12L. (reference Part66 Appendix VII — basic knowledge requirements for category L aircraft maintenance licence).
Study resources
The study resources have been assembled by the BGA to support self-study. The exam questions have been developed by the CAA from several unidentified sources. Sources of information favoured by the CAA are two out of date documents no longer published by the CAA. The BGA has sourced these two documents – CAIP 1 and CAIP 2 – which are linked below under ‘other study resources’. As the UK gains experience of these CAA exams, the study resources will be fine tuned.
The exams
The exams are listed below with links to CAA learning objectives, study resources and in some cases question topics.
1L Basic knowledge
1L – study resources:
Aviation Maintenance Technician Handbook – General (FAA-h-8083)
- Chapter 1, Safety
- Chapter 3, Mathematics
- Chapter 5, Physics for aviation
- Chapter 12, Fundamentals of Electricity and Electronics
AC43-13-1B (FAA) Acceptable methods, techniques and practices – aircraft inspection and repair
- Chapter 1, Section 2, Health and Safety
2L – Human factors
2L – study resources:
- CAP718 (Human factors in maintenance)
- Aviation Maintenance Technician Handbook – General (FAA-h-8083)
3L – Aviation legislation
3L – Aviation legislation learning objectives
3L – study resources:
- Continuing Airworthiness Regulations (CAA)
- CS-22
- CS-STAN
- CAP747 (Mandatory requirements for airworthiness)
4L – Airframe wooden, metal tube and fabric
4L – study resources:
Aviation Maintenance Technician Handbook—Airframe (Volume 1):
- Chapter 3, Aircraft Fabric Covering
- Chapter 6, Aircraft Wood and Structural Repair
- Chapter 8, Aircraft Painting and Finishing
AC43-13-1B (FAA) Acceptable methods, techniques and practices – aircraft inspection and repair
- Chapter 1 Wood Structure
- Chapter 2 Fabric covering
- Chapter 4 Metal structure, welding and brazing
- Chapter 6 Corrosion Inspection and protection
- Chapter 7 Aircraft hardware, control cables and turnbuckles
Standard repairs to gliders (BGA)
The BGA glue inspection is now an official source of data
Question topics include:
Welded steel tube airframes, welding, fungus infection on a wooden airframe structure, minimum acceptable gradient of grain in wood for an airframe repair, calculating the splice for a tapered beam repair, identifying a heavy landing a compression failure in a beam, stitching a repair to a fabric tear, applying dope to a polyester fabric, Oratex compared to Dacron, inspecting a possible crack in a welded airframe using dye penetrant, repairing corrosion detected on a tube, corrosion protection for the inside of a steel tube, identifying use of urea-formaldehyde glues, specification for aviation grade plywood, use of adhesive lines in plywood when scarfing fasteners.
5L – Airframe composite
5L – study resources:
AC43-13-1B (FAA) Acceptable methods, techniques and practices – aircraft inspection and repair. Chapter 3. Fibreglass and plastics.
- Repairs
- Canopy repairs
Aviation Maintenance Technician Handbook (FAA-H-8031 31) —Volume 1 and Volume 2 Chapter 7. Composites.
Standard repairs to gliders (BGA)
Plastic plane patch primer (Ursula Hanle)
Question topics include:
Resins, fillers, inspecting spar root and end fittings, joining two halves of a wing, preparing a hole for repair, effecting repair of a puncture/impact damage less than 5cm close to the main spar near the spar, inspecting a fuselage after a heavy landing using a tap test, use of hand tools when sanding a repair, repairing an FRP balsa sandwich panel which has a puncture penetrating both skins, FRP balsa sandwich panel core repair, balsa use and repair.
6L – Airframe metal
6L – study resources:
Aviation Maintenance Technician Handbook – General (FAA-h-8083)
Chapter 7 Aircraft Materials, Hardware, and Processes
Chapter 8 Cleaning and Corrosion Control.
Chapter 10 Inspection Concepts and Techniques
Chapter 11 Hand Tools and Measuring Devices
Aviation Maintenance Technician Handbook—Airframe (FAA-H-8083-31 Volumes 1 en 2):
- Chapter 4, Aircraft Metal Structural Repair
- Chapter 5, Aircraft Welding
- Chapter 13, Aircraft Landing gear systems
AC43-13-1B (FAA) Acceptable methods, techniques and practices – aircraft inspection and repair.
- Chapter 3 Section 2 Metallic sandwich secondary structure repairs
- Chapter 4 Metal structure, welding and brazing
- Chapter 5 Non-destructive inspection
- Chapter 6 Corrosion Inspection and protection
- Chapter 7 Aircraft hardware, control cables and turnbuckles
- Chapter 9 Aircraft systems and components
Standard repairs to gliders (BGA)
Question topics include:
Use of duraluminium rivets, rivet clearance, use of lower spec rivets, dimpling, doubler plates, bending, identifying corrosion, dissimilar metal corrosion, nitriding components, cadmium plating, welding, fasteners.
7L – Airframe general
7L – study resources:
Aviation Maintenance Technician Handbook—General:
- Chapter 6, Weight & Balance
- Chapter 7, Materials
- Chapter 9, Fluid lines
- Chapter 10, Inspection concepts and techniques
- Chapter 12, Fundamentals of Electricity & Electronics, 12-81, 12-89-94
Aviation Maintenance Technician Handbook (FAA-H-8031 31)
- Chapter 1, Aircraft structures
- Chapter 7, Composites, 7-15 Non destructive inspection
- Chapter 10, Aircraft Instruments
- Chapter 11, Communication and Navigation
- Chapter 12, Hydraulic and pneumatic systems
- Chapter 13 Landing gear
- Chapter 14 Aircraft Fuel Systems
AC43-13-1B (FAA) Acceptable methods, techniques and practices – aircraft inspection and repair.
- Chapter 5, Non Destructive testing
- Chapter 7, Aircraft hardware
- Chapter 8, Engines, Fuel, Exhaust, propellers, Section 1, 8-8 & 9, Section 2, 4, 5, 6
- Chapter 9 Aircraft Systems and components; section 1 Landing gear, section 2 Hydraulics, section 3 Emergency equipment, section 4 Cabin interior
- Chapter 10 Weight & Balance
- Chapter 11 Aircraft Electrical Systems
- Chapter 12 Aircraft avionics
Standard repairs to gliders (BGA)
Question topics include:
Fault finding variometers, maximum forward load for instruments when installing or replacing CS22/CS-STAN specified instruments,
8L – Powerplant
8L – study resources:
Aviation Maintenance Technician Handbook— Power Plant Volume 1 and Volume 2.
- Chapter 9, propellers
- Chapter 10, Aircraft Instruments and systems, page 3-11
- Chapter 14 Aircraft Fuel Systems
AC43-13-1B (FAA) Acceptable methods, techniques and practices – aircraft inspection and repair.
- Chapter 8, Engines, Fuel, Exhaust, propellers, Section 1, 2, 3, 4, 5, 6
12L – Radio, Com, ELT, transponder, instruments
12L – study resources
AC43-13-1B (FAA) Acceptable methods, techniques and practices – aircraft inspection and repair.
- Chapter 11 Aircraft Electrical Systems
Aviation Maintenance Technician Handbook—Airframe
- Volume 1 Chapter 9 Aircraft Electrical System
Aviation Maintenance Technician Handbook—Airframe
- Volume 2 Chapter 11 Aircraft Electrical System
Transponders and radios:
Other study resources
AC65-9a (FAA) A&P Mechanic General Handbook
AC65-12a (FAA) A&P Mechanic Powerplant Handbook
AC65-15a (FAA) A&P Mechanic Airframe Handbook
BGA airworthiness and maintenance webpages
CAA CAIP Part 1 – Basic – legacy (unamended)
CAA CAIP Part 2 – Aircraft – legacy (unamended)
CAA CAP 562 Civil Aircraft Airworthiness Information and Procedures
CAA Part-66 information webpage
Jeppesen manuals:
There appears to be a good second market for these. The BGA CTO managed to buy them all for less than £25 total from https://www.wob.com/en-gb
A&P Technician Airframe textbook. ISBN 0-89100-395-9
A&P Technician Powerplant text book. ISBN 0-88487-207-6
A&P Technician General text book. ISBN 0-88487-559-8
This one is not on the CAA list, but is very useful. Airframe Test Guide 2012 by Dale Crane ISBN 10 1560278560
Theoretical knowledge testing
CAA published Part66L e-exams and module information
Please note that the CAA are responsible for the content of their exams. The Part66L examinations are only available online. The first step is for the candidate to register for the CAA customer portal. Once registered, the candidate can then engage with e-examination process. This candidate user guide explains in detail.
The training organisation is BGA and the reference number is GBR.DTO.0007.
Booked examinations are managed by BGA invigilators* who have been specifically approved by the CAA. Candidates are encouraged to contact the BGA office in good time so that an invigilator can be allocated for an online examination. Candidates are advised to only book exams once they feel fully prepared.
During the exam, those taking the exams can report issues to the CAA.
Further guidance is available from the BGA Chief Technical Officer.
*Current invigilators are Kate Byrne (SGC, Scotland & Borders), Pete Stratten (BGA office), Paul Whitehead (North East), Colin Watt (South East)p
Practical experience requirements
While the details of how the practical experience will be assessed are being agreed with the CAA, the BGA Inspector PER is a useful reference for the required experience.