This page is designed to be a focal point for engineers seeking information about engineer licences for Part-21 light aircraft. This includes piston engine aircraft, ELA1 and ELA 2 aircraft, sailplanes and balloons.
It is designed to provide guidance to interpret regulatory requirements and should be read alongside the other Part 66 licence pages.
Part‑66 has provision for licence categories relevant to light and general aviation.
This section explains the Part‑66 licence categories that are commonly used in light aircraft and general aviation maintenance.
Each category is described separately to help applicants and organisations understand the scope of privileges and the typical maintenance environment in which the licence is used.
Category A2 – Aeroplanes (piston)
Category A2 applies to piston‑engine aeroplanes.
Holders of an A2 licence may certify minor scheduled line maintenance and simple defect rectification tasks, as authorised by their organisation.
This category is typically used for:
- Routine line maintenance tasks
- Task trained authorisations for specific simple tasks
- May only certify for work personally performed
- May be used as a starting point and extended to other licence categories
Category A4 – Helicopters (piston)
Category A4 applies to piston‑engine helicopters.
Holders of an A4 licence may certify minor scheduled line maintenance and simple defect rectification tasks, as authorised by their organisation.
This category is typically used for:
- Routine line maintenance tasks
- Task trained authorisations for specific simple tasks
- May only certify for work personally performed
- May be used as a starting point and extended to other licence categories
Category B1.2 – Aeroplanes (piston)
Category B1.2 applies to piston‑engine aeroplanes.
Holders of a B1.2 licence may perform and certify:
- Maintenance on aircraft structure
- Powerplant and mechanical systems
- Electrical systems
- Minor avionics work requiring only simple tests
Category B1.2 is commonly used in general aviation maintenance organisations, including those supporting multiple light aircraft types.
A B1.2 licence holder may apply to the CAA for a B3 licence with the same limitations as the B1.2 licence. Dependant on the type ratings held on the B1.2 licence a type (oral) examination may be required for the issuance of a B3.
A B1.2 licence holder endorsed with the Group 3 can apply to the CAA for a fully rated licence in subcategories L1 and L2, with the same limitations as the B1.2 licence held.
Category B2 – Avionics
Category B2 applies to avionic and electrical systems on all aircraft types, including light aircraft.
Holders of a B2 licence may certify:
- Avionic and electrical systems
- Electrical and avionic tasks in powerplant and mechanical systems which only require simple tests to prove serviceability
- Minor scheduled line maintenance and defect rectification on specific task trained authorisations issued by a Part 145 for personally performed maintenance within the specific Part 145 organisation limited to a rating endorsed on the B2 licence.
- Category B2 does not include a Category A
This category is typically used by specialists supporting avionics maintenance in general aviation environments. Most tasks will not require a B2 licence holder.
Category B2L – Limited avionics
Category B2L applies to electrical and avionic systems on aircraft, except those in aircraft Group 1.
The licence is limited to the specific system ratings endorsed on the licence, such as:
- Communication and navigation
- Instruments
- Autoflight
- Surveillance
- Airframe systems (electrical and avionic tasks within the powerplant and mechanical system only requiring simple tests to prove serviceability)
Category B2L is often used in light aircraft maintenance organisations where a full B2 licence is not required.
Category B3 – Piston‑engine non‑pressurised aeroplanes
Category B3 applies to piston‑engine, non‑pressurised aeroplanes with a maximum take‑off mass of 2000 kg or below.
The maintenance privileges are similar to those of Category B1.2, but limited to this aircraft group.
This category is commonly used where maintenance activity is restricted to lighter general aviation aircraft and does not extend to larger or pressurised aeroplanes.
A B3 licence does not require type ratings. It will normally be issued with any of the following limitations, which shall be endorsed on the licence for aircraft construction methods that the applicant has not demonstrated experience upon.
- wooden-structure aeroplanes,
- aeroplanes with metal-tubing structure covered with fabric,
- metal-structure aeroplanes,
- composite-structure aeroplanes.
A B3 licence holder endorsed with the rating ‘piston engine non-pressurised aeroplanes of 2000 kg MTOM and below’, may apply to the CAA for a fully rated licence in subcategories L1 and L2, with the same limitations as the B1.2/B3 licence held.
Category L – Light aircraft maintenance
Category L applies to specific light aircraft types, including sailplanes, balloons, airships and some light aeroplanes.
The Category L subcategories are:
L1C – Composite sailplanes
Applies to sailplanes constructed primarily from composite materials.
L1 – Sailplanes
Applies to non‑powered sailplanes, including non‑composite types.
L2C – Composite powered sailplanes and composite ELA1 aeroplanes
Applies to composite powered sailplanes and composite aeroplanes within the ELA1 definition.
L2 – Powered sailplanes and ELA1 aeroplanes
Applies to powered sailplanes and ELA1 aeroplanes. This subcategory overlaps most closely with light general aviation aeroplanes.
L3H – Hot‑air balloons
Applies to hot‑air balloons only.
L3G – Gas balloons
Applies to gas balloons only.
L4H – Hot‑air airships
Applies to hot‑air airships.
L4G – ELA2 gas airships
Applies to gas airships that meet the ELA2 definition.
L5 – Gas airships (other than ELA2)
Applies to gas airships outside the ELA2 definition and normally requires specific type ratings.
The holder of a B1.2 or B3 licence with the appropriate type ratings may apply for licences in the L1 and L2 subcategories under the following conditions:
- A B1.2 licence endorsed with the Group 3 rating or in category
- A B3 endorsed with the rating ‘piston engine non-pressurised aeroplanes of 2000 kg MTOM and below’,
- Any limitations on the B1.2 or B3 licence will be reflected on an Category L1 or L2 issued.
Category B2L – Limited avionics
Category B2L applies to electrical and avionic systems on aircraft, except those in aircraft Group 1.
The licence is limited to the specific system ratings endorsed on the licence, such as:
- Communication and navigation
- Instruments
- Autoflight
- Surveillance
- Airframe systems (electrical and avionic tasks within the powerplant and mechanical system only requiring simple tests to prove serviceability)
Category B2L is often used in light aircraft maintenance organisations where a full B2 licence is not required.
Category C – Base maintenance
Category C applies to certification following base maintenance. The privileges apply to the aircraft in its entirety and the issuance of a certificate of release to service, following the completion of all maintenance completed by category B1, B2, B2L, B3 and L, support staff, as appropriate, following base maintenance.
ELA 1 and ELA2 aircraft
ELA1 aircraft means the following manned European light aircraft:
- an aeroplane with a maximum take-off mass (MTOM) of 1200 kg or less that is not classified as complex motor-powered aircraft;
- a sailplane or powered sailplane of 1200 kg MTOM or less;
- a balloon with a maximum design lifting gas or hot air volume of not more than 3400 m3 for hot air balloons, 1050 m3 for gas balloons, 300 m3 for tethered gas balloons;
- an airship designed for not more than four occupants and a maximum design lifting gas or hot air volume of not more than 3400 m3 for hot air airships and 1000 m3 for gas airships;
ELA2 aircraft means the following manned European Light Aircraft:
- an aeroplane with a Maximum Take-off Mass (MTOM) of 2000 kg or less that is not classified as complex motor-powered aircraft;
- a sailplane or powered sailplane of 2000 kg MTOM or less;
- a balloon;
- a hot air ship;
- a gas airship complying with all of the following characteristics:
- 3 % maximum static heaviness,
- non-vectored thrust (except reverse thrust),
- conventional and simple design of structure, control system and ballonet system, and
- non-power assisted controls;
- a Very Light Rotorcraft;
Once all requirements have been met, complete the Aircraft Maintenance Licence online application form on the CAA Portal. For more information and guidance regarding the new process, refer to AMEL portal form user guide.
If you have not used the CAA Customer Portal before, you will need to create an account before you can access the online application form. Once registered, you can start your application by clicking on the ‘Aircraft maintenance licence applications’ link under the list of available services.