Regulatory framework UK Part 21 aircraft and UK non Part 21 aircraft

Definitions of the regulatory framework for UK-registered aircraft.

Note that references to EU regulations are to those regulations as retained and amended in UK domestic law under the European Union (Withdrawal) Act 2018 and are referenced hereafter as “UK Regulation (EU) year/number” or “UK Regulation (EU) No. number/year”.

Categories of aircraft

UK registered aircraft fall into one of two groupings: Part 21 aircraft and Non-Part-21 aircraft.

UK Part 21 aircraft

Aircraft in this category are those that were previously managed by the European Union Aviation Safety Agency (EASA) and were considered as EASA types. These are regulated under UK Regulation (EU) 2018/1139 (known as the UK Basic Regulation) and its implementing regulations covering airworthiness, operations, flight crew licensing, etc.

UK non-Part 21 aircraft

Aircraft in this category are managed nationally under the UK Air Navigation Order. Airworthiness requirements for these aircraft are set out in the provisions of British Civil Airworthiness Requirements (BCAR).

To be classified as Non- Part 21, an aircraft has to meet one or more of the following criteria:

1. Manned aircraft set out in UK Basic Regulation Annex I (known as ‘Annex I aircraft’):

a. Historic aircraft meeting the following criteria:
i. Aircraft whose:
— initial design was established before 1 January 1955, and
— production has been stopped before 1 January 1975;
or
ii. Aircraft having a clear historical relevance, related to:
— A participation in a noteworthy historical event,
— A major step in the development of aviation, or,
— A major role played into the armed forces of a State;
or
b. Aircraft specifically designed or modified for research, experimental or scientific purposes, and likely to be produced in very limited numbers;
c. Aircraft, including those supplied in kit form, where at least 51% of the fabrication and assembly tasks are performed by an amateur, or a non-profit making association of amateurs, for their own purposes and without any commercial objective;
d. Aircraft that have been in the service of military forces, unless the aircraft is of a type for which a design standard has been adopted by the UK CAA;
e. Aeroplanes having measurable stall speed or the minimum steady flight speed in landing configuration not exceeding 35 knots calibrated air speed (CAS), helicopters, powered parachutes, sailplanes and powered sailplanes, having no more than two seats and a Maximum Take-Off Mass (MTOM) of no more than:

When an amphibian or a floatplane/helicopter is operating both as a floatplane/helicopter and as a land plane/helicopter, it must fall below the applicable MTOM limit.

f. Single and two-seater gyroplanes with a MTOM not exceeding 600 kg;
g. Replicas of aircraft meeting the criteria of points (a) or (d), for which the structural design is similar to the original aircraft;
h. Balloons and airships having a single or double occupancy and a maximum design volume of, in the case of hot air not more than 1,200 m³, and in the case of other lifting gas not more than 400 m³;
i. Any other manned aircraft which has a maximum empty mass, including fuel, of no more than 70 kg.

2. Unmanned aircraft set out in UK Basic Regulation Annex I:
a. Tethered aircraft with no propulsion system, where the maximum length of the tether is 50 m, and where:
i. The MTOM of the aircraft, including its payload, is less than 25 kg, or
ii. In the case of a lighter-than-air aircraft, the maximum design volume of the aircraft is less than 40 m³; or
b. Tethered aircraft with a MTOM of no more than 1 kg.

3. Manned aircraft that have been ‘opted out’ by states pursuant to article 2(8) of the UK Basic Regulation, either:

a. Aeroplanes that the UK have ‘opted out’ of the UK Basic Regulation further to CAA General Exemption ORS4.1501 published on 19 August 2021. These are Non-Part-21 aeroplanes that are designed to carry not more than 2 persons and which have:

• An MTOM of not more than 600kg (landplanes) or 650kg (floatplanes/amphibians); and

– A stalling speed or minimum steady flight speed in landing configuration, at the maximum take-off mass, of not more than 45 knots calibrated air speed.

– Are of an approved design. See the microlight aeroplanes page for more details.

b. Aeroplanes, helicopters and sailplanes that EU member states have themselves ‘opted-out’ under article 2(8).

NOTE: certain types within this group of aircraft may be manufactured and certified to Part-21 regulations further to UK Basic Regulation article 2(9); finally

4. Manned or unmanned aircraft carrying out military, customs, police, search and rescue, firefighting, border control, coastguard or similar activities under the control and responsibility of the UK undertaken in the public interest by or on behalf of the UK government, further to article 2(3)(a) of the UK Basic Regulation.