Part-66 Experience Requirements (66.A.30) Explained

Part-66 experience requirements are often the longest part of getting a licence. You can pass modules in a few years of evenings, but the licence will not be issued until you can also show enough hands-on maintenance on real aircraft. This guide sets out the 66.A.30 durations for every category, explains recent experience and what counts, shows how to log it, and covers the UK-specific points that catch applicants out.

Part-66 Prep is an independent study aid, not an authority or a Part-147 organisation. The requirements are in 66.A.30 of Part-66: for the EU, see Regulation (EU) No 1321/2014 and the consolidated EASA Easy Access Rules for Continuing Airworthiness; for the UK, see UK Part-66 on legislation.gov.uk. The overall career route is in how to become an aircraft engineer.

Part-66 experience requirements by category (66.A.30)

The basic requirement is practical maintenance experience on operating aircraft. How much you need depends on the category and on your training.

Category	No relevant technical training	Skilled worker in a relevant technical trade	Part-147 approved basic course
A, B1.2, B1.4, B3	3 years	2 years	1 year
B1.1, B1.3, B2	5 years	3 years	2 years
B2L	3 years, covering the system ratings	2 years	1 year, plus 3 months per added system rating

The durations are the same in the EU and UK texts. Three rules apply on top of the table:

1. Recent experience. At least one year of the required experience must be recent maintenance experience on aircraft of the category or subcategory you apply for (66.A.30(d)).
2. Ten-year window. The experience, like the module exams, must have been gained within the 10 years before the application.
3. Representative cross-section. The experience must be practical and cover a representative cross-section of the maintenance tasks of the category, not one narrow task repeated.

Key fact: The Part-147 basic course is the fastest route by a wide margin: 2 years of experience instead of 5 for B1.1 or B2, and 1 year instead of 3 for category A. That is the main reason people pay for an approved course rather than self-studying.

Category C

Category C (base maintenance release of the whole aircraft) is reached from an existing licence or a degree, not from scratch. Routes include 3 years exercising B1.1, B1.3 or B2 privileges on complex motor-powered aircraft (or working as B1 or B2 support staff in base maintenance), or 5 years exercising B1.2 or B1.4 privileges. There is also an academic route for holders of a relevant degree, with a period of experience in base maintenance. The details are in 66.A.30(a); the licence categories guide explains what C holders do.

Adding a category to an existing licence

When you add a category, for example B2 to a B1.1 licence, you need experience relevant to the new category. The recent experience requirement is relaxed: 66.A.30(d) allows less than one year for an addition, but at least three months. How much total experience the authority wants for the addition depends on what you already have and how close the categories are, so ask before you plan.

Worked examples: how long will it take you?

Four common situations, with the experience rule that applies. Exams usually run alongside, so the experience is often what sets the date of your licence.

Who	Target	Rule that applies	Experience needed
Apprentice on a UK Part-147 B1.1 basic course	B1.1, UK licence	Part-147 route	2 years, with the last year on turbine aeroplanes
Mechanic with no formal aviation training, working on airliners in the UK	B1.1, UK licence	No relevant training (skilled-worker reduction not available in the UK)	5 years
Qualified electrician moving into avionics in the UK	B2, UK licence	Same as above: the CAA recognises no course for the skilled-worker reduction	5 years, unless they take a Part-147 B2 course (then 2)
Light aircraft mechanic at a flying club in the EU	B3, EASA licence	No relevant training, or skilled-worker if the authority accepts the trade qualification	3 years (2 if accepted as skilled worker)

Two things to check in your own case. First, the clock only counts practical maintenance on operating aircraft, so time in a classroom or in a non-maintenance job does not add to it. Second, the recent year must match the category: a B1.1 applicant who spent the last year on piston aeroplanes has a recency problem even with five years in total.

Apprenticeships

In the UK, many people reach a licence through an engineering apprenticeship that combines a Part-147 basic course with structured on-the-job experience. Check that the training element is delivered by a Part-147 approved organisation for your category: that is what gives you the reduced experience requirement. An apprenticeship that is not linked to approved Part-147 training may still give you good experience, but at the full 3 or 5 year duration.

Part-time work and gaps

Neither text sets a weekly minimum, but the authority must be satisfied that the experience is equivalent to the stated years of practical maintenance. If you work part-time in maintenance, or have gaps, expect the authority to look closely at the volume and variety of tasks in your logbook, and ask it how it will assess your case before you apply.

What counts as relevant experience

Practical work on operating aircraft

The rule says "practical maintenance experience on operating aircraft". In practice that means hands-on work on aircraft in service: inspections, servicing, component changes, rectification, functional tests and modifications. Typical evidence shows you doing the task, not watching it.

Usually counts	Usually counts for little or nothing
Line and base maintenance tasks on in-service aircraft	Classroom training and theory lessons
Fault-finding and rectification	Purely administrative or planning roles
Inspections and functional checks	Repeating the same task with no variety
Component removal and installation, with tests	Workshop work on parts with no link to the aircraft (the authority decides how much it accepts)
Supervised work during an apprenticeship	Experience on aircraft outside the category you apply for

Matching the category

The experience must fit the licence you want:

• B1 applicants need structure, powerplant and mechanical systems work, plus electrical tasks.
• B2 applicants need avionics and electrical work, including troubleshooting. The UK CAA lists missing troubleshooting tasks among common reasons for rejected applications.
• Category A applicants need the routine line tasks the licence covers.
• B3 applicants need experience on piston-engined, non-pressurised aeroplanes of 2,000 kg MTOM and below.

The B1 licence guide and B2 licence guide describe each category's scope, which is the best guide to the tasks your logbook should show.

Military and non-European experience

66.A.30 allows experience gained outside a civil Part-145 or Part-CAO environment to be accepted when it is equivalent, for example in military aviation or under another country's civil rules. The authority decides, case by case, and EASA notes this in its Part-66 FAQs. Authorities generally also expect part of the experience in a civil approved organisation. The UK CAA lists military applicants without 12 months of civil experience among common rejections, so if you are leaving the forces, plan for a period of civil maintenance before you apply.

Exam tip: Experience and exams run in parallel. Most people pass their modules while gaining experience, so a typical self-study plan fits the modules into the same 2 to 5 years. The self-study guide shows how.

The UK position on the skilled-worker route

66.A.30 reduces the requirement for applicants with training as a skilled worker in a relevant technical trade: 2 years instead of 3 for category A, B1.2, B1.4 and B3, and 3 instead of 5 for B1.1, B1.3 and B2. The UK CAA's guidance says there is currently no course it recognises as meeting this requirement, so the reduction is not available for UK licences. In practice UK applicants use either the full duration or the Part-147 route.

EU authorities apply the skilled-worker reduction according to their own assessment of national trade qualifications. If you are relying on it for an EASA licence, ask the authority which qualifications it accepts before you count on the shorter period.

How to log your experience

UK: CAP 741

The CAA publishes CAP 741, the aircraft maintenance engineer's logbook (version 4, October 2026). The CAA's guidance asks for:

• entries for each task, with the aircraft, date, task description and ATA chapter, organised in ATA order;
• verification by a supervisor or certifying engineer;
• a certified true copy of each page with the application.

Type-rating experience can also be shown through the CAA's type-rating records. Gaps in experience, lack of recent experience and missing troubleshooting tasks are among the common reasons the CAA gives for rejected applications.

EASA states

Each EU authority sets its own format. Some publish their own logbook, others accept the records of the Part-145 organisation you work for, or a recognised generic logbook. If you search for an authority's logbook, for example the Irish Aviation Authority's, use the version on the authority's own website, not a copy from a third-party site, and check whether it wants a specific format for your category.

Good logbook habits

1. Start on day one. Rebuilding years of experience from memory is slow and less convincing.
2. Record variety. Aim for tasks across the ATA chapters your category covers.
3. Get entries signed promptly, while your supervisor remembers the job.
4. Keep copies of the logbook and of any organisation task records, ideally digital.
5. Check recency before you apply: your last year must be on the category you are applying for.

Why UK applications get sent back

The CAA's application guidance lists the problems it sees most often. Check your file against them before you apply:

1. Gaps in the experience record, with months unaccounted for.
2. Not enough recent experience on the category applied for (66.A.30(d)).
3. Missing troubleshooting tasks, especially for B2.
4. Military applicants without 12 months of civil maintenance experience.
5. EASA certificates of recognition dated after 31 December 2022, which the CAA no longer accepts for a UK licence.

After the licence: keeping privileges valid

Experience does not stop mattering once you hold a licence. Under 66.A.20(b), to use your privileges you need at least 6 months of relevant maintenance experience in the preceding 2 years, in line with the privileges you use. This is a condition for exercising privileges, separate from the 5-year administrative renewal of the licence document. Your employer's certification authorisation procedures will check it.

Where the experience fits in the full route

A typical sequence:

1. Start work in maintenance, or start a Part-147 course or apprenticeship.
2. Begin your logbook and study modules alongside the experience; take a category diagnostic to choose a starting module.
3. Pass all modules for your category, checking each is within the 10-year window. The Part-66 modules guide lists them.
4. Complete the experience, with at least one recent year on your category.
5. Apply for the licence; the licence application guide covers forms, fees and timings. The UK CAA aims to process an initial licence in 31 working days.

For a summary of experience, categories and modules in one note, read the free licence categories study note.

Your study plan

1. Find your row in the 66.A.30 table and note the date you started relevant work.
2. Open a logbook today if you do not have one, and back-fill recent tasks while you can still verify them.
3. Take the free B1.1 diagnostic or the one for your category to plan which modules to sit first.
4. Fit one module at a time around your shifts, using each module's free quick practice and paper 1.
5. Six months before you expect to meet the experience requirement, check that every module pass is still within 10 years and that your recent year is on the right category.