From aircraft mechanic to A licence certifying staff: practical training and company authorisation

If you work as an aircraft mechanic and want to certify your own maintenance, a UK Part-66 Category A licence may be the next step. It can help you progress from carrying out tasks under supervision to certifying defined line maintenance within an approved Part-145 organisation.

However, obtaining the licence is only part of the process. You also need suitable practical experience, reliable evidence that the work was completed correctly and company authorisation before you can exercise certification privileges at work.

What does an A licence allow you to do?

A Category A aircraft maintenance licence allows the holder to certify their own work within defined limits. Typical tasks may include:

• Wheel and tyre changes
• Brake pack replacement
• Oxygen servicing
• Life vest replacement
• Simple defect rectification
• Certain component changes
• Other straightforward line maintenance tasks listed in the organisation's procedures

The precise privileges depend on the licence category, aircraft type or subcategory and the approval held by the maintenance organisation. Read our guide to UK Part-66 A licence privileges and limitations for further context.

An A licence is not the same as a B1 or B2 licence. A B1 engineer generally certifies mechanical and electrical work across a broader range of aircraft systems, while a B2 engineer focuses mainly on avionics and electrical systems. Category A certification is more limited, but it remains valuable in commercial operations where aircraft must be returned to service efficiently.

The licence and company authorisation are different

One of the most important points for new applicants is that a Part-66 licence does not automatically give you the right to certify maintenance for an airline or maintenance organisation.

You normally need both:

1. A UK Part-66 Aircraft Maintenance Licence, issued by the UK Civil Aviation Authority.
2. Company authorisation, issued by the approved Part-145 organisation where you work.

The UK CAA's Part-66 guidance sets out the regulatory framework for aircraft maintenance licences. The Part-66 licence confirms that you have met the regulatory requirements for licensing. Company authorisation confirms that your employer has assessed you as competent to perform and certify particular tasks under its own procedures.

A Part-145 organisation will usually consider factors such as:

• Your licence category
• Aircraft type and fleet experience
• Practical competence
• Familiarity with the organisation's maintenance data
• Human factors and company procedures training
• Recent experience
• Your ability to work safely and accurately
• The specific tasks the organisation wants you to certify

Holding the licence makes you eligible to be considered for certification privileges. The organisation still decides whether to authorise you.

The practical experience requirement

Applicants for a UK Part-66 aircraft maintenance licence must demonstrate practical maintenance experience on operating aircraft. This experience must comply with UK Acceptable Means of Compliance (AMC) 66.A.30(e) and must be submitted in a form and manner acceptable to the UK CAA.

The experience must be signed by an appropriate signatory. The CAA expects it to be genuine, traceable and representative of the maintenance work relevant to the category of licence being requested. Applicants should check the CAA's current Part-66 licensing requirements before preparing an application.

This involves more than proving that you have worked around aircraft. Your records should show that you personally participated in relevant maintenance tasks on aircraft in service.

How much experience is required?

The duration of experience is set out in 66.A.30. The precise requirement depends on factors such as:

• The licence category being requested
• Whether you are applying for your first licence or adding a category
• Your previous technical qualifications
• Whether your experience was gained on complex motor-powered aircraft
• Whether your experience was gained in a Part-145 environment
• Whether you have previously exercised B1 or B2 privileges
• Whether any military experience meets the relevant civil aviation requirements

One route described in the requirements is three years of experience exercising Category B1 or B2 privileges on aircraft other than complex motor-powered aircraft, working as support staff under point 145.A.35, or a combination of both.

Your experience should be practical and include a representative cross-section of maintenance tasks on operating aircraft relevant to the category being requested. A logbook containing only one repeated task, or experience that is mainly workshop-based, may not demonstrate the required breadth.

The skilled-worker route and the two-year reduction

The UK CAA also refers to a route involving:

• Two years of practical maintenance experience on operating aircraft, covering the corresponding system rating or ratings
• Training considered relevant by the CAA for a skilled worker in a technical trade

Applicants should understand the current position carefully. There is not currently a recognised course considered relevant by the CAA for fulfilling the skilled-worker requirement. Consequently, this particular reduction in the experience period is not currently available through a standard approved course.

Do not assume that completing a general aircraft maintenance or engineering course will automatically reduce the practical experience requirement. The CAA must consider the training relevant, so applicants should plan their experience route carefully.

If you have an EU or EASA background, check the UK CAA's guidance on the acceptability of EU or EASA Certificates of Recognition for engineer licensing requirements after 1 January 2023. A qualification or certificate that was acceptable for an EASA licensing route may not automatically satisfy the requirements for a UK Part-66 licence.

What counts as acceptable evidence?

Your experience must be supported by clear records. Evidence may include:

• A personal maintenance experience logbook
• Completed worksheets
• Job cards
• Work packages
• Task records
• Certified colour copies of logbook pages or worksheets
• Employer statements
• Records showing the aircraft registration, task and date
• Evidence of the organisation where the work was completed

The records should identify the work performed and allow the CAA to establish that it was carried out on operating aircraft.

The evidence should also be signed by an appropriate person. Depending on the circumstances, this may include:

• A licensed engineer with the relevant privileges
• A certifying staff member authorised to supervise the task
• A person authorised by the UK CAA for this purpose
• An appropriately authorised military maintenance supervisor

The task supervisor should confirm each entry by adding their name, signature and licence number in the appropriate section of the record.

Keep original records securely and ensure that copies are certified where required. Missing signatures, unclear task descriptions and unexplained gaps can create problems when the CAA reviews an application. Our guide to common CAP 741 logbook mistakes explains how weak entries can delay a licence application.

For additional support with organising maintenance evidence, you can analyse your Part 66 logbook before submitting your application.

Military experience and the civil aviation environment

Military aircraft maintenance experience can be valuable, but it may not automatically satisfy every Part-66 requirement.

The purpose of the relevant experience provisions is to ensure that the applicant understands the civil aircraft maintenance environment. This distinction may involve more than aircraft technology. Civil maintenance also relies on specific:

• Part-145 procedures
• Approved maintenance data
• Airworthiness release processes
• Record-keeping standards
• Configuration control
• Defect reporting
• Shift handover practices
• Human factors principles
• Regulatory responsibilities

A person authorised by the UK CAA may include someone authorised to supervise and certify the maintenance task within an organisation maintaining aircraft on behalf of the military. Even so, applicants with military backgrounds should review 66.A.30(e) carefully and confirm that their experience meets the civil licensing requirements.

Training for the A licence

Theoretical knowledge training is normally completed through an approved Part-147 training organisation or another route accepted under the applicable Part-66 requirements. Use our directory of Part-147 training schools to compare potential training routes.

For an A licence, this may involve examinations covering the relevant Part-66 modules, depending on the licence category and the applicant's previous qualifications. Training provides the necessary knowledge foundation, but it does not replace practical maintenance experience.

A competent mechanic must also understand how technical knowledge is applied in the workplace. This includes becoming familiar with:

• Aircraft maintenance manuals
• Task cards and engineering orders
• Minimum Equipment List procedures
• Defect rectification
• Component and part traceability
• Independent inspections
• Tool control
• Shift handovers
• Technical log entries
• The organisation's exposition and procedures

The ability to find, understand and correctly apply approved maintenance data is as important as knowing how the aircraft systems work.

Type training and practical training

If you are applying for a type rating, the relevant theoretical and practical type-rating training must be completed through an approved UK Part-147 training organisation or through a course with Direct Course Approval in accordance with UK Part-66.B.130.

Check that the training provider and course are acceptable before starting. A course completed with an organisation that does not hold the correct approval may not support the intended licence application.

If you are adding your first Group 1 aircraft type rating to a Part-66 licence, you must also complete structured approved on-the-job training, commonly known as OJT. This OJT must be completed within an approved UK Part-145 organisation and should support the relevant theoretical and practical Certificates of Recognition.

OJT is intended to demonstrate that you can apply your knowledge in a real maintenance environment. It should cover a structured range of tasks, rather than simply recording whichever jobs happen to be available during a shift.

Moving from mechanic to certifying staff

1. Build a suitable maintenance record

Start recording your maintenance experience early. Include enough detail for an independent reviewer to understand:

• What task was performed
• Which aircraft and system were involved
• Whether the task was completed under supervision
• Which maintenance data was used
• Who supervised or signed the work
• When and where the task was completed

Do not wait until you are ready to apply for the licence. Reconstructing several years of experience from memory is difficult and often leaves gaps.

2. Complete the required knowledge examinations

Pass the relevant Part-66 examinations and retain the examination results or Certificates of Recognition. Ensure that the modules match the category and licence route you are pursuing.

3. Gain experience on operating aircraft

Work in an environment where you can build practical experience across a representative range of tasks. Line maintenance is particularly relevant to an A licence, but the experience must still be broad enough to demonstrate competence rather than repetition.

4. Apply for the UK Part-66 licence

Submit the required application and evidence to the UK CAA. This normally includes proof of identity, examination evidence, practical experience records and supporting documentation.

The CAA may request clarification or additional evidence. A well-organised application is easier to assess and less likely to be delayed by missing information.

5. Complete company competence assessments

After you obtain the licence, your employer will normally assess your competence against its own authorisation requirements. This may involve:

• A practical assessment
• A written or verbal knowledge check
• Familiarisation training
• Aircraft and company procedures training
• Human factors training
• Safety management training
• Supervised task performance
• A review of recent experience

6. Receive company authorisation

Once the organisation is satisfied that you meet its requirements, it may issue a Category A authorisation. The authorisation will normally specify the aircraft, tasks or scope of work you are permitted to certify.

You must remain within that scope. If a task is outside your authorisation, refer it to an appropriately authorised engineer.

What does an A licence holder actually certify?

An A certifying staff member generally certifies their own work after completing an authorised task. This means confirming that:

• The correct task was performed
• The correct maintenance data was used
• The required inspections were completed
• Parts and materials were acceptable
• Tools and equipment were suitable
• The work area was left in a safe condition
• The aircraft or component meets the applicable requirements
• The maintenance records are complete and accurate

Certification is not simply a signature at the end of a job. It is a formal statement that the maintenance task has been completed correctly and that the aircraft may be released within the limits of the authorisation.

Maintaining your privileges

An A licence and company authorisation carry ongoing responsibilities. You must maintain competence and recent experience, follow company procedures and keep your knowledge current.

Your organisation may review:

• The tasks you have certified
• Your recent aircraft experience
• Errors or technical findings
• Recurrent training
• Procedural compliance
• Feedback from supervisors and quality staff

A company authorisation may be suspended, restricted or withdrawn if competence is not maintained. A licence holder should also not certify work when tired, unfamiliar with the task or unable to access the correct maintenance data.

The practical reality

The route from aircraft mechanic to A licence certifying staff is not only a matter of passing examinations. It combines formal knowledge, practical experience, accurate record-keeping and employer confidence.

The most successful applicants usually:

• Plan their licensing route early
• Choose an approved training organisation carefully
• Keep detailed, properly signed experience records
• Build experience across a representative range of tasks
• Understand the difference between a licence and an authorisation
• Ask their employer what it requires for Category A certification
• Check current UK CAA requirements rather than relying on older EASA guidance
• Treat every certification as a professional safety responsibility

For a mechanic working in commercial aviation, the A licence can be a practical first step into licensed engineering. It provides a route to certifying defined maintenance tasks while building the experience, judgement and technical understanding needed for future B1 or B2 progression.