How to Build Qualifying Aircraft Maintenance Experience for a Part-66 B1 Licence

Passing the Part-66 examinations is only one part of becoming a B1 aircraft maintenance engineer. You must also demonstrate practical experience gained while maintaining operating aircraft.

For applicants in the UK, the relevant licensing authority is the UK Civil Aviation Authority (CAA). In Europe, applications are normally made to an EASA Member State competent authority under EASA Part-66. Although application processes vary, the underlying principle is the same: your experience must be genuine, relevant, properly recorded and supported by acceptable evidence.

Understand the Part-66 experience requirement

For a B1.1 licence covering turbine-engine aeroplanes, the commonly applicable routes include:

• Five years of practical maintenance experience where the applicant has no previous relevant technical training.
• Three years where the applicant has completed technical training recognised by the competent authority as relevant skilled-worker training.
• Two years where the applicant has completed an approved Part-147 basic training course.
• A relevant aeronautical degree or higher technical qualification may reduce the experience requirement in some competent-authority pathways. The authority must confirm whether the qualification is acceptable.

These periods are not simply employment-duration targets. The authority assesses the quality, relevance and breadth of the maintenance work you have performed, not merely the number of years shown on an employment contract.

At least part of the experience must normally be recent and relevant to the category or subcategory requested. For a B1.1 application, your records should demonstrate practical work on turbine-powered aeroplanes and their associated systems. Always check the current requirements before applying in the EASA Part-66 guidance or the relevant UK CAA Part-66 information.

What counts as practical maintenance experience?

Part-66 experience is based on practical maintenance carried out on operating aircraft. This normally means aircraft being maintained in service or within an operational maintenance environment, rather than work performed solely on training rigs, components or classroom projects.

Suitable experience may be gained through roles such as:

• Line maintenance technician or mechanic
• Base maintenance technician
• Aircraft mechanic working under a Part-145 organisation
• Maintenance work carried out within an appropriately approved or recognised organisation
• Certain military aircraft maintenance roles, subject to competent-authority recognition

The work should involve real maintenance activity, including inspection, defect rectification, component replacement, testing, servicing, troubleshooting and scheduled maintenance. General workshop work, stores duties and administrative tasks may support an employer, but they will not normally provide sufficient evidence of B1 practical experience by themselves.

It is also important to understand how maintenance data supports your work. Tasks should be performed using applicable approved or acceptable data, such as the aircraft maintenance manual, structural repair manual, illustrated parts catalogue or wiring diagrams. Our guide to aircraft maintenance manuals and technical publications explains how these documents are used in practice.

Build both line and base maintenance exposure

A strong experience record should cover both the operational pace of line maintenance and the more extensive inspection and rectification work associated with base maintenance.

Line maintenance

Line maintenance can include:

• Transit and daily checks
• Defect investigation and rectification
• Servicing and replenishment
• Wheel, brake and tyre replacement
• Battery and electrical system tasks
• Operational and functional checks
• Troubleshooting using the aircraft maintenance manual
• Completion of technical log entries and maintenance records
• Work on deferred defects under applicable minimum equipment procedures

Line work demonstrates that you can work safely and accurately under operational pressure while following approved maintenance data. It may also involve defect assessment and rectification under an operator's minimum equipment list. See our guide to deferring aircraft defects using the MEL for more context.

Base maintenance

Base maintenance provides exposure to more extensive tasks, including:

• Scheduled inspections
• Structural inspections and repairs
• Flight-control rigging
• Landing-gear maintenance
• Powerplant removal and installation
• System testing and fault isolation
• Wiring inspections and repairs
• Non-routine defect rectification
• Modifications and embodiment of service bulletins
• Maintenance release and certification procedures

Base maintenance is particularly valuable because it exposes you to larger work packages, inspection findings, engineering instructions and coordination between several maintenance disciplines. The process used to set aircraft maintenance check intervals can also help explain why different types of scheduled work appear in your experience record.

Cover a broad range of aircraft systems

Your logbook should show more than repeated work on one narrow task. For B1.1, aim to build evidence across the systems relevant to mechanical and associated B1 privileges, including:

• Airframe structures
• Flight controls
• Landing gear
• Hydraulic and pneumatic systems
• Fuel systems
• Ice and rain protection
• Environmental control systems
• Electrical power generation and distribution
• Instruments and indication systems
• Automatic flight systems
• Engines and engine systems
• Propellers, where relevant to the aircraft operated
• Fire protection

You are not expected to perform every task on every aircraft type. However, a record dominated by one repetitive activity, such as wheel changes or routine servicing, may not demonstrate the breadth expected for a B1 licence.

Record your experience as you perform it

Do not wait until you are ready to submit your licence application before reconstructing several years of maintenance history. Evidence is considerably stronger when it is recorded contemporaneously.

For UK applicants, the CAP 741 Aircraft Maintenance Engineer's Log Book is a widely used format for documenting experience. The UK CAA CAP 741 information should be checked for the latest expectations and instructions.

A suitable record should identify, where applicable:

• Date of the task
• Aircraft registration
• Aircraft type and model
• Aircraft or engine serial number, where relevant
• Maintenance organisation or employer
• Work order, task-card or job-card reference
• Description of the maintenance task
• ATA chapter or system
• Whether the work was line or base maintenance
• Your role in carrying out the work
• The name, licence details and signature of the supervising or authorised signatory

A CAP 741 logbook is not a substitute for acceptable experience, and using one does not automatically make every entry valid. The content must demonstrate practical work on operating aircraft and be supported by an appropriate signatory.

If a formal logbook is not available, the UK CAA may accept other evidence, such as certified copies of worksheets, task cards, employer records or maintenance documentation. The evidence must be in a form and manner acceptable to the authority and should be signed or certified by an appropriate person.

Before submitting an application, review your entries against this CAP 741 logbook checklist and avoid the common errors described in our guide to CAP 741 logbook mistakes.

Ready to check your records? Analyse Your Part-66 Logbook Today and identify gaps before they delay your licence application.

Keep supporting evidence

A licensing authority may require more than a summary of tasks. Retain supporting evidence such as:

• Certified copies of logbook pages
• Task cards and work packages
• Maintenance worksheets
• Employer statements
• Training and authorisation records
• Aircraft type and fleet details
• Records showing line or base maintenance activity
• Evidence of military service and technical employment
• Details of the organisation's approval status
• Records confirming the identity and authority of the signatory

Avoid recording confidential operator information unnecessarily. Where documents contain sensitive data, ask the employer or organisation how the evidence can be redacted while retaining the information needed for licensing assessment.

Use the correct signatory

Experience records should be signed by someone who can credibly verify the work. Depending on the organisation and the authority's requirements, this may be an appropriately authorised certifying staff member, quality representative, maintenance manager or another recognised signatory.

A signature without sufficient authority or traceability can weaken an application. Before starting a new role, establish:

1. Who will verify your work?
2. What evidence will they sign?
3. How frequently will records be reviewed?
4. Does the organisation maintain task and employment records?
5. Will the signatory be available when you apply?

Regular monthly or quarterly reviews are preferable to leaving the entire record until the end of an employment period. This is especially important where tasks involve an independent inspection, because inspection and certification responsibilities must be clearly understood and documented.

Make your experience relevant to the licence category

Experience must match the licence category being requested. For a B1.1 application, the record should be centred on turbine aeroplanes. Experience on piston-engine aeroplanes, helicopters or other aircraft may be professionally useful, but it may not count in the same way as turbine-aeroplane experience for a B1.1 application.

If your employment includes multiple aircraft types, separate them clearly in your records. Identify the aircraft category, propulsion type, systems worked on and nature of the task. This allows the competent authority to assess which parts of the experience are relevant.

The same principle applies when seeking additional category or type privileges later. Experience on one aircraft type does not automatically demonstrate competence across every other type or system.

Military maintenance experience

Military service can provide substantial practical experience, particularly in aircraft servicing, inspections, defect rectification, component replacement and technical documentation. UK applicants should obtain formal evidence through the appropriate UK Ministry of Defence recognition pathways and retain service records, trade certificates, employment histories and task evidence.

Military experience is not automatically converted into a civil Part-66 licence. The UK CAA must assess whether the duties, aircraft, systems, maintenance environment and documentation are comparable with the relevant civil requirements. A service statement should cover:

• Aircraft types and variants
• Dates and duration of technical employment
• Maintenance level and responsibilities
• Systems and tasks performed
• Whether the work was line or base maintenance
• Supervision and authorisation arrangements
• Any civil or military technical qualifications held

Applicants should contact the relevant licensing authority before relying on military service as their principal evidence. EASA authorities may apply their own procedures, so UK Ministry of Defence recognition should not be assumed to transfer automatically to an EASA Part-66 application. Those comparing routes into maintenance may also find our guide to civilian and military aviation apprenticeships useful.

Do not confuse training with practical experience

Part-147 basic training can reduce the amount of practical experience required for a B1.1 application, but classroom instruction does not replace the remaining aircraft maintenance experience.

Short professional courses can improve technical knowledge without counting as Part-66 practical experience. Only training accepted by the competent authority for the relevant Part-66 route can reduce the required experience period. Use the Part-147 training schools resource to research approved training options, then confirm acceptance with the licensing authority before enrolling.

Plan your first maintenance role carefully

When choosing an entry-level position, assess the role against the evidence you will eventually need. A suitable role should offer:

• Access to operating aircraft
• Exposure to both routine and non-routine maintenance
• Work across several ATA chapters
• Supervised task performance
• Access to approved maintenance data
• A reliable task-recording process
• Regular sign-off by authorised personnel
• Opportunities to participate in line and base maintenance

A role described as aircraft maintenance may still consist largely of stores, cleaning, logistics or component preparation. Those activities may support the maintenance operation, but they are unlikely to provide enough qualifying experience on their own.

Ask the employer how practical experience is recorded before accepting the position. This is particularly important for contractors, temporary staff and employees working across several sites. If you are beginning your career, read our guide to starting a career in aircraft maintenance.

Check your evidence before applying

Before submitting a UK CAA or EASA application, review your records against the relevant authority's requirements. Confirm that:

• The total experience period is correct
• The required proportion is recent
• The aircraft category matches the licence application
• Both line and base exposure are identifiable
• The tasks demonstrate a reasonable range of systems
• Entries relate to operating aircraft
• Signatures and certifications are traceable
• Employer and military records support the logbook
• Any claimed training reduction is formally acceptable
• Copies of documents are certified where required

The final decision rests with the competent authority. If your experience is unusual, particularly where it involves military service, overseas employment, component maintenance or mixed aircraft categories, seek confirmation before submitting the application.

The key principle

Qualifying Part-66 B1 experience is not measured only by time served. It is demonstrated through a controlled record of practical maintenance on operating aircraft, supported by credible documentation and appropriate signatories.

For a UK or EASA B1.1 application, the strongest experience profile combines line and base maintenance, covers a broad range of turbine-aeroplane systems, includes proper technical documentation and is recorded continuously from the beginning of your career. Planning that evidence early can prevent years of otherwise useful maintenance work from becoming difficult to verify when you apply for the licence.