Module 7.20-7.21 Maintenance procedures, documentation and communication

Knowledge levels

Sub-module	A	B1 / B3	B2 / B2L
7.20 Maintenance procedures	1	2	2
7.21 Documentation and communication	1	2	2

7.21 was added by Regulation (EU) 2023/989; the UK retained syllabus does not list it as a separate sub-module. The regulatory details are in Module 10; here the focus is on practice.

7.20 Maintenance procedures

Maintenance planning

• The aircraft maintenance programme (AMP), approved by the authority or CAMO process, defines tasks and intervals (flight hours, cycles, calendar) based on the manufacturer's maintenance planning document (MPD/MRB report), plus ADs and operator experience.
• Planning turns tasks into work packages with task cards, schedules hangar slots, manpower, tools, parts and documentation, and considers human factors (shift times, fatigue, critical tasks).
• Line maintenance (daily/weekly checks, transit checks, defect rectification) vs base maintenance (heavy checks, modifications, structural inspections).

Modification procedures

• A modification changes the design of the aircraft or a component. It must be embodied according to approved design data (manufacturer service bulletin approved, STC, minor/major change approval) - never by "local" invention.
• Embodiment is recorded in the aircraft records and the configuration/modification status updated; weight and balance and manuals revised where affected.
• Airworthiness directives (ADs) are mandatory and must be complied with in the prescribed time.

Stores procedures

• Parts must be from approved sources with release documentation (e.g. EASA Form 1 / authorised release certificate; UK CAA Form 1 for UK) and traceable.
• Receiving inspection: correct part and serial numbers, condition, documentation, shelf-life items.
• Segregation of serviceable, unserviceable (red/quarantine) and scrap parts; mutilation of scrap life-limited parts to prevent misuse.
• Controlled storage conditions (temperature, humidity, ESD, rubber shelf life, fluids with expiry dates); first-in-first-out.
• Suspected unapproved parts must be quarantined and reported.

Certification/release procedures

• After maintenance, a certificate of release to service (CRS) is issued by appropriately authorised certifying staff, confirming the work was done according to approved data and the organisation's procedures and that the aircraft is ready for release regarding that work.
• Incomplete tasks, deferred defects (within the minimum equipment list - MEL - or approved deferral limits) must be recorded and the operator informed.
• Certifying staff must have personally checked or been satisfied that work was properly done - including any independent inspection on critical tasks (flight controls, engines).

Interface with aircraft operation

• Technical log (aircraft tech log): crew report defects; maintenance records rectification or deferral; CRS entries.
• Communication with flight crew and operations control about aircraft status, MEL items, operational restrictions.
• Return-to-service flights or engine runs when required.

Maintenance inspection, quality control and quality assurance

• Inspection: checking work and aircraft condition against standards.
• Quality control (QC): product-oriented checks (e.g. inspections, independent inspections, test results).
• Quality assurance (QA): system-oriented - independent audits of procedures and compliance (Part-145 compliance monitoring), feedback and corrective actions; supported by the safety management system.

Additional maintenance procedures

• Critical task identification and error-capturing methods (independent inspections, re-inspection).
• Tool control, FOD prevention, shift handover, use of approved data, reporting of errors and occurrence reporting (mandatory reporting to authority).
• Control of borrowed tools and equipment; calibration.

Control of life-limited components

• Life-limited parts (LLPs) - e.g. engine discs, landing gear components - have mandatory limits (cycles, hours, calendar).
• Records must give the complete back-to-birth history; remaining life tracked; parts removed before limits; LLPs reaching their limit are scrapped and mutilated.
• Hard time (removal at a fixed limit), on-condition (inspect and continue while acceptable) and condition monitoring (no fixed interval; reliability monitoring) are the classic maintenance processes.

Key fact: A modification needs approved design data; an AD is mandatory; a life-limited part must be traceable back to birth and removed before its limit.

7.21 Documentation and communication

Writing work reports

Good work reports and technical records are:

• Clear - plain technical language, standard terminology, no ambiguous abbreviations.
• Comprehensive - what was found, where (zone, station, part/serial numbers), what was done, reference to approved data (AMM task, SRM figure, revision), measurements and test results, parts fitted/removed, tools with calibration control where required.
• Concise - no unnecessary detail.
• Accurate and legible, signed/stamped and dated by the person who did the work, entered at the time (not later from memory).

Troubleshooting reports

• Symptom as reported; conditions (ground/flight, phase); fault messages; checks carried out and results; components replaced (P/N, S/N off and on); final test; whether the fault is confirmed rectified or monitored; any recurring-defect references.

Shift handover

• Formal, preferably face-to-face plus written, at a dedicated time.
• Content: tasks completed, tasks in progress (exact stage reached, what remains, open panels, disconnected items, temporarily installed tools or equipment), problems found, parts/tools awaited, safety issues, deferred items.
• Incoming staff confirm understanding and ask questions; partly completed tasks are clearly marked on task cards (stage sheets).
• Poor handovers have been a cause of major accidents - this links to Module 9 (human factors).

Communication

• Clear, comprehensive, concise - use the standard language of the organisation (often English), standard phrases, read-back of critical information.
• Communicate with the right people: supervisors, certifying staff, planning, stores, flight crew.
• Never assume - verify. Report errors and hazards without fear (just culture).