Maintenance Practices
Core concepts
This is the largest practical domain. Cover safety practices (COSHH-type hazards, fire, working at height), workshop practice and tools, engineering drawings and diagrams, fits and clearances, maintenance planning and documentation, defect reporting, inspection and testing, and the rules governing maintenance release. Know the purpose and handling of the technical log, work packs, task cards, service bulletins and airworthiness directives, and the meaning of approved data and acceptable data.
Traps to watch
- Approved versus acceptable data: approved data (e.g. type certificate data, approved manuals, ADs) can be used directly; acceptable data may need approved-data backup.
- Certification privilege: only authorised certifying staff can issue a certificate of release to service, within their scope.
- Torque and safetying: torque values apply to dry or lubricated threads differently; always re-check safety wire direction and tension.
- Tool calibration: precision instruments must be within calibration; out-of-calibration tools invalidate results.
- FOD and cleanliness: foreign object debris prevention is a discipline, not an afterthought.
Worked example
A task card requires a torque of 20 N·m on a fastener with a specified lubricant. Torque is applied with a calibrated wrench in the specified sequence, then the fastener is locked and the work signed off. If the wrench's calibration label has expired, the task cannot be certified - the work must be redone with a calibrated tool.
Rule of thumb
Ask: "Is the data approved, is the tool calibrated, and am I authorised?" If any answer is no, stop. This triad answers a large share of maintenance-practice questions.