Maintenance Practices
What you must understand
This is the largest practical domain. Know safety precautions, hangar and ramp discipline, fire precautions and the correct extinguishing medium for each fire class. Understand maintenance documentation: task cards, work orders, technical logs, certificates of release to service, and the rules for recording work and certifying it. Study inspection philosophy (scheduled, unscheduled, conditional), the meaning of tolerances, clearances and limits, and the use of calibrated tools. Know torque procedures, lockwiring, safetying, and the discipline of tool control and foreign object debris prevention. Understand ground handling and storage, aircraft weighing, jacking, towing and mooring precautions, plus fuel safety and defuelling. Understand the purpose of functional tests, duplicate inspections on critical tasks, and the handling of discrepancies.
Traps in questions
- Fire extinguisher choice: water conducts, CO₂ is unsuitable for some confined spaces, dry powder contaminates avionics; match medium to fire class.
- Duplicate inspection: required for specific critical tasks where a single error could be catastrophic; both signatures are needed.
- Calibration: an out-of-calibration tool invalidates the measurement, even if the reading seemed right.
- FOD: prevention is procedural; questions test where FOD is most likely introduced.
- Recording: if it is not recorded, it did not happen - certification depends on accurate records.
Worked example
A torque wrench with a stated accuracy of ±4% is set to 50 N·m. Acceptable applied torque lies between 48 and 52 N·m. If the wrench is out of calibration, the result cannot be certified regardless of the indicated value.
Rule of thumb
Before any task, ask: is the documentation current, is the tool calibrated, is the area safe, and who certifies the result?