Disassembly, Inspection, Repair, Assembly and Maintenance Procedures
From work order to release
Maintenance is a controlled sequence: plan against approved data (AMM, SRM, IPC, wiring practices manual, service bulletins, airworthiness directives), raise a work card, and only then touch the aircraft. Disassembly means tagging every part and connection, bagging and boxing hardware, recording the as-found condition, and protecting open lines and connectors. Inspection uses visual, borescope and NDT methods (dye penetrant, magnetic particle, eddy current, ultrasonic, radiography) and the method must match the material - magnetic particle only on ferromagnetic parts.
Repair must be to approved data: a structural repair manual or an approved design, never workshop improvisation. Assembly covers cleanliness, lubrication, correct hardware, torque with a calibrated wrench in the specified sequence, correct locking devices, rigging, and functional testing before release. Maintenance programmes classify tasks as hard time, on-condition or condition monitoring, and MSG-3 logic decides which applies.
Human factors matter: distraction, complacency, fatigue, pressure and poor communication are the recurring causes of maintenance error, so independent and duplicate inspections exist for critical tasks such as flight controls, engine changes and pressurisation.
Traps: re-using a self-locking nut beyond its permitted cycles, fitting an unapproved part, skipping a duplicate inspection, and releasing an aircraft without a certificate of release to service.
Rule of thumb: if it is not written on the card and in the approved data, it did not happen - document as you go and count the tools before closing the panel.