Aircraft Structures and Systems Inspection
Method drives the finding
An inspection is only as good as the access and technique used. Visual inspection after cleaning and opening panels finds most discrepancies; tap testing, eddy current, ultrasonic, radiographic, magnetic particle, and dye penetrant extend it. The inspector chooses the method appropriate to the suspected failure mode: corrosion in seams and wet areas, fatigue cracking at fatigue-critical structure identified in the airworthiness limitations, stress corrosion at fittings, delamination and impact damage in composites, and loose or chafed hardware.
Structures
Look where the design concentrates load and moisture: spar caps and webs, wing attach fittings, empennage attachments, engine mounts, pressure bulkheads, stringer-to-skin splices, control surface hinges and balance weights, and landing gear trunnions. Corrosion control guidance (AC 43-4) treats corrosion as a condition to be treated, not a cosmetic issue, and any blister, exfoliation, or Intergranular attack on primary structure deserves evaluation.
Systems and appliances
Check flight control cable tension, rigging, and turnbuckle safety; fuel and hydraulic lines for chafing, deterioration, and date-limited hose; wiring for chafe, arcing, and improper splices; exhaust systems for cracks that can leak carbon monoxide; engine condition via compression, oil analysis, magnetic plugs, and borescope; propeller blades for nicks, corrosion, and tracking, and hubs for cracks.
Traps
A trending discrepancy - one cylinder low, one crack, one hot section - usually means look further. Manufacturer's inspection recommendations become mandatory only through ADs, airworthiness limitations, or an approved program. Installing a TSO article does not by itself approve the installation.
Rule of thumb
When you find damage that exceeds the manufacturer's published repair limits, stop and require FAA-approved data before any repair is designed.