Maintenance, Repair, and Alteration
What this domain tests
This domain tests the boundary between permitted maintenance and work that requires approved data or higher authority. It also tests repair technique and documentation. Expect questions about tears, patches, line replacement, hardware replacement, and alterations.
Core rules and concepts
- Approved data first. Repair limits come from the manufacturer’s instructions, the packing data card, or other approved data. A rigger may perform maintenance and minor repairs within certificate privileges and repair limits; major repairs or alterations require approved data and, where applicable, FAA acceptance.
- Damage assessment. Classify the damage: location, size, direction, and whether it crosses a structural seam or load path. A tear in a low-load panel may be repairable within limits; a tear across a line attachment or load-bearing seam may require canopy replacement or factory repair.
- Patch and seam repair. Use compatible material, rounded corners, correct overlap, and specified stitching. Do not create a hard point or distort canopy trim. Remove damaged hardware rather than bending it back into service.
- Line replacement. Use approved line material and size. Set length under the specified tension and attach with the specified knot, loop, or bartack. Verify trim across the canopy.
- Alteration. Changing design, adding hardware, or modifying a TSO-approved assembly without approval is not minor maintenance. Document all work and update records.
Worked example
A canopy panel has a 4-inch tear. The manufacturer’s manual permits a fabric patch only for tears up to 3 inches in that panel. The rigger should not “make it fit” by trimming the tear or using a larger patch outside the manual. The repair exceeds the minor-repair limit, so the canopy must be referred for approved repair or replacement. The reasoning is based on approved limits, not on how strong the finished patch might feel.
Traps that cost marks
- Performing a field repair beyond the manufacturer’s size or location limit.
- Using unapproved patch fabric or thread because it matches in color.
- Bending bent hardware back into shape instead of replacing it.
- Altering a TSO-approved assembly without approved data and records.