FAA Aviation Mechanic Airframe (AMA)Airframe StructuresHard
During a scheduled inspection, a technician finds a dent in a wing skin panel. Before deciding whether the aircraft can be returned to service without repair, which reference should the technician consult to determine whether the damage falls within allowable limits?
- AThe Type Certificate Data Sheet (TCDS)
- BThe manufacturer's Structural Repair Manual (SRM) allowable damage limits
- CThe Illustrated Parts Catalog (IPC)
- DThe aircraft's weight and balance report
Show answer & explanationAnswer & explanation
Correct answer: B. The manufacturer's Structural Repair Manual (SRM) allowable damage limits
The Structural Repair Manual contains allowable damage limit charts that specify dimensions, depth, and location criteria for damage that can be left as-is (negligible damage) versus damage that requires blend-out, repair, or replacement. This is the correct source for evaluating skin damage against approved limits.
Why the other options are wrong
- A. The TCDS provides certification basis and limitations data, not detailed damage tolerance criteria for specific structure.
- C. The IPC lists part numbers and breakdowns for ordering parts, not damage limits.
- D. Weight and balance data has no bearing on evaluating structural damage limits.
SRM Allowable Damage Limits
The Structural Repair Manual contains charts and criteria defining the maximum dent, scratch, or crack dimensions that can remain in service without repair (negligible damage) versus damage requiring repair.
- Found in the manufacturer's SRM
- Specifies limits by structure zone, depth, length, and location
- Guides decision: no action, blend-out, or repair
- Exceeding limits requires an engineered repair or manufacturer approval
Memory trick: When skin gets dinged, check the SRM before you sing 'it's fine' or 'fix it.'