A mechanic is inspecting the inlet guide vanes of a turbine engine compressor through the inlet duct using a flashlight and finds several vanes with small dents and one vane with a visible bend that exceeds the manufacturer's blend/repair limits. What is the correct course of action?
- ABlend the bent vane using a file since it is accessible from the inlet
- BStraighten the vane by hand and re-inspect at the next 100-hour inspection
- CReject the vane from service and refer to the manufacturer's manual for repair, replacement, or engine removal as required
- DSince the engine still runs smoothly, defer the repair until the next scheduled inspection
Show answer & explanationAnswer & explanation
Correct answer: C. Reject the vane from service and refer to the manufacturer's manual for repair, replacement, or engine removal as required
When a damaged component such as an inlet guide vane exceeds published blend or repair limits, it can no longer be corrected by simple field blending; the mechanic must consult the engine manufacturer's maintenance manual to determine whether the vane can be repaired by an approved process, replaced, or whether the engine requires removal for shop repair, since exceeding limits can affect airflow and downstream compressor blade loading, risking further damage or failure.
Why the other options are wrong
- A. Blending is only permitted within published limits; exceeding limits requires manufacturer guidance, not further field blending.
- B. Hand-straightening a guide vane is not an approved repair method and can further damage the vane or induce cracks.
- D. Deferring known damage beyond limits risks further compressor damage and is not appropriate.
Compressor Inlet Guide Vane Damage Limits
Inlet guide vanes are inspected for dents, nicks, and bends against published blend limits; damage exceeding limits requires repair, replacement, or engine removal per the manufacturer's manual, not field correction.
- Minor damage may be blended within specified limits and re-inspected
- Damage beyond limits is not field-repairable by blending or straightening
- Excess damage can disturb airflow and increase loading on downstream blades
Memory trick: Beyond the limit? Don't file it — follow the manual's verdict