FAA Aviation Mechanic Powerplant (AMP)Turbine EnginesMedium
A technician performs a borescope inspection of a turbine engine's hot section as part of a scheduled inspection program. Which type of defect is this inspection method primarily intended to detect?
- AImproper N1/N2 speed sensor calibration
- BFuel nozzle spray pattern misalignment found during bench flow testing
- CTurbine blade cracking, erosion, or thermal distress
- DIgnition exciter output voltage decay
Show answer & explanationAnswer & explanation
Correct answer: C. Turbine blade cracking, erosion, or thermal distress
Borescope inspection allows a technician to visually examine internal hot section components, such as combustion liners and turbine blades, without engine disassembly, to detect cracking, erosion, burning, or other thermal distress.
Why the other options are wrong
- A. Speed sensor calibration is checked electronically, not visually.
- B. Fuel nozzle spray patterns are checked on a flow bench, not with a borescope.
- D. Ignition exciter performance is tested electrically, not via borescope.
Borescope Inspection
A visual inspection technique using a flexible or rigid optical instrument inserted through access ports to examine internal engine components, such as the hot section, without disassembly.
- Used to detect cracks, erosion, and burning on blades and liners
- Avoids costly engine teardown
- Performed at scheduled intervals per maintenance manual
Memory trick: 'Borescope peeks inside without a break-up' - inspect without disassembly