Metallurgical Failure Analysis of Low Pressure Turbine (LPT) Components From Jet Engine
Background to Failure Analysis Investigation
- Excess vibration reported in Engine by Airplane Pilot
- Engine teardown performed by Airline showed damage in LPT stages
- Nozzle in Stage 2 NGV suspected to be root cause for failure
- LPT components shipped to Kars’ Labs for metallurgical failure analysis
Objectives of Metallurgical Failure Analysis Investigation
- What caused failure?
- Did failure occur because of design issue, repair or manufacturing defect?
- What steps need to be taken to prevent reoccurrence?
Failure Analysis Methodology
- Test protocol written by Kars’ Labs
- Tests witnessed by Airline, Engine Manufacturer and Repair Shop
- Tests included Macrophotgraphy, Scanning Electron Microscopy, Metallurgical Cross Sections and Ultrasonic Tests
Failure Analysis Tests
Scanning Electron Microscopy
Summary & Recommendations
- Degradation of NGV Segment caused failure
- Failure of related to material condition and not repair
- Need for NDT technique to detect/measure IGO along inner surfaces of blades/segments
- Number of repairs need to be limited