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misalignment of the outer race with respect to the compressor shaft. The offcentering of the balls
exerted overbearing stresses on one side (displaced from the middle) of the inner and outer races
inducing heavy deformation on their surfaces. The rotation of the bearing and the main compressor
shaft became difficult and led to the accident. To get in between the balls and the races, the cage
had to break. The fatigue failure features on the fracture surface of the cage confirmed the above
hypothesis [5].

5. CONCLUSION
It has been conclusively shown that the cause of the accident was the failure of the CMB cage.
The cage failed due to fatigue. No material defect could be traced at the site of crack initiation.
Acknowle&emenrs-The authors are grateful to Mr Badar Habib, Mr Tahir Mehmood and Mr Altaf Hussain for their help
in photography and compilation of the paper.

REFERENCES

1. Widner, R. L., Metals Handbook, vol. I1,9th edn., American Society for Metals, Metals Park, OH 44073, 1986, pp. 490-
513.
2. Neal, M. J., ed., BearingeA Tribology Handbook, 2nd edn., Butterworth-Heinemann Ltd., Oxford, 1993, pp. 97-1 16.
130-1 34.
3. Kossowskii, R., Emerging Technologies Inc., USA, private communication.
4. Walker, C. R. and Starr, K. K., Failure Analysis Handbook, Pratt & Whitney Report August 1989, Materials Laboratory,
Wright Research and Development Center, OH 45433-6533, pp. 206,267,272,354,358.
5. Widner, R. L. and Wolfe, J. O., Merul Progress, April 1968, pp. 52-59.