Failure of an aerospace component
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1. Failure of an aerospace component ----------------------- 3-4
2. Cause of failure----------------------------------------------- 5-6
3. Principles of material science of the failure
(i) Wear--------------------------------------------------------- 7
(ii)Fatigue------------------------------------------------------ 7-8
(iii)Corrosion--------------------------------------------------- 8-10
(iv)Fracture----------------------------------------------------- 10-14
4. Solution to the failure of the aerospace component------ 15-16
5. Conclusion/Lessons ------------------------------------------ 17-18
6. Sources of information---------------------------------------- 19
1.Failure of an aerospace component
On January 31 2000, Alaska Airline flight 261 crashed into the Pacific Ocean. The plane faced problems with its longitudinal trim system, unable to control the elevator at the horizontal stabilizer, encountered pitching problem at around 28000 feet. The problem exacerbated even after initial success of getting back control of the longitudinal trim system, and suffered an irreversible nose-dived of the plane and crash into the Pacific Ocean.
The aerospace component that failed is the acme nut threads of the horizontal stabilizer trim system jackscrew. The jackscrew was shafted through this acme nut and connected directly to the stabilizer, mechanically shifting it up or down so as to control the pitch of the plane. In this case, the threads in the acme nut were sheared off and after the debris was found, it was discovered that almost 90% of the threads were already smoothened out and there were even remnants of the spirals found on the jackscrew(*pic 1). The wear-off of the threads loosened the grip of the acme nut on the jackscrew and the jackscrew came off disastrously. A mechanical stop was designed to prevent the jackscrew from rotating past the...