| About this Abstract |
| Meeting |
Materials Science & Technology 2019
|
| Symposium
|
Failure Analysis: Industry Specific Failures
|
| Presentation Title |
Helicopter Main Rotor Servo Disconnect Failure Due to Self-locking Nut Reuse |
| Author(s) |
Richard McSwain, William Carden, Eric Van Iderstine, Leah Godwin |
| On-Site Speaker (Planned) |
Richard McSwain |
| Abstract Scope |
A helicopter accident investigation revealed that a main rotor servo disconnected in flight. Examination of the accident wreckage showed a missing fastener for the servo that was to be secured with a nylon insert self-locking nut. Laboratory testing of the subject-type fastener and self-locking nut revealed loss of the self-locking feature effectiveness after several installation and removal cycles. It was concluded that the reuse of the nylon insert self-locking nut led to the loss of fastener torque and loss of the main rotor servo fastener in flight. |