1、Lessons Learned Entry: 0170Lesson Info:a71 Lesson Number: 0170a71 Lesson Date: 1992-10-22a71 Submitting Organization: KSCa71 Submitted by: David PenningtonSubject: OPF Payload Bay Bucket Limit Switches. Description of Driving Event: Failure of one or more of these component switches 1S8, 2S8, 3S8, o
2、r 4S8 in the closed position would cause a short circuit of relay K11, thus not allowing any of the 16 bucket proximity limit switches on both buckets to stop travel. This can result in damage to flight hardware (payload and/or vehicle) due to buckets hitting hardware.Lesson(s) Learned: Failure of o
3、ne or more components (1S8-4S8) in the closed position would prevent the limit switches from stopping downward travel of the buckets.Recommendation(s): Design a fail safe control system that will stop all movement of the bucket if a critical component fails or fails to perform properly.Evidence of R
4、ecurrence Control Effectiveness: N/ADocuments Related to Lesson: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-N/AMission Directorate(s): N/AAdditional Key Phrase(s): a71 HardwareAdditional Info: Approval Info: a71 Approval Date: 1994-06-06a71 Approval Name: James G. Klinea71 Approval Organization: KSC/HEIa71 Approval Phone Number: 407-867-7614Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
