REG NASA-LLIS-0062-1992 Lessons Learned - LRU Platform Hoist and Tube Assembly Platform Hoist Tube Assembly UP Limit Switch Bypass.pdf

1、Lessons Learned Entry: 0062Lesson Info:a71 Lesson Number: 0062a71 Lesson Date: 1992-03-05a71 Submitting Organization: KSCa71 Submitted by: David PenningtonSubject: LRU Platform Hoist and Tube Assembly; Platform Hoist Tube Assembly “UP“ Limit Switch Bypass Description of Driving Event: Three sections

2、 of a telescoping tube assembly at Pad B rotating service structure (RSS) fell while being extended to incorporate a planned modification (MOD). The MOD intended to eliminate binding that had been experienced during testing and verification. The falling tubes impacted and severely damaged the RSS an

3、d orbital maneuvering system pod covers. The contributing factor to this failure is that the fillet welds on tube “D“ provided an outward ramp effect that caused excessive wear on the keepers and the eventual bowing of tube “C“ which allowed less surface contact area between the welded stops and the

4、 keepers.Lesson(s) Learned: 1. Excessive wear of the load bearing surfaces on the keepers of tube “C“ was the result of impact during approximately 30 retraction cycles.2. To stow the tubes, normal operations required bypassing the “up“ limit switch and using observers to determine when to stop the

5、upward travel.Recommendation(s): 1. Design tube hoist assemblies that do not incorporate fillet welds on the inside of the tubes and opposite the tubes stops. This will reduce/eliminate wearing down of the tube stops.2. Add “up“ limit switches exclusively dedicated to tube stowage operations.Evidenc

6、e of Recurrence Control Effectiveness: N/AProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Documents Related to Lesson: N/AMission Directorate(s): N/AAdditional Key Phrase(s): a71 Facilitiesa71 Ground Operationsa71 Ground Equipmenta71 Lifting Devicesa

7、71 Packaging Handling Storagea71 Parts Materials & ProcessesAdditional Info: Approval Info: a71 Approval Date: 1994-06-15a71 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-,-,-