1、Lessons Learned Entry: 0001Lesson Info:a71 Lesson Number: 0001a71 Lesson Date: 1991-04-10a71 Submitting Organization: JSCa71 Submitted by: L. UnderwoodSubject: Implementation of Procedural Controls in Additional Procedures Beyond the Procedure Under Investigation and Correction Description of Drivin
2、g Event: During prelaunch check out of shuttle orbiter OV-104 for flight STS-36, the AC2 buss phase a voltage fluctuated between 112 and 122V for one minute. The inverter supplying that buss was removed and replaced. The vendors inspection of the failed inverter found loose mounting screws on the el
3、ectrical buss internal to the inverter, which caused the voltage fluctuations. An identical problem had been previously discovered that prompted a change to the manufacturing procedures to include a specified torque for the mounting screws. The failed flight unit had been reworked, but the manufactu
4、ring procedural change had not been incorporated into the rework process.Lesson(s) Learned: Recurrence controls to prevent an original manufacturing defect should be expanded to address any items already deployed in field including those to be reprocessed or reworked.Recommendation(s): Ensure that a
5、ny process modifications are considered for implementation in all units that were previously distributed or deployed - not just to those units processed after the process was modified.Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: Provided by IHSNot for ResaleNo reprod
6、uction or networking permitted without license from IHS-,-,-N/AMission Directorate(s): a71 Exploration Systemsa71 Sciencea71 Space Operationsa71 Aeronautics ResearchAdditional Key Phrase(s): a71 Configuration Managementa71 Flight Equipmenta71 Hardware Additional Info: Approval Info: a71 Approval Date: 1993-09-09a71 Approval Name: Ron Montaguea71 Approval Organization: JSC/NS3a71 Approval Phone Number: 281-483-8576Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
