1、Lessons Learned Entry: 0149Lesson Info:a71 Lesson Number: 0149a71 Lesson Date: 1992-10-08a71 Submitting Organization: KSCa71 Submitted by: Lisa L. MusgraveSubject: Space Shuttle Main Engine (SSME) Vertical Installer Operations Description of Driving Event: The SSME vertical installer is used to posi
2、tion the engine for mounting on or removal from the orbiter. During SSME vertical installer operations, it was discovered that the air piston had a scored land ring. This scoring was due to the end of the stop groove being peened over. This peened condition happened when the stops came into hard con
3、tact with the end of the grooves. This condition occurs when the piston sticks in the cylinder due to a lack of lubrication and/or foreign material in the cylinder. Pressure then builds up until the piston breaks free. When the piston breaks free it can travel to the stops with enough momentum to ca
4、use this peening condition. A failure of the vertical installer caused by this scoring/peening could prevent positive control over the SSME and lead to unexpected movement during the installation/removal process.Lesson(s) Learned: Material deterioration of operating parts in SSME vertical installer
5、may cause engine to contact flight hardware/personnel and cause damage/injury.Recommendation(s): Prior to installation/removal of SSME, inspect air piston and bore for material defects/wearing to preclude vertical installer failure.Evidence of Recurrence Control Effectiveness: Provided by IHSNot for
6、 ResaleNo reproduction or networking permitted without license from IHS-,-,-N/ADocuments Related to Lesson: N/AMission Directorate(s): a71 Space Operationsa71 Exploration SystemsAdditional Key Phrase(s): a71 Ground Operationsa71 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-,-,-
