1、 Public Lessons Learned Entry: 3257Lesson Info:a71 Lesson Number: 3257 a71 Submitting Organization: KSC a71 Submitted by: Annette Pitt Subject: Passive Element Failure Modes and Effects Abstract: Classically, Failure Modes and Effects Analysis (FMEA) and System Assurance Analysis (SAA) have omitted
2、passive elements of the design. These elements must be included to have a complete and effective maintenance plan and to avoid potential catastrophic failures. Description of Driving Event: During the ascent of STS-93, an AC 1 Phase A short occurred. It was caused by a mid-body close-out panel screw
3、 piercing an AC 1 Phase A power wire that feeds the Main Engine Controllers. This short tripped the AC 1 Phase A circuit breaker for SSME 1 Controller A, which interrupted power to that circuit and could have caused the loss of an engine during ascent. The subsequent investigation revealed there was
4、 inadequate protection of the Orbiter wire bundles and virtually no maintenance of the Orbiters passive wiring elements. As a result of these findings, program management gave an action to evaluate the need to perform periodic maintenance-type inspections and/or tests of the flight and ground suppor
5、t passive system elements to avoid potential system failures that could result in the failure of flight or ground hardware, subsequent launch aborts, harm to the crew, or early mission termination. Lesson(s) Learned: Performing periodic tests and inspections of passive flight and ground support syst
6、em elements such as wiring, mechanical fasteners, and pressurized tubing that support critical flight and ground support systems can help to avoid catastrophic failures of these systems. Recommendation(s): Periodic tests and inspections of passive flight and ground support system elements (such as w
7、iring, mechanical fasteners, and pressurized tubing) that support critical flight and ground support systems should be performed to avoid catastrophic failures of these systems, which could result in loss of crew or vehicle, launch aborts, or early mission termination. Evidence of Recurrence Control
8、 Effectiveness: N/A Documents Related to Lesson: Click here to download Passive SFP Review Plan Click here to download Launch and Landing Findings Closeout Briefing Click here to download Launch and Landing Reusable Hardware Maintenance Assessment Overview to ASAP Mission Directorate(s): a71 Space O
9、perations Additional Key Phrase(s): a71 Program Management.Risk management a71 Additional Categories.External Relations Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-a71 Engineering Design (Phase C/D).Launch Systems a71 Mission Operations and Groun
10、d Support Systems.Ground support systems a71 Mission Operations and Ground Support Systems.Launch support systems a71 Mission Operations and Ground Support Systems.Mission operations systems a71 Safety and Mission Assurance.Reliability a71 Safety and Mission Assurance.Maintenance a71 Systems Enginee
11、ring and Analysis.Engineering design and project processes and standards Additional Info: a71 Project: Space Shuttle Program Approval Info: a71 Approval Date: 2010-11-17 a71 Approval Name: mbell a71 Approval Organization: HQ Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
