REG NASA-LLIS-0302--1993 Lessons Learned Galileo Wiring Harness Contact Crimp Problem.pdf

1、Lessons Learned Entry: 0302Lesson Info:a71 Lesson Number: 0302a71 Lesson Date: 1993-09-15a71 Submitting Organization: JPLa71 Submitted by: B. J. Wagoner / J. BillittiSubject: Galileo Wiring Harness Contact Crimp Problem Abstract: After a wiring modification to the Galileo Computer Data System (CDS)

2、wiring harness, a wire pulled out of a crimped contact barrel that was too large for the wire.When crimped contacts are to be used in cable harness assemblies, require that color coded contacts and pull tests be incorporated into acceptance test procedures. Description of Driving Event: During a con

3、tinuity test of the Galileo Computer Data System (CDS) wiring harness, after a wiring modification, an open circuit was detected between two connectors. Investigation revealed that a wire had pulled out of a crimped contact barrel in a connector, causing the open. Further analysis revealed that the

4、problem was caused by a crimp contact sized for No. 20 AWG wire being used for a No. 28 AWG wire. The fabrication error was difficult to detect because the crimp connection failed only after extensive handling stress to the harness.The resolution of the problem was to color band the smaller crimp co

5、ntacts for positive identification, and the development of a pull-test tool for 100% verification of each crimped wire in a connector. No crimped contact failures have reoccurred at JPL since the inception of this practice in 1984.Reference(s): PFR #40886 and PFR #41229Lesson(s) Learned: Visual insp

6、ections and continuity checks are not adequate verification that cable harness assemblies Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-have been fabricated correctly.Recommendation(s): When crimped contacts are to be used in spacecraft or ground s

7、upport equipment cable harness assemblies, a requirement should be imposed on the fabricators, that color coded contacts and pull tests be incorporated into acceptance test procedures.Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): N/AAddition

8、al Key Phrase(s): a71 Parts Materials & Processesa71 Test & VerificationAdditional Info: Approval Info: a71 Approval Date: 1990-01-26a71 Approval Name: Carol Dumaina71 Approval Organization: 125-204a71 Approval Phone Number: 818-354-8242Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-