REG NASA-LLIS-0447--1995 Lessons Learned - Component Anomalies Log - Scout Program.pdf

1、Lessons Learned Entry: 0447Lesson Info:a71 Lesson Number: 0447a71 Lesson Date: 1995-06-12a71 Submitting Organization: LERCa71 Submitted by: Judy TerlepSubject: Component Anomalies Log - Scout Program Description of Driving Event: At the Loral Vought Systems in Dallas, Texas prior logbook test data h

2、istory was evaluated as part of a normal failure investigation. During this review a trend in data was sometimes observed that indicated a prior drift or shift towards an out-of-tolerance condition.The Scout Program initiated a test data monitoring program on selected assemblies. Design, quality and

3、/or reliability engineers reviewed the test data after each retest on the assembly or vehicle level. The appropriate engineer maintained supplementary notes. The list of assemblies to be monitored grew as additional parameters were identified.Typical parameters monitored were:A. Spin-up time, mass u

4、nbalance and null voltages on gyrosB. Receiver and transmitter frequencies on beacon transpondersC. Output frequencies of voltage controlled oscillatorsD. Resistance measurements on relay assembliesE. Discharge times at constant current on rechargeable batteriesF. De-spin time on bearingsThis practi

5、ce has been in place since the beginning of the Scout Program in 1960.Lesson(s) Learned: Components may have anomalies that are within specification and which later become the source of other problems.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-R

6、ecommendation(s): Responsible system engineers should maintain a log for all components, which have anomalies that are within specification.Evidence of Recurrence Control Effectiveness: Because of this monitoring, many failures were prevented by rejecting the identified assembly prior to flight fail

7、ure or by the early detection of potential out-of-tolerance parameters. This evaluation of test data resulted in attaining a higher reliability of flight performance and prevented costly component replacement in the field.Documents Related to Lesson: N/AMission Directorate(s): N/AAdditional Key Phra

8、se(s): a71 Hardwarea71 Parts Materials & Processesa71 Safety & Mission AssuranceAdditional Info: Approval Info: a71 Approval Date: 1996-09-13a71 Approval Name: Sell Jamesa71 Approval Organization: 501-4a71 Approval Phone Number: 216-433-8618Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-