1、Lessons Learned Entry: 0077Lesson Info:a71 Lesson Number: 0077a71 Lesson Date: 1992-05-20a71 Submitting Organization: KSCa71 Submitted by: David PenningtonSubject: OMS/RCS System Control Logic Description of Driving Event: While pressurizing the oxidizer propellant tank, a change in ullage pressure
2、of 8 psi occurred and caused the computer program to indicate that the interface and supply valves were closed. At this point, the engineer felt it was safe to close the dome load valve, in reality opening it. He then opened the interface valve, the pressure online with the module was 190 psig, the
3、supply valve was then opened and the pressure spiked to approximately 400 psig, which ruptured the burst disk. The computer program indicated the incorrect status of the system because the control logic limits were not adjusted/reset prior to starting the operation.Lesson(s) Learned: OMS/RCS Systems
4、 program control logic does not reset each time the program is activated, allowing inadvertent over-pressurization of the system.Recommendation(s): Add a step to all OMS/RCS system OMIs that are monitored by control logic, to adjust logic limits prior to changing pressure.Evidence of Recurrence Cont
5、rol Effectiveness: N/ADocuments Related to Lesson: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-N/AMission Directorate(s): N/AAdditional Key Phrase(s): a71 Energetic Materials - Explosive/Propellant/Pyrotechnica71 Pressure Vesselsa71 SoftwareAdditional Info: Approval Info: a71 Approval Date: 1994-06-15a71 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-,-,-
