REG NASA-LLIS-0055-1992 Lessons Learned - Quick Disconnect F O D Quick Disconnect (QD) Design SCAPE Operations.pdf

1、Lessons Learned Entry: 0055Lesson Info:a71 Lesson Number: 0055a71 Lesson Date: 1992-01-28a71 Submitting Organization: KSCa71 Submitted by: David PenningtonSubject: Quick Disconnect F.O.D.; Quick Disconnect (QD) Design; SCAPE Operations Description of Driving Event: During servicing of the oxidizer o

2、n the forward reaction control system (FRCS), a ground half quick disconnect (QD) failed. The failure mode was such that an open flow path was created to the outside of the QD and 15 to 20 gallons of oxidizer (N2O4) flowed overboard prior to isolating the flow sources. The failure of the ground-half

3、 QD was attributed to an accumulation of iron nitrate lodged between the probe and the dynamic head. The presence of iron nitrate was traced to contaminated fuel.Lesson(s) Learned: 1. Fuel contaminants can lodge between the poppet and dynamic head of a QD preventing leak-free closure.2. QD poppet an

4、d dynamic head may fail to actuate properly, allowing liquid to flow through the QD and exit in the release collar area.3. A design flaw in the quick disconnects provides an additional leak path, allowing liquid to flow through the QD and exit in the release collar area.4. SCAPE technicians need rea

5、dy access to fire fighting equipment when working with hazardous/combustible materials.Recommendation(s): 1. Modify procedures to include testing for fuel contamination prior to flow through the system.2. Quick disconnects designed with positive seals in the release collar would reduce accidental Pr

6、ovided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-leakage.3. Leaks detected during future hypergolic operations should be terminated prior to scuppers overflowing.4. Prior to beginning SCAPE operations, SCAPE personnel should prepare a fire handline (cha

7、rged and layed out) nearby for emergency use.Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): a71 Space Operationsa71 Exploration SystemsAdditional Key Phrase(s): a71 Emergency Preparednessa71 Energetic Materials - Explosive/Propellant/Pyrotech

8、nica71 Fire Protectiona71 Flight Equipmenta71 Ground Operationsa71 Ground Equipmenta71 Hardwarea71 Hazardous/Toxic Waste/Materialsa71 Launch Processa71 Launch Vehiclea71 Packaging Handling Storagea71 Parts Materials & Processesa71 Personal Protective Equipmenta71 SpacecraftAdditional Info: Provided

9、by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Approval Info: a71 Approval Date: 1994-06-01a71 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-,-,-