1、Lessons Learned Entry: 0621Lesson Info:a71 Lesson Number: 0621a71 Lesson Date: 1999-14a71 Submitting Organization: JPLa71 Submitted by: Larry CombesSubject: Post Mission Hardware Drop Incident (1998) Abstract: CHeX: In 1998 the CHeX space flight hardware was damaged due to a drop caused by failure o
2、f the lift fixture during transfer of the cryoprobe to a support structure. CHeX: Implement positive means of assuring lift fixtures are assembled in the same configuration as proof-tested. Assure operators and supervisors are trained to perform critical lifts.Description of Driving Event: The CHeX
3、space flight hardware was damaged at a collaborating university during disassembly and testing after completion of the mission. The cryoprobe, a high value component of the experiment hardware, was dropped approximately 18 inches onto a concrete floor causing significant repairable damage. The drop
4、was caused by failure of the lift fixture during transfer of the cryoprobe to a support structure.Review of the mishap revealed that the lift fixture design was structurally adequate, with load carrying capability of the vertical axis dependent on a double lock-nut system. Prior to the operation, th
5、e unassisted lift fixture operator did not detect that the lock nut was missing and that the remaining nut was close to disengagement. This nut did disengage, allowing the flight hardware to drop. The fixture design and test planning were not robust enough to reasonably preclude flight hardware dama
6、ge.Contributing to the mishap was a failure to follow NASA critical lift procedures for flight hardware, including:1. Inadequate fail-safe design of the lift fixture.2. Improper assembly of the lift fixture.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS
7、3. Inadequate pre-operation inspection of the lift fixture.4. Inadequate supervision of the operator.Additional Keyword(s): Human Factors, Crane, HoistReference(s):1. CHeX Hardware Failure Review, 7941:TL-98-007:tl2. NSS/GO-1740.9B, NASA Safety Standard for Lifting Devices and Equipment, Nov. 1
8、9913. LLIS Number 0267 (JPL #11-115), TOPEX/POSEIDON Near-Drop Incident4. LLIS Number 0273 (JPL #11-113), Solar Array Drive (SAD) DropLesson(s) Learned: 1. The same care that is provided during pre-flight operations should be given to flight hardware after completion of its mission.2. Assure that li
9、ft fixture design and lift procedures are fail-safe.3. Implement positive means (tagging and tethering) of assuring lift fixtures are assembled in the same configuration as proof-tested.4. Assure operators and supervisors are trained to perform critical lifts, including pre-operational inspections.5
10、 Implement the buddy system, or provide adequate supervision, while handling critical hardware.Recommendation(s): See lesson(s) learnedEvidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): N/AAdditional Key Phrase(s): Provided by IHSNot for ResaleN
11、o reproduction or networking permitted without license from IHS-,-,-a71 Human Factorsa71 Lifting DevicesAdditional Info: Approval Info: a71 Approval Date: 1999-30a71 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-,-,-
