1、Lessons Learned Entry: 1200Lesson Info:a71 Lesson Number: 1200a71 Lesson Date: 1990-06-04a71 Submitting Organization: KSCa71 Submitted by: Paul D. Myers Jr./ Eric RaynorSubject: Improper Raising of Orbiter 103 Payload Bay Door Mishap Description of Driving Event: On June 4, 1990, in High Bay 1 of th
2、e Orbiter Processing Facility (OPF) at the Kennedy Space Center (KSC), the aft bridge of the Payload Bay Bridge and Hoist System was moved approximately 78 inches aft of its set position for Payload Bay Door (PLBD) operations. The right-hand PLBD Zero-G System was configured to support a scheduled P
3、LBD closing operation on first shift, June 4, 1990, except the Zero-G weight baskets were left pinned to their weight cages. The right Payload Bay Door (PLBD) was supported by the Zero-G cabling (not pinned to the platform). Movement of the bridge put the Zero-G cabling into tension and at an angle
4、sufficient to shear a portion of the weight basket pulley “V,“ fray the Zero-G cabling, move the weight basket off its track, and deflect the C-hook approximately 2 to 3 inches. Since the weight basket was pinned, the aft movement of the bridge also caused the right PLBD aft portion to rise approxim
5、ately 31 to 33 inches (calculated).Lesson(s) Learned: Failure of the bridge operator to follow the approved procedure, which requires verification that the Zero-G System is not hooked up prior to bridge movement and assignment of an observer, was the major contributing cause of this mishap. The seco
6、nd contributing cause involved multiple deficient control systems to preclude bridge operation while connected to the Zero-G Simulator. Supervisory control of the bridge power key was nonexistent, allowing technicians free access to bridge keys. Procedural steps included in Operations and Maintenanc
7、e Instruction (OMI) V3575 to tag the bridge/bucket system out of service and secure the key during Zero-G operations were not referenced in the OMI V9023 that configured the PLBD and Zero-G System for PLBD operations. Shift tie-in from the third shift Mechanical/Electrical/TCS Supervisor to the firs
8、t shift Electrical/TCS Supervisor did not occur. In addition, the first shift Electrical/TCS Supervisor was not aware of the scheduled PLBD operations status nor did he perform a complete walkdown. Therefore, the supervisor assigning work requiring bridge operations Provided by IHSNot for ResaleNo r
9、eproduction or networking permitted without license from IHS-,-,-was not aware the Zero-G System was connected. The work assigned to the bridge operator involved in this mishap did not appear either on the Orbiter Processing Facility (OPF) shop schedule or the KSC Integrated Contractor Schedule (KIC
10、S). Had this work been properly integrated into the KICS schedule, work involving bridge movement would have been scheduled to occur after use of the Zero-G Simulator was complete. The third contributing cause is attributed to this lack of integrated scheduling. Improper raising of the right PLBD pr
11、ompted a detailed inspection of the door structure but no damage was found that could be directly attributed to this mishap. Recommendation(s): Primary Cause Finding: Aft movement of Bridge 9A of the Payload Bay Area Bridge and Bucket Hoist System with the Payload Bay Door Zero-G Simulator connected
12、 (right side only) caused the improper raising of Orbiter 103s (OV-103) right payload bay door (PLBD). Contributing Causes: 1. The operator of bridge 9A, in support of TPS No. VTCS-3-11-138, TCS Blanket Rework - Aft Bulkhead, failed to follow the approved procedure covering bridge/bucket operations
13、(OMI V3575, OPF PLB Access Bridge/Bucket System) as follows: A) A thorough walkdown/inspection of bridge 9A was not performed per sequences 03 and 04 of OMI V3575 to verify Zero-G Simulator was not connected. Appendix A checklist only was used to checkout the bridge/bucket system. B) A bridge/bucket
14、 observer was not assigned.Recommendation: Delete Appendix A checklist and require use of OMI V3575 applicable sequences for bridge/bucket checkout and operation. 2. Control systems utilized by Shuttle Processing Contract (SPC) to preclude bridge operation while connected to the Zero-G Simulator wer
15、e deficient as follows: A) Control of the bridge/bucket keys was nonexistent. The technician had virtually free access to the keys. B) No provision is set forth in OMI V9023 (Orbiter Payload Bay Door Operations - Horizontal/Vertical) to tag bridge/bucket system out of service and secure the key duri
16、ng Zero-G operations per OMI V3575 requirements. C) Shift tie-in from third shift Mechanical/Electrical/TCS Supervisor to first shift Electrical/TCS Supervisor did not occur. Supervisor was not aware of scheduled PLBD operations status nor did he perform a complete walkdown. Therefore, the superviso
17、r assigning TPS No. VTCS-3-11-138 was not aware the Zero-G System was connected.Recommendation: SP-?018(2)K IOPF Payload Bay Access Equipment (Buckets) Operation and Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Control and OPF Fixed Platform Movem
18、ent Control, paragraph 6.1.1.b, which provides for specific key control, should be enforced. Recommendation: OMI V3575 steps to tag bridge/bucket system out of service and secure keys during Zero-G operations should be incorporated into OMI V9023. Recommendation: SPC OPF management needs to formaliz
19、e and enforce third to first shift tie-in. A formal end of shift tie-in needs to be established. Recommendation: The sustaining engineering design organization should incorporate a positive, actively controlled lockout device to prevent improper operation of the bridge system while the Zero-G Simula
20、tor is connected. 3. TPS VTCS-3-11-138 did not appear on the OPF shop schedule or the KSC Integrated Control Schedule (KICS) for June 4, 1990. This TPS was in response to MCR No. 14725 and should have been scheduled through the KICS system. Had TPS VTCS-3-11-138 been properly integrated into the KIC
21、S schedule, work involving bridge movement would have been scheduled to occur after use of the Zero-G Simulator was complete.Recommendation: All OPF shop work (non-hazardous) should be fully integrated with the KICS. OBSERVATIONS 1. Keys for both forward and aft bridge/buckets are fully interchangea
22、ble. Interchangeability of keys compounds the key control issue in another finding.Recommendation: Bridge control key locks should be recoded to provide unique key control (1 key) for each bridge in both high bays. Secondary keys should be maintained by the Orbiter Processing Chief (OPC). 2. Hands-o
23、n training for firs-?time operator certifications for the bridge/bucket system is performed while Orbiters are in the high bays. This practice increases flight hardware exposure to possible damage.Recommendation: Schedule hands on training during periods when high bays are empty. Create a stand-alon
24、e OMI to support this training process. 3. The constraints log kept with the out-of-TAIR OMI V3575 in the mechanical mid-body shop area book may not contain the complete list of open Problem Reports (PRs) due to the time lag to annotate constraints from the bridge/bucket TAIR book to the mid-body bo
25、ok. In addition, there is no official method for recording other operational constraints against OMI V3575.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Recommendation: SPC should develop a system to ensure all applicable PRIs and operational const
26、raints are recorded against OMI V3575 in a timely manner. 4. QC personnel, both NASA and SPC, do not receive any formal training on the operation of or hazards associated with the bridge/bucket system.Recommendation: Provide QC personnel with a familiarization course on bridge/bucket operations and
27、hazards. Training of such personnel could enhance the check and balance system by providing additional awareness of the hazards associated with improper operation and checkout of the bridge/bucket system. 5. Technical training given for bridge/bucket operations appears to be generally adequate. Howe
28、ver, based on interviews with operators, there are different interpretations of the significance of finding the bridge inhibit switch on.Recommendation: Training should emphasize that finding the inhibit switch on.should prompt the operator to find out why this switch was left on prior to operating
29、the bridge (e.g., steps in OMI V9023 require inhibit switches to be turned on after the Zero-G System is connected). OMI V3575 should be revised to instruct the operator what to do when inhibit switches are found on. 6. The training instructor for bridge/bucket operations is not on distribution for
30、OMI V3575 revisions or deviations.Recommendation: The training instructor should ensure that he receives the latest OMI V3575 revision/deviations to ensure training material is consistent with current operating procedures. 7. There are common/similar findings between this mishap and the 1985 bridge/
31、bucket mishap. These finds are: A) inadequate bridge key control, B) Inadequate bridge tag-out (out of service) procedures, and C) Deficient shift-to-shift tie-in communications.8. There are 86 bridge/bucket certified operators. This appears to be excessive number to support OPF operations.Recommend
32、ation: SPC should reassess and justify the need for the number of certified operators with a view towards elimination of “incidental“ operators. 9. The Preliminary Evaluation Report (PER) did not address damage to flight hardware even though it was stated on the PER that the Payload Bay Door lifted
33、approximately 10 to 12 inches.Recommendation: Even if there is no obvious damage to flight hardware that has been involved in a Mishap/Incident, it should be included in item number ten (Equipment Damaged) on the PER. The PER should be revised to include a block for flight hardware that could possib
34、ly be damaged. The Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-initial estimate in item ten will then be a TBD until the flight hardware can be examined. 10. SPC OPF Supervision, as evidenced by interviews, are not generally aware of the NASA/KSC
35、 mishap investigation process per KHB 1711.lC,“Reporting and Investigation of Mishaps.“ In addition, the SPC SPI SF-505(8)KV, Rev. C-1, “Mishap Reporting,“ lacks specificity on the mishap investigation process. This lack of awareness and specificity led to:A) A SPC Mishap Investigation Team was esta
36、blished June 4, 1990, by the Director of OPF/HMF/VAB Shops outside of the authority of Launch Site Directive 002, “Standing Accident Investigation Boards.“ An informal LSOC Assessment Team was subsequently established by a letter from the Launch Site Director on June 5, 1990. B) Incomplete communica
37、tions to and within the SPC flow management organization permitted mishap-related, failed hardware to be removed without the SPC Mishap Investigation Team Chairmans approval. Recommendation: Revise SPI SF-505(8)KV to provide SPC personnel a more detailed guide to follow during a mishap investigation
38、 process. 11. A review of SAA09FY093-006, “System Assurance Analysis of the Payload Bay Area Access Bridge at the Orbiter Processing Facility High Bay 1 and 2,“ Section 4, “Hazards Analysis,“ reveals there are ten controlled hazards in this system. The primary risk acceptance rationale for control o
39、f these hazards involves procedural checks, inspections, warning notes, and testing principally via OMI V3508 (now V3575). In light of this mishap and the 1985 bucket mishap findings, the hazard control verification aspects of OMI V3575 are not being implemented as fully or rigorously as envisioned
40、in the SAA.Recommendation: SAA09FY093-006 should be revisited and acceptability of the controlled risk rationale and verification method via OMI V3575 reassessed. 12. On Friday, June 22, 1990, a “near miss“ incident involving bridge/bucket checkout per OMI V3575 was recorded. During the forward/aft
41、motion check of OPF-1 aft bridge/bucket 9A per OMI V3575, the right-hand Zero-G counterweight basket lifting pulley and mount bracket came close to striking a workstand that extended into the bridge path. The Problem Report (PR) for which the workstand was being used (PRC70-00-002-0026) was not list
42、ed as a constraint against OMI V3575.Evidence of Recurrence Control Effectiveness: See “Recommendations“ section above.Documents Related to Lesson: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-N/AMission Directorate(s): a71 Space Operationsa71 Exp
43、loration SystemsAdditional Key Phrase(s): a71 Configuration Managementa71 Flight Equipmenta71 Flight Operationsa71 Ground Equipmenta71 Ground Operationsa71 Hardwarea71 Launch Processa71 Mishap Reportinga71 Parts Materials & Processesa71 Payloadsa71 SpacecraftMishap Report References: Improper Raising of Orbiter 103 Payload Bay Door MishapAdditional Info: Approval Info: a71 Approval Date: 2002-05-06a71 Approval Name: Gena Bakera71 Approval Organization: KSCa71 Approval Phone Number: 321-867-4261Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
