1、Lessons Learned Entry: 1199Lesson Info:a71 Lesson Number: 1199a71 Lesson Date: 1990-09-03a71 Submitting Organization: KSCa71 Submitted by: J.L. Sullivan/ Eric RaynorSubject: OV-104 STS-38 Avionics Bay Platform Beam Assembly Incident - Formal Accident Investigation Board Report Description of Driving
2、 Event: On October 3, 1990, at approximately 0940 hours at the Vertical Assembly Building Transfer Aisle, the OV-104 Orbiter was being rotated toward the vertical position when three loud, thud noises were heard emanating from the Orbiter. IPR 38V-0182 was documented to investigate cause of the nois
3、e. The three (3) thuds occurred in succession, not simultaneously. Discussions were held with Engineering, Operations, Technicians, and Quality personnel to determine possible causes of the noise. A management decision was made to proceed with the soft mate of Orbiter to External Tank, visually insp
4、ect to verify Aft external tank attach nuts were in place prior to mate, mate Orbiter, remove weight of Orbiter from the attach sling (sling weight only on crane), open the Aft section and look for possible cause of noise. All of the mate functions were accomplished and Aft Section 50-1 and 50-2 doo
5、rs were removed to gain access to the Aft Compartment. An avionics platform beam (G070-502677-001) was observed in the Aft Compartment. Preliminary inspection indicated flight hardware had been damaged. Photographs were initially taken of the beam location and surrounding areas. As sufficient platfo
6、rms were installed, additional photos were taken to document damage. Beam G070-502677-001 was installed in the OPF by JC V35-00001 on August 15, 1990. This beam was verified as removed by Tech/Quality on October 1, 1990, prior to close-out of the Aft compartment to support roll-over from the OPF to
7、the VAB for mating operations. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Lesson(s) Learned: The primary and major contributory causes of the mishap were: 1. Failure to remove the beam. If the standard sequence of access platform removal is foll
8、owed, the beam is one of the last components to come out. Also, the beam cannot be safely removed until either the 50-1 or 50-2 entry level platforms are removed. Since other scheduled work was in process, requiring the entry level platforms, the beam was temporarily and intentionally left resting a
9、gainst the 1307 bulkhead for approximately 40 minutes. Due to the elapsed time and remote location of the beam, plus reduced lighting, the beam was forgotten and overlooked.2. The check and balance by the technician and the Quality Control inspector failed. The technician and inspector were using a
10、job card matrix, consisting of prerecorded platform component numbers which had been initially recorded during platform component installation. The removal check-off and accountability operation was being performed at floor level as opposed to the more traditional method of verification where the pl
11、atform components are removed and verified as they cross the access door thresholds. The rationale for this change consisted of three considerations: (A) the bay was destined for maintenance rather than early roll-in of the next orbiter and, therefore, the platform components had to be completely re
12、moved from the work site and stowed; (B) the area where the platform components would have been inventoried and temporarily stowed was congested; (C) an opinion existed that a better check-off and accountability could be accomplished at the floor level rather than at the 50-1 and 50-2 access door ex
13、its.The team responsible for job card matrix execution and ultimate removal verification consisted of one technician and one inspector. Several technicians were transporting the platform set assemblies from the 50-1 and 50-2 doors to the floor. As the technician read component part numbers, the qual
14、ity inspector checked off the pre-recorded matrix. There were reported confusion factors consisting of multiple numbers on components and faded numbers; however, there was no practical correlation between these factors to explain why an error in accounting for the platform components occurred. For a
15、n unknown reason, the G070-502677-001 beam was counted as having been removed, and therefore, no subsequent search for it was made. A probable scenario for the human error follows: piece number G070-502777-001 was mistakenly checked off the inventory list as G070-502677-001. After almost the entire
16、inventory of platforms had been completed, the Tech and QC on the OPP floor started to review the inventory list to account for several items that had not yet been verified. Piece number G070-502777-001 was still not verified. In reviewing the assemblage of components, the Tech and QC found G070-502
17、777-001 in the equipment storage area and marked it off the inventory list. Thus, component G070-502777-001 was probably counted twice as two pieces of equipment. This scenario was not presented by the Tech or QC, but is the most probable sequence of events that the Board feels occurred. Provided by
18、 IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Recommendation(s): FINDINGS, OBSERVATIONS AND RECOMMENDATIONS PRIMARY CAUSE: Avionics Bay Platform Beam Assembly was left in the Aft Compartment of OV-104. Other work unrelated to platform removal and Aft Closeout
19、 had been scheduled for the Aft Compartment during the same period as platform removal and Aft Closeout. This unrelated work required that the entry platforms inside the 50-1 and 50-2 doors remain in place. The unrelated jobs contributed to an excessive man loading in the Aft Compartment, as did som
20、e OJT by NASA QC. The beam could not physically be removed from the Aft with the entry platforms still in place. Therefore, the beam was temporarily positioned against the 1307 bulkhead forward of Avionics Bay 6, awaiting removal of the entry platforms. When the entry platforms were removed, approxi
21、mately 40 minutes later, the platform removal crew had forgotten about the beam. RECOMMENDATIONS All unrelated work should be completed before performing platform removal. Limit personnel access to the Aft Compartment to minimum essential personnel required to perform platform removal and Aft Closeo
22、ut. Judiciously control OJT man loading. CONTRIBUTORY FINDING #1 The platform removal crew made a mistake in verifying the removal of the bean assembly from the Aft. The other half of the platform removal crew conducted a platform component inventory outside the vehicle on the floor near the Aft sho
23、p area. They checked the platform component numbers against a handwritten inventory list contained in the job card. They mistakenly checked off the bean as having been removed from the Aft when it was actually still in the Aft Compartment. Their task was made more difficult because of problems with
24、the job card and the components. For example, the listing of part numbers in the job card matrix (inventory list) is not done in any logical sequence of sub-grouping. the part numbers are hand-written.on the matrix when they are installed in the Aft compartment. RECOMMENDATIONS Develop a bar coding
25、process for the individual subassembly components in this GSE platform set. Group subassembly part numbers by zonal locations. Pre-print the subassembly part numbers on the job card sheets. CONTRIBUTORY FINDING #2 The final visual inspection of the Aft Compartment did not result in the beam being di
26、scovered. The final visual inspection to verify platform set removal was done by two technicians in the platform removal crew from the 50-1 door. They did not enter the Aft Compartment and failed to look at the area in which the beam had been repositioned and missed seeing it. All of the platform Pr
27、ovided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-subassemblies, except the beam, had been removed. As the platforms were being removed, the portable lights were also being removed, leaving a darkened interior. The crew used a. stick light and flashlight
28、 to inspect the interior by observing from outside the Aft Compartment. RECOMMENDATIONS A method for providing improved lighting for the final visual inspection of the Aft interior must be developed. The final visual inspection to verify that all platform items have been removed from the Aft should
29、be done by Quality. Use the platform set ladder to allow safe access to the Aft Compartment after all platforms have been removed. CONTRIBUTORY FINDING #3 The LSOC and NASA inspectors performing the Aft Closeout inspection failed to back-stamp the Aft Compartment zones which contained the beam assem
30、bly. The LSOC and NASA inspectors performing the Aft Closeout inspection were aware of the beam assembly positioned in their zonal area of inspection. Since they were assured that the beam assembly was going to be removed, they elected not to back-stamp their Aft Closeout Job Card to show that the b
31、eam remained in their zonal area of inspection. The backstamp notation would have prompted the inspectors to check on beam assembly removal before being able to complete their job card and Aft Closeout. The LSOC and NASA inspectors also did not ensure that OMI V6003 was available as a reference docu
32、ment during their inspections. The inspectors did not feel the need for the reference OMI because it repeated inspection criteria which they follow in their daily inspections and had committed to memory. If they had referred to V6003, Sequence 48?001, they would have been reminded of their responsib
33、ility for both GSE platform removal verification and flight hardware inspection. RECOMMENDATIONS Reinforce the usage of the back?stamp procedure by Quality inspectors. Reinforce the requirement for reference documentation to be on site or readily available to the aft closeout inspectors. Reinforce t
34、he Aft Closeout inspectors total responsibility for both flight hardware inspection and GSE platform removal verification. Update Job Card V35-10010 to require LSOC and NASA Quality to verify visually by internal inspection inside the Aft Compartment that all platforms have been removed. Delete the
35、word “temporary“ when referring to the Aft Closeout within the job card. Publish an SPC Safety Lessons Learned bulletin to all employees. CONTRIBUTORY FINDING #4 There was no single person in charge of the integrated operation. A Pre-Task Briefing was not conducted for the combined effort (platform
36、removal, aft closeout inspection and aft door installation). The job cards for GSE platform removal, aft closeout inspection and GSE door installation are all independently worked operations. The j ob cards replaced OMI-V1032. There was no KICS integrated mini-schedule published for the Aft Closeout
37、 effort. The job card for GSE door installation is generic and does not define requirements for unique move operations. Communication Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-to personnel performing overall aft closeout functions were vague, w
38、ith no apparent single leadership. RECOMMENDATIONS Develop an integrated aft closeout OMI with a control sequence to provide a single person in charge of the integrated operation. Assign single?point responsibility and accountability to significant processing events. Revise the GSE door installation
39、 job card to verify that all supporting Work Authorization Documents (WADs) are complete before giving an okay to install the doors. Conduct individual and combined Pre?Task Briefings. Provide integrated mini-schedules for all Aft Closeout operations. OBSERVATION #1 Part number on bean was different
40、 than Platform Removal Job Card matrix illustration. Cause: Typo error on sketch. RECOMMENDATION: Correct platform matrix Job Card. OBSERVATION #2 Fatigue, work hours, schedule pressure and experience did not influence events. Evidence of Recurrence Control Effectiveness: See “Recommendations“ secti
41、on aboveDocuments Related to Lesson: N/AMission Directorate(s): a71 Space Operationsa71 Exploration SystemsAdditional Key Phrase(s): a71 Configuration Managementa71 Facilitiesa71 Flight Equipmenta71 Flight Operationsa71 Ground Equipmenta71 Ground OperationsProvided by IHSNot for ResaleNo reproductio
42、n or networking permitted without license from IHS-,-,-a71 Hardwarea71 Human Factorsa71 Launch Processa71 Logisticsa71 Mishap Reportinga71 Parts Materials & ProcessesMishap Report References: OV-104 STS-38 Avionics Bay Platform Beam Assembly Incident - Formal Accident Investigation Board ReportAdditional 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-,-,-
