Narrative:

Rags were found in jackscrew not removed by mechanic, pilot report, unable to trim to zero degrees. My shift on the date of 1/thu/03 began with a tremendous workload to accomplish in a short amount of time, including two sliding seals on two different aircraft, both with late arrivals. The 1ST aircraft arrived at approximately xa:00 pm at gate. Mechanic #2 and myself started working on aircraft #1 first. We worked as per our normal routine with him being on the outside prepping (removal of access panels, etc), while I pulled and tagged circuit breakers and opened the tail cone door. I temporarily put rags on jackscrew to protect myself and avoid possible damage to jack screw. At this time we found damage to the spar and sheetmetal was called to evaluate it. Sheetmetal required engineering assistance. At this time we installed the sliding seal temporarily and back drilled seal per MM 53-31-31. Mechanic #2 removed the pins from links and we went to the hangar to rivet the assembly together. While waiting on engineering evaluation we were unable to install the seal assembly. At this point we left this aircraft and completed a sliding seal assembly on another aircraft at a different gate. We went back to aircraft #1 and met sheetmetal and engineering. It was decided to take the aircraft to the hangar. At this time we were assigned a lav water faucet problem on aircraft #1. We documented work completed on the seal assembly on mig-100 and mig-2A, and mig-2C corrected the lav water faucet problem and remained by aircraft #1. Next shift never showed up for a turnover. We did not document use of rags on the jackscrew because the rags could be seen easily when entering tail compartment to finish the job. We have always entered the tail compartment to complete the installation of attaching hardware. We did not know it was possible to complete the installation of the sliding seal from outside the aircraft. All of the 80-100 sliding seal assemblies that I have helped replace in the last 3 yrs are possibly because of manufacturing/engineering defect from boeing. We have replaced a sliding seal assembly on an aircraft 6 months out of manufacturing. These seals have a very high failure rate. I cannot explain this, but during the past 3 yrs only one B737-200 required lower seal replacement. Also, during the last 3 yrs I (we) have only done two turnovers for seal replacement. Callback conversation with reporter revealed the following information: the reporter stated the sliding seal assembly was fabricated and ready for installation, but no next shift relief showed up. The reporter said the sheet metal systems engineer advised to take the airplane out of service to repair the sheet metal gouge. The reporter stated all doors and compartments were then closed to allow the airplane to be taxied to the hangar. The reporter said there was no verbal turnover at shift change and the sliding seal job card was complete to the steps for installation. The reporter stated no card was initiated to remove the rags and cleanup the compartment. The reporter said the job card for installation of the sliding seal indicated clearly that entry into the jackscrew compartment was necessary. The reporter stated the next shift technician did not enter the compartment, but replaced the seal from the exterior of the aircraft. The reporter said a statement at the end of the job card reads, 'restore the airplane to normal.' the reporter stated the sliding seal is not a required inspection item. Callback from acn 574342: the reporter stated the rags were placed on the jackscrew to prevent drill shavings and dirt from sticking to the greased jackscrew. The reporter said no card was written up to remove the rags and clean the compartment after the sliding seal replacement. The reporter stated it was believed the next shift technician would replace the seal from the interior of the jackscrew compartment and clean the area after the job was completed. The reporter said no verbal turnover was given as the next shift technician was not available, but the job card was complete up to the installation work.

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Original NASA ASRS Text

Title: A B737-400 PLT RPTS UNABLE TO TRIM HORIZONTAL STABILIZER TO 0 DEGS. MAINT DISCOVERED CLEANING RAGS INTERFERING WITH JACKSCREW.

Narrative: RAGS WERE FOUND IN JACKSCREW NOT REMOVED BY MECHANIC, PLT RPT, UNABLE TO TRIM TO ZERO DEGS. MY SHIFT ON THE DATE OF 1/THU/03 BEGAN WITH A TREMENDOUS WORKLOAD TO ACCOMPLISH IN A SHORT AMOUNT OF TIME, INCLUDING TWO SLIDING SEALS ON TWO DIFFERENT ACFT, BOTH WITH LATE ARRIVALS. THE 1ST ACFT ARRIVED AT APPROX XA:00 PM AT GATE. MECH #2 AND MYSELF STARTED WORKING ON ACFT #1 FIRST. WE WORKED AS PER OUR NORMAL ROUTINE WITH HIM BEING ON THE OUTSIDE PREPPING (REMOVAL OF ACCESS PANELS, ETC), WHILE I PULLED AND TAGGED CIRCUIT BREAKERS AND OPENED THE TAIL CONE DOOR. I TEMPORARILY PUT RAGS ON JACKSCREW TO PROTECT MYSELF AND AVOID POSSIBLE DAMAGE TO JACK SCREW. AT THIS TIME WE FOUND DAMAGE TO THE SPAR AND SHEETMETAL WAS CALLED TO EVALUATE IT. SHEETMETAL REQUIRED ENGINEERING ASSISTANCE. AT THIS TIME WE INSTALLED THE SLIDING SEAL TEMPORARILY AND BACK DRILLED SEAL PER MM 53-31-31. MECH #2 REMOVED THE PINS FROM LINKS AND WE WENT TO THE HANGAR TO RIVET THE ASSEMBLY TOGETHER. WHILE WAITING ON ENGINEERING EVALUATION WE WERE UNABLE TO INSTALL THE SEAL ASSEMBLY. AT THIS POINT WE LEFT THIS ACFT AND COMPLETED A SLIDING SEAL ASSEMBLY ON ANOTHER ACFT AT A DIFFERENT GATE. WE WENT BACK TO ACFT #1 AND MET SHEETMETAL AND ENGINEERING. IT WAS DECIDED TO TAKE THE ACFT TO THE HANGAR. AT THIS TIME WE WERE ASSIGNED A LAV WATER FAUCET PROB ON ACFT #1. WE DOCUMENTED WORK COMPLETED ON THE SEAL ASSEMBLY ON MIG-100 AND MIG-2A, AND MIG-2C CORRECTED THE LAV WATER FAUCET PROBLEM AND REMAINED BY ACFT #1. NEXT SHIFT NEVER SHOWED UP FOR A TURNOVER. WE DID NOT DOCUMENT USE OF RAGS ON THE JACKSCREW BECAUSE THE RAGS COULD BE SEEN EASILY WHEN ENTERING TAIL COMPARTMENT TO FINISH THE JOB. WE HAVE ALWAYS ENTERED THE TAIL COMPARTMENT TO COMPLETE THE INSTALLATION OF ATTACHING HARDWARE. WE DID NOT KNOW IT WAS POSSIBLE TO COMPLETE THE INSTALLATION OF THE SLIDING SEAL FROM OUTSIDE THE ACFT. ALL OF THE 80-100 SLIDING SEAL ASSEMBLIES THAT I HAVE HELPED REPLACE IN THE LAST 3 YRS ARE POSSIBLY BECAUSE OF MANUFACTURING/ENGINEERING DEFECT FROM BOEING. WE HAVE REPLACED A SLIDING SEAL ASSEMBLY ON AN ACFT 6 MONTHS OUT OF MANUFACTURING. THESE SEALS HAVE A VERY HIGH FAILURE RATE. I CANNOT EXPLAIN THIS, BUT DURING THE PAST 3 YRS ONLY ONE B737-200 REQUIRED LOWER SEAL REPLACEMENT. ALSO, DURING THE LAST 3 YRS I (WE) HAVE ONLY DONE TWO TURNOVERS FOR SEAL REPLACEMENT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE SLIDING SEAL ASSEMBLY WAS FABRICATED AND READY FOR INSTALLATION, BUT NO NEXT SHIFT RELIEF SHOWED UP. THE RPTR SAID THE SHEET METAL SYSTEMS ENGINEER ADVISED TO TAKE THE AIRPLANE OUT OF SVC TO REPAIR THE SHEET METAL GOUGE. THE RPTR STATED ALL DOORS AND COMPARTMENTS WERE THEN CLOSED TO ALLOW THE AIRPLANE TO BE TAXIED TO THE HANGAR. THE RPTR SAID THERE WAS NO VERBAL TURNOVER AT SHIFT CHANGE AND THE SLIDING SEAL JOB CARD WAS COMPLETE TO THE STEPS FOR INSTALLATION. THE RPTR STATED NO CARD WAS INITIATED TO REMOVE THE RAGS AND CLEANUP THE COMPARTMENT. THE RPTR SAID THE JOB CARD FOR INSTALLATION OF THE SLIDING SEAL INDICATED CLEARLY THAT ENTRY INTO THE JACKSCREW COMPARTMENT WAS NECESSARY. THE RPTR STATED THE NEXT SHIFT TECHNICIAN DID NOT ENTER THE COMPARTMENT, BUT REPLACED THE SEAL FROM THE EXTERIOR OF THE ACFT. THE RPTR SAID A STATEMENT AT THE END OF THE JOB CARD READS, 'RESTORE THE AIRPLANE TO NORMAL.' THE RPTR STATED THE SLIDING SEAL IS NOT A REQUIRED INSPECTION ITEM. CALLBACK FROM ACN 574342: THE RPTR STATED THE RAGS WERE PLACED ON THE JACKSCREW TO PREVENT DRILL SHAVINGS AND DIRT FROM STICKING TO THE GREASED JACKSCREW. THE RPTR SAID NO CARD WAS WRITTEN UP TO REMOVE THE RAGS AND CLEAN THE COMPARTMENT AFTER THE SLIDING SEAL REPLACEMENT. THE RPTR STATED IT WAS BELIEVED THE NEXT SHIFT TECHNICIAN WOULD REPLACE THE SEAL FROM THE INTERIOR OF THE JACKSCREW COMPARTMENT AND CLEAN THE AREA AFTER THE JOB WAS COMPLETED. THE RPTR SAID NO VERBAL TURNOVER WAS GIVEN AS THE NEXT SHIFT TECHNICIAN WAS NOT AVAILABLE, BUT THE JOB CARD WAS COMPLETE UP TO THE INSTALLATION WORK.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.