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A B767 had the left pylon strut installed. During the installation of the fuse pins the pylon must be pre-loaded to 3000 pounds. Pins installed but the pre-load was exceeded.
| Attributes | |
| ACN | 661674 |
| Time | |
| Date | 200506 |
| Place | |
| Locale Reference | airport : zzz.airport |
| State Reference | US |
| Altitude | agl single value : 0 |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | B767 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | ground : parked |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | maintenance : technician |
| ASRS Report | 661674 |
| Person 2 | |
| Affiliation | company : air carrier |
| ASRS Report | 661672 |
| Events | |
| Anomaly | aircraft equipment problem : critical maintenance problem : improper documentation maintenance problem : improper maintenance non adherence : far non adherence : company policies non adherence : published procedure |
| Independent Detector | other other : 1 |
| Resolutory Action | none taken : detected after the fact |
| Consequence | other other Other |
| Factors | |
| Maintenance | contributing factor : tooling contributing factor : schedule pressure contributing factor : engineering procedure performance deficiency : installation performance deficiency : non compliance with legal requirements performance deficiency : scheduled maintenance |
| Supplementary | |
| Problem Areas | Environmental Factor Chart Or Publication Aircraft Maintenance Human Performance |
| Primary Problem | Maintenance Human Performance |
Narrative:
Exceeded manual limits of 3000 pounds force up or down on pylon strut (engine removed) in aircraft maintenance manual. Exceeded eco limit of 5000 pounds force up or down per card #X. Used improper fixture for pre-load; used lifting fixture per lead technician instead of proper fixture and went to 6500 pounds pre-load twice. On jun/tue/05 on aircraft X on the modification line; we were installing fuse pins on the left pylon. In order to do so sometimes we have to put a pre-load on the strut (engine off). This pre-load per aircraft maintenance manual is maximum 3000 pounds up or down. The eco says maximum 5000 pounds up or down. To put this pre-load on the strut; the aircraft maintenance manual says to use what we call a pogo stick with 2 gauges to record force (pounds); one up; one down. At first instead of hooking up the pogo stick; per the manual; we were using the lifting fixture for the pylon strut per the lead technician. The next step was to get a pre-load on the pylon so the fuse pins will easily spin with the socket (less than 125 inch/pounds). The outboard was tight; at the direction of the lead technician we went to a pre-load of 6500 pounds; twice; which exceeds manual limits of either 3000 pounds per aircraft maintenance manual; or 5000 pounds per eco. I feel putting that kind of pre-load may have damaged the pylon. I remember the video of the forklift being used to lift an engine and damaging a pylon and that engine later falling off.
Original NASA ASRS Text
Title: A B767 HAD THE L PYLON STRUT INSTALLED. DURING THE INSTALLATION OF THE FUSE PINS THE PYLON MUST BE PRE-LOADED TO 3000 LBS. PINS INSTALLED BUT THE PRE-LOAD WAS EXCEEDED.
Narrative: EXCEEDED MANUAL LIMITS OF 3000 LBS FORCE UP OR DOWN ON PYLON STRUT (ENG REMOVED) IN ACFT MAINT MANUAL. EXCEEDED ECO LIMIT OF 5000 LBS FORCE UP OR DOWN PER CARD #X. USED IMPROPER FIXTURE FOR PRE-LOAD; USED LIFTING FIXTURE PER LEAD TECHNICIAN INSTEAD OF PROPER FIXTURE AND WENT TO 6500 LBS PRE-LOAD TWICE. ON JUN/TUE/05 ON ACFT X ON THE MODIFICATION LINE; WE WERE INSTALLING FUSE PINS ON THE L PYLON. IN ORDER TO DO SO SOMETIMES WE HAVE TO PUT A PRE-LOAD ON THE STRUT (ENG OFF). THIS PRE-LOAD PER ACFT MAINT MANUAL IS MAX 3000 LBS UP OR DOWN. THE ECO SAYS MAX 5000 LBS UP OR DOWN. TO PUT THIS PRE-LOAD ON THE STRUT; THE ACFT MAINT MANUAL SAYS TO USE WHAT WE CALL A POGO STICK WITH 2 GAUGES TO RECORD FORCE (LBS); ONE UP; ONE DOWN. AT FIRST INSTEAD OF HOOKING UP THE POGO STICK; PER THE MANUAL; WE WERE USING THE LIFTING FIXTURE FOR THE PYLON STRUT PER THE LEAD TECHNICIAN. THE NEXT STEP WAS TO GET A PRE-LOAD ON THE PYLON SO THE FUSE PINS WILL EASILY SPIN WITH THE SOCKET (LESS THAN 125 INCH/LBS). THE OUTBOARD WAS TIGHT; AT THE DIRECTION OF THE LEAD TECHNICIAN WE WENT TO A PRE-LOAD OF 6500 LBS; TWICE; WHICH EXCEEDS MANUAL LIMITS OF EITHER 3000 LBS PER ACFT MAINT MANUAL; OR 5000 LBS PER ECO. I FEEL PUTTING THAT KIND OF PRE-LOAD MAY HAVE DAMAGED THE PYLON. I REMEMBER THE VIDEO OF THE FORKLIFT BEING USED TO LIFT AN ENG AND DAMAGING A PYLON AND THAT ENG LATER FALLING OFF.
Data retrieved from NASA's ASRS site as of January 2009 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.