Narrative:

On arrival in ZZZ, aircraft xyz, the gate agent reported door 1L hard to open and close. Upon troubleshooting, we decided to replace the door snubber. We pulled the maintenance manual for removal and installation. We proceeded to change the snubber. When we removed the snubber, the door still operated hard, so we then decided to check the guide arm adjustment. This extended delay further. We installed the new snubber. We finished the paperwork and dispatched the aircraft. It returned to the field later with an excessive door leak at the lower hinge area. We later found out that we installed the snubber incorrectly (the snubber can be reversed for and aft as well as inboard versus outboard). We installed it incorrectly inboard versus outboard. This caused the actuator filler port screw to push out on the hinge cover via the hinge cover making an airscoop, causing the door squeal. The crew reported the squeal so bad the flight attendants could not perform their duties. After reviewing the paperwork more carefully, we noticed a caution referring to the filler plug. It was observed in the maintenance manual 'caution' that the snubber could inadvertently be installed wrong in the for and aft position. We did not therefore pay attention to the 'note' referring to the plug. Complacency. We thought the job so simple that there was no need to refer to the paperwork completely. A closer (and uninterrupted) look at the maintenance manual caution. Would have clearly pointed out the possibility of incorrectly installing the snubber in the inboard versus outboard position. Although I take full responsibility for this error in maintenance, I do believe these human factors play a part.

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Original NASA ASRS Text

Title: A B737-300 WAS DISPATCHED IN NON COMPLIANCE WITH THE L FORWARD ENTRANCE DOOR SNUBBER INSTALLED BACKWARDS.

Narrative: ON ARR IN ZZZ, ACFT XYZ, THE GATE AGENT RPTED DOOR 1L HARD TO OPEN AND CLOSE. UPON TROUBLESHOOTING, WE DECIDED TO REPLACE THE DOOR SNUBBER. WE PULLED THE MAINT MANUAL FOR REMOVAL AND INSTALLATION. WE PROCEEDED TO CHANGE THE SNUBBER. WHEN WE REMOVED THE SNUBBER, THE DOOR STILL OPERATED HARD, SO WE THEN DECIDED TO CHK THE GUIDE ARM ADJUSTMENT. THIS EXTENDED DELAY FURTHER. WE INSTALLED THE NEW SNUBBER. WE FINISHED THE PAPERWORK AND DISPATCHED THE ACFT. IT RETURNED TO THE FIELD LATER WITH AN EXCESSIVE DOOR LEAK AT THE LOWER HINGE AREA. WE LATER FOUND OUT THAT WE INSTALLED THE SNUBBER INCORRECTLY (THE SNUBBER CAN BE REVERSED FOR AND AFT AS WELL AS INBOARD VERSUS OUTBOARD). WE INSTALLED IT INCORRECTLY INBOARD VERSUS OUTBOARD. THIS CAUSED THE ACTUATOR FILLER PORT SCREW TO PUSH OUT ON THE HINGE COVER VIA THE HINGE COVER MAKING AN AIRSCOOP, CAUSING THE DOOR SQUEAL. THE CREW RPTED THE SQUEAL SO BAD THE FLT ATTENDANTS COULD NOT PERFORM THEIR DUTIES. AFTER REVIEWING THE PAPERWORK MORE CAREFULLY, WE NOTICED A CAUTION REFERRING TO THE FILLER PLUG. IT WAS OBSERVED IN THE MAINT MANUAL 'CAUTION' THAT THE SNUBBER COULD INADVERTENTLY BE INSTALLED WRONG IN THE FOR AND AFT POS. WE DID NOT THEREFORE PAY ATTN TO THE 'NOTE' REFERRING TO THE PLUG. COMPLACENCY. WE THOUGHT THE JOB SO SIMPLE THAT THERE WAS NO NEED TO REFER TO THE PAPERWORK COMPLETELY. A CLOSER (AND UNINTERRUPTED) LOOK AT THE MAINT MANUAL CAUTION. WOULD HAVE CLRLY POINTED OUT THE POSSIBILITY OF INCORRECTLY INSTALLING THE SNUBBER IN THE INBOARD VERSUS OUTBOARD POS. ALTHOUGH I TAKE FULL RESPONSIBILITY FOR THIS ERROR IN MAINT, I DO BELIEVE THESE HUMAN FACTORS PLAY A PART.

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.