An a&P mechanic, forced to work his job alone, fails to tighten the oil line properly on the #4 scav...

Attributes
ACN	554987
Time
Date	200207
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl single value : 0
Environment
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Flight Phase	ground : maintenance
Person 1
Affiliation	company : air carrier
Function	maintenance : technician
Qualification	technician : airframe technician : powerplant
Experience	maintenance technician : 16
ASRS Report	554987
Person 2
Affiliation	company : air carrier
Function	maintenance : technician
Events
Anomaly	aircraft equipment problem : critical maintenance problem : improper maintenance non adherence : published procedure other anomaly other
Resolutory Action	flight crew : diverted to another airport none taken : detected after the fact
Consequence	other other Other
Factors
Maintenance	contributing factor : schedule pressure contributing factor : lighting performance deficiency : repair performance deficiency : installation performance deficiency : testing performance deficiency : inspection
Supplementary
Problem Areas	Flight Crew Human Performance Maintenance Human Performance Company Aircraft
Primary Problem	Maintenance Human Performance

Narrative:

On jul/fri/02, I was assigned to aircraft X to work 'right engine oil seal' status message with mr Y as my partner. After troubleshooting, it led to the removal of the #4 bearing scavenge transmitter. At this point, I started to remove transmitter located at 9 O'clock position. At this time mr Y was removed from job to go on a field service. On installation, I noticed from maintenance manual that I had removed wrong transmitter. I then began to reinstall transmitter. After tightening oil lines, I was having trouble installing electrical connector. So I decided to loosen oil line to lower 'B' nut so I could put a mirror in to check pins and slot of connector on transmitter. I then was able to connect cannon plug and oil line. I then noticed a tight clearance between 'B' nut and air pressure line and checked for proper clearance using mirror. Clearance was sufficient, and I believe at this time I failed to tighten oil pressure line on pressure transmitter. I then continued job removing correct scavenge transmitter located at 6 O'clock position. I then installed new transmitter and tightened oil line and cannon plug. I then had run manual run engine for 5 mins at idle and checked for leaks and none noted at this time. Status message was cleared at this time and item signed off. Aircraft was then released for service. On initial flight on the next day, ZZZ-sfo, crew encountered loss of #2 engine oil pressure and shut #2 engine on approach to mci for corrective maintenance action. Maintenance found main oil pressure transmitter line loose tightened and performed all required maintenance. Aircraft was released for service. It is in my judgement that some human factors contributed to the event. The loss of my partner from the job did make me upset and after removing the incorrect transmitter, I was very discouraged and should have taken a break. To make up for lost time, I began to rush job and failed to rechk oil lines for proper torque.

Original NASA ASRS Text

Title: AN A&P MECH, FORCED TO WORK HIS JOB ALONE, FAILS TO TIGHTEN THE OIL LINE PROPERLY ON THE #4 SCAVENGE XMITTER FOR #2 ENG OF A B757-200 WHICH, ON THE NEXT DAY, RESULTS IN AN INFLT ENG SHUTDOWN AND DIVERSION OF THE FLT TO MCI, MO.

Narrative: ON JUL/FRI/02, I WAS ASSIGNED TO ACFT X TO WORK 'R ENG OIL SEAL' STATUS MESSAGE WITH MR Y AS MY PARTNER. AFTER TROUBLESHOOTING, IT LED TO THE REMOVAL OF THE #4 BEARING SCAVENGE XMITTER. AT THIS POINT, I STARTED TO REMOVE XMITTER LOCATED AT 9 O'CLOCK POS. AT THIS TIME MR Y WAS REMOVED FROM JOB TO GO ON A FIELD SVC. ON INSTALLATION, I NOTICED FROM MAINT MANUAL THAT I HAD REMOVED WRONG XMITTER. I THEN BEGAN TO REINSTALL XMITTER. AFTER TIGHTENING OIL LINES, I WAS HAVING TROUBLE INSTALLING ELECTRICAL CONNECTOR. SO I DECIDED TO LOOSEN OIL LINE TO LOWER 'B' NUT SO I COULD PUT A MIRROR IN TO CHK PINS AND SLOT OF CONNECTOR ON XMITTER. I THEN WAS ABLE TO CONNECT CANNON PLUG AND OIL LINE. I THEN NOTICED A TIGHT CLRNC BTWN 'B' NUT AND AIR PRESSURE LINE AND CHKED FOR PROPER CLRNC USING MIRROR. CLRNC WAS SUFFICIENT, AND I BELIEVE AT THIS TIME I FAILED TO TIGHTEN OIL PRESSURE LINE ON PRESSURE XMITTER. I THEN CONTINUED JOB REMOVING CORRECT SCAVENGE XMITTER LOCATED AT 6 O'CLOCK POS. I THEN INSTALLED NEW XMITTER AND TIGHTENED OIL LINE AND CANNON PLUG. I THEN HAD RUN MANUAL RUN ENG FOR 5 MINS AT IDLE AND CHKED FOR LEAKS AND NONE NOTED AT THIS TIME. STATUS MESSAGE WAS CLRED AT THIS TIME AND ITEM SIGNED OFF. ACFT WAS THEN RELEASED FOR SVC. ON INITIAL FLT ON THE NEXT DAY, ZZZ-SFO, CREW ENCOUNTERED LOSS OF #2 ENG OIL PRESSURE AND SHUT #2 ENG ON APCH TO MCI FOR CORRECTIVE MAINT ACTION. MAINT FOUND MAIN OIL PRESSURE XMITTER LINE LOOSE TIGHTENED AND PERFORMED ALL REQUIRED MAINT. ACFT WAS RELEASED FOR SVC. IT IS IN MY JUDGEMENT THAT SOME HUMAN FACTORS CONTRIBUTED TO THE EVENT. THE LOSS OF MY PARTNER FROM THE JOB DID MAKE ME UPSET AND AFTER REMOVING THE INCORRECT XMITTER, I WAS VERY DISCOURAGED AND SHOULD HAVE TAKEN A BREAK. TO MAKE UP FOR LOST TIME, I BEGAN TO RUSH JOB AND FAILED TO RECHK OIL LINES FOR PROPER TORQUE.

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.

An a&P mechanic, forced to work his job alone, fails to tighten the oil line properly on the #4 scavenge transmitter for #2 engine of a B757-200 which, on the next day, results in an in-flight engine shutdown and diversion of the flight to mci, mo.