B747-400 returned to the field due to loss of oil pressure in #3 engine.

Attributes
ACN	364269
Time
Date	199703
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : zzz
State Reference	US
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B747-400
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	other other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	other personnel other
Qualification	other other : other
ASRS Report	364269
Person 2
Affiliation	company : air carrier
Function	other personnel other
Qualification	other other : other
ASRS Report	364269
Events
Anomaly	aircraft equipment problem : critical non adherence : published procedure other anomaly other
Independent Detector	other flight crewa other other : unspecified cockpit
Resolutory Action	flight crew : overcame equipment problem other
Consequence	Other
Supplementary
Air Traffic Incident	other

Narrative:

Replaced fuel pump on aircraft X for a time change on mar/tue/97. We followed the maintenance manual procedure for the removal and installation of the fuel pump and fuel pump drive seal. Wrote a card to have the engine run and leak checked and performance check. On the next flight engine lost oil pressure. We believe we followed procedure properly per the maintenance manual. Procedure took place in a service center on #3 engine on aircraft X. Callback conversation with reporter revealed the following information: the reporter was contacted and revealed the following details. Loss of oil from #3 engine was caused by the pump drive shaft 'O' ring seal not being installed. Reporter advises the maintenance manual did require the seal installation. 2 mechanics worked this pump change and each had assumed the seal was installed by the other mechanic. The reporter states the FAA has made no contact regarding this incident.

Original NASA ASRS Text

Title: B747-400 RETURNED TO THE FIELD DUE TO LOSS OF OIL PRESSURE IN #3 ENG.

Narrative: REPLACED FUEL PUMP ON ACFT X FOR A TIME CHANGE ON MAR/TUE/97. WE FOLLOWED THE MAINT MANUAL PROC FOR THE REMOVAL AND INSTALLATION OF THE FUEL PUMP AND FUEL PUMP DRIVE SEAL. WROTE A CARD TO HAVE THE ENG RUN AND LEAK CHKED AND PERFORMANCE CHK. ON THE NEXT FLT ENG LOST OIL PRESSURE. WE BELIEVE WE FOLLOWED PROC PROPERLY PER THE MAINT MANUAL. PROC TOOK PLACE IN A SVC CTR ON #3 ENG ON ACFT X. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR WAS CONTACTED AND REVEALED THE FOLLOWING DETAILS. LOSS OF OIL FROM #3 ENG WAS CAUSED BY THE PUMP DRIVE SHAFT 'O' RING SEAL NOT BEING INSTALLED. RPTR ADVISES THE MAINT MANUAL DID REQUIRE THE SEAL INSTALLATION. 2 MECHS WORKED THIS PUMP CHANGE AND EACH HAD ASSUMED THE SEAL WAS INSTALLED BY THE OTHER MECH. THE RPTR STATES THE FAA HAS MADE NO CONTACT REGARDING THIS INCIDENT.

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.