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When the left center tank fuel pump failed to turn off as the tank neared empty; the flight crew of a B747-400 elected to enter the lower equipment bay to locate and open the associated circuit breaker to prevent the possibility of an overheated pump igniting fuel vapors.
| Attributes | |
| ACN | 974558 |
| Time | |
| Date | 201110 |
| Local Time Of Day | 1801-2400 |
| Place | |
| Locale Reference | ZOA.ARTCC |
| State Reference | US |
| Environment | |
| Light | Night |
| Aircraft 1 | |
| Make Model Name | B747-400 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Cruise |
| Flight Plan | IFR |
| Component | |
| Aircraft Component | Fuel Booster Pump |
| Person 1 | |
| Function | Captain Pilot Flying |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Experience | Flight Crew Last 90 Days 240 Flight Crew Total 19000 Flight Crew Type 5000 |
| Events | |
| Anomaly | Aircraft Equipment Problem Critical Deviation - Procedural Published Material / Policy Inflight Event / Encounter Fuel Issue |
Narrative:
During cruise; we turned off the center tank override/jettison pumps in accordance with SOP. The left pump failed to turn off as evidenced by a green line on the fuel synoptic failing to extinguish. We checked the central maintenance computer and found a hard fault 'left center tank override/jettison pump on when commanded off' message.we called maintenance control for advice. At first the controller did not want us to take any action. He kept stating 'follow your flight handbook.' unfortunately; this problem is not covered in our aom. Also; we were very aware and concerned about the ad resulting from [a previous serious incident] and we were very concerned that the center tank; now holding 2;500 pounds of fuel; would soon scavenge dry with the pump continuing to run for hours before we could land. We determined that the tank would run dry before we could land at any location and that something had to be done to disable the pump to preclude a possible explosion.another maintenance controller came on duty and we worked with him. The decision was made to enter the lower equipment bay and pull the fuel pump breaker. We accomplished this just as the tank scavenged dry. Good coordination between the flight crew; maintenance control; flight attendants; the duty manager; and dispatch were crucial in accomplishing the procedure in time.suggestions: 1) pilots have little or no information on the layout of the lower equipment bay. We had trouble locating the circuit breaker. A card; placard; or some information diagramming the location of the circuit breaker panels would have been very helpful. 2) we had difficulty opening the lower equipment bay door because it was stuck due to dirt and debris. It had to be pried open. Maintenance should exercise these doors on occasion. 3) we could not locate the light switch for the bay. More information is needed in case an emergency entry is required. Our flight landed normally.
Original NASA ASRS Text
Title: When the left center tank fuel pump failed to turn off as the tank neared empty; the flight crew of a B747-400 elected to enter the lower equipment bay to locate and open the associated circuit breaker to prevent the possibility of an overheated pump igniting fuel vapors.
Narrative: During cruise; we turned off the center tank override/jettison pumps in accordance with SOP. The left pump failed to turn off as evidenced by a green line on the fuel synoptic failing to extinguish. We checked the central maintenance computer and found a hard fault 'left center tank override/jettison pump on when commanded off' message.We called Maintenance Control for advice. At first the Controller did not want us to take any action. He kept stating 'follow your flight handbook.' Unfortunately; this problem is not covered in our AOM. Also; we were very aware and concerned about the AD resulting from [a previous serious incident] and we were very concerned that the center tank; now holding 2;500 LBS of fuel; would soon scavenge dry with the pump continuing to run for hours before we could land. We determined that the tank would run dry before we could land at any location and that something had to be done to disable the pump to preclude a possible explosion.Another Maintenance Controller came on duty and we worked with him. The decision was made to enter the lower equipment bay and pull the fuel pump breaker. We accomplished this just as the tank scavenged dry. Good coordination between the flight crew; Maintenance Control; Flight Attendants; the Duty Manager; and Dispatch were crucial in accomplishing the procedure in time.Suggestions: 1) Pilots have little or no information on the layout of the lower equipment bay. We had trouble locating the circuit breaker. A card; placard; or some information diagramming the location of the circuit breaker panels would have been very helpful. 2) We had difficulty opening the lower equipment bay door because it was stuck due to dirt and debris. It had to be pried open. Maintenance should exercise these doors on occasion. 3) We could not locate the light switch for the bay. More information is needed in case an emergency entry is required. Our flight landed normally.
Data retrieved from NASA's ASRS site as of April 2012 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.