 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
A first officer explains why he believes an incorrect deferral was applied to a B747-400 aircraft for a malfunctioning tank-4 forward fuel boost pump pressure indication light not illuminating; when the pump switch was positioned to 'off.'
| Attributes | |
| ACN | 1144101 |
| Time | |
| Date | 201401 |
| Place | |
| Locale Reference | ZZZ.Airport |
| State Reference | US |
| Environment | |
| Flight Conditions | VMC |
| Aircraft 1 | |
| Make Model Name | B747-400 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Parked |
| Component | |
| Aircraft Component | Fuel Booster Pump |
| Person 1 | |
| Function | First Officer Pilot Flying |
| Events | |
| Anomaly | Aircraft Equipment Problem Critical Deviation - Procedural Maintenance Deviation - Procedural MEL Deviation - Procedural Published Material / Policy |
Narrative:
An incorrect deferral was issued for a malfunctioning tank-4 forward (fwd) fuel boost pump. During cockpit prep; the tank-4 fwd fuel boost pump switch light was not illuminated; as it should be with the pump 'off'; indicating that there was pump pressure with the switch 'off.' there was EICAS confirmation [of fuel pressure] with the lack of an engine # 4 EICAS fuel pressure message; as there should be and like there was for engine/tank-1. The mechanic said it was a faulty pressure switch on the tank-4 fwd pump system. But there was an engine-4 fwd pump 'on;' when commanded 'off' error in the central maintenance computer (cmc). The mechanic erased it; recycled the system; circuit breakers (C/B); and switches. The message came back to the cmc; and the light indications returned; indicating that the pump was running when it [the fuel pump] should be 'off.' he said he was going to defer the pressure switch; so we could leave. The captain agreed; but I continued to advocate that he needs [maintenance to] troubleshoot the malfunctioning [fuel] pump; not the pressure switch. A faulty pressure switch would not extinguish the engine-4 fuel pressure EICAS message because it is on the other side of a one way valve in the fuel system and would not cause a fuel pump 'on' when commanded to the 'off' position. Cmc message. Errors: procedural; problem with other company policy/ procedures.
Original NASA ASRS Text
Title: A First Officer explains why he believes an incorrect deferral was applied to a B747-400 aircraft for a malfunctioning Tank-4 Forward Fuel Boost Pump Pressure indication light not illuminating; when the pump switch was positioned to 'Off.'
Narrative: An incorrect deferral was issued for a malfunctioning Tank-4 Forward (Fwd) Fuel Boost Pump. During cockpit prep; the Tank-4 Fwd Fuel Boost Pump switch light was not illuminated; as it should be with the pump 'Off'; indicating that there was pump pressure with the switch 'Off.' There was EICAS confirmation [of fuel pressure] with the lack of an Engine # 4 EICAS Fuel pressure message; as there should be and like there was for Engine/Tank-1. The Mechanic said it was a faulty Pressure switch on the Tank-4 Fwd Pump System. But there was an Engine-4 Fwd Pump 'On;' when commanded 'Off' error in the Central Maintenance Computer (CMC). The Mechanic erased it; recycled the System; Circuit Breakers (C/B); and switches. The message came back to the CMC; and the light indications returned; indicating that the pump was running when it [the fuel pump] should be 'Off.' He said he was going to defer the Pressure switch; so we could leave. The Captain agreed; but I continued to advocate that he needs [Maintenance to] troubleshoot the malfunctioning [fuel] pump; not the pressure switch. A faulty pressure switch would not extinguish the Engine-4 Fuel Pressure EICAS message because it is on the other side of a one way valve in the fuel system and would not cause a fuel pump 'On' when commanded to the 'Off' position. CMC message. Errors: Procedural; problem with other Company Policy/ Procedures.
Data retrieved from NASA's ASRS site 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.