Information in this Flight Crew Operations Manual (FCOM) bulletin is recommended by The Boeing Company, but may not be FAA approved at the time of writing. In the event of conflict with the FAA approved Airplane Flight Manual (AFM), the AFM shall supersede. The Boeing Company regards the information or procedures described herein as having a direct or indirect bearing on the safe operation of this model airplane.
THE FOLLOWING PROCEDURE AND/OR INFORMATION IS EFFECTIVE UPON RECEIPT
Background Information
Inspections of Hydro-Aire fuel pumps found evidence of a chafed stator lead wire bundle that may cause the wire to contact the rotor and produce arcing, thus creating a potential ignition source. Inspections of other damaged Hydro-Aire pumps found evidence of localized overheating of parts in the priming and vapor pump section of the fuel pump, possibly due to extended dry running.
Because of these findings, the FAA issued Airworthiness Directive (AD) 2002-19-52 in September 2002 and AD 2002-24-51 in November 2002 to require flight crews to maintain certain minimum fuel levels in the center fuel tanks when operating any Hydro-Aire fuel pump.
The Operating Instructions of this bulletin provide the procedures as required by the two ADs. In response to numerous requests from operators, however, Boeing has also developed procedures that will minimize dry running of the center tank fuel pumps, while reducing the potential for large quantities of fuel remaining in the center tank. These alternate procedures have been approved by the FAA per
Flight Crew Operations Manual Bulletin No. SHZ-29 R3, dated July 07, 2003 (continued)
Approval Letter 140S-03-189 for those airplanes in which the center tank fuel pumps have been inspected via an approved inspection process to ensure proper wire bundle positioning. These alternate procedures are described in the Alternate Operating Instructions section below. In addition, alternate procedures have been approved per Approval Letters 140S-02-376 and 140S-02-363 to provide relief during ground defueling and fuel transfer and are also presented below.
Per AD 2002-19-52, placards are to be installed on all airplanes with affected pumps installed in the center fuel tank. Once both center tank fuel pumps on an individual airplane have been inspected or replaced, the airplane placard may be removed and the Alternate Operating Instructions contained in this bulletin may be used.
Boeing is revising the Master Caution system logic to illuminate the Master Caution and the FUEL system annunciator lights when either center tank fuel pump experiences low pressure. This will provide a more direct indication of a single pump low pressure state and help minimize unintentional dry running of the center tank fuel pumps. In addition, Boeing is revising the control logic for the center tank fuel pumps to incorporate an automatic shutoff feature to further reduce dry running of the pumps. These updates will be available no later than first quarter 2004 via Boeing service bulletin.
The procedures described below in the Operating Instructions sections of this bulletin remain in effect until the Master Caution system logic change and the center tank fuel pump automatic shutoff feature are incorporated.
Operating Instructions (AD 2002-19-52 and AD 2002-24-51)
These procedures are essentially unchanged from those previously published in accordance with AD 2002-19-52 and AD 2002-24-51. Minor changes have been made for clarification.
NORMAL PROCEDURES
The center tank fuel quantity indication system must be operative to dispatch with fuel in the center fuel tank.
The center tank fuel pump switch(es) must be turned OFF at the first indication of fuel pump low pressure any time during the flight. This includes LOW PRESSURE indications that may occur because of pitch attitude changes.
Takeoff and Initial Climb
Both center tank fuel pump switches must be OFF for takeoff if center tank fuel is less than 5000 pounds (2300 kilograms) with the airplane readied for initial taxi. Both center tank fuel pumps should be repositioned ON above 10,000 feet or after the pitch attitude has been reduced to begin acceleration to a climb speed of 250 knots or greater, if more than 1000 pounds (500 kilograms) remain in the center tank.
Flight Crew Operations Manual Bulletin No. SHZ-29 R3, dated July 07, 2003 (continued)
Climb and Cruise
Both center tank fuel pump switches must be turned OFF during climb and cruise when the center tank fuel quantity reaches approximately 1000 pounds (500 kilograms). A center tank fuel pump switch must be turned OFF at the first indication of fuel pump low pressure any time during the flight. This includes low pressure indications that may occur as a result of pitch attitude changes.
Descent
Both center tank fuel pump switches must be turned OFF at the beginning of the descent if less than 3000 pounds (1400 kilograms) of fuel remain in the center tank. If an extended period of level flight is required prior to approach and landing, i.e., holding, the center tank fuel pump switch(es) may be re-positioned ON if more than 1000 pounds (500 kilograms) remain in the tank. The fuel pump must be turned OFF at the first indication of pump low pressure.
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