Airworthiness Directive · Amendment 39-17499 · Aircraft fuel system
The Boeing Company Airplanes
This AD applies to The Boeing Company Model 747-400, -400D, and -400F series airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin 747-28A2330, dated April 2, 2012.
We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 747-400, -400D, and -400F series airplanes. This AD was prompted by reports of two in-service occurrences on Model 737-400 airplanes of total loss of boost pump pressure of the fuel feed system, followed by loss of fuel system suction feed capability on one engine, and in-flight shutdown of the engine. This AD requires repetitive operational tests of the engine fuel suction feed of the fuel system, and other related testing and corrective actions if necessary. We are issuing this AD to detect and correct loss of the engine fuel suction feed capability of the fuel system, which, in the event of total loss of the fuel boost pumps, could result in multi- engine flameout, inability to restart the engines, and consequent forced landing of the airplane.
Within 30,000 flight hours after the effective date of this AD: Perform an operational test of the engine fuel suction feed of the fuel system, and do all applicable corrective actions, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-28A2330, dated April 2, 2012; or Boeing Service Bulletin 747-28A2330, Revision 1, dated November 30, 2012. Do all applicable corrective actions before further flight. Repeat the operational test thereafter at intervals not to exceed 30,000 flight hours. Thereafter, except as provided in paragraph (h) of this AD, no alternative procedures or repetitive test intervals will be allowed.
