Airworthiness Directive · Amendment 39-17450 · Aircraft fuel system
the Boeing Company Airplanes
This AD applies to all The Boeing Company Model 737-300, -400, and -500 series airplanes, certificated in any category.
We are adopting a new airworthiness directive (AD) for all The Boeing Company Model 737-300, -400, and -500 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 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 dual engine flameout, inability to restart the engines, and consequent forced landing of the airplane.
Within 7,500 flight hours or 24 months after the effective date of this AD, whichever occurs first: 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 737-28A1407, dated May 14, 2012. Do all applicable corrective actions before further flight. Repeat the operational test thereafter at intervals not to exceed 7,500 flight hours or 24 months, whichever occurs first. Thereafter, except as provided in paragraph (h) of this AD, no alternative procedures or repetitive test intervals are allowed.
