Airworthiness Directive · Amendment 39-16683 · Engine exhaust
The Boeing Company Model 747-400, 747-400D, and 747-400F Series Airplanes Equipped With General Electric CF6-80C2 or Pratt & Whitney PW4000 Series Engines
This AD applies to The Boeing Company Model 747-400, 747-400D, and 747-400F series airplanes; certificated in any category; equipped with General Electric CF6-80C2 series engines or Pratt & Whitney PW4000 series engines, as applicable.
We are adopting a new airworthiness directive (AD) for the products listed above. This AD requires modifying certain thrust reverser control system wiring to the flap control unit (FCU). This AD was prompted by a report of automatic retraction of the leading edge flaps due to indications transmitted to the FCU from the thrust reverser control system during takeoff. We are issuing this AD to prevent automatic retraction of the leading edge flaps during takeoff, which could result in reduced climb performance and consequent collision with terrain and obstacles or forced landing of the airplane.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
For Model 747-400 and -400F airplanes equipped with Pratt & Whitney Model PW4000 series engines: Within 36 months after the effective date of this AD, modify the thrust reverser control system wiring to the FCU in the P252 and P253 thrust reverser relay panels, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-78A2184, Revision 1, dated December 23, 2010.
(h) For Model 747-400, -400D, and -400F airplanes equipped with General Electric Model CF6-80C2 series engines: Within 36 months after the effective date of this AD, modify the thrust reverser control system wiring to the FCU in the P414 and P415 power distribution panels, in accordance with Boeing Special Attention Service Bulletin 747-78-2183, Revision 1, dated December 23, 2010.
(i) Modifying the thrust reverser control system wiring before the effective date of this AD, in accordance with Boeing Special Attention Service Bulletin 747-78-2183 or Boeing Alert Service Bulletin 747-78A2184, both dated January 12, 2010, as applicable, is acceptable for compliance with the corresponding modification required by paragraph (g) or (h) of this AD.
