Airworthiness Directive · Amendment 39-13975 · Boeing Model 747-400, -400D, and -400F Series Airplanes
Boeing Model 747-400, -400D, and -400F Series Airplanes
This AD applies to Model 747-400, -400D, and -400F series airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin 747-27A2386, dated March 13, 2003.
The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 747-400, -400D, and -400F series airplanes. This AD requires replacing at least one flap control unit (FCU) in the main equipment center with a new or modified FCU. This AD is prompted by a report indicating that, after takeoff, an airplane was required to return to the airport because the autopilot disengaged. The report also indicated that, after selecting flaps for landing, the flaps indication display did not indicate the flap setting, requiring the airplane to land in alternate flap mode. We are issuing this AD to prevent disconnection of autoland/autopilot functions and loss of primary flaps control and flaps indication display due to disengagement of all three FCUs at the same time, which could lead to a non-normal high speed landing with the flaps retracted, increased pilot workload, and possible runway departure at high speeds during landing.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
At the earliest of the times specified in paragraphs (f)(1), (f)(2), and (f)(3) of this AD: Replace at least one FCU having P/N 285U0011-207 with a new or modified FCU having P/N 285U0011-208 in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-27A2386, dated March 13, 2003.
(1) Within 60 months after the effective date of this AD.
(2) Within 25,000 flight hours after the effective date of this AD.
(3) Within 4,000 flight cycles after the effective date of this AD.
Note 1: Boeing Alert Service Bulletin 747-27A2386, dated March 13, 2003, refers to Boeing Component Service Bulletin 285U0011-27-06, dated March 13, 2003, as an additional source of service information for modifying an FCU having P/N 285U0011-207 to P/N 285U0011-208.
For airplanes identified in Boeing Service Bulletin 747-27-2319, dated January 24, 1991: Before or concurrent with the accomplishment of paragraph (f) of this AD, replace the three FCUs having P/N 285U0011-205 or 285U0011-206 with new or modified FCUs having P/N 285U0011-207 in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-27-2319, dated January 24, 1991.
Note 2: Boeing Service Bulletin 747-27-2319, dated January 24, 1991, refers to Boeing Component Service Bulletin 285U0011-27-04, dated January 24, 1991, as an additional source of service information for modifying the FCUs having P/N 285U0011-205 or 285U0011-206 to P/N 285U0011-207.
As of the effective date of this AD, no person may install on any airplane an FCU having P/N 285U0011-205 or -206.
