Airworthiness Directives; The Boeing Company Airplanes
We are superseding Airworthiness Directive (AD) 2004-07-11 for all The Boeing Company Model 767-400ER series airplanes. AD 2004-07-11 requires repetitive high frequency eddy current (HFEC) inspections of the aft lower lugs of the deflection control track of the outboard flap for cracks, and replacement of any cracked deflection control track with a new track assembly. This AD retains those requirements, provides optional terminating action for the repetitive inspections, and adds airplane models to the applicability. This AD was prompted by our determination that additional airplane models require repetitive HFEC inspections of the aft lower lugs of the deflection control track of the outboard flap for cracks, and replacement of any cracked deflection control track with a new track assembly. We are issuing this AD to detect and correct fatigue cracking in the aft lower lug run-out region of the deflection control track, which could result in the loss of the secondary load path for the outboard flap, resulting in the loss of the outboard flap and consequent reduced controllability of the airplane in the event that the primary load path also fails.