Summary
The FAA proposes to supersede Airworthiness Directive (AD) 2015-13-06, which applies to certain The Boeing Company Model 747-400 and 747-400F series airplanes. AD 2015-13-06 requires repetitive inspections of the longeron extension fittings for cracking, repetitive high frequency eddy current (HFEC) inspections of any modified, repaired, or replaced longeron extension fitting for cracking, and applicable on-condition actions. Since the FAA issued AD 2015-13-06, the FAA has determined that additional airplanes are affected by the identified unsafe condition. This proposed AD would retain the requirements of AD 2015-13-06 and include additional airplanes in the applicability. For those additional airplanes, this proposed AD would require only repetitive inspections of the longeron extension fittings for cracking and repair if necessary. The FAA is proposing this AD to address the unsafe condition on these products.