Action
Final rule.
Summary
The FAA is superseding Airworthiness Directive (AD) 2016-09- 01, which applied to certain The Boeing Company Model 777-200 and -300 series airplanes. AD 2016-09-01 required repetitive inspections for cracking of the left- and right-side forward outer chords of the pivot bulkhead, and related investigative and corrective actions if necessary. AD 2016-09-01 also provided a modification of the pivot bulkhead, which terminated the repetitive inspections. This AD was prompted by reports of fatigue cracking of the forward outer chord of the station (STA) 2370 pivot bulkhead, and the determination that the compliance times need to be reduced, post-modification inspections must be done, and the inspections areas need to be expanded due to additional cracking found prior to the inspection times required by AD 2016-09-01. This AD retains certain requirements of AD 2016-09-01. This AD also requires doing repetitive detailed and high frequency eddy current (HFEC) inspections of the longeron fitting, and, for post- repair and post-modification inspections, the bulkhead assembly structure, for any cracking, and doing all applicable on-condition actions. The FAA is issuing this AD to address the unsafe condition on these products.