Action
Final rule.
Summary
The FAA is adopting a new airworthiness directive (AD) for certain The Boeing Company Model 747-400 and 747-400F series airplanes. This AD was prompted by an evaluation that determined fatigue cracks could develop in the underwing longerons. This AD requires repetitive inspections of the underwing longerons and certain fuselage skins for any crack, and applicable on-condition actions. The FAA is issuing this AD to address the unsafe condition on these products.