Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to supersede three existing airworthiness directives (ADs) that apply to The Boeing Company Model 757-200, - 200PF, and -200CB series airplanes. The existing ADs currently require repetitive inspections and audible tap tests of the upper and lower skins of the trailing edge wedges on certain slats, and related investigative and corrective actions if necessary. Since we issued these ADs, we have received reports of slats disbonding on airplanes on which the terminating actions of the existing ADs were completed and also reports of slats disbonding on airplanes outside of the applicability of the existing ADs. This proposed AD would require a determination of the type of trailing edge wedges of the leading edge slats, repetitive inspections on certain trailing edge wedges for areas of skin-to-core disbonding, and corrective actions if necessary. This proposed AD would also provide an optional terminating action for the repetitive inspections. This AD would revise the applicability of the existing ADs to include additional airplanes. We are proposing this AD to prevent delamination of the trailing edge wedge of the leading edge slats, possible loss of pieces of the trailing edge wedge assembly during flight, reduction of the reduced maneuver and stall margins, and consequent reduced controllability of the airplane.