Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to all McDonnell Douglas Model DC-10 and MD-11 series airplanes and KC-10A (military) airplanes. This proposal would require repetitive inspections to detect corrosion or failure of the steel Hi-Lok fasteners at the inboard flap inboard track, and replacement of corroded/failed steel Hi-Lok fasteners with inconel Hi-Lok fasteners. The proposed AD also provides for termination of the repetitive inspections by replacing all of the steel Hi-Lok fasteners with inconel Hi-Lok fasteners. This proposal is prompted by reports of failed and/or corroded steel fasteners found in the inboard flap inboard track due to stress corrosion. The actions specified by the proposed AD are intended to prevent such stress corrosion, which could result in binding of the flap and inability of the flap to extend or retract; this situation may lead to asymmetric flap deployment and subsequent reduced controllability of the airplane during flight.