Airworthiness Directives; Sikorsky Aircraft Corporation (Sikorsky) Model S-92A Helicopters

Résumé

This document proposes adopting a new airworthiness directive (AD) for the Sikorsky Model S-92A helicopters. This proposal would require inspecting each tail rotor blade (blade) for mislocated aluminum wire mesh in the blade skin. This proposal is prompted by the discovery that blades were manufactured with aluminum wire mesh mislocated, leaving portions of the graphite torque tube (spar) region unprotected from a lightning strike. This condition can exist in both the upper and lower blade skin airfoils. The actions specified by this proposed AD are intended to detect mislocated blade wire mesh and to prevent spar delamination, loss of the blade tip cap during a lightning strike, blade imbalance, loss of a blade, and subsequent loss of control of the helicopter.