Summary
This document proposes adopting a new airworthiness directive (AD) for Robinson Helicopter Company (RHC) Model R44 helicopters. This proposal would require establishing a life limit of 2200 hours time-in-service (TIS) for affected horizontal stabilizers. This proposal is prompted by engineering analysis, which indicates that certain vertical-to-horizontal stabilizer attach channels (channels) will crack sooner than the original life limit of the horizontal stabilizer. The actions specified by the proposed AD are intended to prevent a crack through a channel, separation of the stabilizers, and subsequent loss of directional control of the helicopter.