Summary
This document revises an earlier proposed superseding airworthiness directive (AD) for the specified Bell Helicopter Textron Canada (BHTC) helicopters. That proposal would have required inspecting the tailboom skins for a crack, replacing a cracked tailboom with a modified tailboom before further flight, and implementing a recurring inspection of the modified tailboom. That proposal was prompted by several reports of cracks found during mandatory inspections. This supplemental notice of proposed rulemaking (SNPRM) renews and revises the proposal by providing a terminating action, incorporating a more recent revision to the alert service bulletin (ASB), and increasing the compliance time for performing the inspections. The actions specified by this proposal are intended to detect a crack in the tailboom and to prevent separation of the tailboom from the helicopter and subsequent loss of control of the helicopter.