Summary
This document revises an earlier proposed airworthiness directive (AD) for Eurocopter Deutschland GMBH (ECD) Model BO-105CB-5 and BO-105CBS-5 helicopters that would have superseded an existing AD. The existing AD requires, before further flight, creating a component log card or equivalent record and determining the calendar age and number of flights on each tension-torsion (TT) strap. The proposed AD would have required establishing a life limit for certain main rotor TT straps. That proposal was prompted by a need to establish a life limit for certain TT straps because of an accident in which a main rotor blade (blade) separated from an ECD Model MBB-BK 117 helicopter due to fatigue failure of a TT strap. The same part-numbered TT strap is used on the ECD Model BO-105 helicopters. This new action revises the proposed rule by requiring that you establish a life limit for certain main rotor TT straps before further flight instead of by January 1, 2001, as indicated in the previous proposal. This new action also removes some of the requirements that were previously proposed. The actions specified by this new proposed AD are intended to prevent fatigue failure of a TT strap, loss of a blade, and subsequent loss of control of the helicopter.