Summary
We propose to adopt a new airworthiness directive (AD) for Eurocopter Deutschland GmbH (ECD) Model BO-105A, BO-105C, BO-105S, BO- 105LS A-1, BO-105LS A-3, MBB-BK 117 A-1, MBB-BK 117 A-3, MBB-BK 117 A- 4, MBB-BK 117 B-1, MBB-BK-117 B-2, and MBB-BK 117 C-1 helicopters to require inspections for corrosion or thread damage to each tail rotor balance weight (weight) and each tail rotor control lever (lever). This proposed AD is prompted by a European Aviation Safety Agency (EASA) AD and a Transport Canada Civil Aviation (TCCA) AD, both issued based on a report that corrosion was detected on a weight in the area of the attachment thread on a model BO-105 helicopter. The proposed actions are intended to detect corrosion and thread damage in the threaded area of the weight and lever, and to prevent failure of a weight or lever, separation of tail rotor parts, severe vibration, and subsequent loss of control of the helicopter.