Summary
We propose to adopt a new airworthiness directive (AD) for Airbus Helicopters Deutschland GmbH (Airbus) (formerly Eurocopter Deutschland GmbH) Model MBB-BK 117C-2 helicopters with an external mounted hoist system wiring harness installed. This proposed AD would require inspecting the hoist control pendant wiring harness for chafing, and if there is chafing, before the next hoist operation, replacing the wiring harness. This proposed AD would also require a installing a protection sleeve on the hoist control pendant wiring harness. This proposed AD is prompted by an uncommanded hoist release involving chafing on the wiring harness of the hoist control pendant and on the wiring. The proposed actions are intended to prevent loss of an external load or person from the hoist resulting in injury to persons being lifted and loss of control of the helicopter.