Summary
We propose to adopt a new airworthiness directive (AD) for all Eurocopter Deutschland GmbH Model MBB-BK117 C-2 helicopters with certain Generator Control Units (GCU) installed. This proposed AD is prompted by reports of internal short circuits in certain GCUs. The proposed actions are intended to replace any affected GCUs to prevent a short circuit, which could result in a loss of electrical generating power, loss of systems required for continued safe flight and landing, and subsequent loss of control of the helicopter.