AD FAA-2011-0859

This amendment adopts a new airworthiness directive (AD) for ECF Model EC120B helicopters. This action requires inserting an emergency procedure appendix from an ECF Emergency Alert Service Bulletin into the Rotorcraft Flight Manual (RFM). This action also requires modifying the emergency switch electrical wiring and performing tests to ensure correct operation of the emergency switch. This action also requires removing the emergency procedure appendix from the RFM after modifying the emergency switch electrical wiring and performing tests to ensure correct operation. This amendment is prompted by the discovery that simultaneously setting the emergency switch to the low position "CUT-OFF" and the generator (GENE) pushbutton to "OFF" position caused the starter-generator to restart. Investigation revealed that cross-wiring at the emergency switch caused this malfunction. This condition, if not corrected, could lead to the inability to isolate electrical equipment during an emergency, creating the risk of an uncontrolled electrical fire and subsequent loss of control of the helicopter.