AD FAA-2011-1037

We are superseding an existing airworthiness directive (AD) for all Turbomeca S.A. Makila 1A2 turboshaft engines. That AD currently requires replacement of certain serial number (S/N) N2 sensor harnesses. This AD requires replacement of the same S/N harnesses, and requires replacement of additional S/N N2 sensor harnesses. This AD was prompted by corrosion detected in affected N2 sensor harnesses. We are issuing this AD to prevent inadvertent activation of the 65% N1 back up mode, resulting in N2 speed fluctuation, significant power loss, and emergency landing of the helicopter.