posted on March 06, 2013 17:24
The FAA is 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. The FAA is issuing this AD to prevent inadvertent activation of the 65 percent N1 back up mode, resulting in N2 speed fluctuation, significant power loss, and emergency landing of the helicopter.