Airworthiness Directives; MD Helicopters Inc. Model 369D, 369E, 500N, and 600N Helicopters

This amendment adopts a new airworthiness directive (AD) applicable to MD Helicopters Inc. (MDHI) Model 369D, 369E, 500N, and 600N helicopters with certain analog/digital turbine outlet temperature (TOT) indicators installed. This action requires repetitive calibration testing of the TOT indicating system and corrective actions if necessary. This amendment is prompted by seven reports of erroneous TOT readings and two reports of incorrect wiring harness terminal lugs on the thermocouple wiring. The actions specified in this AD are intended to prevent an erroneous TOT indication, damage to critical engine components, loss of engine power, and a subsequent forced landing.