Airworthiness Directives; Raytheon (Beech) Model 400, 400A, and 400T Series Airplanes; and Raytheon (Mitsubishi) Model MU-300 Airplanes

The FAA is adopting a new airworthiness directive (AD) for all Raytheon (Beech) Model 400, 400A, and 400T series airplanes; and Raytheon (Mitsubishi) Model MU-300 airplanes. This AD requires revising the airplane flight manual to modify the Operating Limitations, Abnormal Procedures, and Normal Procedures, as applicable, for flight in icing conditions. This AD results from multiple reports of high- altitude, dual-engine flameouts on airplanes operating in certain meteorological conditions. We are issuing this AD to advise the flightcrew that the buildup of ice on certain internal areas of the engine could result in a dual-engine flameout and what action they must take to avoid this hazard.