Airworthiness Directives; Mitsubishi Heavy Industries, LTD. Models MU-2B-10, -15, -20, -25, -26, -26A, -30, -35, -36, -36A, -40, and -60 Airplanes

This amendment adopts a new airworthiness directive (AD) that applies to Mitsubishi Heavy Industries, LTD. Models MU-2B-10, -15, -20, -25, -26, -26A, -30, -35, -36, -36A, -40, and -60 airplanes. This action requires revising the Limitations Section, the Procedures Section, and the Master Minimum Equipment List (MMEL) of the Airplane Flight Manual (AFM). These revisions require establishing a minimum airspeed for sustained level flight in icing conditions, limitations for the use of flaps for flight in icing conditions, cues for recognizing hazardous conditions, exiting procedures in icing conditions that are specific to Mitsubishi MU-2B series airplanes, and ensuring the wing illumination and taxi lights are operable prior to flight at night into known or forecast icing conditions. Several fatal accidents, involving certain Mitsubishi MU-2B series airplanes while flying in icing conditions, prompted this action. The actions specified by this AD are intended to prevent operating in conditions that are beyond the capability of the icing protection system, prevent aerodynamic stall at higher than normal airspeed because of icing conditions, and immediately provide the pilot with cues for recognizing hazardous conditions and exiting these conditions, which if not followed, could result in loss of the airplane.