Airworthiness Directives; Honeywell International Inc. Turboprop Engines (Type Certificate Previously Held by AlliedSignal Inc., Garrett Engine Division; Garrett Turbine Engine Company; and AiResearch Manufacturing Company of Arizona)

We are adopting a new airworthiness directive (AD) for certain Honeywell International Inc. TPE331-5, -5A, -5AB, -5B, -10, -10R, -10U, -10UF, -10UG, -10UGR, and -10UR model turboprop engines. This AD was prompted by engine propeller shaft coupling failures, leading to unexpected propeller pitch changes causing increased aerodynamic and asymmetric drag on the airplanes using these engines. This AD requires removing certain part number (P/N) engine propeller shaft couplings from service. This AD also requires inserting a copy of certain airplane operating procedures into applicable flight manuals. We are issuing this AD to prevent loss of airplane control, leading to an accident.