Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Rolls-Royce Limited Dart series turboprop engines. This proposal would require a one-time visual inspection of the interior of the switch to determine the type of low torque switch, and removal from service of unapproved Klixon low torque switches and replacement with serviceable parts. This proposal is prompted by the discovery of unapproved low torque switches in fleet operation. The actions specified by the proposed AD are intended to prevent possible low torque switch failure, which could result in failure of a propeller to auto-feather following an engine power loss, resulting in possible loss of control of the airplane due to high asymmetric drag.