Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to Rolls-Royce Ltd. (R-R) Dart 511, 511-7E, 514-7, 528, 528-7E, 529-7E, 532-7, 532-7L, 532-7N, 532-7P, 532- 7R, 535-7R, 551-7R, and 552-7R turboprop engines. This proposal would require the installation of a feathering probe and a steel retaining ring in the reduction gear housing (RGH), and replacement of a transfer bobbin installed in the torquemeter. This proposal is prompted by two reports of the failure of a propeller to feather following the failure of the RGH annulus gear, which resulted in the propeller overspeeding and the release of a propeller blade, causing damage to the airplane. The actions specified by the proposed AD are intended to prevent a propeller from overspeeding and the release of a propeller blade after a failure of the RGH annulus gear, which could result in damage to an adjacent engine or to the airplane.