Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Learjet Model 60 airplanes. This proposal would require modification of the aft core cowl nozzle of the engine nacelles. This proposal is prompted by a report that the sealant material in the aft core cowl nozzle of the engine nacelle was found to extend higher than the nozzle's forward flange, which can allow it to interfere with the proper operation of the emergency fuel shutoff actuating mechanism. The actions specified by the proposed AD are intended to prevent physical interference of the emergency fuel shutoff actuating mechanism and resultant engine shutdown.