Summary
This document proposes the supersedure of an existing airworthiness directive (AD), applicable to all Boeing Model 737-100, - 200, and -200C series airplanes, that currently requires periodic inspections to detect missing nuts and/or damaged secondary support hardware adjacent to the aft engine mount, and replacement, if necessary. That AD also provides for optional terminating action for certain inspections and a torque check. This action would mandate accomplishment of the previously optional terminating action. This proposal is prompted by the FAA's determination that the repetitive inspections required by the existing AD may not be providing the degree of safety assurance necessary for the transport airplane fleet. The actions specified by the proposed AD are intended to prevent failure of the secondary support to sustain engine loads in the event of failure of the aft engine mount cone bolt, which could result in the separation of the engine from the wing.