Summary
This document proposes the supersedure of an existing airworthiness directive (AD), applicable to all Boeing Model 727 series airplanes, that currently requires repetitive pre-modification inspections to detect cracks in the forward support fitting of the number 1 and number 3 engines; and repair, if necessary. That AD also provides for an optional high frequency eddy current inspection, and, if possible, modification of the fastener holes; and various follow-on actions; which would terminate the repetitive pre-modification inspections. This action would expand the area to be inspected; require accomplishment of the previously optional (and subsequently revised) modification, which would terminate certain repetitive inspections; and add repetitive post-modification inspections to detect cracking of the fastener holes, and corrective actions if necessary. The actions specified by the proposed AD are intended to prevent fatigue cracking of the forward support fitting of the number 1 and number 3 engines, which could result in failure of the support fitting and consequent separation of the engine from the airplane. This action is intended to address the identified unsafe condition.