Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to all British Aerospace Model BAC 1- 11 200 and 400 series airplanes. This proposal would require repetitive ultrasonic inspections to detect cracking of the lugs of the engine mounting beams, and replacement of the beam with a serviceable part, if necessary. This proposal is prompted by reports of fatigue cracking of the lugs of the engine mounting beams. The actions specified by the proposed AD are intended to detect and correct such cracking of the engine mounting lugs, which could result in reduced structural capability of the engine mount.