Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain British Aerospace Model BAC 1-11-200 and -400 series airplanes. This proposal would require various inspections to detect discrepancies of fuselage frames at certain stations, and correction of discrepancies; and rework to limit the maximum differential operating pressure of the fuselage. This proposal would also require eventual modification of fuselage frames at certain stations, which would terminate the repetitive inspection requirements. This proposal is prompted by reports of fatigue cracking in certain fuselage frames in the vicinity of the passenger door at floor level due to fatigue-related stress. The actions specified by the proposed AD are intended to prevent such fatigue-related cracking, which could result in reduced structural integrity of the fuselage pressure vessel and possible decompression of the pressurized cabin.