Summary
This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain British Aerospace Model BAC 1-11 200 and 400 series airplanes. That AD currently limits the number of operations at increased cabin pressure differential, and requires repetitive structural inspections for cracking of the fuselage, and repair or replacement of parts, if necessary. This action would require additional repetitive inspections for cracking of the fuselage. This proposal is prompted by the determination that airplanes operating at increased cabin pressure differential are more likely to develop fatigue cracking earlier in their service lives than those airplanes operating at normal cabin differential pressures. The actions specified by the proposed AD are intended to detect and correct fatigue cracking of the airplane fuselage, which could result in reduced structural integrity of the airplane.