Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 737-300, - 400, and -500 series airplanes. This proposal would require repetitive inspections to detect cracking of certain areas of the forward pressure bulkhead, and repair, if necessary. This proposal also would require certain preventive modifications, which, when accomplished, would terminate the repetitive inspections for the affected areas. This action is necessary to prevent fatigue cracking on critical areas of the forward pressure bulkhead, which could result in rapid decompression of the airplane fuselage. This action is intended to address the identified unsafe condition.