Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 727, 727-100C, 727-200F, and 727C series airplanes. This proposal would require repetitive open-hole high frequency eddy current inspections for cracks in the fuselage skin, strap (bearstrap), and doubler at the forward and aft hinge fittings for the main deck cargo door, and repair of any cracks found. This action is necessary to detect and correct such cracks, which could reach critical crack length and result in rapid decompression of the airplane. This action is intended to address the identified unsafe condition.