Airworthiness Directives; Boeing Model 737-200 and -300 Series Airplanes Equipped with a Main Deck Cargo Door Installed in Accordance with Supplemental Type Certificate (STC) SA2969SO

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Boeing Model 737-200 and -300 series airplanes, that currently requires a one-time inspection to detect cracks of the lower frames and reinforcing angles of the main deck cargo door where the door latch fittings attach between certain fuselage stations and water lines, and replacement of any cracked part with a new part having the same part number. That AD was prompted by reports that, during the inspections required by the existing AD, cracks were found in the reinforcing angles of the main deck cargo door frame. This amendment requires, among other actions, an inspection to detect cracks of the lower frames and reinforcing angles of the main deck cargo door; replacement of any lower frame or reinforcing angle of the main deck cargo door when it has reached its maximum life limit. The actions specified by this AD are intended to detect and correct cracking of the lower portion of the main deck cargo door frames, which could result in sudden depressurization, loss or opening of the main deck cargo door during flight, and loss of control of the airplane.