Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 707 and 720 series airplanes. This proposal would require installation of a new support structure for the trailing edge beam and main landing gear uplock mechanism. This action is necessary to prevent cracking in the frame and adjacent structure near the attach bolt of the main landing gear uplock mechanism, which could lead to compromised structural integrity. This action is intended to address the identified unsafe condition.