Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 757-200, -200PF, and -200CB series airplanes. This proposal would require an inspection of certain ballscrews of the trailing edge flap system to find their part numbers, and replacement of the ballscrews with new, serviceable, or modified ballscrews if necessary. This action is necessary to prevent a flap skew due to insufficient secondary load path of the ballscrew of the trailing edge flaps in the event that the primary load path fails, which could result in possible loss of a flap and reduced controllability of the airplane. This action is intended to address the identified unsafe condition.