Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 757 series airplanes. This proposal would require a one-time inspection of a wire bundle in the front left wing spar for chafing and for proper installation of a Teflon sleeve; corrective action, if necessary; and installation of extra protection against chafing. This action is necessary to prevent chafing between the wire bundle and the front left wing spar, which could result in electrical arcing and subsequent ignition of flammable vapors and possible uncontrollable fire. This action is intended to address the identified unsafe condition.