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 an inspection to determine the serial numbers of geared rotary actuators (GRA) for the leading edge slats, and replacement of certain actuators with new or reworked actuators. This action is necessary to prevent a fractured spring washer in a GRA, which could lead to a disconnect in the GRA, and result in a slat skew condition and consequent reduced controllability of the airplane. This action is intended to address the identified unsafe condition.