Airworthiness Directives; Boeing Model 757 Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 757 airplanes. This AD requires installing a control wheel damper assembly at the first officer's drum bracket assembly and aileron quadrant beneath the flight deck floor in section 41; doing a functional test and adjustment of the new installation; and doing related investigative/corrective actions if necessary. For certain airplanes, this AD also requires doing an additional adjustment test of the re-located control wheel position sensor, and an operational test of the flight data recorder and the digital flight data acquisition unit. This AD also requires installing vortex generators (vortilons) on the leading edge of the outboard main flap on certain airplanes. This AD results from several reports that flightcrews experienced unintended roll oscillations during final approach, just before landing. We are issuing this AD to prevent unintended roll oscillations near touchdown, which could result in loss of directional control of the airplane, and consequent airplane damage and/or injury to flightcrew and passengers.