Boeing 757 operators have been ordered to inspect aileron components following an in-service report of an issue that limited a flight crew’s ability to move the flight-control surfaces.
Airworthiness directives issued by the FAA and European Aviation Safety Agency require operators to inspect 757 aileron trim actuator bearings and attachment lugs within 1,760 flight hours—roughly six months—from each directive’s July 12 effective date. Actuators with cracked lugs or bearings that do not rotate freely must be replaced immediately.
The directives, issued in late June, are based on Boeing service information issued to operators in late March that recommended the inspections following the in-service incident, which Boeing shared with the regulator.
"The FAA received a report indicating that a flight crew could not center the ailerons with a left or right turn on the aileron trim control wheel during a flight control check,” the agency said. "Maintenance personnel found that the aileron trim actuator attachment lug had broken off of its support box assembly but was still attached to the aileron trim actuator….The lug failure resulted in a free-floating aileron trim actuator and subsequent loss of feel force, wheel centering and lateral trim."
Boeing determined that the separation was likely caused by a seized actuator bearing. A redesigned component “is still in development and will be rolled out” to operators when it is ready, Boeing said. Until then, operators must do repetitive checks every 1,100 flight hours after the initial inspections.
Aviation Week’s Fleet Database shows 667 757s in service worldwide. FAA lists 451 aircraft on the U.S. registry that must comply with its directive.