Airworthiness Directives; Learjet Model 31, 31A, 35, 35A, and 60 Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to certain Learjet Model 31, 31A, 35, 35A, and 60 airplanes, that requires a visual inspection of the spoiler actuators to determine the serial number of the spoiler actuators; and replacement of the spoiler actuators with new actuators, if necessary. This amendment is prompted by failure of a spoiler actuator piston rod during the first production flight of a Model 60 airplane due to an incomplete heat treatment process. The actions specified by this AD are intended to prevent failure of the spoiler actuator, which could result in the spoiler panel floating and inducing an uncommanded roll of the airplane.