Airworthiness Directives; Learjet Model 60 Airplanes

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Learjet Model 60 airplanes. This action requires repetitive measurements of the brake wear dimension between the housing subassembly and the pressure plate that is adjacent to the top pistons of the brake assembly; and follow-on corrective actions, if necessary. This amendment is prompted by reports of abnormal (uneven) brake wear. The actions specified in this AD are intended to detect and repair an abnormal brake wear condition, which could result in loss of brake effectiveness and cause the airplane to leave the runway surface.