Airworthiness Directives; Empresa Brasileira de Aeronautica S.A.

This amendment adopts a new airworthiness directive (AD) that is applicable to certain EMBRAER Model EMB-135 and -145 series airplanes. This action requires a one-time inspection of the clutch assembly of the horizontal stabilizer actuator (HSA) to verify that at least one locking tab on the key washer is bent into the locking groove of the clutch nut, and follow-on actions. This action is necessary to prevent a loose or disengaged clutch nut on the HSA clutch assembly, which could result in loss of pitch trim and consequent reduced controllability of the airplane. This action is intended to address the identified unsafe condition.