AD 97-04-05 Amendment 39-9929

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Jetstream Model 4101 airplanes. This action requires a one-time inspection of the airplane records to determine the modification status of the elevator trim servo, and, if necessary, inspections to determine the serial number of the servo, and repetitive inspections for looseness or movement of the motor housing of the servo. This action also requires replacement of certain elevator trim servos with a serviceable assembly. This amendment is prompted by reports of the motor housing separating from the elevator trim servo and the consequent release of certain component parts, due to inadequate locking of screws that were installed during assembly of the servos. The actions specified in this AD are intended to prevent the motor housing of the elevator trim servo from separating and releasing component parts that could lodge in and jam the elevator controls, and result in reduced pitch control of the airplane.