Airworthiness Directives; Gulfstream Aerospace Corporation Model G-159 (G-I) Airplanes

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Gulfstream Model G-159 (G-I) airplanes, that currently requires repetitive inspections to detect cracking in the mounting lugs of the elevator trim tab actuators, and replacement, if necessary. This amendment requires the installation of improved elevator trim tab actuators that are not susceptible to the subject cracking. This amendment is prompted by the development of a modification that positively addresses the identified unsafe condition. The actions specified by this AD are intended to prevent failure of the mounting lugs on the elevator trim tab actuator due to cracking; such failure could result in severe vibration during flight and/or reduction or loss of elevator trim tab capability, which could lead to reduced controllability of the airplane.