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 chafe wear on the upper diagonal engine mount tube, and replacement or repair, if necessary. This amendment requires the installation of chafe guards at the engine mounts, which terminates the currently required inspections. It also requires that the chafe guards then be repetitively inspected for chafe wear. This amendment is prompted by the development of a modification that will provide better protection of the subject area against future chafe wear. The actions specified by this AD are intended to prevent excessive chafe wear in the area of the upper diagonal engine mount tubes and trusses; if not detected and corrected, such wear could result in failure of the engine mount assembly and possible separation of the engine from the airplane.