Airworthiness Directives; Gulfstream Model G-1159, G-1159A, G-1159B, G-IV, and G-V Series Airplanes

This amendment corrects and clarifies information in an existing airworthiness directive (AD), applicable to certain Gulfstream Model G-1159, G-1159A, G-1159B, G-IV, and G-V series airplanes, that currently requires an inspection to determine if certain door control valves of the landing gear are installed, and modification of the valve, if necessary. The actions specified in that AD are intended to prevent loss of hydraulic system fluid due to failure of the door control valve of the landing gear, which could require the flight crew to use alternate gear extension procedures (landing gear blow down) for landing of all models. This amendment corrects the requirements of the current AD by specifying appropriate alert customer bulletins for certain airplane models, and clarifying the compliance time for the modification of the door control valve of the landing gear. This amendment is prompted by operators' comments on the existing AD.