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

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Gulfstream Model G-1159, G-1159A, G-1159B, G- IV, and G-V series airplanes. This action requires an inspection to determine if certain door control valves of the landing gear are installed, and modification of the valve, if necessary. This action is necessary 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 action is intended to address the identified unsafe condition.