Airworthiness Directives; Robinson Helicopter Company Model R22 Helicopters

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 98-21-09, which was sent previously to all known U.S. owners and operators of Robinson Helicopter Company (RHC) Model R22 helicopters by individual letters. This AD requires installing fuel tank vent tube(s), with modified attachment to the mast tube, if not previously accomplished; installing a spring into the flexible tube leading to the main fuel tank; and installing a spring into the flexible tube leading to the auxiliary fuel tank, if an auxiliary fuel tank is installed. This amendment is prompted by an incident in which the flexible vent connecting the rigid vent tube to the main fuel tank kinked, resulting in fuel starvation and a hard landing after uncommanded engine shutdown. The actions specified by this AD are intended to prevent fuel starvation, loss of engine power, and a subsequent forced landing.