Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to Robinson Helicopter Company (Robinson) Model R22 helicopters with a Lycoming O-360-J2A engine installation. This proposal would require replacing the carburetor and carburetor air temperature (CAT) gage with an improved carburetor that does not require manual leaning of the fuel/air mixture during flight, and a remarked CAT gage; and revising the Rotorcraft Flight Manual to remove the reference to leaning the engine. This proposal is prompted by a report from the Civil Aviation Authority of Great Britain that cautioned that the mixture control could inadvertently be placed in the idle cutoff position during in-flight manual leaning of the fuel/air mixture in the carburetor of the Lycoming O-360-J2A engine. The actions specified by the proposed AD are intended to prevent inadvertent placement of the mixture control to the idle cutoff position during in- flight leaning of the engine, which could result in an engine shutdown and subsequent loss of control of the helicopter.