Summary
This document proposes the supersedure of an existing airworthiness directive (AD), applicable to Robinson Helicopter Company (Robinson) Model R22 helicopters, that currently requires installation of an improved throttle governor; an adjustment to the low RPM warning unit threshold to increase the revolutions-per minute (RPM) at which the warning horn and caution light activate; and revisions to the R22 Rotorcraft Flight Manual that prohibit flight with the improved throttle governor selected off, except in certain situations. This action would require the same compliance actions required by the existing AD, as well as require an insertion of procedures for the improved throttle governor into the Normal and Emergency sections of the R22 Rotorcraft Flight Manual and correct the applicability section of the existing AD. This proposal is prompted by the need to insert normal and emergency procedures for the improved throttle governor in the flight manual, as well as clarify the helicopter serial numbers to which the AD applies. The actions specified by the proposed AD are intended to minimize the possibility of pilot mismanagement of the main rotor (M/R) RPM, which could result in unrecoverable M/R blade stall and subsequent loss of control of the helicopter.