FAA Federal Aviation Regulations (FARS, 14 CFR)

(a) Each oil shutoff must meet the requirements of §29.1189.

(b) The closing of oil shutoffs may not prevent autorotation.

(c) Each oil valve must have positive stops or suitable index provisions in the "on" and "off" positions and must be supported so that no loads resulting from its operation or from accelerated flight conditions are transmitted to the lines attached to the valve.