§27.1509 Rotor speed.

(a) Maximum power-off (autorotation). The maximum power-off rotor speed must be established so that it does not exceed 95 percent of the lesser of-- (1) The maximum design r.p.m. determined under Sec. 27.309(b); and (2) The maximum r.p.m. shown during the type tests. (b) Minimum power off. The minimum power-off rotor speed must be established so that it is not less than 105 percent of the greater of-- (1) The minimum shown during the type tests; and (2) The minimum determined by design substantiation. (c) Minimum power on. The minimum power-on rotor speed must be established so that it is-- (1) Not less than the greater of-- (i) The minimum shown during the type tests; and (ii) The minimum determined by design substantiation; and (2) Not more than a value determined under Sec. 27.33(a)(1) and (b)(1).