CS 27.1509 Rotor speed

• ED Decision 2003/15/RM found in: CS-27 Amdt 10 - Small Rotorcraft (Feb 2023)

CS 27.1509 Rotor speed ED Decision 2003/15/RM (a) *Maximum power-off (autorotation).* The maximum power-off rotor speed must be established so that it does not exceed 95% of the lesser of – (1) The maximum design rpm determined under [CS 27.309(b)](#_DxCrossRefBm8893831); and (2) The maximum rpm 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% 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 [CS 27.33(a)(1) and (b)(1)](#_DxCrossRefBm8893791). CS 27.1509 Rotor speed ED Decision 2003/15/RM (a) *Maximum power-off (autorotation).* The maximum power-off rotor speed must be established so that it does not exceed 95% of the lesser of – (1) The maximum design rpm determined under [CS 27.309(b)](#_DxCrossRefBm472493266); and (2) The maximum rpm 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% 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 [CS 27.33(a)(1) and (b)(1)](#_DxCrossRefBm472493233).