ED Decision 2023/001/R
(a) The never-exceed speed, VNE, must be established so that it is:
(1) Not less than 74 km/h (40 knots) (CAS); and
(2) Not more than the lesser of:
(i) 0.9 times the maximum forward speeds established under CS 27.309;
(ii) 0.9 times the maximum speed shown under CS 27.251 and 27.629; or
(iii) 0.9 times the maximum speed substantiated for advancing blade tip mach number effects.
(b) VNE may vary with altitude, rpm, temperature, and weight, if:
(1) No more than two of these variables (or no more than two instruments integrating more than one of these variables) are used at one time; and
(2) The ranges of these variables (or of the indications on instruments integrating more than one of these variables) are large enough to allow an operationally practical and safe variation of VNE.
(c) For helicopters, a stabilised power-off VNE denoted as VNE (power-off) may be established at a speed less than VNE established pursuant to sub-paragraph (a), if the following conditions are met:
(1) VNE (power-off) is not less than a speed midway between the power-on VNE and the speed used in meeting the requirements of:
(i) CS 27.65(b) for single-engine helicopters; and
(ii) CS 27.67 for multi-engine helicopters.
(2) Unless it is automatically displayed to the crew, the VNE (power-off) is –
(i) A constant airspeed; or
(ii) A constant amount less than power-on VNE; or
(iii) A constant airspeed for a portion of the altitude range for which certification is requested, and a constant amount less than power-on VNE for the remainder of the altitude range.
Small rotorcraft never-exceed speed (VNE) must be established, with a minimum of 74 km/h. The maximum VNE is limited by forward speeds, rotor speeds, or blade tip Mach effects. VNE can vary with altitude, RPM, temperature, or weight, using limited variables. A lower power-off VNE is permissible under specific performance and display conditions.
* Summary by Aviation.Bot - Always consult the original document for the most accurate information.
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