14 CFR § 27.65

For rotorcraft other than helicopters—

The steady rate of climb, at VY, must be determined—

With maximum continuous power on each engine;

With the landing gear retracted; and

For the weights, altitudes, and temperatures for which certification is requested; and

The climb gradient, at the rate of climb determined in accordance with paragraph (a)(1) of this section, must be either—

At least 1:10 if the horizontal distance required to take off and climb over a 50-foot obstacle is determined for each weight, altitude, and temperature within the range for which certification is requested; or

At least 1:6 under standard sea level conditions.

Each helicopter must meet the following requirements:

VY must be determined—

For standard sea level conditions;

At maximum weight; and

With maximum continuous power on each engine.

The steady rate of climb must be determined—

At the climb speed selected by the applicant at or below VNE;

Within the range from sea level up to the maximum altitude for which certification is requested;

For the weights and temperatures that correspond to the altitude range set forth in paragraph (b)(2)(ii) of this section and for which certification is requested; and

With maximum continuous power on each engine.