14 CFR §27.65

1. (a)For rotorcraft other than helicopters—
   1. (1)The steady rate of climb, at VY, must be determined—
      1. (i)With maximum continuous power on each engine;
      2. (ii)With the landing gear retracted; and
      3. (iii)For the weights, altitudes, and temperatures for which certification is requested; and
   2. (2)The climb gradient, at the rate of climb determined in accordance with paragraph (a)(1) of this section, must be either—
      1. (i)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
      2. (ii)At least 1:6 under standard sea level conditions.
2. (b)Each helicopter must meet the following requirements:
   1. (1)VY must be determined—
      1. (i)For standard sea level conditions;
      2. (ii)At maximum weight; and
      3. (iii)With maximum continuous power on each engine.
   2. (2)The steady rate of climb must be determined—
      1. (i)At the climb speed selected by the applicant at or below VNE;
      2. (ii)Within the range from sea level up to the maximum altitude for which certification is requested;
      3. (iii)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
      4. (iv)With maximum continuous power on each engine.