Text in force at CS27-10: from CS27-1, effective 30 Nov 2007.
(a) For helicopters:
(1) The hovering ceiling must be determined over the ranges of weight, altitude, and temperature for which certification is requested, with:
(i) Take-off power;
(ii) The landing gear extended; and
(iii) The helicopter in ground effect at a height consistent with normal take-off procedures; and
(2) The hovering ceiling determined in sub-paragraph (a)(1) of this paragraph must be at least:
(i) For reciprocating engine-powered helicopters, 1219 m (4 000 ft) at maximum weight with a standard atmosphere; or
(ii) For turbine engine-powered helicopters, 762 m (2 500 ft) pressure altitude at maximum weight at a temperature of standard +22°C (+40°F).
(3) The out-of-ground effect hovering performance must be determined over the ranges of weight, altitude, and temperature for which certification is requested, using take-off power.
(b) For rotorcraft other than helicopters, the steady rate of climb at the minimum operating speed must be determined, over the ranges of weight, altitude, and temperature for which certification is requested, with:
(1) Take-off power; and
(2) The landing gear extended.
ED Decision 2007/013/R · Source