Navigate / EASA

CS 27.45  General

ED Decision 2003/15/RM

(a)     Unless otherwise prescribed, the performance requirements of this Subpart must be met for still air and a standard atmosphere.

(b)     The performance must correspond to the engine power available under the particular ambient atmospheric conditions, the particular flight condition, and the relative humidity specified in sub-paragraphs (d) or (e), as appropriate.

(c)      The available power must correspond to engine power, not exceeding the approved power, less:

(1)     Installation losses; and

(2)     The power absorbed by the accessories and services appropriate to the particular ambient atmospheric conditions and the particular flight condition.

(d)     For reciprocating engine-powered rotorcraft, the performance, as affected by engine power, must be based on a relative humidity of 80% in a standard atmosphere.

(e)     For turbine engine-powered rotorcraft, the performance, as affected by engine power, must be based on a relative humidity of:

(1)     80%, at and below standard temperature; and

(2)     34%, at and above standard temperature plus 28°C (50°F) between these two temperatures, the relative humidity must vary linearly.

(f)      For turbine engine-powered rotorcraft, a means must be provided to permit the pilot to determine prior to take-off that each engine is capable of developing the power necessary to achieve the applicable rotorcraft performance prescribed in this Subpart.