CS 25.1045 Cooling test procedures

(a)Compliance with CS 25.1041 must be shown for the take-off, climb, en-route, and landing stages of flight that correspond to the applicable performance requirements. The cooling tests must be conducted with the aeroplane in the configuration, and operating under the conditions, that are critical relative to cooling during each stage of flight. For the cooling tests, a temperature is ‘stabilised’ when its rate of change is less than 1°C (2°F) per minute.

(b)Temperatures must be stabilised under the conditions from which entry is made into each stage of flight being investigated, unless the entry condition normally is not one during which component and engine fluid temperatures would stabilise (in which case, operation through the full entry condition must be conducted before entry into the stage of flight being investigated in order to allow temperatures to reach their natural levels at the time of entry). The take-off cooling test must be preceded by a period during which the powerplant component and engine fluid temperatures are stabilised with the engines at ground idle.

(c)Cooling tests for each stage of flight must be continued until –

(1)The component and engine fluid temperatures stabilise;

(2)The stage of flight is completed; or

(3)An operating limitation is reached.