Heat stress in an aircraft cockpit during ground standby.

Measurements have been made of cockpit temperatures in a Buccaneer aircraft exposed to high air temperatures and radiation loads. With the canopy open 8 cm, and with the wind direction unfavourable for convective cooling, air temperatures inside the cockpit exceeded those outside by approximately 20 degrees C. This reduced to 10 degrees C with a favourable wind direction. An assessment of the likely heating effect of cockpit avionic equipment indicated that the addition of 1 kW and 2 kW of heat would raise cockpit temperatures by 20 degrees C and 30 degrees C respectively. Prediction of the combined effect of solar and avionic heat suggests that, in hot weather conditions, cockpit temperatures will be considerably in excess of the upper limit for effective physiological temperature regulation. Therefore, if aircrews are to be required to remain on ground standby within their aircraft under such conditions, maximum use must be made of convective cooling of the cockpit by the prevailing wind, and of sun shades to eliminate the greenhouse effect completely.