/* Specify a pressure-altitude layer. 
The routine sets the  */
bool pressure_isa_layer(int index)
/* Specify a pressure-altitude layer. 
The routine sets the  */
bool pressure_isa_layer(int index)
{
	if ((layer_min <= index) && (index <= layer_max)) {
		layer = index;
		RL_g0 = (R_g0 * Lb);
		RT_g0 = (R_g0 * Tb);
		return true;
	}
	return false;
}