As in the real world, the Turbine Dukes simulate the fact that the air conditioning system struggles to maintain cabin temperature when operating at higher flight levels. This can result in the cabin temperature dropping well below freezing, if allowed to continue.

If your cabin temperature starts to drop and your %SpO2 starts to drop as you climb, first turn on the oxygen valve on the left cabin sidewall, then pull the two "Intercooler Shutoff" valve controls, above the red levers on the right side of the panel. These will isolate the cold intercooler air from the cabin supply and allow the air conditioning heater to provide warm air.

It should also be noted that the cabin heater in the nose is disabled in the Turbine Duke as it is not certified to run on JETA fuel.

The effect of these actions can be seen on the Cabin page of the EFB, as well as on the main panel temperature gauge.