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Cabin climate

Overview

The Cabin Climate system exists for two reasons: for flavor and as a consumer of the heating system which is driven by bleed air.

It's a low-fidelity three-zone thermal model (cockpit / cabin / aft cabin) with air and structure temperatures for the zones.

Heat comes from the heating system (driven by engine bleed air), avionics, passenger body heat and a directional solar greenhouse effect (sun geometry × heading, mitigated by cloud cover).

Cooling is provided by by ram air (unless you're moving, this needs the vent fan), radiation to the sky, and, if ambient conditions allow, by opening the doors on the ground (ideally opposed doors in a breeze). The cockpit fans (missing in the visual model) help with the heat exchange between cockpit air and cockpit structures, they can help cool the avionics.

On a cold-and-dark spawn the conditions are based on the assumption that the empty aircraft been sitting on the apron for a few hours by replaying the preceding hours of sun position. As a simplification, the model assumes the weather didn't change during that time.

Air quality

A cabin air model tracks CO₂, O₂ and humidity, shown on the EFB Climate tab alongside the three zone temperatures and the duct. This is purely for flavor and to provide some incentive to let fresh air in.

L:vars

L:var R/W Meaning
DHC6_CABIN_TEMP_COCKPIT R Cockpit zone air temperature
DHC6_CABIN_TEMP_MID R Mid-cabin zone
DHC6_CABIN_TEMP_AFT R Aft-cabin zone
DHC6_CABIN_DUCT_TEMP R Bleed-air duct temperature
DHC6_DUCT_OVERHEAT R Duct overheat flag
DHC6_CLIMATE_MODE R/W Manual / Off / Auto
DHC6_CLIMATE_MANUAL R/W Manual COOL / Hold / WARM
DHC6_CLIMATE_TEMP_SET R/W Temperature selector
DHC6_CABIN_VENT_FAN R/W Vent fan — a cockpit switch exists, but worth a hardware binding
DHC6_COMPT_FANS R/W Compartment fans

Reviewed 2026-08-05.