VENTILATION APPARATUS

An apparatus for preparing a ventilation gas mixture, the apparatus comprising: a first gas feed configured to receive carbon dioxide via a first gas valve; a second gas feed configured to receive oxygen via a second gas valve; a gas mixing device configured to receive the carbon dioxide and the oxygen from the first and second gas feeds and combine the carbon dioxide with the oxygen in the gas mixing device to form a ventilation gas mixture; wherein the first and second gas valves are adjustable between an open position and a closed position in order to adjust the relative amounts of carbon dioxide and oxygen forming the ventilation gas mixture; and wherein the first and a second gas valves are arranged to be adjusted based on a G-force that is imparted on the apparatus.