diff --git a/preferences.xml b/preferences.xml
index 1f35816f0..5881f01cc 100644
--- a/preferences.xml
+++ b/preferences.xml
@@ -619,7 +619,7 @@ Started September 2000 by David Megginson, david@megginson.com
   <params>
    <real-world-weather-fetch type="bool">false</real-world-weather-fetch>
    <metar-max-age-min type="long">240</metar-max-age-min>
-   <control-fdm-atmosphere type="bool">false</control-fdm-atmosphere>
+   <control-fdm-atmosphere type="bool">true</control-fdm-atmosphere>
    <contrail-altitude>30000</contrail-altitude>
   </params>