diff --git a/src/modules/simu/simuv4/atmosphere.cpp b/src/modules/simu/simuv4/atmosphere.cpp
index 8cbcfcf64..2e893db71 100644
--- a/src/modules/simu/simuv4/atmosphere.cpp
+++ b/src/modules/simu/simuv4/atmosphere.cpp
@@ -26,10 +26,16 @@ void SimAtmosphereConfig(tTrack *track)
     SimRain = track->local.rain;
     SimTimeOfDay = track->local.timeofday;
     SimClouds = track->local.clouds;
-    Tair = track->local.airtemperature + 273.15;
+    Tair = track->local.airtemperature + 273.15f;
     SimAirPressure = track->local.airpressure;
     SimAirDensity = track->local.airdensity;
 
+    if (SimAirPressure == 0.0f)
+        SimAirPressure = 101300.0f;
+
+    if (SimAirDensity == 0.0f)
+        SimAirDensity = 1.290f;
+
     GfLogDebug("SimAirPressure = %3f - SimAirDensity = %3f\n", SimAirPressure, SimAirDensity);
 
     if (SimTimeOfDay < 6.00 * 60 *60 && SimTimeOfDay > 19 * 60 * 60)