Fix the temperature computation.

diff --git a/src/Environment/environment.cxx b/src/Environment/environment.cxx
index f915e526194fc088905ba444263fa8ce6b3c94fb..edf3ef8c9ad305ad38b9ab37ba02cebb45efa4ec 100644 (file)
--- a/src/Environment/environment.cxx
+++ b/src/Environment/environment.cxx
@@ -646,7 +646,7 @@ FGEnvironment::_recalc_sl_temperature ()
   double t_strato = ISA_def[1].temp - atmodel::freezing;
   if (temperature_degc < t_strato) temperature_sea_level_degc = t_strato;
   else temperature_sea_level_degc = 
-      temperature_degc - elevation_ft * ISA_def[0].lapse;
+      temperature_degc + elevation_ft * atmodel::foot * ISA_def[0].lapse;
 
 // Alternative implemenation:
 //  else temperature_sea_level_inhg = T_layer(0., elevation_ft * foot,