diff -r b3b55b03d499 -r 2bb7141496a9 share/hedgewars/Data/Missions/Challenge/User_Mission_-_RCPlane_Challenge.lua
--- a/share/hedgewars/Data/Missions/Challenge/User_Mission_-_RCPlane_Challenge.lua	Sun Sep 02 20:57:33 2018 +0200
+++ b/share/hedgewars/Data/Missions/Challenge/User_Mission_-_RCPlane_Challenge.lua	Sun Sep 02 21:26:44 2018 +0200
@@ -279,7 +279,7 @@
 end
 
 function onNewTurn()
-	TurnTimeLeft = -1
+	SetTurnTimeLeft(cMaxTurnTime)
 end
 
 function onGearAdd(gear)