Reply...
486_Col_Wolf,
Ah! Then do this...
Create a warning trigger by picking a percentage point you want to use as a warning. (Say 50%) Then create a trigger under "status," using "speed, equals zero."
When the first trigger (health) warning is activated, in the event description, say something like "Your ___ has taken heavy damage, you can't make it back to ___. Set your plane down on any flat space you can find; this will end the mission."
Once you set up the damage warning, use that event again, and this time include the speed trigger. What this will amount to is that the successful landing will only be active if the plane takes that damage. After a few seconds, say something in the event description like "Good work, you landed safely and have lived to fight another day." Then, after several more seconds, use the "end mission" event under "Misc."
But this will only work if you land in friendly territory. If you land in enemy territory, you will be captured.
If you don't want to use speed zero as a trigger, you can use wheel brakes as an alternative.