There is not. What you do is:
1. Start a flight in career mode
2. Create a new airframe
3. Run through the checklists until "all check lists done and verified and systems armed and ready for a flight"
4. Save the state through the airframe manager window
Then, next time you want to start "on runway threshold" you would:
1. Start a flight in career mode
2. Select the aforementioned airframe and saved state from the airframe manager, unchecking the "restore position" checkbox
3. Fly!
Any future questions please use the appropriate support forum: https://forums.x-pilot.com/forums/forum/266-challenger-650/