I thank you for your answer but I had already tried your solution and it does not work
Yes, it does. You are not pressing the keys correctly.
I even changed the number of exits to 6 and still nothing happens. So I started a new post not only to solve the problem with the B737-800 exits but also to learn how can I add more exits.
You still don't understand: the default 737-800 it's a SPECIAL CASE. It WAS modeled with 3 sets of doors ( main, cargo and emergency ) but the number_of_exists parameter in the aircraft.cfg was wrongly set to 2 instead of 3.
By setting it to 3, you only set it to the value it should have been, which is correct for ITS .MDL FILE.
NO other value will work, you just can't auto-magically creates exits from thin air, by simply changing the aircraft.cfg, in order to work an exit must be:
1) Modeled in the 3d model file of the airplane, the .MDL file
AND
2) Animated in the 3d model file
AND
3) Associated with a simulation variable, so the animations is controlled by that variable
AND
4) Active in the aircraft.cfg
An airplane needs to have ALL 4 STEPS completed.
The default 737-800 missed ONLY the 4th, that's why it was so simply to fix. You just can't apply the same magical trick on any airplane out there!!