Thank you for the answer, since I was able to make it work somehow, but I'm not sure how. I moved around the ramp starts a bit giving them more space. (but they never touched in the first place)
I used the art controls log_spawn, but the log only show that the airliners spawned in the air,, didn't get info on why.
debug_ramp_starts , the only thing I noticed is the debug marker on the ramp start position. is there any other info with this dataref I can use ?
On another airfield for GA aircraft only I was not able to make it work at all. It have ATC, ATC tower frequency ATC rutes ramp starts, taxiways , long and wide grass runway, but no aircraft spawn on the filed , just in the air, would be nice to debug it.