The problem when designing the solo behaviour was to find something acceptable for all airports without asking the user to manually program local rules at every new airport, when they could be inferred from the taxiway layout or reasonably approximated. All of it with extremely noisy data: taxiways missing, lack of apt.dat conventions for names or of spec for various features like stop lines... For the H/O to TWR, aircraft must also report ready for departure before TKOF clearance can be expected, which had to be somewhere ATC-pie could guess the taxi route for line-up without tedious implementation only for local exceptions.
I remember it being an interesting challenge, but not an easy balance to strike. The present compromise is: GND hands over to TWR when aircraft is ready, which is only reported by ACFT if it knows its departure RWY and is near its first half.
So of course there would be many possible adjustments but the following statement is in theory incorrect.
LoCall wrote in Thu Jul 08, 2021 12:07 am:GND have to instruct plane to "enter the plane on the RWY / line up " then he become able to handover to TWR" ...
If you bring the ACFT near enough it should report ready for DEP without your having to taxi it onto the runway.