I have RTL_autoland set to 2, so that the plane will find this do_land_start marker and fly there instead of home. It seems like DO_LAND_START is simply a flag/marker rather than a waypoint. i.e. the plane will fly to the waypoint after do_land_start, not do_land_start itself. This is understandable. However, what about altitude ? The plane will use ALT_HOLD_RTL, which is the target altitude above home for RTL mode. However, since we are not returning to home, this altitude is not the most appropriate.
Shouldn’t we allow DO_LAND_START to have an altitude parameter? Or at least use the next-waypoint altitude after do_land_start, instead of using ALT_HOLD_RTL.