So… If controlling at London City for example and there are two aircraft taxiing to R27 what is the correct way to get them both to back taxi at the same time and turn off to the short taxiway at the end, holding short at that point. Or even if there is only one aircraft and simply I want him to back taxi and wait off the runway while an inbound lands before then instructing him to line up and wait.
There are only 2 ATC commends.
Back taxi, line up and wait - that’s ok if you want them to stay on the runway when they finish back taxi.
Back Taxi, Contact Ground when off the runway - that would sort of work as it indicates you want them to get off the runway when they get to the end, but why would they contact Ground. What would they request form Ground, what would Ground say to them other than asks them to contact Tower…?
Should there not be an option to back taxi, exit runway and hold short?
So I think you want to tell the first aircraft to back taxi and tell the second aircraft to hold short of RWY 27. When aircraft 1 takes off, give aircraft 2 permission to back taxi
You can tell both aircraft to “Back taxi runway 27, contact ground once off the runway.” Once they contact ground, ground will tell them to hold short runway 27.