Originally Posted by NewbieRunner

The only way to go from a B bus gate to a Z gate without using the Skyline train that I am aware of is to go through passport control, walk through the terminal landside, then go through security and passport control into Z. How long it will take depends on the length of queues at passport control in B and security in Z, but you should have enough time if that's your concern.

Flights from ABZ seem to arrive at A or B bus gates. If arriving at an A bus gate simply go up the escalator and through security at the top. However, for the last few days at least LH975 arrived at a B bus gate, and it's either the Skyline train or passport control twice.