Red is push one way,blue is generally the other way,and green is push and a tow forward on a limited pax stands.If the controllers says pushback red,blue,or push tow forward green,then the tug crew will push you to the tug stop point on the push back chart.On occasion you may get a, for example, pushback blue and extend the push to abeam Stand xxx.I used to use that so you could escape out of H8 for example,and get another push out of the Echo stands.The system basically came in when the airport opened on a single runway,and we had a stick to a ridged flow system on the taxiways.
The apron is a very bad design.Lord Foster may have made a nice terminal but the push system is the way it is because so many stands are crammed into the space.If you get 3 or more wanting start at the same time from adjacent stands,then the delays can be 20 plus mins as each a/c has to push to the same tug stop point.How I didn't get a nose to nose on that apron,was more luck than judgement.Then there were the Tows....Ahh
Ps Five Green,
The red ,blue can end up facing all direction depending where you are.The system was on the North,South,West,and Cargo aprons.Each stand had a specific tug stop point depending on the type of push.Very easy system which hardly went wrong.Just had to get the pilots to READBACK.
