As a qualified Jetbridge driver at LHR
, it is basically upto the jetbridge operator which door to use, although the airlines themselves have their own preferences.
At the airline I work for, the preference is to use door 2, but on some stands the bridge will not reach door 2, so we have to use door 1.
On dual jetbridge stands, again we will normally only use door 2 due to the fact that we are required to have a security guard positioned at the boarding door, and we would have to pay for another guard were we to use both bridges, although if one bridge is broken then we will use the other, but only on the 747 as in T3
, the fixed jetbridges cannot be used on other a/c types. Very rarely will we ever use 2 bridges, the only time we do is for offloading passengers on an extremely tight turn round, this is mainly due to the layout of the gates in T3
, and as I said before, the requirement to have a guard on the door.
On a/c with only 1 door forward of the wing, then obviously you would use that door.
"She Rolls, 45 knots, 90, 135, nose comes up to 20 degrees, she's airborne - She flies, Concorde Flies"