Originally Posted by
tow1709
Could it be a noise reason? Aircraft landing very early at LHR T4 (< 6am?) have to wait for a tug rather than taxi under their own power. Happened to me (SLF) several times inbound from Abu Dhabi on B767.
It sometimes can be due noise controls, and certainly some but not all of the LHR T4 stands are (or at least used to be) "tow on" during curfew hours due to the proximity of some stands to the south perimeter road.
OTOH most places if it's a "tow on" as others have said it's done when the parking is "tight", to avoid jet blast and/or supposedly
reduce the chances of clipping a wing tip...