As always BOAC is correct. Had the pleasure of marshalling a 737/200 off of stand about 4 years ago. It was based in Africa and the front gear had a particular pair of ski's connected to it for landing in dessert conditions, thus not allowing any towbar to be connected.
Don't really see much of that any more, all you get nowaday's is Ryanairs 737/200s using reverse thrust along the taxi ways to slow them down from 90kts taxi speed
S.C.
