I've seen a few Chinooks come back from flights missing aft landing gear. You fly it like a Blackhawk and it's possible to break them off. Depending on how the landing continues, obviously a rollover is a real possibility, though none of our incidents ended up that way.
One of the better write-ups came from one of these incidents: "Aft left landing gear took first and second dunes allright, could not handle third"
Mike