The Collaborative International Dictionary of English v.0.48:

Guide rope \Guide rope\ (A["e]ronautics)
   A rope hung from a balloon or dirigible so as trail along the
   ground for about half its length, used to preserve altitude
   automatically, by variation of the length dragging on the
   ground, without loss of ballast or gas.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

guide rope
    n 1: a rope used to guide the movement of the load of a crane