Most Oxfords in the UK were equipped with a knotted rope from the pilot's seat to the rear door to assist evacuation should the plane inadvertently be put into a spin, which it was almost impossible to recover from. When the pilot(s) released their seat belts centripetal force would hurl them to the rear of the plane, beyond the exit door, from which it was impossible to crawl forward to the door. The rope was installed as a response to a test by four "boffins" who tried to recover from a spin from 18,000 ft. When no recovery happened no matter what was tried the four released their harness and were hurled to the rear of their plane and there remained helpless as the spiral descent continued. However all was not lost. The plane was in such a flat spin when it reached the ground that it skidded sideways over the surface of a field until the tail section hit a haystack and broke off. The four "boffins" walked away relatively unharmed, the knotted rope being their only positive remedy for an Oxford in a spin.