Ok, Thanks for the replies. It looks like most are agreed that it would not effect the flight too badly.

I was trying rule out some possible causes of a crash. My mate was flying as described in the first post the other day and he said whilst turning the plane it flipped on its back quickly but despite holding in right aileron the plane went out of control and no input seemed to make any difference. He shouted my name and as I looked up I just saw it go in. It trashed the plane but we checked every thing was working before we picked up the bits.

It range checked ok, battery is still good, but I noticed the clevis was out of the horn for the rudder. But it does now seem this happened in the crash considering every thing that has been said here.

I remember hearing him shut the throttle before it hit so we are probably looking at a short radio hit or some turbulence caught him out, tipped it over and possibly stalled the wing which he could not get out of. He did say that the plane slowed up before tumbling to the ground as he described it.