Originally Posted by
Pilot DAR
Certainly, freeplay in a flight control is an invitation to flutter (Jimmy Leeward's P-51 at Reno). When I have done dive testing in the GA airplanes I have flight tested, I have done very careful walk arounds checking for exactly that - nothing loose, no freeply.
It's a long time since I was in flight test and it was avionics not aero. However, I recall that Douglas Long Beach did flutter testing with specially installed control links that had maximimum allowed in-service slop (free play). A flutter test with zero free play links would not be representative of conditions experienced during the life of the airframe.