Issue link: http://itf.uberflip.com/i/536583
14 U. ON-SITE DECISIONS AND APPEALS 1. Questions of Fact A Question of Fact is defined as an issue relating to what actually occurred during a specific instance. Questions of Fact arising during a match shall be determined by the on-court officials for that match and such determinations are binding on the players and Referee. A player may request verification by the Chair Umpire of a call or other determination of fact on a point-ending call made by an on-court official. The request, verification and resumption of play must all be completed within the twenty (20) seconds allowed between points, unless the Chair Umpire determines that an extension is necessary. If an extension is granted it shall be concluded with the announcement "Let's Play". a. Player Appeal A player may never appeal a determination on a Question of Fact to the Referee. b. Overrule The Chair Umpire may overrule a Line Umpire only in the case of a clear mistake by the Line Umpire and only if the overrule is made promptly after the mistake is made. i. Clear Mistake It is difficult to define a "Clear Mistake" any more precisely. As a matter of practice the Chair Umpire must be in a position to make a determination that a call was erroneous beyond any reasonable doubt. Chair Umpires should never make an overrule on a ball that is a close call. As a practical matter, to overrule a ball determined "good" by a Line Umpire, the Chair Umpire must have been able to see a space between the ball and the line. Likewise to overrule an "Out" or "Fault" call by a Line Umpire, the Chair Umpire must have seen the ball hit on or inside the line. ii. Promptly The Rules of Tennis requires in addition to a "Clear Mistake" that the Chair Umpire must overrule promptly, i.e. immediately after the Line Umpire makes the Clear Mistake. The overrule call must be made almost simultaneously with the Clear Mistake of the Line Umpire. A Chair Umpire may never make an overrule as a result of a protest or appeal by a player. A Line Umpire may never change a call as a result of a protest or appeal by the player.