Issue link: http://itf.uberflip.com/i/237831
the on-court officials for that match and such determinations are binding on the players and ITF Supervisor/ 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". 1 Player Appeal A player may never appeal a determination on a Question of Fact to the ITF Supervisor/Referee. 2 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. a 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 wrong beyond any reasonable doubt. Chair Umpires should never make an overrule on a ball that is a close call. 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. To overrule an "Out" or "Fault" call by a Line Umpire, the Chair Umpire must have seen the ball land on or inside the line. Clear foot faults not called by a Line Umpire shall be called by the Chair Umpire consistent with the procedures for handling clear mistakes. b 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 a player. 3 Ball Mark Inspection Procedures a Ball mark inspections can only be made on clay courts. b A ball mark inspection requested by a player (team) shall be allowed only if the Chair Umpire cannot determine the call with certainty from his/her chair on either a point-ending shot or when a player (team) stops playing the point during a rally (returns are permitted but then the player must immediately stop). c When the Chair Umpire has decided to make a ball mark inspection, he/she should go down from the chair and make the inspection himself. If he/she does not know where the mark is, he/she can ask the Line Umpire for help in locating the mark, but then the Chair Umpire shall inspect it. 9