We believe the trial court erred in excluding interrogatories and answers thereto as to the policy of Boca Aviation, Inc. to require certain minimum flying experience on the part of persons renting its aircraft. Reese v. Seaboard Coastline Railroad, 360 So.2d 27 (Fla. 4th DCA 1978), cert. dismissed, 366 So.2d 884 (Fla. 1978). Because there is evidence that this policy was violated and that the violation may have had some causal connection to the accident in question, we cannot conclude that the error was harmless. Accordingly, we reverse and remand for a new trial.