Section 343.5 - Rules of evidence; impeachment of own witness by proof of prior contradictory statement1. When, upon examination by the party who called him, a witness in a delinquency proceeding gives testimony upon a material issue of the case which tends to disprove the position of such party, such party may introduce evidence that such witness has previously made either a written statement signed by him or an oral statement under oath contradictory to such testimony.2. Evidence concerning a prior contradictory statement introduced pursuant to subdivision one may be received only for the purpose of impeaching the credibility of the witness with respect to his testimony upon the subject, and does not constitute evidence in chief.3. When a witness has made a prior signed or sworn statement contradictory to his testimony in a delinquency proceeding upon a material issue of the case, but his testimony does not tend to disprove the position of the party who called him and elicited such testimony, evidence that the witness made such prior statement is not admissible, and such party may not use such prior statement for the purpose of refreshing the recollection of the witness in a manner that discloses its contents to the court.N.Y. Family Court Law § 343.5