N.Y. FCT Law § 343.5

§ 343.5. Rules of evidence; impeachment of own witness by proof of\nprior contradictory statement. 1. When, upon examination by the party\nwho called him, a witness in a delinquency proceeding gives testimony\nupon a material issue of the case which tends to disprove the position\nof such party, such party may introduce evidence that such witness has\npreviously made either a written statement signed by him or an oral\nstatement under oath contradictory to such testimony.\n 2. Evidence concerning a prior contradictory statement introduced\npursuant to subdivision one may be received only for the purpose of\nimpeaching the credibility of the witness with respect to his testimony\nupon the subject, and does not constitute evidence in chief.\n 3. When a witness has made a prior signed or sworn statement\ncontradictory to his testimony in a delinquency proceeding upon a\nmaterial issue of the case, but his testimony does not tend to disprove\nthe position of the party who called him and elicited such testimony,\nevidence that the witness made such prior statement is not admissible,\nand such party may not use such prior statement for the purpose of\nrefreshing the recollection of the witness in a manner that discloses\nits contents to the court.\n