837.4—Other material.

(a) Production prohibited unless approved. Except in the case of the material referenced in § 837.3, no employee or former employee of NTSB shall, in response to a demand of a private litigant, court, or other authority, produce any material contained in the files of the NTSB (whether or not agency records under 5 U.S.C. 552) or produce any material acquired as part of the performance of the person's official duties or because of the person's official status, without the prior written approval of the General Counsel.