Section 249.3 - Preservation of records(a) All records listed in §§ 249.20 and 249.21 may be preserved on either paper or nonerasable microfilm (see § 249.4 ) . However, a paper or microfilm record need not be created to satisfy the requirements of this part if the record is initially prepared in a machine-readable medium such as punched cards, magnetic tapes, and disks. The records maintained in machine-readable media and the underlying data used in their preparation shall be preserved for the periods prescribed in §§ 249.20 and 249.21 . A paper or microfilm record shall not be destroyed after transfer to a machine-readable medium before expiration of the prescribed period: however, a waiver permitting the early destruction of paper or microfilm records transferred to a machine-readable medium may be granted by the Director, Office of Airline Information, when it is demonstrated by the requesting carrier that the substantive purpose of the retention requirement will be met by retention of the information in machine-readable form (see § 249.10 ) .(b) Each record kept in a machine-readable medium shall be accompanied by a statement clearly indicating the type of data included in the record and certifying that the information contained in it is complete and accurate. This statement shall be executed by a person having personal knowledge of the facts contained in the records. The records shall be indexed and retained in such a manner so that they are easily accessible, and the carrier shall have the facilities available to locate, identify and reproduce the records in readable form without loss of clarity. Authorized representatives of the DOT shall be given immediate access to the carrier's facilities upon request.(c) If any record which must be retained under the provisions of §§ 249.20 and 249.21 is included as an exhibit to another document which must also be retained, the carrier need only keep in its files one copy of the record to satisfy these record retention requirements. In these cases, the carrier shall establish adequate cross-references to assist in locating the record.(d) The provisions in this part do not excuse noncompliance with requirements of any other governmental body, Federal or State, prescribing longer retention periods for any records.ER-1214, 46 FR 25415, May 6, 1981, as amended at 60 FR 66725, Dec. 26, 1995