19 CFR § 122.49 - Correction of air cargo manifest or air waybill.
(a) Shortages -
(iii) On a copy of the cargo manifest, which shall be marked “Shortage Declaration,” and must list the merchandise involved and the reasons for the shortage.
(i) Shortage merchandise was not imported, or was properly disposed of; or
(b) Overages -
(i) On a Customs Form 5931; or
(ii) On a separate copy of the cargo manifest which is marked “Post Entry” and lists the overage merchandise and the reason for the overage.
(3) Evidence. Satisfactory proof of the reasons for the overage shall be kept on file by the carrier for one year from the date of the report.
(c) Statement on cargo manifest. If the air cargo manifest is used to report shortages or overages, the Shortages Declaration or Post Entry must include the signed statement of the aircraft commander or agent as follows:
I declare to the best of my knowledge and belief that the discrepancy described herein occurred for the reason stated. I also certify that evidence to support the explanation of the discrepancy will be retained in the carrier's files for a period of at least one year and will be made available to Customs on demand.
(d) Notice by port director. The port director shall immediately notify the aircraft commander or agent of any shortages or overages that were not reported by the aircraft commander or agent. Notice shall be given by sending a copy of Customs Form 5931 to the aircraft commander or agent, or in any other appropriate way. The aircraft commander or agent shall make a satisfactory reply within 30 days of entry of the aircraft or receipt of the notice, whichever is later.
(e) Correction not required. A correction in the manifest or air waybill is not required if:
(1) The port director is satisfied that the difference between the quantity of bulk merchandise listed on the manifest or air waybill, and the quantity unladen, is the usual difference caused by absorption or loss of moisture, temperature, faulty weighing at the airport, or other such reason; and
(2) The marks or numbers on merchandise packages are different from the marks or numbers listed on the cargo manifest for those packages if the quantity and description of the merchandise is given correctly.
(f) Statutes applicable. If an aircraft arrives in the U.S. from a foreign area with merchandise and unaccompanied baggage for which a manifest or air waybill must be filed, section 584 (concerning manifest violations), Tariff Act of 1930, as amended (19 U.S.C. 1584, applies.