9903.03.16 Explained: Section 338 Canada Civil-Aircraft Exemption

HTS 9903.03.16 is an exemption heading within the Section 338 Canada tariff program. It applies to civil-aircraft articles that qualify under General Note 6 (GN6), as specified in U.S. note 51(d), and it carries zero percent additional duty. Importers and brokers shipping Canadian-origin civil-aircraft parts or components covered by GN6 must claim this heading on entries filed on or after August 19, 2026, to preserve the exemption.

What the Section 338 Canada Program Is

Section 338 is a trade-action program established under Proclamations 11046 through 11048. The program creates a set of Chapter 99 headings, 9903.03.12 through 9903.03.16, that govern additional duties on specific Canadian goods. Each heading in that range targets a distinct product category or, as in this case, carves out an exception to additional duties for qualifying goods. These codes are separate and distinct from the earlier Section 122 block (9903.03.01 through 9903.03.11), which carried different rates, a different legal basis, and different sunset rules. Never confuse the two.

The legal authorities for 9903.03.16 are Proclamations 11046, 11047, and 11048, together with U.S. note 51(d) to Chapter 99 of the HTSUS. The facts in this article reflect data as of August 5, 2026.

What 9903.03.16 Covers

The official heading text reads: "Exception: GN6 civil-aircraft articles per U.S. note 51(d) - claim-based, no additional duty."

• Product scope: Civil-aircraft articles that qualify under General Note 6 of the HTSUS.
• Claim-based: The exemption is not automatic. The importer must affirmatively claim this heading on the entry to obtain the zero-duty benefit.
• No additional duty: A valid 9903.03.16 claim results in zero percent additional duty under the Section 338 Canada program.

If you are unsure whether your specific civil-aircraft articles qualify under GN6, confirm the classification with your customs broker or attorney and review U.S. note 51(d) in the current HTSUS. The facts block for this article does not detail every product covered by GN6, so do not rely solely on this article to make that determination.

Effective Date and Entry Timing

This heading takes effect on August 19, 2026. As of August 5, 2026, that date is still in the future. Key practical points:

• Entries filed before August 19, 2026 are not covered by 9903.03.16 and cannot claim it.
• Entries filed on or after August 19, 2026 are eligible to carry the claim, provided the goods meet the GN6 civil-aircraft definition and U.S. note 51(d) requirements.
• Plan your shipment schedules and broker instructions accordingly so the claim is ready the day this heading goes live.

How 9903.03.16 Appears on a Customs Entry

Chapter 99 codes never stand alone on an entry. The mechanics work like this:

1. The imported goods are classified in their regular Chapter 1-97 HTSUS heading, which determines the standard column 1 or column 2 duty rate.
2. The Chapter 99 code, 9903.03.16, is added as a secondary line on the same entry to invoke the Section 338 Canada exemption.
3. CBP reads the combination: the base chapter rate applies from the Chapter 1-97 line, and the Section 338 additional duty is zero because of the 9903.03.16 claim.

Because the claim is importer-asserted, documentation supporting GN6 qualification should be retained in your entry records. For a broader look at how Chapter 99 codes interact with 2026 tariff actions, see our 2026 tariff code overview.

For context on other Section 338 Canada codes in the same block, see our companion articles on 9903.03.12 (Canadian alcohol, 50% rate) and 9903.03.14 (Canadian motor vehicles).

Stacking with Other Duties

9903.03.16 exempts the importer from the Section 338 Canada additional duty only. It does not affect:

• The standard HTSUS column 1 (MFN) rate on the Chapter 1-97 classification line.
• Any other Chapter 99 additional duties that may apply to the same goods under separate trade actions (for example, Section 232 duties, if applicable to your product).
• Harbor maintenance fees, merchandise processing fees, or other CBP-assessed fees.

Verify with your broker whether any other Chapter 99 codes apply to your specific goods on the same entry, and whether those separate programs have their own exemption or exclusion mechanisms. The USITC HTS online tool is the authoritative source for the current text of U.S. note 51(d) and General Note 6.

Record-Keeping and Correction Posture

Because this is a claim-based heading, CBP can request documentation to verify that your goods genuinely qualify as GN6 civil-aircraft articles. Keep your supporting records, including supplier certifications, bills of materials, and airworthiness documentation, organized and accessible. If you file entries before August 19, 2026 and later wish to amend them once the heading is live, consult your broker about the appropriate correction vehicle; post-summary corrections have their own processing rules.

What Importers Should Do

• Confirm GN6 eligibility now. Review U.S. note 51(d) and General Note 6 in the current HTSUS with your broker or trade counsel before August 19, 2026 to determine whether your civil-aircraft articles qualify.
• Update broker instructions in advance. Brief your customs broker to add 9903.03.16 as a secondary line on all qualifying entries filed on or after August 19, 2026. Entries filed before that date are not covered.
• Gather and retain claim documentation. Collect supplier certifications and other evidence of GN6 civil-aircraft status before shipments arrive, so the claim is supportable if CBP requests records.
• Check for stacking duties. Confirm with your broker whether any other Chapter 99 additional duties apply to the same goods and whether separate exemptions or exclusions exist for those programs.

This article is general information, not legal advice.