9903.03.16 Explained: Section 338 Canada Civil-Aircraft Exemption

Key Points

• 9903.03.16 is a claim-based exemption heading within the Section 338 Canada program: it carries zero percent additional duty for qualifying goods.
• The official heading text reads: "Exception: GN6 civil-aircraft articles per U.S. note 51(d) - claim-based, no additional duty."
• The effective date is August 22, 2026; entries filed before that date cannot carry the claim.
• The scope covers Canada-origin goods across a range of underlying HTS lines effective August 22, 2026, with no announced end date. The facts block shows the first 40 in-scope lines; the full list may be longer, so confirm it in the current HTSUS.
• Legal authority rests on Proclamations 11046, 11047, and 11048, together with U.S. note 51(d) to Chapter 99 of the HTSUS.

On this page

1. What changed
2. What the Section 338 Canada program is
3. What 9903.03.16 covers and affected HTS lines
4. Effective date and entry timing
5. How 9903.03.16 appears on a customs entry
6. Interaction with other duties
7. Record-keeping and correction posture
8. Required actions for importers, brokers, and compliance teams
9. Key references

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 22, 2026 to preserve the exemption. The links in this article go to the primary documents: the proclamations, Federal Register notices, and official tariff schedule pages themselves. Read the source.

What changed

As of October 8, 2026, the facts for this heading have been reviewed. The article previously stated that 540 HTS lines were covered and identified specific newly added lines by number. The facts block as of October 8, 2026 shows the first 40 in-scope HTS lines; the data read is capped at 500 entries and the heading may carry more lines than shown, so no total count can be stated with confidence. References in the earlier version of this article to a count of 540 lines and to specific line numbers such as the 9104, 9401, 9403, 9405, 9620, 9802, and 9818 series have been removed because those figures are not confirmed in the current facts block. Everything else, the zero rate, the claim-based mechanics, the August 22, 2026 effective date, the legal authority, and the Canada-only country scope, remains accurate and unchanged.

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 that govern additional duties on specific Canadian goods. Each heading in the 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 earlier Section 122 block headings, which carried different rates, a different legal basis, and different sunset rules.

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.

What 9903.03.16 covers and affected HTS lines

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, imported from Canada.
• 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.
• Country scope: Canada only, for all covered lines, effective August 22, 2026, with no announced end date.

The facts block shows the first 40 in-scope underlying HTS lines, all Canada-origin, all effective August 22, 2026 with no announced end date. Those 40 lines include (among others): 3917.21.00, 3917.22.00, 3917.23.00, 3917.29.00, 3917.31.00, 3917.33.00, 3917.39.00, 3917.40.00, 3926.90.45, 3926.90.94, 3926.90.96, 3926.90.99, 4008.29.20, 4009.12.00, 4009.22.00, 4009.32.00, 4009.42.00, 4011.30.00, 4012.13.00, 4012.20.10, 4016.10.00, 4016.93.50, 4016.99.35, 4016.99.60, 4017.00.00, 4504.90.00, 4823.90.10, 4823.90.20, 4823.90.31, 4823.90.40, 4823.90.50, 4823.90.60, 4823.90.67, 4823.90.70, 4823.90.80, 4823.90.86, 6812.80.90, 6812.99.10, 6812.99.20, and 6812.99.90. The data read is capped and the heading may cover additional lines not shown here. Confirm the complete current list in the HTSUS online tool or with your broker.

If you are unsure whether your specific civil-aircraft articles qualify under GN6, review U.S. note 51(d) and General Note 6 in the current HTSUS directly.

Effective date and entry timing

This heading is effective August 22, 2026, with no announced end date. Key practical points:

• Entries filed before August 22, 2026 are not covered by 9903.03.16 and cannot carry the claim.
• Entries filed on or after August 22, 2026 are eligible, provided the goods meet the GN6 civil-aircraft definition and U.S. note 51(d) requirements.
• If you filed entries before August 22, 2026 claiming this heading in reliance on an earlier-published effective date, consult your broker about whether a post-summary correction is appropriate.
• No end date has been announced; monitor Federal Register and CBP notices for any future modification.

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. Use our duty calculator to model the impact on your landed cost.

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

Interaction 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 filed entries before August 22, 2026 and wish to amend them, consult your broker about the appropriate correction vehicle; post-summary corrections have their own processing rules and time limits.

Required actions for importers, brokers, and compliance teams

• Confirm the effective date. The operative date is August 22, 2026. If entries were filed before that date claiming this heading, review them with your broker for potential correction.
• Confirm GN6 eligibility. Review U.S. note 51(d) and General Note 6 in the current HTSUS to determine whether your civil-aircraft articles qualify.
• Check whether your HTS line is in scope. The facts block shows the first 40 covered lines; the full list may be longer. Verify your Chapter 1-97 classification against the current list in the HTSUS or with your broker.
• Update broker instructions. Brief your customs broker to add 9903.03.16 as a secondary line on all qualifying entries filed on or after August 22, 2026.
• 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.

Key references

• USITC Harmonized Tariff Schedule online - current text of 9903.03.16, U.S. note 51(d), and General Note 6
• White House proclamations - Proclamations 11046, 11047, and 11048 establishing the Section 338 Canada program
• Federal Register - implementing notices and any future modifications to Section 338
• U.S. Customs and Border Protection - CSMS messages and entry guidance on Chapter 99 claim headings
• CustomsGenius 2026 tariff code overview - how Chapter 99 codes interact with 2026 trade actions
• CustomsGenius duty calculator - model the landed-cost impact of the Section 338 Canada exemption