UK government representatives insist they will work to defend jobs in Bombardier's Northern Ireland facility following the adverse US ruling over the Canadian airframer's CSeries jet.
Prime minister Theresa May's office states that it is "bitterly disappointed" by the initial ruling by the US Department of Commerce, which found that the CSeries received "countervailable subsidies" of just under 220%.
The decision is subject to final consideration by the Department of Commerce and the US International Trade Commission.
If the ruling is confirmed, and CSeries imports are found to "threaten material injury" to the US aircraft industry, a final countervailing duty order will be issued on 8 February next year.
"Subsidisation of goods by foreign governments is something that the Trump administration takes very seriously," says secretary of commerce Wilbur Ross.
"We will continue to evaluate and verify the accuracy of this preliminary determination."
Boeing has driven the US government's investigation into the CSeries, which competes in the 100- to 150-seat sector.
The Department of Commerce says it will "instruct" US customs authorities to collect cash deposits from importers of aircraft in this range based on the subsidy rate calculated – effectively trebling the price of the CSeries to US customers.
Bombardier's plant in Belfast produces a range of aerostructures but, crucially, builds the wings for both variants of the CSeries, the CS100 and CS300.
"The government will continue to work with the company to protect vital jobs for Northern Ireland," says the prime minister's office.
Delta Air Lines' order for 75 CSeries jets last year triggered the Boeing complaint and the subsequent investigation.
Source: Cirium Dashboard