Dispute about having level playing field, says Boeing
Bombardier has accused rival Boeing of "hypocrisy" in their ongoing bitter dispute.
The two have been locked in a dispute after Boeing called in US authorities to investigate if the Canadian firm has been given an unfair advantage in selling its C Series jet - which is made in apart in Belfast.
The complaint was brought to the fore over Delta Airlines ordering the Canadian company's new jet for its fleet.
Boeing has said it was seeking "to restore a level playing field in the US single-aisle airplane market".
So far Bombardier has only said its Belfast operation is crucial to the C Series programme. The company is Northern Ireland's biggest employer in the manufacturing industry and thousands of jobs in Belfast have been caught in the middle of the row.
On Monday evening, bombardier released a statement on Boeing's "hyprocrisy".
"Bombardier shares Boeing's commitment to a level playing field, but in this case, they were not even on the field," it said.
"Delta ordered the C Series because Boeing stopped making an aircraft of the size Delta needed years ago.
"It is pure hypocrisy for Boeing to say that the C Series launch pricing is a 'violation of global trade law' when Boeing does the same for its new aircraft.
No-one is saying Bombardier cannot sell its aircraft anywhere in the world. Boeing
"Boeing's self-serving actions threaten thousands of aerospace jobs around the world, including thousands of UK and US jobs and billions of purchases from the many UK and US suppliers who build components for the C Series.
"The US government should reject Boeing's attempt to tilt the playing field in its favor and impose an indirect tax on the US flying public through unjustified import tariffs."
In response, Boeing said the C Series had been offered in America at "absurdly low prices".
"This is a classic case of dumping and it was made possible by a major injection of public funds," it said.
"This violation of global trade law is the only issue at stake at the US International Trade Commission - one sale in the US at a price millions lower than Bombardier is charging in the Canadian market.
“No-one is saying Bombardier cannot sell its aircraft anywhere in the world. But sales must be according to globally-accepted trade law, not violating those rules seeking to boost flatlining business artificially."
Boeing values its 80-year partnership with the UK. Boeing
Boeing has highlighted how other aircraft makers have made similar complaints against Bombardier. Brazilian aerospace conglomerate Embraer asked the World Trade Organisation to intervene over subsidies given to Bombardier.
"Accusations that Boeing receives billions in subsidies are not just false but have been proved to be so by WTO rulings," Boeing continued in its statement.
“Boeing values its 80-year partnership with the UK. We have doubled our own direct employment in this country since 2011 and have tripled direct spending with the UK supply chain over the same period, to more than £2 billion in 2016.
"Indeed, just last week Boeing broke ground for its first factory in Europe, in Sheffield. We are pleased to work with the government and provide such a vote of confidence in the UK.
"We all have a duty to ensure that global trade rules are respected around the world to deliver long-term benefits to all in the aerospace sector, which employs around 100,000 people in the UK. More than 16,500 of these employees work in Boeing’s direct UK supply chain and we are proud to work with them.
"We all have a shared interest in a level playing field. That is what this dispute is about.”
The matter has been raised at the highest levels. PM Theresa May has raised the matter with US President Donald Trump and intends to do so again. Canadian premier Justin Trudeau has even hinted at his government pulling military contracts from the firm.
And the matter has brought together DUP leader Arlene Foster and Sinn Fein leader Michelle O'Neill who wrote a joint letter to the US Vice President over the matter.
The US Department of Commerce is expected to announce a decision on whether to impose duties against Bombardier on September 25. Should it find against Bombardier it could impose financial penalties.