In perhaps the most back-handed compliment one manufacturer can pay another, Boeing feels so threatened by the Bombardier CSeries that it has filed a formal complaint with the US government.

Mirroring a previous move by Embraer with the Brazilian government, Boeing accuses the Canadian manufacturer of exploiting billions in explicit government subsidies to sell commercial aircraft well below cost.

The complaint to the US International Trade Commission is Boeing’s opening salvo in a process that could lead to a case at the World Trade Organization.

Boeing’s grievance is not without supporting facts. Bombardier did receive loans from the UK and Canadian governments to launch the CSeries programme in 2008. It then obtained billions more in direct cash investments by the Quebec government to rescue the programme. Bombardier used its healed balance sheet to sell 125 CSeries aircraft to Air Canada and Delta Air Lines at a loss of nearly $500 million.

Strangely, Boeing attempts to embellish these facts with absurd claims, such as an unfounded accusation that Bombardier sold the 75 CS100s to Delta for $19.6 million each. Bombardier responds that such a figure is “millions” of dollars too low, and it is right. Such a price would have caused it to book a forward-loss provision of $930 million, rather than $500 million.

Boeing also makes questionable charges of damages, such as an alleged loss of the Delta order. But the Atlanta carrier ordered 110-seat CS100s – a model against which Seattle’s smallest narrowbodies do not compete.

The Boeing petition may also distort the fundamental commercial truth of the CSeries marketing plan. Quebec’s cash investment indeed saved Bombardier from certain bankruptcy, but it is not a blank cheque that will distort market prices forever.

In reality, Bombardier cannot afford to continue shifting CSeries aircraft at prices millions below market cost. At some point, the airframer must prove it can sell the CSeries for a profit or the product will fail. Unfortunately, the jury is still out. After last year’s orders windfall, Bombardier has not booked another CSeries deal in more than 12 months.

Moreover, Boeing is not in the best position to complain about unfair trade practices. The WTO ruled last November that the airframer benefits from an illegal tax break that is thought to be worth somewhere between $1 billion and $5.6 billion – in other words, about the same as Bombardier’s subsidies.