One day after Boeing filed its formal trade complaint against Montreal-based Bombardier, Australia was knocking at Canada's door wondering if the Trudeau government was interested in buying used fighter jets, newly released documents show.

Australia's military sales office sent a letter, dated April 28, 2017, through Australia's defence attache in Ottawa "requesting an expression of interest" from Canada for "the purchase of surplus F-18" warplanes, said a written response, recently tabled in the House of Commons, to a question posed by the Opposition Conservatives.

When the letter arrived the ink was barely dry on Chicago-based Boeing's incendiary trade complaint, which was filed with the U.S. Commerce Department on April 27, 2017.

At the time, the Trudeau government had been on track to purchase 18 brand new Super Hornet jet fighters from Boeing.

Defence Minister Harjit Sajjan was evasive on Tuesday about whether a formal decision had been made to scrap the Boeing deal in favour of the Australian plan.

He wouldn't confirm a report by the Reuters news agency, citing three sources, which said an announcement giving the green light to the used jets would be made next week.

"I look forward to making the announcement at the appropriate time," Sajjan said following question period.

The documents tabled in Parliament draw into question long-standing Liberal talking points, which insist that they have — from the outset — considered all options when it comes to providing the air force with stopgap fighters.

A timeline, which details the interaction between Australia and Canada, shows clearly that interest in the used F-18 "classic" Hornets did not get started until after the proposed deal with Boeing — worth $6.3 billion — began to fall apart.

U.S. approval

The Liberals, according to their Order Paper Question response, were expecting a cost proposal from the government of Prime Minister Malcolm Turnbull "by the end of December," but any agreement would still require approval by the U.S. State Department.

That's because the fighters, which are the same age as Canada's CF-18s, were originally exported by the United States.

Scrapping the Boeing deal would not come as a complete surprise.

Since last spring, a parade of federal politicians all of the way up to the prime minister have gone out of their way to emphasize that Boeing is no longer a trusted partner and that Canada wouldn't be doing business with it.

In the fall, the U.S. Commerce Department backed Boeing in its challenge of Bombardier and recommended enormous import tariffs and duties totaling nearly 300 per cent on sales of the Canadian aerospace manufacturer's CSeries passenger jet.

An announcement next week scrapping Canada's deal with Boeing could very well be politically calibrated by the Liberals because the U.S. International Trade Commission is slated to hold hearings on Dec. 18, one of the last steps before import duties are finalized.

Scathing assessment

A bevy of Australian air force and defence officials, including their director of aerospace equipment, have weighed in on the possible Canadian purchase, providing a large cache of technical reports on the old jets.

Among the records sent to Canada is a "brief history of fatigue cracking" on the fighters, which were originally purchased between 1984 and the early 1990s. Such reports are critical in light of the Australian government's own reports.

That country's defence materiel group produced a scathing 2012 assessment that noted that the "classic" Hornets were rapidly running out of airframe life and required bigger and bigger slices of the maintenance budget.

"The incidence of discovery of airframe corrosion in the Hornet fleet is increasing, and the annual cost of corrosion‐related repairs has increased significantly," said the report, which CBC News reported on in October.

The Australians are phasing out their FA-18s because they intend to buy Lockheed Martin-built F-35s, a purchase which Canada's Liberal government vowed not to make in the last election.