WASHINGTON — Canada on Tuesday issued a final solicitation for its much-hyped fighter competition, which will replace its fleet of aging CF-18s with 88 new jets.

Four vendors are expected to respond to the final request for proposals: Lockheed Martin, which is offering the F-35 Joint Strike Fighter; Boeing, which is putting forward the F/A-18 Super Hornet; Swedish plane manufacturer Saab with its Gripen E; and Airbus, which will propose the Eurofighter Typhoon.

Those companies will have two chances to submit bids, according to a news release by the Canadian government. A first “security” offer is due in fall 2019. Vendors will then be permitted to revise and resubmit their proposals in spring 2020.

Canada intends to award a contract in early 2022, with the first of the new fighters coming online as early as 2025. The program has an expected value of CA$19 billion (U.S. $15 billion).

"Our government is delivering on its promise to replace Canada's fighter jet fleet through an open and transparent competition,” said Carla Qualtrough, Canada’s procurement minister. “Today marks an important step in the process that will provide the women and men of the Royal Canadian Air Force with the aircraft they need to help ensure the safety and security of Canadians, at the right price and with the most economic benefit to Canada."

Harjit Sajjan, Canada’s minister of national defense, said it was “essential that we get the right equipment,” as the new jets will be used by the Royal Canadian Air Force for decades.

Each company’s bid will be evaluated on the basis of technical merit — which comprises 60 percent of the entrant’s score — as well as cost and economic benefits, each weighted at 20 percent.

“This procurement attributes one of the highest weightings to economic benefits for Canada in its history,” said Canada’s Public Services and Procurement department, which is responsible for military acquisition. “All suppliers will be required to provide a plan for economic benefits equal to the value of their proposed contract, with maximum points only being awarded to suppliers who provide contractual guarantees.”

This approach has been somewhat controversial among the potential bidders.

The U.S. government has argued Canada’s initial industrial requirements — which would have stipulated that companies guarantee workshare — would not allow the F-35 to compete, as international partners must bid for work on the F-35 program, with contracts going to the company that can provide the best value.

“We cannot participate in an offer of the F-35 weapon system where requirements do not align with the F-35 partnership," Vice Adm. Mat Winter said in a December 2018 letter, when he was the F-35 program executive.

Lockheed Martin has also made the case that Canada’s role as a partner in the program has led to economic benefits for the country, with Canadian companies having received more than $1.5 billion in contracts since the start of the program.

The Canadian government announced in May that it would take a more “flexible” approach to grading an offering’s economic benefit, with higher scores going to competitors that could guarantee workshare, the Ottawa Citizen reported.

The new criteria likely puts Lockheed at a disadvantage, but the company intends to bid.

“Lockheed Martin has received the final Request for Proposal for Canada’s Future Fighter Procurement Competition and we look forward to participating in the competition,” the company said in a statement Tuesday. “The F-35 is the most capable, best value fighter with significant, long-term industrial opportunities and as the competitive process continues, we are excited to share more about the F-35’s ability to strengthen defense, enhance ally partnerships and drive economic growth in Canada.”

Other companies appear less certain about participating in the competition.

On July 9, Reuters reported that Boeing and Airbus were considering dropping from the program due to perceived favoritism toward Lockheed. Both companies wrote letters to the Canadian government expressing their dissatisfaction about the decision to allow Lockheed to compete.

A spokeswoman for Boeing acknowledged that the company had seen the RFP but had not made a firm decision on whether it would move forward with the competition.

“At this point we can confirm we have received and are reviewing the request for proposal to determine if we’ll participate,” Boeing spokeswoman Andrea Peterson said in a statement Tuesday. “We appreciate Canada’s willingness to solicit feedback from Boeing and continue to believe the Super Hornet is the best choice for Canada’s defence and aerospace industry.”

In a statement to the Canadian Broadcasting Corporation, Airbus said it was carefully reviewing the RFP.

One major defense aerospace manufacturer has already pulled out of the competition. In November, France’s Dassault Aviation withdrew from the competition over extensive information-sharing requirements.