The Liberal government says it will begin the process of buying 18 Boeing Super Hornet jet fighters to meet what it deems to be the urgent needs of the air force, but was unable to say Tuesday when the aircraft will be purchased and how much they will cost.

In addition, Defence Minister Harjit Sajjan announced the Trudeau government will launch a full-fledged replacement program for the entire existing fleet of CF-18s before the end of the end of its term in three or four years.

He promised an "open and transparent competition" to replace the aging fighters — purchased in the 1980s — and said the decision must be guided by the country's defence needs, which are still being formulated.

"The competition for a permanent fleet will be informed by the outcomes of the defence policy review next year," Sajjan said.

Significantly, he added that the competition will produce "a new fleet that will be fully operational in the late 2020s," which pushes the transition to new jets further into the future than the former Conservative government had planned. The previous government had planned to stop flying the current fleet by 2025.

"That means we must continue to fly the legacy CF-18s throughout the 2020s, no matter what," said Sajjan.

Late Tuesday, in an interview with CBC Radio's As It Happens, Sajjan said the old fighters might be required to keep flying until 2032.

Public Works Minister Judy Foote said the planned competition will ensure that the country gets the right fighter jet at the right price, but it could take as long as five years to prepare and run. That is despite multiple consultations with industry and an exhaustive, independent panel review conducted under the Conservatives.

The urgent, sole-source purchase of Super Hornets is intended to cover what Sajjan says is a growing "capability gap" where Canada is strained to meet all of its NATO and North American air defence commitments.

The government plans to enter into discussions with the U.S. government and Boeing immediately to acquire the jets, but Sajjan would not say how long it will take, nor how much each plane might cost. ​

Cabinet approves plan

The decision to sole-source is controversial, the kind of arbitrary political move the Liberals railed about when the former Conservative government essentially promised to do the same thing with the F-35 stealth fighter.

Cabinet met today and gave its blessing to the plan.

The Liberals have struggled since coming to office on how to deal with the toxic political legacy of the F-35 debate, which played out over many years with the former Harper government.

Prime Minister Justin Trudeau promised during the last election not to buy the Lockheed Martin-manufactured stealth fighter.

The Conservatives had put the F-35 program on hold in 2012 after a scathing report by the auditor general, who accused National Defence and Public Works of understating the enormous lifetime cost and not doing their homework.

Sajjan first floated the notion of an urgent "capability gap" last spring, but the concept has remained ill-defined.

The country's chief of defence staff said Tuesday there is a fear that with a dwindling number of serviceable jets the air force might not be able to meet unforeseen events, such as a Sept. 11-style attack, which tested the country's air defences.

'Interim purchase'

The idea of an "interim purchase" of Super Hornets was also raised as a possibility last spring by anonymous sources, but savaged by critics who suggested it amounted to nothing more than the flip side of the Conservative F-35 plan.

Sajjan has insisted the capability gap is not "fiction" as the Conservative opposition has suggested.

But that stands in contrast to testimony last spring before a House of Commons committee by the commander of the air force.

Lt.-Gen. Mike Hood told MPs he was confident, based upon available information, that the air force had enough capacity to carry out its duties with the existing CF-18s until 2025, as long as $400 million in upgrades promised by the Conservatives were carried out and that the Liberal government made a decision on a replacement within five years.

Upgrades to the structure of the CF-18s have been continuing for years, and to date 28 fighters have received improvements, but the full-blown life-extension is still in "options analysis" phase by the air force.

Former defence procurement official Alan Williams said he doesn't understand why there is a delay in a full competition.

"We had certainly expected to have replacements in 2018-20. Now we're talking about another decade," he said.

"Given all of the work that's gone on in the last six-seven years, at least. Within one year you could have selected a winner."

It was the Liberals who tied Canada into the development of the F-35 back in the late 1990s, and the complex defence-industrial partnership has seen $825 million in contracts awarded to Canadian aerospace firms — agreements that Lockheed Martin suggested could be in jeopardy if the federal government shopped elsewhere.

However, timing is everything, and the Liberals recently launched the competition to replace the country's frigates, a multibillion dollar program that in its totality dwarfs the fighter jet procurement.

Lockheed Martin is one of the competitors in the warship bid and will have to carefully measure its response to the sole-source to its Boeing rival, which it did on Tuesday.

The U.S. defence giant says it recognizes the decision to buy Super Hornets is an interim measure.

"Although disappointed with this decision, we remain confident the F-35 is the best solution to meet Canada's operational requirements at the most affordable price, and the F-35 has proven in all competitions to be lower in cost than fourth-generation competitors," said the statement.

"The F-35 is combat ready and available today to meet Canada's needs for the next 40 years."