The report by a panel of independent experts, part of a package of documents put before the federal cabinet last summer, warns that the aging jets should not be flown much past that date because that would pose an unacceptable, costly risk.
All of the research was done to help the Harper government decide whether to continue with the oft-maligned F-35 stealth fighter program, or hold an open competition.
"No decision has been made on the purchase of replacements for the CF-18s," Public Works Minister Diane Finley told the Commons prior to the release of both the panel report and an annual assessment of the cost of the F-35.
Earlier this year, Defence Minister Rob Nicholson's office announced the CF-18s would get life extension upgrades to keep them flying for another 11 years, but his department released no details on cost or risks.
The panel's analysis, which looked at four different fighter jets, found each is equally capable of meeting Canada's future needs, although both the Harper government and the air force have insisted for years that the F-35 was the only choice to replace the CF-18s.
There is a caveat in the review, however, which suggests the suitability depends on the kind of missions the government expects the planes to perform.
The report suggested it's unlikely Canada will face a state-to-state conflict in the future — one where a cutting-edge jet would make the difference — and even if it did “the government is not obliged to undertake such a mission.”
Keeping the current fleet in service and avoiding a political firestorm in the run-up to the next year's election seems to be the Conservative strategy, but the report is explicit on the risks.
In order to phase out the CF-18s by 2025 and ensure a smooth transition, the replacements will have to be chosen and begin arriving by 2020, the analysis said.
The federal government would need at least three years to run an open competition and placing an order for F-35s requires up to three years lead time, according to the jet's manufacturer, Lockheed Martin.
Liberal defence critic Joyce Murray says the transition period laid out in report suggests there could be shortage of jet fighters as individual aircraft fleets are swapped out.
By refusing make a decision, the government is not only paying for costly upgrades, it is opening up a possible capability gap, she said.
"The way to avoid that is to hold an open competition now," Murray said.
The NDP's Jack Harris said the government has had the reports for months but hasn't decided what to do.
"It hardly seems likely that a decision hasn't already been made," he said.
A second, separate report that keeps track of the F-35 program, released Wednesday, suggested if the government elects to proceed with the stealth jet, there's increasingly less wiggle room in the $9-billion budget set aside to buy 65 aircraft.
Continuing to postpone the decision carries increasing risk, the expert panel market analysis said.
"Beyond 2025, however, the operational relevance of the CF-18 will decline quite rapidly," said the panel.
Maintenance requirements will grow and the reliability of key systems and components will decrease as the aircraft age.
"This aging process increases the demand for spare parts and so drives up sustainment costs."
Further extending the life until 2030 is possible, but it would require an another $1.5 billion in major upgrades to the airframes.
"An estimated life expectancy of 2030 is technically feasible. However, it represents a far more risky endeavour," the report said. "This option would require the entire fleet to undergo significant structural refurbishment investments and procurement of wings and flight controls. This option is a high-risk one."
Some experts have suggested that Canada could follow Australia's lead and buy a handful of Boeing Super Hornets — the updated version of the CF-18 — and wait until the F-35 program works out its technical glitches or the Pentagon comes up with a new fighter program.
The panel rejected the notion of a mixed fleet.
"The analysis found that a mixed fleet of higher-capability aircraft able to fulfil the most challenging NATO missions and lower-capability aircraft able to fulfil Canada's NORAD obligations totalling more than 65 aircraft could not provide the same overall capability as the single fleet of 65 higher-capability aircraft," the report said.
"Moreover, there was strong evidence that unless the purchase cost of the fleet of lower-capability aircraft was half the purchase cost of the fleet of higher-capability aircraft, a mixed fleet would provide less capability at a higher cost."