OTTAWA —  The air force has finished the first phase of a costly program to modernize 80 of its CF-18 jets, even as it ponders how to replace them in 10 years or so.

The CF-18s are 20 years old and the double-barrelled, $2.3-billion update program will give them a lease on life to about 2017.

The first phase of the program, just completed, keyed on electronics. The planes were given a new radar system, jam-resistant radios known as "Have-Quick,'' new computers and navigation systems and an updated transponder which identifies the planes as friendly to allied radar systems.

In the aftermath of the 1999 Kosovo bombing campaigns, there were fears that the outdated radios and radars on the CF-18s would make it impossible for them to fly alongside American and allied aircraft.

The solution was to sign on to a program designed by the U.S. navy to upgrade its own F-18 jets. This first phase took five years.

The second stage, to run until 2009, will install new data-link communications systems and provide a helmet-mounted display so pilots don't have to look down at their instruments.

The pilots will also get an improved electronic warfare system to deal with modern anti-aircraft missiles.

Other improvements, not formally included in the two-stage upgrade program, include structural strengthening.

The planes were also equipped to fire a new weapon, the advanced, medium-range, air-to-air missile, known as AMRAAM.

Once the whole upgrade project is finished, the air force expects to have state-of-the-art aircraft good until 2017.

Lt.-Gen. Steve Lucas, commander of the air force, said the project will ensure the CF-18 will remain "fully interoperable with coalition forces and provide the flexible and precise air power that is needed in the fight against terrorism and in national sovereignty operations.

"With the completion of Phase II, the CF-18 will be able to conduct a full range of combat operations well into the future.''

The question is, then what?

When the air force bought its 138 CF-18s between 1982 and 1988, they were up-to-date war planes whose design dated back to the mid-1970s.

Over the years, accidents and wear and tear have whittled away at the fleet.

It lost 17 in crashes, three were sold and about 20 others simply wore out.

There was money to modernize 80 planes; 62 single-seaters and 18 two-seat trainers.

The debate on their replacements is already under way in air force circles.

There are some analysts who argue it's time for Canada to give up air combat capability.

In 2001, New Zealand decided not to purchase new war planes, saying they were never likely to be used and the costs were unsustainable.

But New Zealand has 4.1 million people and covers 267,000 square kilometres. Canada has 32 million people and stretches over 9.9 million square kilometres.

Some have argued that by the time the CF-18s are ready for the scrap yard, technology will be sufficiently advanced to allow unpiloted robot drones to replace combat planes. They would be cheaper to operate and would keep humans out of the line of fire.

Paul Manson, a retired chief of the defence staff and now head of the Conference of Defence Associations Institute, was director of the program which eventually selected the CF-18s in the 1980s.

He says the idea of using robots is a pipe dream.

"With the best of computers, with the best of intentions, the human cannot be taken out of the system,'' he said. The ability of the human pilot to be on-the-spot and making the decisions is vital.

There are other options. The United States is pushing the joint strike fighter project, which has enlisted a number of allied countries, including Canada, in the development of what is known as the F-35. Canada has spent more than $300 million on the project, which is supposed to produce the standard, next-generation fighter plane.

There are other potential candidates for CF-18 replacements, including a new Eurofighter or even new Russian jets.

Manson, a fighter pilot himself, isn't picking among the candidates, but he does say there must be a replacement. Canada can't give up air combat.

"My personal opinion, based on 50 years of experience, is that Canada would make a very serious mistake if we opted out of the high-performance, fighter-type aircraft a decade from now,'' he said.

"We would be giving up one of the fundamental roles of the armed forces.''

He said it would be akin to the navy abandoning warships or the army disbanding its fighting units.

The air force is debating the whole complex issue of how to replace the CF-18s now and it's not a minute too soon, given the long lead times to buy items like planes, Manson said.

"Within a relatively short period of time, Canada is going to have to make a decision.''

For a 2017 delivery date, the decision will have to come by 2010 at the latest.