Ottawa has halted a $1.6-billion upgrade that would extend the life of Canada's fleet of Aurora patrol aircraft, CBC News has learned.

The 30-year-old Aurora fleet may be replaced with new planes.
(CBC)

The Department of National Defence has already spent more than half of the budget of the planned 10-year overhaul — adding $1 billion worth of new equipment, such as navigation systems and flight data recorders, to the 18 planes.

Defence Minister Peter MacKay on Thursday confirmed DND is considering winding down the 30-year-old fleet and replacing it with new planes.

"We want to make sure we have planes that can fly safely, planes that can continue to play an important role in surveillance," said MacKay.

The fleet monitors Canada's coasts, watching for illegal fishing, polluters, drug smugglers and foreign vessels challenging Canada's sovereignty.

Critics say Ottawa shouldn't waste the many millions of dollars already spent on upgrades.

"What kind of plane might replace the Aurora? Is it one that's going to be more costly or less costly? So at this point I think we have a lot of unanswered questions," said John Williamson, federal director of the Canadian Taxpayers Federation.

NDP MP Joe Comartin said he thinks the federal auditor general should be involved in this kind of decision.

"There has to be accountability found," he said.

Retired air force pilot Terry Wiseman said replacing the fleet will take years. In the interim, the Auroras will continue to age without the upgrades necessary to continue patrolling as often as they should.

"As the Aurora is allowed to atrophy, its capabilities are allowed to atrophy, we're concerned that we will be deaf, dumb and blind in our northern regions," said Chester.

The Department of National Defence says it will make a decision by Nov. 20 on whether to replace the Auroras. Ottawa could face financial penalties if the hundreds of millions of dollars in contracts is cancelled.