HALIFAX - The Canadian officer who will oversee the first flights of Canada's new fleet of navy helicopters next year says the choppers currently can't pass an endurance test that requires them to fly for nearly three hours in extreme conditions.

"It (the helicopter) falls short of the endurance requirement as allowed under the revised contract," Col. Sam Michaud, commander of Nova Scotia's 12 Wing Shearwater airbase, said in an interview Tuesday.

The MH-92 Cyclone helicopter's original contract had specified that 28 choppers be delivered, at a rate of one per month, beginning in November 2008.

However, a revised contract announced last year allowed for the delivery of the helicopters to begin in November 2010, two years behind schedule. It also doesn't require the choppers to meet the 170-minute flying time until after the 19th helicopter has been delivered in 2012.

But Michaud said he's confident the Cyclones will satisfy the requirement, and that the aging fleet of Sea King helicopters can keep operating until then.

Still, he acknowledges there will be some limits -- such as shorter missions and the need to use more helicopters to perform the same mission -- until the endurance requirement is met.

"So right now, the issue with the interim maritime helicopters is they're having some challenges getting to that endurance number that we've asked for," said Michaud.

The base commander explained that the helicopter is heavier than originally expected, and as a result fuel is consumed more quickly.

"That's why the whole weight issue is a big one," Michaud said.

He said that's why the federal government requirement of flying two hours and 50 minutes in conditions where temperatures surpass 35 Celsius won't be met when the first choppers arrive.

Paul Jackson, a spokesman for Sikorsky, confirmed the interim maritime helicopter will be 10 to 20 minutes short of the 170-minute requirement.

But he said the company has little doubt it can achieve the federal government's performance requirements under the revised contract.

"Meeting the final configuration performance as required in the extreme conditions that this customer operates (in) is important," he said in an email.

"We do not consider weight as a big issue."

He added that the company will achieve the requirement by decreasing the aircraft's weight and improving the engine's power capabilities and transmission.

Lianne LeBel, a spokeswoman for the Defence Department, said the final helicopter will have "an enhanced version" of the engine as designed in the original Cyclone.

That engine will be designed to lift the 13,185 kilograms the helicopter is expected to weigh by 2012, LeBel said.

The federal government has already stated the new engines and other changes will add $117 million to the original $5-billion project cost.

It will be up to Sikorsky to determine how it meets the revised contract requirements, LeBel said.

"Sikorsky has the flexibility right now to design the helicopter to meet the requirements. So right now we have our specified requirements and it's up to Sikorsky to meet those requirements," said LeBel.

Michaud explained that when the helicopter's operation requirements were written in the 1990s, defence research experts determined the harsher conditions the aircraft would have to endure, and then calculated the periods of time it would have to stay in the air to carry out missions.

"To succeed at that mission, to have a probability of success, you need to be able to fly for two hours and 50 minutes," he said.

He noted that when the helicopter arrives at 12 Wing Shearwater airbase, it will be capable of performing the majority of its missions, as it will be over sea water in cooler air that's considered more dense.

The choppers are considered to be the "eyes and ears" of the navy, and are used to fly missions from Canadian frigates that roam the world. They are also frequently assigned to assist with search and rescue missions.

The Cyclone's design was based on Sikorsky's H-92 civilian helicopter, which is used in the offshore oil industry.

The redesigned, military version has seen the addition of a folding tail and rotors for storage aboard warships, anti-submarine warfare electronics, and a system that allows the aircraft to be flown by computer.