OTTAWA -- Canada's air force has begun a shopping spree, looking to buy heavy-lift helicopters, transport aircraft and search-rescue planes, all within about five years, a military spokesman said Thursday. Military planners are working late every day examining options and drafting requirements before issuing tenders for the lucrative contracts, said Capt. Jim Hutchison. A special priority has been placed on the helicopter purchase, where options include used American Chinooks, similar to the troop transports that Canada sold to the Netherlands in 1991 as part of federal cost-cutting. "It's an exciting time to be in the air force," said Hutchison. "The directorate of air requirements staff have been putting in the overtime hours like crazy in the past six months or so. "There's a whole lot of work to be done." Navy Lieut. John Nethercott said while used Chinooks are among the helicopter options under consideration, the preferred route is to buy new ones. Canada's last major foray into used military equipment - four British submarines obtained for about $850 million in the 1990s - proved a bust. They were plagued with problems and required numerous upgrades. One, HMCS Chicoutimi, caught fire on her maiden transatlantic voyage under Canadian command. A sailor died and the submarine now needs $20 million in repairs. Last week, a transformer aboard the only sub in service, HMCS Windsor, suffered a meltdown. No one was hurt and the boat continued her cruise. Nethercott, an air force spokesman, said the navy experience isn't a factor in the air force decision. "The air force will explore all options," he said. "We're looking at long-term solutions and we think that those can be gained by buying new aircraft." The last federal budget and April's defence policy statement outlined aviation requirements for the military, citing the need to support newly conceived expeditionary forces in far-flung regions of the world. The chief of defence staff, Gen. Rick Hillier, wasted no time forming planning groups to get the process underway last spring. But he said even before deliberations began that transport helicopters and replacements for the military's aging fleet of Hercules aircraft, some of which are more than 40 years old, are must-haves. Hutchison said the army and air force have been working closely on the requirements for a heavy-lift helicopter and are looking at four main options - Sikorsky's S-92 and H-53 and Boeing's Chinook, either new or used. Planners are drafting requirements, describing the conditions in which the new choppers will have to operate - hot, dusty, high altitudes - and the jobs it will have to do - move troops and equipment around war zones. Three years ago, Canadian fighting troops in Afghanistan had to rely on U.S. helicopters for transport and resupply. They often found themselves at or near the bottom of the Americans' priority lists.