The Harper government has been under pressure to address the issue since last year's stinging critique by the auditor general and the high-profile death of a young boy in Labrador two years ago.
Two research reports, which crunch the numbers on both search-and-rescue incidents as well as the cost of a 24-hour, seven-day posture for air crews, were recently delivered to the Canadian Joint Operations Command, the headquarters that oversees both domestic and out-of-country missions.
A defence spokesman, Daniel Blouin, would not say what the studies have concluded or when a decision would be made on their findings.
The research builds on a 2008 air force study that rejected the higher level of alert as expensive and only marginally better than the existing framework in terms of saving lives.
In order to meet the around-the-clock posture, the military would need to add between nine and 11 extra crews to the rotations and buy extra aircraft — or reassign existing ones.
The 2008 study projected the air force would need up to $2.6 billion more in aircraft and infrastructure and $314 million in additional sustained operations funding to make the plan work.
The military planners, who penned the earlier report, pointed to data that suggested out of 1,054 rescue missions, nine were time sensitive. Of those, a 30-minute response time might have made a difference in three cases.
Currently, rescue crews — operating from five main bases across the country — are able to get airborne within 30 minutes between 8 a.m. and 4 p.m., Monday to Friday. On weekends and holidays, the response time drops to two hours.
Auditor general Michael Ferguson's report a year ago said the air force could do better, and then-defence minister Peter MacKay gave rescue area commanders the authority to alter hours of operation as needed.
But at the same time, internal documents show MacKay's office also asked for more information on what it would take to shift to an around-the-clock operation.
The department responded with a copy of the air force analysis, which was nearly five years old.
Ferguson's audit warned that the overall rescue system was in distress — notably because of a shortage of trained pilots and aircrew. Other elements, he concluded, were near the "breaking point."
The air force staffs its rescue squadrons — including pilots — to 100 per cent of the target levels and has introduced measures to boost training, Blouin said.
National Defence is also filling the gap with a short-term loan program with pilots from the Royal Air Force, French Air Force and the German Air Force.
The auditor general also said the country doesn't have enough — or the right type — of aircraft to respond to emergencies across Canada's vast open spaces of land and sea.
The Harper government has yet to put out a tender to replace the country's fixed-wing search planes, a project stuck in the bureaucratic mud since it was first announced a decade ago.
The existing aircraft, notably the C-130 Hercules, don't have high-tech sensing technology common in other search fleets, the auditor complained.
Blouin said they're waiting for the new aircraft, which will have advanced sensors.
The availability and reliability of the air force's CH-149 Cormorant helicopters has improved after a continuous spare-parts problem limited their operations for almost a decade.
To solve their parts problem, National Defence spent $164 million to buy and cannibalize nine VH-71 helicopters from a U.S. program that was cancelled by President Barack Obama.
Before he was shuffled out of Defence last year, MacKay asked the department to take another look at whether some of the aircraft could be made fully operational and turned into rescue helicopters.
Both the air force and the department's material branch had insisted the American helicopters were only suitable for spare parts because they lacked air worthiness certificates and the electronics required for search and rescue.
Defence spokeswoman Ashley Lemire did not close the door on the idea entirely, saying a preliminary assessment has determined that further detailed studies are necessary.