On a June evening in 2005, Air Canada Jazz Flight 8105 was carrying 64 passengers from Houston to Calgary when, just after crossing the border, the plane began to vibrate.
The control column shook and an alarm sounded in the cockpit. The plane tumbled into a dive, stabilized, then dove again. The problem? The captain, worn out from an irregular schedule and a fitful sleep, had twice allowed the plane to slow so much that it was on the verge of stalling.
"Fatigue likely resulted in a degradation of his concentration," concluded a report by the Transportation Safety Board of Canada.
The near-accident is a glaring example of what pilots would say is wrong with Canadian aviation regulations. In the last 12 years, fatigue was investigated as a possible factor in nine aviation incidents in Canada, involving 23 deaths, according to a review of TSB records.
Yet pilots claim the federal government isn't doing enough to guard against these mishaps. They argue that current rules are outdated, and that workday hour limits are ineffective in keeping tired pilots out of the cockpit.
Their criticisms come amid an international outcry over pilot fatigue. In Europe, pilots held public protests last month calling for tougher rules. In Dubai, Emirates airlines faced allegations that tiredness was behind a near-crash in Melbourne. And in the United States, authorities are promising more stringent standards following the Colgan Air crash near Buffalo last winter that killed all 50 people onboard.
"Finally it's happening in the States. We want that process to start in Canada as soon as possible," said Air Transat Captain Martin Gauthier, a member of a panel on fatigue of the Air Line Pilots Association. "There's a consensus in the pilot community in Canada that the rules have to change."
But that doesn't appear likely any time soon. The United Nations agency that sets global aviation standards has asked countries to update their regulations by this week; federal officials say Canadian standards are consistent with those guidelines.
"We deem that our norms are adequate," said Transport Canada spokesman Patrick Charette. "In some areas we are ahead of the curve."
That assessment differs sharply with the view of pilots, who claim that flight-limit rules don't take into account all sorts of situations that leave them exhausted. Canadian regulations allow a crew to be on duty for 14 hours within a 24-hour period (which can be stretched if there are unplanned problems), but they ignore aggravating factors such as night work, irregular start times, routes that cross several time zones or multiple takeoffs and landings.
The European Union, by contrast, has a 13-hour daily maximum that is trimmed if more than two legs are flown or if the shift starts between 2 a.m. and 6 a.m. And while American pilots can be on duty for up to 16 hours a day, Randolph Babbitt, head of the Federal Aviation Administration has pledged stricter standards.
Daniel Slunder, who worked at Transport Canada's operational standards branch until July, said he didn't sense that flight-time limits were a pressing issue for Canadian regulators.
"Any change to the regulation with respect to pilot fatigue is not about to occur any time soon and that is a pity," predicted Mr. Slunder, chairman of the Canadian Federal Pilots Association, which represents Transport Canada pilots responsible for aviation inspection.
Pilots for all the major carriers have negotiated contracts with tougher rules than what federal regulations allow, but they argue that regulations need to be stiffened to prevent further mishaps.
One of the biggest problems is IRROPS, or irregular operations. For example, a crew on its last flight of the day risks running over its daily limit - not a rare thing with winter weather delays.
"If you're in the U.S. or in a smaller centre, there is no reserve crew [and] that means sending 150 passengers to a hotel and flying in a reserve crew," Capt. Gauthier said. "The bill is enormous. And we're not insensitive to that. It's our breadwinner. We don't want the company to have excessive IRROPS costs."
The way flights are assigned to pilots can also pose a hazard. Air Canada and Jazz pilots are paid by hours of flight time and routes are picked by seniority, so that "people in the bottom third get the dregs," said one Jazz pilot.
Those dregs would include what is called continuous or stand-up duty, where pilots handle a late evening flight, stay overnight at their destination, and then fly back in the morning. While this fits within the mandatory 14-hour limit, it means pilots are able to manage only a few hours sleep before stepping back into the cockpit.
"It's just enough to mess you up," the Jazz pilot said, describing the "head bobs" of fatigued pilots.
Canadian rules allow major swings in sleep time within a short span.
In the case of the Houston-Calgary Jazz flight that nearly stalled, the captain was given adequate time to rest but, arriving in Houston at 2 a.m. that day, he slept fitfully for just 31/2 hours.
In February, 2004, a First Air Boeing 737 charter ferrying 31 miners from Nunavut missed the runway when it landed in dark, foggy conditions in Edmonton. The pilots had awakened in Edmonton at 5:30 a.m. the day before, flown to Yellowknife, and then got a break during the afternoon before flying through the night. They were up for 24 hours straight because they could not sleep during the day.
"We can't just turn it on and off," said one Air Canada pilot.
Philippe Cabon, a professor of ergonomics at Paris Descartes University who studies pilots' sleep patterns, notes that fatigue doesn't accumulate or dissipate in a linear fashion. Pilots who accumulate a 10-hour sleep debt won't sleep 10 hours longer when given a rest.
"The timing of the break is more important than its duration," Dr. Cabon said.
Air Canada spokesman Peter Fitzpatrick noted the airline allows pilots to abandon a shift if they feel too tired. But exhausted pilots can't properly assess their fitness to fly. Others confessed they will simply tough it out, hoping that the other pilot is in better shape.
"Let's touch wood and hope nothing major happens," said Capt. Gauthier of Air Transat. "But let's not wait until something major happens to change the rules."