As the temperature plunged in Toronto on Monday, Air Canada officials moved to avert a potential disaster at their operations at Canada's busiest airport.
Late Monday night, they put in place a "ground stop," which halted flights into the Air Canada terminal at Pearson International Airport. The Greater Toronto Airports Authority, which manages the airport, made a similar call for other airlines at roughly the same time.
Air Canada's move was made "to prevent complete and utter gridlock," Nick Careen, the carrier's vice-president of airports, said Wednesday in the airline's station operations control centre at Pearson. "We could see we were walking across a cliff."
The GTAA instituted what is called a Tier 2 ground stop at 11 p.m. on Monday, according Nav Canada, which provides air navigation services.
A Tier 1 ground stop halts landings for regional flights, such as those from Winnipeg and Montreal; Tier 2 covers a wider area (inbound North American flights); and Tier 3 is a complete shutdown, Nav Canada spokeswoman Michelle Bishop said.
The cold hampered operations, said GTAA vice-president of strategy development Toby Lennox. Equipment was sluggish and ground crews were being rotated to keep from getting too chilled. "Everything started slowing down," Mr. Lennox said. "Because of the volume that you deal with in a major international airport like Pearson, you do get more delays than you would at other airports."
The GTAA briefed air carriers and Nav Canada at 5:45 p.m. on Monday as it became apparent the congestion was getting worse. The conference call was part of the daily briefing on traffic management. The Tier 2 ground stop was initially in effect for two hours, from 11 p.m. on Monday until 1 a.m. Tuesday. Since air traffic in the period after 1 a.m.
is slow, the ground stop wasn't re-instituted until 5:55 a.m. That stoppage lasted until 10 a.m. Tuesday.
By mid-day Wednesday, the ramifications of the decisions by Air Canada and the GTAA were still noticeable at Pearson, with some customers furious about flight delays.
The reasons for the shutdown were evident as Air Canada's Flight AC087, bound for Shanghai, took on fuel and workers loaded luggage. A tug vehicle pulling a baggage train spun its wheels on the ice that still coated much of the tarmac around the Boeing 777. The tug and the baggage train had to be pushed free by another tug.
That ice was a critical factor in the partial shutdown that created chaos at Pearson on Tuesday.
"I will acknowledge that it was known that the weather was coming. What was unexpected was the severity of the winds that picked up and the snow squalls that came through," Mr. Lennox said. "Weather changes and conditions change. You do everything that you can do to try to prepare for it."
Although there are other air hubs that operate routinely in colder temperatures, the GTAA executive brushed aside comparisons. "To suggest that you can merely point to another airport and say 'do that' both simplifies too much what happened here [and] creates parallels between airports that may not exist," he said.
Critics of the GTAA's decision to close the airport to landings from North America probably were not aware of the rain and snow that fell Sunday and Monday, then hardened into thick ice in a flash freeze, Mr. Careen and other Air Canada officials said. Mr. Lennox noted that the chemicals they use to clear ice don't work at extremely cold temperatures.
The hard ice froze on top of the caps of the in-ground fuel tanks used to refuel planes. That meant the carrier had to use fuel trucks, which can take twice as long to tap the in-ground tanks, said Kevin Brady, the airline's manager of general operations. He sits at a desk in a darkened room in the bowels of the airport, keeping watch on four computer screens that reveal the status of Air Canada flights on the ground at Pearson.
Some conveyor belts that carry luggage out of the bellies of airplanes froze.
The tugs that haul airplanes from gates to hangars lift and cup the front wheels of an airplane, enabling a plane to be hauled to a hangar in 20 minutes. Those tugs wouldn't work in the ice and snow, so Air Canada had to revert back to the traditional method, which takes more than three times as long. The ice-covered tarmacs were also holding many more planes than usual, so tugs and loading trucks had to be driven with extra care.
More than half of the 1,560 scheduled departures and arrivals were cancelled at Pearson on Tuesday.
WestJet estimates that it had to scrap nearly 200 flights over the past three days, mostly related to congestion at the Toronto terminal.
"It's way too soon to be arm-chair quarterbacking," WestJet spokesman Robert Palmer said. "Our focus is on getting people and their baggage to where they are supposed to be."