"The solar flares are causing some disruption on our high frequency voice-radio communications,'' he said.
Flights that go north of latitude 57 degrees, which runs from northern Scotland across Hudson Bay to the lower tip of Alaska and across Russia, were required to stay on specific routes Wednesday, Garneau said. Those flights include commercial jets crossing the North Atlantic and transport planes flying over the Arctic.
By prohibiting route changes, such as altitude shifts to deal with high winds, air traffic controllers can pinpoint a specific plane's location more easily, Garneau said.
"It reduces the complexity of the airspace,'' he said. "We're not stopping any traffic movement, we're just restricting the routes taken by aircraft so we can ensure we have a better estimate of their position.''
Richard Wright, a spokesman for Britain's national air traffic services, said British controllers were keeping trans-Atlantic jets on more southerly routes than usual to avoid solar flare interference with communications. He said the flare had not affected planes over Britain itself.
"It's an inconvenience more than a problem,'' Wright said.
"We've been cooperating with our Canadian colleagues to set more southerly routes than usual in order to avoid the interference,'' he said. "It's not a problem because, of course, solar flares happen ... on a fairly regular cycle.''
High frequency, or HF, communications involve the radio contact between planes that are out of radar range or very high frequency _ VHF _ range. That generally applies to planes crossing oceans or flying over vast undeveloped regions such as the Arctic. On approaching airports, the planes have radar and VHF contact.
Planes also have satellite tracking devices and emergency VHF communications to make contact in the event of a problem, Garneau said.
Even if the solar flares knocked out all satellite and HF radio contact, he said, it was likely a troubled plane could make VHF contact with another aircraft or military monitoring station.
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