Why some planes can land in Whitehorse in bad weather and others can't

Recent flight cancellations, delays and detours by Air Canada flights in and out of Whitehorse have some passengers wondering why Air North flights were able to land and take off at Erik Nielsen International Airportunder similar conditions.

Joe Sparling, Air North's president, saidhe can't comment on circumstances specific to Air Canada, but did provide an explanation as to why his aircraft were able to land.

Sparling said an aircraft's ability to land under various weather conditions depends on the instrumentation of both the aircraft and the airport, as well as the experience of the crew.

He said Air North has invested in aircraft instrumentation specific to landing at the Whitehorse airport, because that's its main airport.

"As a comparison, we have not chosen to invest in the aircraft and crew capability of landing in the absolute lowest weather minimums in Vancouver."

Sparling said landinglimits at the Whitehorse airport vary depending on the cloud ceiling, as well as the aircraft's direction of approach, which in turn depends onthe strength and direction of the wind.

He said there are more options when landing from the southbecause of airport instrumentation, but that's not always available.

Sparling said weather earlier this week dictated landing from the north.

"For the last couple of days we've had a very unusual and unique weather situation at Whitehorse where we've had a low ceiling and very strong winds from the south.

"If the air carrier doesn't have the equipment in the aircraft to operate to the lower limits on the second approach from the north, then they wouldn't be able to get it."

Going to Yakutat?

Sparling said his aircraft weren't able to landat the Dawson City Airport when the ceiling wasbelow the allowable landing limit recently, because of the airport's limited instrumentation.

"They don't have the approach facilities to let us land at weather below the lower minimums."

As for why Air Canada chose to land in Anchorage, Alaska, on Monday rather than returning to Vancouver, Sparling said he couldn't comment.

But he saidsometimes, the alternate airport for Air North flights into Whitehorse is Watson Lake,Norman Wells, N.W.T., or Juneau or Yakutat in Alaska.

"You don't always go back to your point of origin."

CBC contacted Air Canada for comment and has not yet received a response.