A US Airways plane floats in the Hudson River off New York City. ((WNBC-TV/Associated Press))

Calgary airport officials say they work around the clock to keep the runways clear of birds that could fly into an aircraft.

US Airways Flight 1549 had just departed from LaGuardia Airport in New York City on Thursday and was headed to Charlotte, N.C., when the pilot reported a "double bird strike" about six minutes after takeoff.

The pilot steered the jet toward the river and slowly brought it down on the water, keeping the fuselage intact. Everyone got out safely.

Birds and planes

Birds are most likely to hit aircraft during takeoff or landing, and not at high altitudes, according to the National Research Council's Institute of Aerospace Research. Collisions typically occur less than 1,500 metres above ground and near airports. Because of this risk near airports, planes are mandated not to fly faster than 650 km/h.

But at that speed, even small birds can do plenty of damage, according to Ron Gould, a technical officer at the institute.

What kind of damage depends on where it hits, said Gould.

"If the bird strikes on the windshield, you are going to lose the optics. They are laminated glass windows, and they are going to crack, and that's why there is more than one window and more than one person looking out through the windows," he said.

Engine strikes are more problematic, he explained, since a bird that passes through the turbine can get into the engine duct. Aircraft can fly with only one working engine, but in the case of US Airways Flight 1549, where multiple bird strikes disabled both engines, the pilot has few options other than an emergency landing, he said.

At the Calgary airport, Terry Thompson said airport officials use loud, explosive noises to scare birds away, along with bird scare tape and other methods.

"The idea is to just keep them harassed on property so they don't find the airport a good place to come to," he said.

"When we notice that there are areas they seem to come back to we find the attraction and try to eliminate or prevent them from getting to it. For instance our open water storm drainage ponds we have bird wire strung across … which prevents them landing in the water."

Transport Canada is constantly reviewing the program to make sure the airport is minimizing the risk as much as possible, Thompson added.

At Mount Royal College in Calgary, aircraft simulator instructor Mark Benson said his students can learn a lot from the dramatic emergency landing on the Hudson River.

His simulator is an effective and safe way of showing student pilots what to do in such emergency situations, he said.

"They essentially lose all their engine power and they're usually surprised by it," he said.  "They work through their procedures to see if they can determine the cause of the loss of power and if they can't, they start looking for a suitable landing place and setting up the aircraft so it will land in that area safely."