Ever hear a small thump as you’re taking off in an airplane? It might have been a bird.
Since 1990, the Federal Aviation Administration has recorded more than 2,570 “wildlife strikes,” or instances of planes hitting animals, at Minnesota airports. The data show collisions with all manner of fauna: mostly small to medium-sized birds, but also bats, coyotes, foxes, deer and one unfortunate muskrat.
In most cases, these strikes are not safety issues for planes or passengers. But the FAA tracks wildlife strikes because they can be costly and in extremely rare cases, dangerous.
Plane eats crow
Just like people driving cars have to worry about wildlife on the road, pilots flying planes have been concerned about animals on runways and in the sky for as long as people have been flying, said Brian Willis, the director of aviation safety at the University of North Dakota’s Department of Aviation.
While it’s not something passengers are necessarily aware of, wildlife strikes can pose safety issues in very rare cases and can be costly — both in terms of delays caused by sidelining planes and the cost to actually repair them.
The reported costs of wildlife strikes in the Minnesota database exceeded $11 million in inflation-adjusted dollars since 1990.
The costliest wildlife strike in the Minnesota database happened at Minneapolis-St. Paul International Airport in June of 2012. According to the report, a Compass Airlines plane hit an American coot, causing sparks to come out of the engine, which failed. The plane landed without incident, but the estimated engine replacement costs were $5.9 million in inflation-adjusted dollars.
The second costliest, at $1.5 million, happened when a crow hit a Northwest Airlines plane at MSP in 2002. The report says a thump was heard before a burnt meat smell filled the cabin. After consulting with dispatch, the plane continued to Chicago’s Midway Field (the plane was carrying the Chicago White Sox Baseball team). After landing, damage was found in the compressor blades and engine.
Even if a plane hits a small bird, protocol dictates that the plane be inspected before flying again, Willis said.
Most of the time, wildlife strikes are of little consequence. There are exceptions, though. The most famous recent example is the 2009 incident of US Airways Flight 1549, when pilot Chesley “Sully” Sullenberger landed a plane in the Hudson River after both engines were taken out by a flock of geese (big planes typically have multiple engines, so Willis said the fact this took out both made it a one-in-a-billion thing). Two people died in a UND plane crash in Minnesota in 2007 after their plane hit geese.
Willis emphasized that cases like that are exceedingly uncommon, (you’re far more likely to die in a car crash than a plane crash), but said the potential danger is why pilots learn about wildlife safety in flight school. It’s also why airports put a lot of time and money into trying to prevent planes from hitting animals.
Some wildlife strike mitigation strategies include unmanned aircraft systems (basically, drones) to scare birds, air cannons that make loud noises to discourage birds from landing and radar.
“I think there’s a couple airports up in Alaska that actually have dogs,” Willis said. “Their job is to scare the birds off the runway.” (Just look at this bird-chasing, goggle-wearing border collie.)
The vast majority of wildlife-plane collisions at Minnesota airports involve birds. In the FAA dataset, 2,483 of the 2,570 Minnesota wildlife collisions reports — or 97 percent of them — were bird-related.
The species of bird involved was unidentified in about 40 percent of the bird-related incidents. But of the identified strikes, horned larks, barn swallows, Canada geese were the most common. Planes also struck gulls, ducks, owls, eagles and, in one incident, a loon.
More specific species identified in strikes — like Franklin’s gulls and chimney swifts, aren’t necessarily indicative of pilots’ birding skills, Willis said. Those are likely attributable to the fact that bird specimens are sometimes sent to the Smithsonian for identification.
Apart from birds, the most common species identified in collisions are bats (41 incidents), followed by deer (26), coyote (8) fox (3) and skunk (2). There are single reports of collisions with muskrats, jackrabbits, raccoons. Luckily for Minnesota pilots, no moose (as have been reported in collisions in Alaska).
One Minnesota wildlife strike report describes how a plane, on a landing roll at dusk at Anoka County-Blaine Airport hit two deer. It was damaged and had to be towed off the runway.
“Once you’re on the runway and you’re going a hundred miles an hour, if there’s a deer there, you’re not going to swerve off the runway and avoid the deer,” Willis said. “You’re going to take the animal, because that’s safer than trying to veer off — that would cause a bunch of other problems.”
As far as timing goes, wildlife-plane collisions are most frequent during landing, but also happen often during take-offs and climbs — these are times when planes are at the same altitudes that birds tend to be. They’re also most common in the fall, during the mass-migration of birds.