Image: Bird strike on plane
AFP - Getty Images file
A Ryanair Boeing 737-800 is seen Nov. 10 after an emergency landing at Rome's Ciampino airport earlier in the day — after a collision with a flock of birds.
Image: Bill Dedman
By Bill Dedman Investigative reporter
updated 1/16/2009 8:16:05 AM ET 2009-01-16T13:16:05

Talk about unintended consequences. “Bird strikes” — or collisions between birds and aircraft  — are increasing for two reasons, according to the federal government’s leading expert on the phenomenon: The environment is cleaner and airplanes are quieter.

While federal authorities have not confirmed initial reports that the US Airways jet that crashed Thursday in New York’s Hudson River hit a flock of birds shortly after taking off from LaGuardia airport, Dr. Richard A. Dolbeer told that such bird-aircraft collisions are on the rise.

"The key thing is that we’ve seen a remarkable increase in populations of many or most large birds — birds such as great blue heron, osprey, bald eagle, snow goose, Canada goose,” said Dolbeer, a retired ornithologist with the Department of Agriculture at the Wildlife Services in Sandusky, Ohio. "These populations are increasing because we’ve done a really good job of wildlife conservation in North America for many species, because we’ve cleaned up the environment, gotten rid of DDT, enacted the the Clean Water Act. All good things, but because of these, we’ve had incredible surges of many species that are hazardous to aviation.

"And at the same time, these species have adapted to being around people and all our activities. Related to that is the fact that modern jet aircraft, turbofan aircraft like the Airbus 320, the engines are very quiet. There’s very little noise out of the front of the airplane. Most of the noise is to the rear. There’s been a lot of attention paid to making the area around airports quieter. Birds have less ability to detect and avoid the aircraft.”

FAA statistics indicate that the number of aircraft bird strikes reported in the U.S. quadrupled from 1990 to 2007, rising from 1,738 per year to 7,439, These strikes caused 3,094 precautionary landings, 1,442 aborted takeoffs, 312 engine shutdowns and 1,162 minor negative effects, it said.

Worldwide, crashes of more than 25 large aircraft were caused by bird strikes since 1960, according to a published study by Dolbeer. In 23 of these incidents, the strike occurred below 400 feet. More than 219 people were killed and more than 200 aircraft destroyed in accidents attributed to bird strikes since 1988, Dolbeer and other researchers found.

In the U.S., most bird strikes happen between July and October, when bird populations are highest. But they can happen at any time of the year.

Using data from the FAA's National Wildlife Strike Database for Civil Aviation, he concluded that management of birds should focus on the airport environment. Most bird strikes happen on approach, less frequently on takeoff.

The threat from bird strikes has increased, Dolbeer found, because:

  • The populations of many species of wild fowl commonly involved in strikes have increased markedly in the last few decades, and the birds have adapted to living in urban environments, including airports. For example, from 1980 to 2006, the resident (non-migratory) Canada goose population in the USA and Canada increased at an average rate of 7.3 percent per year.
  • Air traffic has increased.
  • Commercial airlines are replacing their older three- or four-engine aircraft fleets with more efficient and quieter two-engine aircraft, increasing the chance of a fatal incident because the plane has less backup power.

"As a result of these factors, experts within the Federal Aviation Administration (FAA), U.S. Department of Agriculture (USDA), and U.S. Air Force expect the risk, frequency, and potential severity of wildlife-aircraft collisions to grow over the next decade," Dolbeer reported.

Aviation authorities have attempted to reduce the risk of bird-strike accidents.

In 1960, after 62 people died when an Eastern Airlines plane went down after hitting a bird during takeoff from Boston Logan Airport, the FAA imposed bird-ingestion standards for turbine-powered engines.

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Video: The dangers of bird strikes

  1. Transcript of: The dangers of bird strikes

    ANN CURRY, co-host: Listen, you know, a flock of birds. It's hard to imagine that it could bring down a commercial airliner , but in fact, it's happened before , and in fact, it's a growing problem. NBC 's Tom Costello is at Reagan National Airport with more on this part of the story. Tom , good morning.

    TOM COSTELLO reporting: Ann , good morning. As you probably know, the Reagan Airport here sits right on the Potomac River . You can see it right off of the runway there, and they have a constant problem here with birds. So every 30 -- every 90 seconds to three minutes they fire a cannon off to scare those birds away. But here's

    the issue: The geese population in this country is surging. Meanwhile, planes are getting quieter so the geese can't hear them coming. That makes the risk of an altercation with a flock of geese very real. From Manchester , England , YouTube video of a bird strike on a 757 nearly two years ago. Within seconds, the pilot realizes he's lost an engine.

    Offscreen Voice #1: Mayday, mayday, mayday.

    COSTELLO: It's not unusual. Bird strikes have been a problem since the Wright brothers started flying. In 2007 , there were more than 7600 bird and wildlife strikes on civil aircraft in the US. Since 1988 , more than 219 people have been killed worldwide because of bird strikes with the Canadian geese population up 400 percent since 1990 . This Pratt Whitney video shows the massive damage a large bird can inflict on an engine, turning the fan blades into flying shrapnel.

    Mr. RICHARD DOLBEER (Retired USDA Scientist): And if it collides with a Canada goose , which weighs about 10 pounds, that's the equivalent of taking a 1,000-pound weight and dropping it from a height of 10 feet . Tremendous force generated.

    COSTELLO: In New York , once the pilot realized he'd lost both engines, he put the plane down on the water, and because it was an Airbus A320 , he had an advantage.

    Mr. GREG FEITH: One of the things about the Airbus , the A320 Airbus , is that they actually have a button called the ditching button, where the crew will push that button. When they do it, all of the outflow valves, all of the ram air ports, everything that has an air flow through it in the fuselage seals up. So when the airplane then goes into the water, the fuselage is air-tight.

    Offscreen Voice #2: Inflate your vests, jump into the water.

    COSTELLO: And flight attendants practice for water landings, learning to never open the rear door first, since that can sink a plane . The 1549 crew did exactly that, following procedures and only opening the front doors and inflating the slides. Had they opened the rear door, the plane could have sunk tail first. Yeah, everything went just exactly as it was supposed to go. Listen, back to the bird issue for a moment, Ann. Airports around the country have been dealing with this issue with the surging bird population. Cannons, one option. They use strobes, they use dogs, they use falcons. But again, this is an issue that across the country they have been dealing with, wrestling with, and there's no quick, easy fix. Back to you.


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