Bird Strike

From student pilots on up, we only see them from a distance now and then, but at the same time we all know what a bird strike can mean… or do we? Birds were around long before we were, but it’s always been dangerous for feathered and aluminum (or composite) wings to share the same sky… now the threat seems to be on the rise. In addition, officials believe that some 80 percent of bird strikes go unreported. Translation: It is likely that the problem is greatly underestimated.

A RISING THREAT
The first bird strike was reported by Orville Wright in 1908. Back then of course, airplanes were slow enough to be struck from behind! But it wasn’t long before pilots understood the hazard. On April 3rd 1912, Calbraith Rogers — the first person to fly across the US — struck a gull and drowned under the wreckage of the famous ‘Vin Fizz‘ in the surf at Long Beach, California. As recently as the 1970’s, bird strikes were relatively uncommon. But because of several factors, such as conservation efforts and the quadrupling of migratory bird populations, suburban sprawl into their habitats, the bigger, quieter, faster, and more numerous airplanes we fly, or fly in (and the more vulnerable fan blades of turbofan engines), things are getting worse. However, it’s likely that increased awareness and reporting probably factor in as well.

DANGER FACTORS:STATISTICALLY SPEAKING
Over 400 people have been killed by bird strikes. Most of those — about 370 — have been recorded since 1960, accounting for some 400 aircraft destroyed. Over 3,000 bird strikes were reported by the Air Force in 2000 alone, and almost 6,000 bird strikes were reported for US civil aircraft in that same year. Although over 600 bird species live in or migrate through the US, and 90% of migratory flights occur below 5000 feet MSL, the most commonly struck bird groups are gulls, followed by blackbirds, raptors, waterfowl, doves (including pigeons), and sparrows. Mostly, the types of birds involved are gulls (31%), waterfowl (31%), and raptors (15%). The turkey vulture is responsible for one percent of bird strikes, but 40% of the damage. Almost half occur under 100 feet AGL; two-thirds under 500 feet and 80% of all strikes occur within the airport environment, below 1500 AGL. Experts say that during the next 10 years, there is about a 25% probability that a large jet transport will be involved in a fatal bird strike related accident in the U.S. or Canada.

• A 12-pound Canada goose struck by an aircraft moving at 130 knots generates the force of a thousand-pound weight dropped from a height of 10 feet. Could your Skyhawk take that? Birds can weigh over 40 pounds; fortunately most North American bird strikes involve birds weighing 4 pounds or less.
• While any airport may have bird strikes, airports adjacent to wetlands or wildlife preserves are at higher risk of having a significant bird strike hazard… it’s not as uncommon as you think.
• In flocks, birds can number in the hundreds.
• By far the greatest number of incidents occur during takeoff/climb (35%), and approach/landing (50%) — low altitude operations.
• Almost three-quarters of all reported strikes involve commercial aircraft.
• The fall and spring are the two peak migration periods for North American waterfowl. More strikes occur during fall migrations because large flocks move to wintering areas in a short time, whereas spring migrations are slower and more irregular.
• There are four major migratory flyways in North America–Atlantic, Mississippi, Central, and Pacific. The Mississippi flyway contains the largest number of birds, followed by the Pacific, Central, and Atlantic. (Refer to the diagram below.)
• There are three peak seasons for bird strikes: March and April during the spring migration; September and October during the fall migration; and July and August when inexperienced birds are present and adults molt their flight feathers.

CATOSTROPHIC RESULTS
In 1960, a departing Lockheed Electra ingested a small flock of starlings into all four engines at Logan Airport and crashed into Boston harbor, killing 62 people. In 1973 a Learjet taking off from Atlanta struck a flock of birds and crashed, killing eight people. In 1995, a Concorde ingested one or two Canada geese while landing at JFK and landed safely — with more than $7 million in damage. Also in 1995, a USAF AWACS ingested Canada geese into two engines during takeoff from Elmendorf AFB in Alaska and crashed, killing all 24 on board. The following year another AWACS suffered extensive damage after a bird ingestion, sliding off the runway during its rejected takeoff in Greece.

BUT BIRDS AREN’T THE ONLY PROBLEM
Deer and other ‘ungulates‘, as well as coyotes and other carnivores (even alligators) can and do wander onto runways. The most commonly struck mammals are deer and coyotes. Someone in my own flying club hit a deer in a Lance two years ago while landing — the airplane was out of commission for months. Still, of all reported wildlife strikes by aircraft, birds outnumber mammals by at least 30-to-one.

AND NOW, THE GOOD NEWS (…if you want to call it that):

• Only about 15% of all bird strikes result in aircraft damage.
• ATC controllers are required to issue advisory information to pilots on any possibly hazardous bird activity, as well as to adjacent facilities and FSS personnel.
• Airports are getting smarter about how to make themselves less attractive to birds. Measures such as habitat control have worked at JFK, which in 1988 reported more bird strikes than any other U.S. airport (300) and it’s since reduced that number by 75 percent.

DEFENSE
Many organizations exist to exchange information, promote the collection and analysis of strike data, and develop standards to cope with bird strikes. One result is the FAA’s National Wildlife Strike Database. The US Air Force’s Bird Aircraft Strike Hazard (note the acronym) team at Kirtland AFB, NM, oversees the military side of strike reduction efforts. Their database is similar, and can be seen at http://safety.kirtland.af.mil/AFSC/Bash/stats.html. Their Bird Avoidance Model (again, clever acronym) at http://www.ahas.com/bam/About/FAA.cfm correlates bird habitat, migration, and breeding characteristics with key environmental and geospatial data. It allows you to map where the birds have been in comparison to where you are and where you’re going. (Below is a view of a high-hazard area near Atlanta.) Even better, the Avian Hazard Advisory System uses NEXRAD radar to keep planes away from birds, monitoring bird activity in near real-time for flight crews.

» U.S. Bird Avoidance Model Example

The Basics…

• Exercise the utmost vigilance during takeoff and landing.
• Check NOTAMs for bird problems at departure and destination airports.
• Fly high — only one percent of GA bird strikes occur above 2500 feet AGL.
• Avoid sanctuaries, landfill sites, fish processing plants (duh…)
• Avoid low flight along rivers or shorelines… navigational features for birds!
• NEVER use an aircraft to scare birds away! If you observe bird activity on the runway, ask airport personnel to disperse them before taking off.
• Use landing lights during takeoff, climb, descent, approach and landing; it makes the aircraft more visible.
• If dense concentrations of birds are expected — and unavoidable — avoid high-speed approaches; half the speed means one quarter the impact energy. Extra speed for maneuverability is not necessary — you will not miss the bird, the bird will miss you.

Extra Measures…

• If you must fly in a high-risk area and there are two pilots on board, discuss emergency procedures beforehand, including how to deal with windshield penetration or pilot incapacitation.
• Carry sunglasses or smoke goggles to deal with a windshield penetration.
• If a strike occurs on the takeoff roll, STOP if there’s sufficient runway remaining.
• If you see birds ahead, attempt to pass above them — birds usually break downward when threatened.
• Familiarize yourself with local and national bird migration routes

Post Collision…

• If the windshield is penetrated, slow the aircraft to reduce the wind blast, debris, precipitation.
• If a collision seems inevitable, duck below the windshield to avoid being hit by the bird and flying plexiglass. Advise passengers to do the same. Protect your eyes and head.
• If a collision occurs, fly the aircraft first! Don’t get distracted by the blood, feathers, smell, and wind blast.
• Assess the damage and decide whether you can make it to an airport or you should make an off-airport landing.
• Declare an emergency; it doesn’t cost anything.
• Even if no damage is visible, divert to the nearest airport and have a mechanic look at the airplane. (Your aircraft will likely have some new aerodynamic modifications that will not have FAA approval.)

Federal Aviation AdministrationAnd if it does ever happens to you, do your share and complete the paperwork! The FAA form for reporting bird strikes, 5200-7, is available at many locations (and no postage is required). It’s also at http://wildlife-mitigation.tc.faa.gov as well as in PDF form at http://www.faa.gov/arp/pdf/bform.pdf You should send the form, along with any feather remains, to the FAA at:

 

• Office of Airport Safety and Standards, AAS-310

 

• 800 Independence Avenue, SW

 

Washington, DC 20591

BOTTOM LINE: All said, bird strikes are not that common, but then, neither are the other things that can kill you in an airplane. The more you know, the safer you are. It never hurts to be prepared.

For Further Reading:
http://www.tc.gc.ca/aviation/aerodrme/birdstke/main.htm
http://www.birdstrike.org
http://wildlife.pr.erau.edu
http://www.pr.erau.edu/~ecology/esa/archives/birds/faastrike.html
http://wildlife.pr.erau.edu/strikeform/birdstrikeform.html