Bird strike (sometimes birdstrike or BASH (bird aircraft strike hazard)) is an aviation term for when there is a collision between a bird and an aircraft. It is a common threat to aircraft safety and has caused a number of fatal accidents.

While the majority of birds are small and light-boned the speed of impact, especially with modern jet engined aircraft, will produce considerable energy and the faster an aircraft moves the less chance a bird has of avoiding an impact. The point of impact is usually the engine, causing damage to the fans or the housing, or airflow ducts although impacts to any forward-facing edge, such as the nose and tail of aircraft, also occur. The bird habit of moving in flocks can lead to multiple strikes, and damage, within a very brief period. Large, flocking birds present the very greatest risk, with geese and gulls causing most serious incidents. Although according to the FAA only 15% of strikes (ICAO 11%) actually result in damage to the aircraft. In the US reported strikes are divided between waterfowl (32%), gulls (28%), and raptors (17%) (Data from the BSC USA). Striking large land-bound animals, such as deer, can also be a problem.

The majority of incidents occur near or on airports (ICAO 90%) during takeoff, landing and associated phases. Less than 1% of strikes occur above 760 m (2,500 feet) and 50% at under 30 m (100 feet)

To control the problem airports invest in bird management and control, changes to terrain around the airport to reduce its attractiveness as habitat to birds, using bird control personnel and frightening devices (sounds, lights or pyrotechnics), and sometimes the use of falcons or similar. Pilots use awareness of bird habits and should avoid migratory routes [1], wildlife reserves, estuaries and other sites where birds may congregate.

Most large commercial jet engines include design features that ensure they can safely shut-down after "ingesting" a bird of weighing up to 1.82 kg (4 lbs). Multiple or large strikes require emergency action to control damage. This limit is also applied to the rest of a modern commercial aircraft - it must be able to safely land after taking a 1.82 kg strike.

At first bird strike testing by manufacturers involved firing a bird carcass from a gas cannon and sabot system into the tested unit. The carcass was soon replaced with suitable density blocks, often gelatin, to ease testing. Currently testing is mainly conducted with computer-based simulation, although final testing usually involves some physical experiments.

The FAA estimates the problem cost US aviation $480 million annually (1990-2002) and has resulted in 195 worldwide deaths since 1988. Estimating that 80% of bird strikes are unreported, there were 4,300 bird strikes listed by the USAF and 5,900 by US civil aircraft in 2003.

The first recorded fatality in this field was reported in 1912 when aero-pioneer Cal Rodgers died after a gull became jammed in his aircraft controls. Orville Wright apparently experienced the first bird strike in 1908. The greatest loss of life directly linked to a bird strike was on October 4, 1960 when an Eastern Airlines Lockheed 180A flying from Boston crashed shortly after take-off due to encountering a flock of starlings, 62 people were killed.

External links

• BSC USA
• http://www.int-birdstrike.com/
• http://wildlife-mitigation.tc.faa.gov/public_html/index.html
• http://wildlife.pr.erau.edu/FAADatabase.htm