bird strike

A bird strike (sometimes birdstrike, bird hit, or BASH - Bird Aircraft Strike Hazard) in aviation is a collision between an airborne animal (usually a bird or bat[1]) and a man-made vehicle, especially aircraft. It is a common threat to aircraft safety, and has caused a number of fatal accidents.[2] Fatalities for civil aircraft are quite low and it has been estimated that there has been only 1 fatal accident to a jetliner in 1000 million flying hours.[3] The majority of bird strikes (65%) cause little damage to the aircraft.[4] Most accidents occur when the bird hits the windscreen or is ingested into the engines. These cause annual damages that have been estimated at $400 million[2] in the United States of America alone to $1.2 billion worldwide to commercial aircraft.[5] Contents [hide] 1 Event description 2 Species 3 Countermeasures 3.1 Vehicle design 3.2 Bird management 3.3 Flight path 4 Incidents 5 References 6 See also 7 External links //

Event description View of fan blades of JT8D Jet engine after a bird strike.

Bird strikes happen most often during take off or landing, or during low altitude flight. [6] However, bird strikes have also been reported at high altitudes, some as high as 6000 to 9000 meters above ground level. The majority of bird collisions occur near or on airports (90%, according to the ICAO) during takeoff, landing and associated phases. According to the FAA wildlife hazard management manual for 2005, less than 8% of strikes occur above 900 meters and 61% occur at less than 30 m (100 ft). A hawk stuck in the nosecone of a C-130

The point of impact is usually any forward-facing edge of the vehicle such as a wing leading edge, nose cone, jet engine cowling or engine inlet.

Jet engine ingestion is extremely serious due to the rotation speed of the engine fan and engine design. As the bird strikes a fan blade, that blade can be displaced into another blade and so forth, causing a cascading failure. Jet engines are particularly vulnerable during the takeoff phase when the engine is turning at a very high speed and the plane is at a low altitude where birds are more commonly found.

The force of the impact on an aircraft depends on the weight of the animal and the speed difference and direction at the impact. The energy of the impact increases with the square of the speed difference. Hence a low-speed impact of a small bird on a car windshield causes relatively little damage. High speed impacts, as with jet aircraft, can cause considerable damage and even catastrophic failure to the vehicle. However, according to the FAA only 15% of strikes (ICAO 11%) actually result in damage to the aircraft. The impact of a 5 kg (12 pound) bird at 240 km/h (150 mph) equals that of a 1/2 ton (1000 pound) weight dropped from a height of 3 meters (10 ft).

Bird strikes can damage vehicle components, or injure passengers. Flocks of birds are especially dangerous, and can lead to multiple strikes,