A bird strike or Bird Aircraft Strike Hazard (BASH) is an incident in which a bird collides with an aircraft. Bird strikes represent a significant aviation hazard, and they are a cause of concern among many pilots, because although they are relatively rare, they can be catastrophic when they occur. A number of techniques can be used to reduce the possibility of bird strikes, and to prevent severe damage when these events do occur.
Typically, a bird strike takes place during takeoff or descent, when the plane is in a low altitude area frequented by birds, although strikes can occur at higher altitudes. In some cases, the bird simply collides with the plane without causing any damage, although it may leave an unsightly mess behind. In other instances, birds can shatter windshields, break through the skin of the aircraft, or cause damage by being sucked into engines. Jet engines are particularly vulnerable to bird strike damage because a cascading effect can be created as the engine's parts are bent and distorted by the impact, distributing the damage to other parts of the engine.
One might reasonably wonder how a small bird like a starling, gull, or goose can possibly cause damage to a huge airplane like a Boeing 747. The answer is physics. The plane is going extremely fast, and when something collides with something which is going very fast, the resulting damage can be very significant. If a bird hits at the right angle or in the right spot, it can bring a plane down, especially in the case of a multiple bird strike, where a plane hits several birds.
Ironically, airports often provide great habitats for birds and other wildlife. Since the area around an airport is cleared for navigational purposes, the off-limits areas around airports create an ideal spot for birds to live, especially around airports in coastal cities, as these airports are often surrounded by natural wetlands. Birds tend to congregate around airports because they provide habitat, and as a result, they increase the risk of bird strikes.
Some airports use a variety of measures to control birds, with the goal of reducing the hazard by reducing the number of birds. Many planes are also designed with failsafes to prevent bird strikes or to ensure that the plane will continue operating if it is damaged by birds, and pilots are trained about bird strikes and how to avoid them. Tools like radar, for example, are used to identify flocks of birds so that they can be avoided. Fatalities are a result of bird strikes are very infrequent, but BASH incidents cause substantial amounts of damage to civil, military, and private aircraft every year.
Incidentally, for those readers who may be wondering, there is an official term for the smear of pulverized bird left behind after a bird strike: snarge. Aviation safety officials often inspect the snarge to identify the species involved and to learn more about the precise path of the bird strike.