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Bird strike
Bird strike
from Wikipedia
F-16 jet fighter after bird strike

A bird strike (sometimes called birdstrike, bird ingestion (for an engine), bird hit, or bird aircraft strike hazard (BASH)) is a collision between an airborne animal (usually a bird or bat)[1] and a moving vehicle (usually an aircraft). The term is also used for bird deaths resulting from collisions with structures, such as power lines, towers and wind turbines (see bird–skyscraper collisions and towerkill).[2]

A significant threat to flight safety, bird strikes have caused a number of accidents with human casualties.[3] There are over 13,000 bird strikes annually in the US alone.[4] However, the number of major accidents involving civil aircraft is quite low and it has been estimated that there is only about one accident resulting in human death in one billion (109) flying hours.[5] The majority of bird strikes (65%) cause little damage to the aircraft;[6] however, the collision is usually fatal to the bird(s) involved.

Vultures and geese have been ranked the second and third most hazardous kinds of wildlife to aircraft in the United States, after deer,[7] with approximately 240 goose–aircraft collisions in the United States each year. 80% of all bird strikes go unreported.[8]

Most accidents occur when a bird (or group of birds) collides with the windscreen or is sucked into the engine of jet aircraft. These cause annual damages that have been estimated at $400 million[3] within the United States alone and up to $1.2 billion to commercial aircraft worldwide.[9] In addition to property damage, collisions between man-made structures and conveyances and birds is a contributing factor, among many others, to the worldwide decline of many avian species.[10]

The International Civil Aviation Organization (ICAO) received 65,139 bird strike reports for 2011–14, and the Federal Aviation Administration counted 177,269 wildlife strike reports on civil aircraft between 1990 and 2015, growing 38% in seven years from 2009 to 2015. Birds accounted for 97%.[11]

Event description

[edit]
View of fan blades of a Pratt & Whitney JT8D jet engine after a bird strike
Inside of a jet engine after a bird strike
An ICE 3 high-speed train after hitting a bird
A bird control vehicle belonging to Copenhagen Airport Kastrup, equipped with various tools

Bird strikes happen most often during takeoff or landing, or during low altitude flight.[12] However, bird strikes have also been reported at high altitudes, some as high as 6,000 to 9,000 m (20,000 to 30,000 ft) above the ground. Bar-headed geese have been seen flying as high as 10,175 m (33,383 ft) above sea level. An aircraft over the Ivory Coast collided with a Rüppell's vulture at the altitude of 11,300 m (37,100 ft), the current record avian height.[13] The majority of bird collisions occur near or at 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 m (3,000 ft) and 61% occur at less than 30 m (98 ft).[citation needed]

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 point of impact. The energy of the impact increases with the square of the speed difference. High-speed impacts, as with jet aircraft, can cause considerable damage and even catastrophic failure to the vehicle. The energy of a 5 kg (11 lb) bird moving at a relative velocity of 275 km/h (171 mph) approximately equals the energy of a 100 kg (220 lb) weight dropped from a height of 15 metres (49 ft).[14] However, according to the FAA only 15% of strikes (ICAO 11%) actually result in damage to the aircraft.[15]

Bird strikes can damage vehicle components, or injure passengers. Flocks of birds are especially dangerous and can lead to multiple strikes, with corresponding damage. Depending on the damage, aircraft at low altitudes or during take-off and landing often cannot recover in time.[16] US Airways Flight 1549 is a classic example of this. The engines on the Airbus A320 used on that flight were torn apart by multiple bird strikes at low altitude. There was no time to make a safe landing at an airport, forcing a water landing in the Hudson River.

Remains of the bird, termed snarge,[17][18] are sent to identification centers where forensic techniques may be used to identify the species involved. These samples need to be taken carefully by trained personnel to ensure proper analysis[19] and reduce the risks of infection (zoonoses).[20]

Species

[edit]

Most bird strikes involve large birds with big populations, particularly geese and gulls in the United States. In parts of the US, Canada geese and migratory snow geese populations have risen significantly[21] while feral Canada geese and greylag geese have increased in parts of Europe, increasing the risk of these large birds to aircraft.[22] In other parts of the world, large birds of prey such as Gyps vultures and Milvus kites are often involved.[5] In the US, reported strikes are mainly from waterfowl (30%), gulls (22%), raptors (20%), and pigeons and doves (7%).[21] The Smithsonian Institution's Feather Identification Laboratory has identified turkey vultures as the most damaging birds, followed by Canada geese and white pelicans,[23] all of which are very large birds. In terms of frequency, the laboratory most commonly finds mourning doves and horned larks involved in the strike.[23]

The largest numbers of strikes happen during the spring and fall migrations. Bird strikes above 500 feet (150 m) altitude are about 7 times more common at night than during the day during the bird migration season.[24]

Large land animals, such as deer, can also be a problem to aircraft during takeoff and landing. Between 1990 and 2013, civil aircraft experienced more than 1,000 collisions with deer and 440 with coyotes.[21]

An animal hazard reported from London Stansted Airport in England is rabbits: they get run over by ground vehicles and planes, and they pass large amounts of droppings, which attract mice, which in turn attract owls, which then become another birdstrike hazard.[25]

Countermeasures

[edit]

There are three approaches to reduce the effect of bird strikes. The vehicles can be designed to be more bird-resistant, the birds can be moved out of the way of the vehicle, or the vehicle can be moved out of the way of the birds.

Vehicle design

[edit]

Most large commercial jet engines include design features that ensure they can shut down after ingesting a bird weighing up to 1.8 kg (4.0 lb). The engine does not have to survive the ingestion, just be safely shut down. This is a standalone requirement, meaning the engine alone, not the aircraft, must pass the test. Multiple strikes (such as from hitting a flock of birds) on twin-engine jet aircraft are very serious events because they can disable multiple aircraft systems. Emergency action may be required to land the aircraft, as in the January 15, 2009 forced ditching of US Airways Flight 1549.

As required by the European Aviation Safety Agency (EASA)'s CS 25.631 or the Federal Aviation Administration (FAA)'s 14 CFR § 25.571(e)(1) post Amdt 25-96, modern jet aircraft structures are designed for continued safe flight and landing after withstanding one 4 lb (1.8 kg) bird impact anywhere on the aircraft (including the flight deck windshields). Per the FAA's 14 CFR § 25.631, they must also withstand one 8 lb (3.6 kg) bird impact anywhere on the empennage. Flight deck windows on jet aircraft must be able to withstand one 4 lb (1.8 kg) bird collision without yielding or spalling. For the empennage, this is usually accomplished by designing redundant structures and protected locations for control system elements or protective devices such as splitter plates or energy-absorbing material. Often, one aircraft manufacturer will use similar protective design features for all of its aircraft models, to minimize testing and certification costs. Transport Canada also pays particular attention to these requirements during aircraft certification, considering there are many documented cases in North America of bird strikes with large Canada geese which weigh approximately 8 lb (3.6 kg) on average, and can sometimes weigh as much as 14.3 lb (6.5 kg).

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. Current certification efforts are mainly conducted with limited testing, supported by more detailed analysis using computer simulation,[26] although final testing usually involves some physical experiments (see birdstrike simulator).

Based on US National Transportation Safety Board recommendations following US Airways Flight 1549 in 2009, EASA proposed in 2017 that engines should also be capable of sustaining a bird strike in descent. During descent, turbofans turn more slowly than during takeoff and climb. This proposal was echoed a year later by the FAA; new regulations could apply for the Boeing NMA engines.[27]

Wildlife management

[edit]
An Airbus A330 of China Eastern behind a flock of birds at London Heathrow

Though there are many methods available to wildlife managers at airports, no single method will work in all instances and with all species. Wildlife management in the airport environment can be grouped into two broad categories: non-lethal and lethal. Integration of multiple non-lethal methods with lethal methods results in the most effective airfield wildlife management strategy.

Non-lethal

[edit]

Non-lethal management can be further broken down into habitat manipulation, exclusion, visual, auditory, tactile, or chemical repellents, and relocation.

Habitat manipulation
[edit]

One of the primary reasons that wildlife is seen in airports is an abundance of food. Food resources on airports can be either removed or made less desirable. One of the most abundant food resources found on airports is turfgrass. This grass is planted to reduce runoff, control erosion, absorb jet wash, allow passage of emergency vehicles, and to be aesthetically pleasing.[28] However, turfgrass is a preferred food source for species of birds that pose a serious risk to aircraft, chiefly the Canada goose (Branta canadensis). Turfgrass planted at airports should be a species that geese do not prefer (e.g. St. Augustine grass) and should be managed in such a way that reduces its attractiveness to other wildlife such as small rodents and raptors.[29][28] It has been recommended that turfgrass be maintained at a height of 7–14 inches through regular mowing and fertilization.[30]

Wetlands are another major attractant of wildlife in the airport environment. They are of particular concern because they attract waterfowl, which have a high potential to damage aircraft.[31] With large areas of impervious surfaces, airports must employ methods to collect runoff and reduce its flow velocity. These best management practices often involve temporarily ponding runoff. Short of redesigning existing runoff control systems to include non-accessible water such as subsurface flow wetlands,[28] frequent drawdowns and covering of exposed water with floating covers and wire grids should be employed.[32] The implementation of covers and wire grids must not hinder emergency services.

Exclusion
[edit]

Though excluding birds (and flying animals in general) from the entire airport environment is virtually impossible, it is possible to exclude deer and other mammals that constitute a small percentage of wildlife strikes. Three-meter-high fences made of chain link or woven wire, with barbed wire outriggers, are the most effective. When used as a perimeter fence, these fences also serve to keep unauthorized people off of the airport.[33] Realistically, every fence must have gates. Gates that are left open allow deer and other mammals onto the airport. 15 foot (4.6 meter) long cattle guards have been shown to be effective at deterring deer up to 98% of the time.[34]

Hangars with open superstructures often attract birds to nest and roost in. Hangar doors are often left open to increase ventilation, especially in the evenings. Birds in hangars are in proximity to the airfield and their droppings are both a health and damage concern. Netting is often deployed across the superstructure of a hangar denying access to the rafters where the birds roost and nest while still allowing the hangar doors to remain open for ventilation and aircraft movements. Strip curtains and door netting may also be used but are subject to improper use (e.g. tying the strips to the side of the door) by those working in the hangar.[30][29]

Visual repellents
[edit]

There have been a variety of visual repellent and harassment techniques used in airport wildlife management. They include using birds of prey and dogs, effigies, landing lights, and lasers. Birds of prey have been used with great effectiveness at landfills where there were large populations of feeding gulls.[35] Dogs have also been used with success as visual deterrents and means of harassment for birds at airfields.[28] Airport wildlife managers must consider the risk of knowingly releasing animals in the airport environment. Both birds of prey and dogs must be monitored by a handler when deployed and must be cared for when not deployed. Airport wildlife managers must consider the economics of these methods.[33]

Effigies of both predators and conspecifics have been used with success to disperse gulls and vultures. The effigies of conspecifics are often placed in unnatural positions where they can freely move with the wind. Effigies have been found to be the most effective in situations where the nuisance birds have other options (e.g. other forage, loafing, and roosting areas) available. Time to habituation varies.[36][28]

Lasers have been used with success to disperse several species of birds. However, lasers are species-specific as certain species will only react to certain wavelengths. Lasers become more effective as ambient light levels decrease, thereby limiting effectiveness during daylight hours. Some species show a very short time to habituation.[37] The risks of lasers to aircrews must be evaluated when determining whether or not to deploy lasers on airfields.[38] Southampton Airport utilizes a laser device which disables the laser past a certain elevation, eliminating the risk of the beam being shone directly at aircraft and air traffic control tower.[39]

Auditory repellents
[edit]

Auditory repellents are commonly used in both agricultural and aviation contexts. Devices such as propane exploders (cannons), pyrotechnics, and bioacoustics are frequently deployed on airports. Propane exploders are capable of creating noises of approximately 130 decibels.[40] They can be programmed to fire at designated intervals, can be remote controlled, or motion activated. Due to their stationary and often predictable nature, wildlife quickly becomes habituated to propane cannons. Lethal control may be used to extend the effectiveness of propane exploders.

Wireless specialized launcher mounted in an airport vehicle

Pyrotechnics utilizing either an exploding shell or a screamer can effectively scare birds away from runways. They are commonly launched from a 12 gauge shotgun or a flare pistol, or from a wireless specialized launcher and as such, can be aimed to allow control personnel to "steer" the species that is being harassed. Birds show varying degrees of habituation to pyrotechnics. Studies have shown that lethal reinforcement of pyrotechnic harassment has extended its usefulness.[41] Screamer type cartridges are still intact at the end of their flight (as opposed to exploding shells that destroy themselves) constituting a foreign object damage hazard and must be picked up. The use of pyrotechnics is considered "take" by the U.S. Fish and Wildlife Service (USFWS) and USFWS must be consulted if federally threatened or endangered species could be affected. Pyrotechnics are a potential fire hazard and must be deployed judiciously in dry conditions.[29][37]

Bioacoustics, or the playing of conspecific distress or predator calls to frighten animals, is widely used. This method relies on the animal's evolutionary danger response.[37] One limitation is that bioacoustics are species-specific and birds may quickly become habituated to them. They should therefore not be used as a primary means of control.[30][29]

In 2012, operators at Gloucestershire Airport in England stated that songs by the American-Swiss singer Tina Turner were more effective than animal noises for scaring birds from its runways.[42]

Tactile repellents
[edit]

Sharpened spikes to deter perching and loafing are commonly used. Generally, large birds require different applications than small birds do.[28]

Chemical repellents
[edit]

There are only two chemical bird repellents registered for use in the United States, methyl anthranilate and anthraquinone. Methyl anthranilate is a primary repellent that produces an immediate unpleasant sensation that is reflexive and does not have to be learned. As such it is most effective for transient populations of birds.[28] Methyl anthranilate has been used with great success at rapidly dispersing birds from flight lines at Homestead Air Reserve Station.[43] Anthraquinone is a secondary repellent that has a laxative effect that is not instantaneous. Because of this, it is most effective on resident populations of wildlife that will have time to learn an aversive response.[28][44]

Relocation
[edit]

Relocation of raptors from airports is often considered preferable to lethal control methods by both biologists and the public. There are complex legal issues surrounding the capture and relocation of species protected by the Migratory Bird Treaty Act of 1918 and the Bald and Golden Eagle Protection Act of 1940. Prior to capture, proper permits must be obtained and the high mortality rates as well as the risk of disease transmission associated with relocation must be weighed. Between 2008 and 2010, U.S. Department of Agriculture Wildlife Services personnel relocated 606 red-tailed hawks from airports in the United States after the failure of multiple harassment attempts. The return rate of these hawks was 6%; the relocation mortality rate for these hawks was never determined.[28]

Lethal

[edit]

Lethal wildlife control on airports falls into two categories: reinforcement of other non-lethal methods and population control.

Reinforcement
[edit]

The premise of effigies, pyrotechnics, and propane exploders is that there be a perceived immediate danger to the species to be dispersed. Initially, the sight of an unnaturally positioned effigy or the sound of pyrotechnics or exploders is enough to elicit a danger response from wildlife. As wildlife become habituated to non-lethal methods, the culling of small numbers of wildlife in the presence of conspecifics can restore the danger response.[29][28]

Population control
[edit]

Under certain circumstances, lethal wildlife control is needed to control the population of a species. This control can be localized or regional. Localized population control is often used to control species that are residents of the airfield such as deer that have bypassed the perimeter fence. In this instance sharpshooting would be highly effective, such as is seen at Chicago O'Hare International Airport.[28]

Regional population control has been used on species that cannot be excluded from the airport environment. A nesting colony of laughing gulls at Jamaica Bay Wildlife Refuge contributed to 98–315 bird strikes per year, in 1979–1992, at adjacent John F. Kennedy International Airport (JFK). Though JFK had an active bird management program that precluded birds from feeding and loafing on the airport, it did not stop them from overflying the airport to other feeding sites. U.S. Department of Agriculture Wildlife Services personnel began shooting all gulls that flew over the airport, hypothesizing that eventually, the gulls would alter their flight patterns. They shot 28,352 gulls in two years (approximately half of the population at Jamaica Bay and 5–6% of the nationwide population per year). Strikes with laughing gulls decreased by 89% by 1992. However this was more a function of the population reduction than the gulls altering their flight pattern.[45][46][28]

Flight path

[edit]

Pilots should not take off or land in the presence of wildlife and should avoid migratory routes,[47] wildlife reserves, estuaries and other sites where birds may congregate. When operating in the presence of bird flocks, pilots should seek to climb above 3,000 feet (910 m) as rapidly as possible as most bird strikes occur below that altitude. Additionally, pilots should slow down their aircraft when confronted with birds. The energy that must be dissipated in the collision is approximately the relative kinetic energy () of the bird, defined by the equation where is the mass of the bird and is the relative velocity (the difference of the velocities of the bird and the plane, resulting in a lower absolute value if they are flying in the same direction and higher absolute value if they are flying in opposite directions). Therefore, the speed of the aircraft is much more important than the size of the bird when it comes to reducing energy transfer in a collision. The same can be said for jet engines: the slower the rotation of the engine, the less energy which will be imparted onto the engine at collision.

The body density of the bird is also a parameter that influences the amount of damage caused.[48]

The United States Air Force (USAF)'s Avian Hazard Advisory System (AHAS) uses near-real-time data from the National Weather Service's NEXRAD system to provide current bird hazard conditions for published military low-level routes, ranges, and military operating areas (MOAs). Additionally, AHAS incorporates weather forecast data with the Bird Avoidance Model (BAM) to predict soaring bird activity within the next 24 hours and then defaults to the BAM for planning purposes when activity is scheduled outside the 24-hour window. The BAM is a static historical hazard model based on many years of bird distribution data from the Christmas Bird Count, the Breeding Bird Survey, and National Wildlife Refuge data. The BAM also incorporates potentially hazardous bird attractions such as landfills and golf courses. AHAS is now an integral part of military low-level mission planning, with aircrew being able to access the current bird hazard conditions at a dedicated website. AHAS will provide relative risk assessments for the planned mission and give aircrew the opportunity to select a less hazardous route should the planned route be rated severe or moderate. Prior to 2003, the USAF BASH Team bird strike database indicated that approximately 25% of all strikes were associated with low-level routes and bombing ranges. More importantly, these strikes accounted for more than 50% of all of the reported damage costs. After a decade of using AHAS for avoiding routes with severe ratings, the strike percentage associated with low-level flight operations has been reduced to 12% and associated costs cut in half.

Avian radar[49] is an important tool for aiding in bird strike mitigation as part of overall safety management systems at civilian and military airfields. Properly designed and equipped avian radars can track thousands of birds simultaneously in real-time, night and day, through 360 degrees of coverage, out to ranges of 10 km (6.2 mi) and beyond for flocks, updating every target's position (longitude, latitude, altitude), speed, heading, and size every 2–3 seconds. Data from these systems can be used to generate information products ranging from real-time threat alerts to historical analyses of bird activity patterns in both time and space. The FAA and United States Department of Defense (DoD) have conducted extensive science-based field testing and validation of commercial avian radar systems for civil and military applications, respectively. The FAA used evaluations of commercial three-dimensional avian radar systems developed and marketed by Accipiter Radar[50] as the basis for an advisory circular[51] and a guidance letter[52] on using Airport Improvement Program funds to acquire avian radar systems at Part 139 airports.[53] Similarly, the DoD-sponsored Integration and Validation of Avian Radars (IVAR)[54] project evaluated the functional and performance characteristics of Accipiter avian radars under operational conditions at Navy, Marine Corps, and Air Force airfields. Accipiter avian radar systems operating at Seattle–Tacoma International Airport,[55] Chicago O'Hare International Airport, and Marine Corps Air Station Cherry Point made significant contributions to the evaluations carried out in the aforementioned FAA and DoD initiatives.

In 2003, a US company, DeTect, developed the only production model bird radar in operational use for real-time, tactical bird–aircraft strike avoidance by air traffic controllers. These systems are operational at both commercial airports and military airfields. The system has widely used technology available for BASH management and for real-time detection, tracking and alerting of hazardous bird activity at commercial airports, military airfields, and military training and bombing ranges. After extensive evaluation and on-site testing, MERLIN technology was chosen by NASA and was ultimately used for detecting and tracking dangerous vulture activity during the 22 Space Shuttle launches from 2006 to the conclusion of the program in 2011. The USAF has contracted DeTect since 2003 to provide the Avian Hazard Advisory System (AHAS) previously mentioned.

The Netherlands Organisation for Applied Scientific Research, a research and development organization, has developed the successful ROBIN (Radar Observation of Bird Intensity) for the Royal Netherlands Air Force (RNLAF). ROBIN is a near real-time monitoring system for flight movements of birds. ROBIN identifies flocks of birds within the signals of large radar systems. This information is used to warn air force pilots during take-off and landing. Years of observation of bird migration with ROBIN have also provided a better insight into bird migration behavior, which has had an influence on averting collisions with birds, and therefore on flight safety. Since the implementation of the ROBIN system at the RNLAF, the number of collisions between birds and aircraft in the vicinity of military airbases has decreased by more than 50%.

There are no civil aviation counterparts to the above military strategies. Some experimentation with small portable radar units has taken place at some airports, but no standard has been adopted for radar warning nor has any governmental policy regarding warnings been implemented.

History

[edit]

In aviation

[edit]
A painting depicting Eugène Gilbert in a Bleriot XI being attacked by an eagle over the Pyrenees in 1911
Rodgers in 1912 fatal crash
A Fw 190D-9 of 10./JG 54 Grünherz, pilot (Leutnant Theo Nibel), downed by a partridge which flew into the nose radiator near Brussels on 1 January 1945
October 31. 1964 Goose wings lie alongside fragments of Freeman's T-38 canopy.

The Federal Aviation Administration (FAA) estimates bird strikes cost US aviation 400 million dollars annually and have resulted in over 200 worldwide deaths since 1988.[56] In the United Kingdom, the Central Science Laboratory estimated[9] that worldwide, birdstrikes cost airlines around US$1.2 billion annually. This includes repair cost and lost revenue while the damaged aircraft is out of service. In 2003, there were 4,300 bird strikes listed by the United States Air Force and 5,900 by US civil aircraft.

The first reported bird strike was by Orville Wright in 1905. According to the Wright brothers' diaries, "Orville [...] flew 4,751 meters in 4 minutes 45 seconds, four complete circles. Twice passed over the fence into Beard's cornfield. Chased flock of birds for two rounds and killed one which fell on top of the upper surface and after a time fell off when swinging a sharp curve."[5]

During the 1911 Paris to Madrid air race, French pilot Eugène Gilbert encountered an angry mother eagle over the Pyrenees. Gilbert, flying an open-cockpit Blériot XI, was able to ward off the large bird by firing pistol shots at it but did not kill it.[57][58]

The first recorded bird strike fatality was reported in 1912 when aero-pioneer Calbraith Rodgers collided with a gull which became jammed in his aircraft control cables. He crashed at Long Beach, California, was pinned under the wreckage, and drowned.[3][59]

A Sikorsky UH-60 Black Hawk after a collision with a common crane (bird), and resulting failure of the windshield
The same UH-60, as seen from the inside

Before the crash of Jeju Air Flight 2216, the then greatest loss of life directly linked to a bird strike was on October 4, 1960, when a Lockheed L-188 Electra, flying from Boston as Eastern Air Lines Flight 375, flew through a flock of common starlings during take-off, damaging all four engines. The aircraft crashed into Boston Harbor shortly after takeoff, with 62 fatalities out of 72 passengers.[60] Subsequently, minimum bird ingestion standards for jet engines were developed by the FAA.

NASA astronaut Theodore Freeman was killed in 1964 when a goose shattered the plexiglass cockpit canopy of his Northrop T-38 Talon. Shards of plexiglass were ingested by the engines, leading to a fatal crash.[61]

On November 12, 1975, the flight crew of Overseas National Airways Flight 032 initiated a rejected takeoff after accelerating through a large flock of gulls at John F. Kennedy International Airport, resulting in a runway excursion.[62] Of the 139 aircraft occupants, all survived, while the aircraft was destroyed by an intense post-crash fire.[62] An investigation was carried out on the #3 engine by General Electric Aircraft Engines (GEAE) in Ohio. Disassembly revealed that several engine fan blades were damaged and broken, causing blades to abrade the epoxy fan shroud; as the epoxy combusted, it ignited jet fuel leaking from a broken fuel line.[62] However, GEAE denied that the ingested birds were the underlying cause of the damage.[62] Company investigators speculated that a tire or landing gear failure had occurred prior to the bird strikes, and that tire, wheel or landing gear debris ingested into the engine caused the fan blade damage and cut the fuel line.[62] To demonstrate that the General Electric CF6 engine was capable of withstanding a bird strike, the National Transportation Safety Board conducted a test with a sample engine.[62]

In 1988, Ethiopian Airlines Flight 604 sucked pigeons into both engines during takeoff and then crashed, killing 35 passengers.[63]

In 1995, a Dassault Falcon 20 crashed at Paris–Le Bourget Airport during an emergency landing attempt after sucking lapwings into an engine, which caused an engine failure and a fire in the airplane's fuselage; all 10 people on board were killed.[64]

On September 22, 1995, a U.S. Air Force Boeing E-3 Sentry AWACS aircraft (Callsign Yukla 27, serial number 77-0354), crashed shortly after takeoff from Elmendorf AFB. The aircraft lost power in both port side engines after these engines ingested several Canada geese during takeoff. It crashed about two miles (3.2 km) from the runway, killing all 24 crew members on board.[65]

On November 28, 2004, the nose landing gear of KLM Flight 1673, a Boeing 737-400, struck a bird during takeoff at Amsterdam Airport Schiphol. The incident was reported to air traffic control, the landing gear was raised normally, and the flight continued normally to its destination. Upon touching down at Barcelona International Airport, the aircraft started deviating to the left of the runway centreline. The crew applied right rudder, braking, and the nose wheel steering tiller but could not keep the aircraft on the runway. After it veered off the paved surface of the runway at about 100 knots, the jet went through an area of soft sand. The nose landing gear leg collapsed and the left main landing gear leg detached from its fittings shortly before the aircraft came to a stop perched over the edge of a drainage canal. All 140 passengers and six crew evacuated safely, but the aircraft itself had to be written off. The cause was discovered to be a broken cable in the nose wheel steering system caused by the bird collision. Contributing to the snapped cable was the improper application of grease during routine maintenance which led to severe wear of the cable.[66]

During the launch of STS-114 on July 26, 2005, a large bird (presumed to be a turkey vulture) was struck by Space Shuttle Discovery shortly after liftoff. The collision proved fatal to the bird; however, the Space Shuttle was undamaged.[67][68]

In April 2007, a Thomsonfly Boeing 757 from Manchester Airport to Lanzarote Airport suffered a bird strike when at least one bird, thought to be a crow, was ingested by the starboard engine. The plane landed safely back at Manchester Airport a while later. The incident was captured by two plane spotters on opposite sides of the airport, as well as the emergency calls picked up by a plane spotter's radio.[60]

On November 10, 2008, Ryanair Flight 4102 from Frankfurt to Rome made an emergency landing at Ciampino Airport after multiple bird strikes caused both engines to fail. After touchdown, the left main landing gear collapsed, and the aircraft briefly veered off the runway. Passengers and crew were evacuated through the starboard emergency exits.[69]

On January 4, 2009, a Sikorsky S-76 helicopter hit a red-tailed hawk in Louisiana. The hawk hit the helicopter just above the windscreen. The impact forced the activation of the engine fire suppression control handles, retarding the throttles and causing the engines to lose power. Eight of the nine people on board died in the subsequent crash; the survivor, a passenger, was seriously injured.[70]

On January 15, 2009, US Airways Flight 1549 from LaGuardia Airport to Charlotte/Douglas International Airport ditched into the Hudson River after experiencing a loss of both turbines. The engine failure was caused by running into a flock of geese at an altitude of about 3,200 ft (980 metres), shortly after takeoff. All 150 passengers and 5 crew members were safely evacuated after a successful water landing.[71] On May 28, 2010, the NTSB published its final report into the accident.[72]

On August 15, 2019, Ural Airlines Flight 178 from Moscow–Zhukovsky to Simferopol, Crimea, suffered a bird strike after taking off from Zhukovsky and crash landed in a cornfield 5 kilometers away from the airport. 74 people were injured, all with minor injuries.[73]

On September 16, 2023, the Italian Frecce Tricolori Aermacchi MB-339 squadron departed from the Turin Airport for an airshow. One jet experienced a sudden loss of engine power shortly after takeoff, possibly due to a bird strike, and crashed. The pilot ejected before the ground impact and was admitted to the hospital for burn injuries. A five-year-old girl died in the crash and subsequent fireball, and three other people were brought to the hospital for burns.[74]

The greatest loss of life directly linked to a bird strike was on 29 December 2024, when a Boeing 737-800, flying from Bangkok, Thailand to Muan, South Korea as Jeju Air Flight 2216, flew through a flock of birds during landing, leading to a dual engine failure. The aircraft crashed at Muan International Airport after a runway excursion into a concrete structure during a belly landing, resulting in 179 fatalities out of 181 occupants.[75]

In ground transportation

[edit]

During the 1952 edition of the Carrera Panamericana, Karl Kling and Hans Klenk suffered a bird strike incident when the Mercedes-Benz W194 was struck by a vulture in the windscreen. During a long right-hand bend in the opening stage taken at almost 200 km/h (120 mph), Kling failed to spot vultures sitting by the side of the road. When the vultures were scattered after hearing the loud W194 coming towards them, one vulture impacted through the windscreen on the passenger side. The impact was severe enough to briefly knock Klenk unconscious. Despite bleeding badly from facial injuries caused by the shattered windscreen, Klenk ordered Kling to maintain speed. He waited until a tire change almost 70 km (43 mi) later to clean himself and the car up, and the two eventually won the race. For extra protection, eight vertical steel bars were bolted over the new windscreen.[76] Kling and Klenk discussed the species and size of the dead bird, agreeing that it had a minimum 115-centimetre (45 in) wingspan and weighed as much as five fattened geese.[77]

Alan Stacey's fatal accident during the 1960 Belgian Grand Prix was caused when a bird hit him in the face on lap 25, causing his Lotus 18-Climax to crash at the fast, sweeping right hand Burnenville curve. According to fellow driver Innes Ireland's testimony in a mid-1980s edition of Road & Track magazine, spectators claimed that a bird had flown into Stacey's face while he was approaching the curve. Ireland stated that the impact might have knocked him unconscious, or possibly killed him by breaking his neck or inflicting a fatal head injury even before the car crashed.[78]

On lap 2 of the 1991 Daytona 500 driver Dale Earnhardt hit a seagull causing cosmetic damage to the front of his car. Despite this he would fight all the way up to second before spinning on the last lap and finishing fifth.

On March 30, 1999, during the inaugural run of the hypercoaster Apollo's Chariot in Virginia, passenger Fabio Lanzoni suffered a bird strike by a goose and required three stitches to his face. The roller coaster has a height of over 200 feet (61 m) and reaches speeds over 70 miles per hour (110 km/h).[79]

Bug strikes

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Flying insect strikes, like bird strikes, have been encountered by pilots since aircraft were invented. Future United States Air Force general Henry H. Arnold, as a young officer, nearly lost control of his Wright Model B in 1911 after a bug flew into his eye while he was not wearing goggles, distracting him.

In 1968, North Central Airlines Flight 261, a Convair 580, encountered large concentrations of insects between Chicago and Milwaukee. The accumulated insect remains on the windshield severely impaired the flight crew's forward visibility; as a result, while descending to land at Milwaukee, the aircraft suffered a mid-air collision with a private Cessna 150 that the Convair's flight crew had been unable to see until a split second before the collision, killing the three occupants of the Cessna and severely injuring the Convair's first officer.[80]

In 1986, a Boeing B-52 Stratofortress on a low-level training mission entered a swarm of locusts. The insects' impacts on the aircraft's windscreens rendered the crew unable to see, forcing them to abort the mission and fly using the aircraft's instruments alone. The aircraft eventually landed safely.[81]

In 2010, the Australian Civil Aviation Safety Authority (CASA) issued a warning to pilots about the potential dangers of flying through a locust swarm. CASA warned that the insects could cause loss of engine power, loss of visibility, and inaccurate airspeed readings via blocking an aircraft's pitot tubes.[82][83]

Bug strikes can also affect the operation of machinery on the ground, especially motorcycles. The team on the US TV show MythBusters – in a 2010 episode entitled "Bug Special" – concluded that death could occur if a motorist were hit by a flying insect of sufficient mass in a vulnerable part of the body. Anecdotal evidence from motorcyclists supports pain, bruising, soreness, stings, and forced dismount caused by collision with an insect at speed.[84]

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  • In the March 1942 Boy's Own Paper story Biggles and the Purple Plague, by Capt. W. E. Johns, a locust swarm threatens the ability of pilots to control their planes.
  • A 1964 episode of the Jonny Quest animated TV show features a giant condor ripping the wing off of a Fokker D.VII World War One fighter plane.
  • In the 1965 film Sands of the Kalahari, a twin-engine plane is brought down by a locust swarm that smears the windscreen and clogs the carburetor intakes.
  • In the 1989 film Indiana Jones and the Last Crusade, Henry Jones Sr. (Sean Connery) uses an umbrella to scare a flock of birds into the path of an attacking Luftwaffe fighter plane, causing it to sustain multiple bird strikes and crash, saving his life and the life of his son, Indiana Jones (Harrison Ford).
  • In the 1997 film The Edge, starring Anthony Hopkins and Alec Baldwin, their floatplane crashes after encountering bird strike, leaving the two stranded in the wilderness with their friend.
  • In the 2011 animated film Rio the plane the smugglers used to escape, a Short SC.7 Skyvan is hit by the film’s main villain, Nigel after being sent flying by a fire extinguisher from Blu, the main protagonist of the film attaching the fire extinguisher to his leg, causing the plane to go down, forcing the smugglers to ditch the plane and jump out of it.
  • The 2016 film Sully shows US Airways Flight 1549 captained by Chesley Sullenberger that was forced to ditch on the Hudson River in 2009 after sustaining a bird strike shortly after takeoff from LaGuardia Airport.
  • In the 2022 film Top Gun: Maverick Phoenix and Bob are forced to eject after a bird strike causes the engines of their F/A-18F to flame out.

See also

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References

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Revisions and contributorsEdit on WikipediaRead on Wikipedia
from Grokipedia
A bird strike is defined as a collision between a bird and an during flight, takeoff, or roll, posing a notable hazard to worldwide. These incidents most frequently occur at low altitudes below 500 feet, particularly during takeoff and phases, when and birds share overlapping near airports. Bird strikes can involve single birds or flocks, with , pigeons, and waterfowl among the most commonly implicated species due to their abundance around aerodromes. In the United States, the (FAA) has documented 319,047 strike reports from 1990 through 2024 (as of 2024), with birds accounting for more than 95% of these events across 2,360 domestic and 343 foreign airports. The frequency of reported strikes has risen steadily, increasing by 14% from 2023 to 2024, reflecting greater air traffic, improved reporting, and expanding populations. Globally, such collisions have led to over 600 hull losses and more than 650 fatalities since the advent of powered flight (as of 2024, with more than 360 destroyed and 643 fatalities from 1990–2024 alone), though most strikes cause no damage or only minor issues. Approximately 62% of bird strikes happen during daylight hours, 30% at night, and the remainder at dawn or dusk, with about 60% involving multiple birds. The impacts of bird strikes can be severe, damaging critical components like engines, windshields, and control surfaces, potentially leading to loss of control or forced landings. In the U.S., these events result in over $900 million in annual to civil and , including repair costs and operational disruptions (as of recent estimates). While fatal accidents are rare—far less than 1% of strikes causing any —historical indicate at least 231 deaths and 80 destroyed civil aircraft from 1912 to 2003 alone. Notable incidents include engine failures from ingested birds, highlighting vulnerabilities in systems. To mitigate risks, the (ICAO) mandates that airports assess and reduce bird hazards through integrated programs. Strategies encompass habitat modification to eliminate food and water attractants, non-lethal harassment using , dogs, or lasers, and advanced technologies like bird-detecting radars and lighting. Pilots are advised to report sightings and avoid known bird concentrations, while ongoing research focuses on bird-resistant designs and of hazardous . These efforts have contributed to declining damage rates per strike despite rising incident numbers.

Definition and Description

Event Mechanics

A bird strike collision is governed by fundamental physical principles, primarily the transfer of from the moving to the aircraft's structure. The involved is calculated using the formula E=12mv2E = \frac{1}{2} m v^2 where mm represents the of the and vv is the between the and the aircraft. This energy dissipates upon impact, generating substantial forces that can deform or aircraft components, depending on factors such as material strength and impact angle. For instance, a 2 kg colliding at 650 km/h possesses approximately 32,600 joules of , equivalent to the force of a small . The event unfolds in distinct stages based on the collision site. In engine ingestion, the bird is drawn into the inlet by high-velocity airflow, where it strikes fan blades at high rotational speeds, often fragmenting and causing imbalance or blade damage that propagates through compressor stages. Windshield impacts occur when the bird hits the forward-facing cockpit glass, designed with layered materials to absorb energy, though severe cases can lead to cracking and visibility impairment. Fuselage collisions, less frequent, involve direct hits to the aircraft body, potentially denting skin panels or penetrating if the bird is large. The bird's anatomy plays a key role here: its feathers, which provide lightweight insulation, tend to shred and disperse upon impact, while hollow, pneumatic bones crush easily, allowing the body to behave somewhat like a fluid mass that conforms to surfaces and transfers energy diffusely rather than rigidly. Common impact locations on aircraft include engine inlets, which account for approximately 9% of reported bird strikes, though they are involved in about 25% of damaging events due to their forward position and suction effect during low-altitude operations. Leading edges of wings are also vulnerable, where strikes can erode aerodynamic surfaces or damage control surfaces, and radomes (the nose cone housing radar) often suffer delamination from high-impact forces. Initial detection poses significant challenges, as birds typically range from 0.1 to 4 kg and fly at speeds up to 100 km/h, while aircraft during takeoff accelerate to 250-300 km/h, resulting in closing speeds that afford pilots mere seconds to react, often rendering avoidance maneuvers ineffective.

Classification by Vehicle Type

Bird strikes are predominantly classified by the type of vehicle or structure involved, with accounting for the majority of formally documented incidents due to mandatory reporting requirements in that sector. In , over 90% of bird strikes occur during takeoff or phases at low altitudes below 500 feet, where speeds and bird densities near airports intersect most frequently. The (FAA) reports approximately 22,000 wildlife strikes with U.S. civil in 2024, with birds involved in about 92% of cases (roughly 20,000 bird strikes), marking a 14% increase from the previous year. These collisions often involve higher relative speeds compared to other vehicle types, amplifying damage potential to both and birds. Ground transportation experiences bird strikes primarily through vehicle windshield impacts and train collisions, which occur at lower speeds but with potentially higher frequency in rural settings where bird populations and road networks overlap extensively. In the United States, an estimated 89 million to 340 million birds die annually from vehicle collisions, with rural roads—comprising over 75% of the nation's lane miles—contributing disproportionately due to higher speed limits and proximity. Train strikes, though less quantified nationally, are documented in studies of lines, where birds like bustards face elevated risks during migration, with intensive monitoring on select European stretches recording up to 19 fatalities over two years on short segments. These incidents highlight behavioral factors, such as birds foraging on tracks, rather than aerodynamic forces dominant in . Other structures, including wind turbines and , represent growing categories of bird strikes influenced by infrastructure expansion. Wind turbine blade strikes particularly affect migratory birds, with U.S. estimates indicating 140,000 to 680,000 avian fatalities annually, driven by turbine placement in migration corridors and increasing deployment. Building collisions, especially with glass surfaces in urban areas, cause over 1 billion bird deaths per year in the U.S., as reflective or transparent facades render structures invisible to birds during flight. Emerging research underscores the rising impacts of renewable energy sites, where blade rotation and height exacerbate collision risks for soaring species. Comparatively, dominates documented bird strike cases, comprising about 95% of reported incidents globally due to regulatory oversight, while non-aviation collisions—though far more numerous in total bird mortality—are increasingly tracked amid and . For instance, while U.S. civil are involved in approximately 20,000 bird strikes annually (as of 2024), and building impacts dwarf this figure at hundreds of millions each, signaling a shift in overall risk profiles as human development expands.

Risk Factors

Bird Species Involved

Bird strikes predominantly involve species that are abundant near airports, exhibit flocking behaviors, or migrate through flight paths, with (family ), geese (family ), European starlings ( vulgaris), and rock pigeons (Columba livia) ranking among the most frequently reported worldwide. According to the (ICAO) Bird Strike Information System () data from 2016 to 2021, hawks, eagles, and vultures accounted for 28% of all reported strikes, perching birds for 27%, and shorebirds—including —for 18%, highlighting the prevalence of raptors and species in aviation hazards. In the United States, the Federal Aviation Administration's National Wildlife Strike Database (1990–2024) identifies Canada geese (Branta canadensis) as the most commonly struck large bird species, comprising a significant portion of incidents involving birds over 1.8 kg, often due to their presence at airports near water bodies. Biological characteristics amplify the risk posed by these species, particularly body mass, which correlates with damage potential, and flocking tendencies that increase collision probabilities. Larger birds like Canada geese, with adult body masses ranging from 3 to 6 kg, inflict greater structural harm to compared to smaller species, as evidenced by hazard rankings in the U.S. database where geese top the list for economic impact per strike. behavior exacerbates risks; for instance, European starlings form murmurations of thousands to millions, while Canada geese aggregate in groups up to 1,000 or more, leading to multiple-bird strikes in about 32% of reported cases involving waterfowl. Migration patterns further concentrate hazards during peak seasonal movements when birds fly at altitudes overlapping low-level corridors, with strikes showing clear seasonal peaks in spring and autumn. Regional variations reflect local ecology and bird distributions, influencing strike profiles. In the United States, waterfowl such as geese and represent about 8% of all reported bird strikes, per analyses from the national database. sees higher involvement from wading and species like northern lapwings (Vanellus vanellus), which are common in agricultural areas near airfields and contribute to seasonal peaks in the and continental reports. In and parts of , large raptors including (family ) pose elevated risks due to their soaring at altitudes up to 11,000 meters, with (Quelea quelea) flocks numbering in the millions driving mass strikes in sub-Saharan regions, though vulture incidents dominate in .

Environmental and Behavioral Contributors

Bird strikes are significantly influenced by habitat attractants near airports, such as landfills, wetlands, and agricultural fields, which draw birds to areas overlapping with operations. Landfills provide scavenging opportunities for like , increasing their presence and behavior around runways. Wetlands and open water bodies similarly attract waterfowl; for instance, impoundments and restored open-water sites have been shown to elevate strike risks by concentrating birds in proximity to airports. Agricultural fields near airports, particularly those with crops like corn or , lure granivorous birds during harvest seasons, exacerbating collision probabilities. has further intensified these issues by expanding human development into bird habitats, thereby increasing encounters between and local avian populations. Seasonal and temporal patterns also play a critical role in elevating strike risks, with peaks occurring during spring and fall migrations when large numbers of birds traverse low-altitude flight paths. Strikes are more frequent at dawn and dusk due to heightened bird activity and reduced visibility for pilots, coinciding with busy airport operations. Weather conditions, such as fog or low clouds, can concentrate birds at lower altitudes by limiting their vertical dispersal, further heightening collision chances during these periods. Behavioral drivers of birds contribute substantially to strike occurrences, as many engage in feeding and breeding activities near runways where food sources like or waste are abundant. Most birds prefer altitudes below 3,000 feet, aligning directly with the typical climb-out and approach phases of aircraft flights, where over 90% of strikes take place. For example, Canada geese often feed in grassy areas adjacent to runways in wetland-proximate airports, amplifying local hazards. Human-induced factors compound these environmental and behavioral risks, particularly through airport lighting that attracts and, subsequently, insectivorous birds at night. Agricultural practices, such as plowing or near airfields, draw flocks to exposed food sources, while broader land-use changes like wetland drainage or planting patterns inadvertently boost bird concentrations in strike-prone zones. As of 2025, strikes continue to rise, with preliminary FAA reports indicating persistent patterns influenced by expanding bird populations.

Impacts and Consequences

Safety Risks

Bird strikes pose significant safety risks to aviation, primarily through the potential for catastrophic engine failures that can lead to loss of thrust and subsequent crashes, particularly in dual-engine aircraft where both powerplants are affected. Globally, wildlife strikes, predominantly involving birds, have resulted in 499 human fatalities and the destruction of 361 aircraft from 1988 to October 2024. These incidents are rare relative to the volume of flights but severe in outcome, with engine ingestion of birds often causing flameouts or structural damage that compromises flight control. For instance, penetration of bird debris into engines can disrupt , leading to compressor stalls and immediate power loss, as seen in cases where pilots must execute emergency procedures to maintain altitude. Injury mechanisms from bird strikes typically involve high-velocity impacts that generate debris capable of penetrating aircraft structures, such as windshields or fuselages, or causing sudden loss of control through aerodynamic disruption. Debris from ingested birds can fragment within engines and puncture cabin areas, injuring occupants via lacerations or blunt force, while windshield strikes may impair pilot visibility or cause structural failure, exacerbating control issues. Approximately 3.7% of reported bird strikes in the United States resulted in aircraft damage in 2024, down from 6% in 1996, highlighting that while most encounters cause minimal harm, the subset leading to penetration or control loss accounts for the majority of injuries and fatalities. Collision mechanics, such as a bird's body deforming upon impact, can transmit kinetic energy sufficient to induce engine flameouts without full penetration. The most vulnerable phases of flight are , which account for about 90% of bird strike incidents due to low altitudes near airports where activity is concentrated. During these critical periods, pilots follow established response protocols to mitigate risks: maintain control as the primary action, notify immediately, monitor parameters for anomalies, and prepare for single- or dual- by configuring for a precautionary . These protocols emphasize avoiding abrupt maneuvers that could worsen damage and include limiting to 250 knots below 10,000 feet to reduce impact energy. Operational disruptions from bird strikes frequently include emergency landings, flight delays, and diversions, which heighten risks during high-workload phases. In , the consequences are amplified by high-performance aircraft, where strikes have prompted pilot ejections; for example, a 2018 U.S. T-38C trainer crashed after a bird-induced , forcing the crew to eject with minor injuries, and a 1998 F-16 incident involved canopy penetration leading to ejection and aircraft loss. Such events underscore the elevated hazards in tactical operations, where rapid response and ejection systems are essential to prevent loss of life.

Economic and Environmental Effects

Bird strikes impose substantial direct economic costs on the industry, primarily through aircraft repairs, which can range from $1 million to $5 million per major incident involving engine damage or structural repairs. and evacuation expenses further contribute to these burdens, particularly in incidents requiring emergency responses. Globally, these direct costs in aviation alone are estimated at $1.2 billion annually. Indirect costs exacerbate the financial strain, encompassing flight cancellations, elevated insurance premiums for airlines, and lost productivity from operational disruptions. For instance, delays from bird strikes can lead to "spillover" effects costing around $25 million annually in the U.S. due to subsequent flight interruptions. In non-aviation sectors, such as rail transport, bird strikes cause train delays and require ongoing maintenance, while wind turbine collisions necessitate repairs that add to operational expenses, though specific figures remain limited compared to aviation. Environmentally, bird strikes result in significant avian mortality, with aviation collisions killing an estimated tens of thousands of birds annually in the U.S., contributing to broader population declines. In non-aviation contexts, turbines cause between 140,000 and 679,000 deaths per year in the U.S., affecting migratory and resident . expansions disrupt habitats by converting natural areas into runways and infrastructure, leading to in migration corridors and heightened strike risks for remaining avian populations. Data trends indicate rising economic pressures, with U.S. strikes increasing from 7,665 in to 10,714 in 2020, reflecting a roughly 40% rise driven by air traffic growth and environmental factors, which amplifies both costs and ecological impacts. This upward trend continued, with strikes reaching over 22,000 in 2024, a 14% increase from 2023.

Prevention and Mitigation

Technological and Design Solutions

Aircraft engines are designed with reinforced inlets to withstand bird ingestion, as mandated by (FAA) certification standards under 14 CFR § 33.76, which require engines to ingest a 4-pound bird at takeoff speed (V0) without exceeding specified power loss or structural damage thresholds. These standards, updated in 2007 to address larger flocking birds over 2.5 pounds, ensure that turbine engines maintain at least 75% power post-ingestion for critical phases of flight. Bird-resistant windshields employ multi-layered acrylic constructions, often combining stretched acrylic panes with outer glass or polycarbonate layers in a fail-safe design that redistributes impact loads if the outer layer fractures. This configuration, common in commercial and military aircraft, absorbs kinetic energy from birds up to 4 pounds at cruise speeds, preventing penetration and maintaining pilot visibility. Advancements in composite materials have enhanced fan blade resilience against bird strikes, with hybrid carbon fiber reinforced polymer (CFRP) laminates demonstrating superior energy absorption compared to monolithic composites. These blades, tested under FAA protocols, exhibit reduced and up to 20% higher impact tolerance due to fiber hybridization, though they require ongoing certification for bird ingestion scenarios. Emerging self-healing polymers, incorporating microcapsules that release healing agents upon impact, show promise for repairing microcracks in composite structures post-strike, potentially restoring 70-90% of original strength in lab tests. Radar-based bird detection systems, such as avian radars, provide real-time alerts to pilots and air traffic controllers by tracking bird flocks up to 11 kilometers away in 3D space, enabling evasive maneuvers during takeoff and landing. These systems, deployed at airports like Seattle-Tacoma International, integrate with displays to reduce strike risks by forecasting bird trajectories with 80-90% accuracy in controlled environments. In non-aviation sectors, wind turbine blades incorporate ultraviolet-reflective coatings to increase visibility and deter birds, while painting one black has been shown to reduce collision rates by 70% in field studies by minimizing motion blur. For high-speed trains, tubular screen designs installed along tracks mitigate bird strikes by deflecting wildlife without obstructing , achieving up to 50% fewer incidents in European rail tests. Emerging integrations include scarers mounted on vehicles, which emit low-power beams to disperse birds proactively, with automated systems achieving up to 40% daily repulsion rates in experimental settings. Recent 2025 explores drone-integrated AI systems for real-time bird detection and deterrence, potentially reducing false alerts and enhancing proactive mitigation. Technological solutions have collectively lowered damaging bird strikes in aviation from approximately 16% of total incidents in 1996 to 3.7% in 2024, with specific implementations like pulsed on reducing strikes by 30-66%. However, limitations persist, as retrofitting small with advanced composites or radars often proves cost-prohibitive, and efficacy drops against large flocks exceeding certification parameters.

Wildlife Control Methods

Wildlife control methods for mitigating bird strikes primarily focus on deterring or managing bird populations in and around through non-lethal and lethal approaches, often integrated into comprehensive hazard management plans. Non-lethal techniques aim to make environments less attractive or to scare birds away without causing harm, prioritizing long-term prevention over reactive measures. Habitat modification is a foundational non-lethal strategy that alters the airport landscape to reduce its appeal to birds. Common practices include draining or filling ponds to eliminate open water sources that attract waterfowl, and planting native grasses taller than 10 inches to discourage by like and geese. These modifications have proven effective and enduring, with studies showing they can significantly lower presence by targeting ecological attractants. For instance, at airports implementing such changes, activity has been reduced by up to 80% in modified areas, as attractants like short grass or standing water are minimized. Auditory and visual deterrents complement habitat efforts by actively dispersing birds. Pyrotechnics, such as propane cannons or screamer shells, produce loud noises or flashes to startle flocks, achieving near-100% immediate dispersal effectiveness in North American airport programs. Visual aids include fake predators like owl decoys or trained dogs, while bioacoustic devices broadcast distress calls to repel specific species. These methods can achieve 70-90% reductions in bird numbers when rotated to prevent familiarity, though efficacy varies by species; for example, geese respond well to border collies herding them away. Lethal methods are employed selectively to reinforce non-lethal tactics, particularly for persistent or high-risk populations, under strict regulatory oversight. The USDA's Wildlife Services program conducts targeted , such as or problematic birds, at approximately 150 U.S. airports annually to reduce local populations and enhance deterrence. Falcons or other raptors are sometimes used for lethal takedowns, though they more often serve in roles. However, these approaches are constrained by the Migratory Bird Treaty Act, which prohibits the take of protected species without depredation permits from the U.S. Fish and Wildlife Service, ensuring ethical and legal compliance. Integrated wildlife management programs combine non-lethal and lethal techniques for sustained impact, adapting to site-specific risks through ongoing monitoring and adjustment. The USDA collaborates with airports to implement these holistic plans, incorporating habitat changes, harassment, and selective removals to address attractants and behaviors. At John F. Kennedy International Airport, such a program has contributed to a notable decline in gull removals (over 70%) and Canada goose strike rates (about 44%) since the 1990s, though overall wildlife strike rates have increased due to higher air traffic and improved reporting. These programs emphasize species-specific targeting, such as focusing on Canada geese via egg addling alongside deterrence. Despite their effectiveness, wildlife control methods face challenges like bird habituation to repeated deterrents, where species such as gulls acclimate to noises or visuals within weeks, reducing long-term efficacy. Seasonal variability exacerbates risks during migration peaks, when bird densities surge unpredictably. To counter these, recent advancements include AI-monitored systems using radar and machine learning for real-time bird detection and automated responses, deployed at airports like Schiphol to enhance proactive deterrence without constant human intervention.

Operational and Regulatory Approaches

Operational procedures for mitigating bird strikes emphasize proactive adjustments in flight paths and aircraft performance. Pilots are advised to climb to higher altitudes when operating near known bird concentration areas, such as wetlands or migration routes, to reduce encounter probabilities, as most strikes occur below 3,000 feet. During peak bird seasons, like spring and fall migrations, air traffic control coordinates with pilots to implement speed reductions on approach and departure, which can lessen impact forces since increases with the square of velocity. These measures, integrated into standard operating procedures, allow birds more reaction time and minimize potential damage without compromising overall flight efficiency. Regulatory frameworks establish mandatory protocols for strike prevention and response. In the United States, the (FAA) requires all aircraft operators to report wildlife strikes using Form 5200-7, with detailed submissions mandatory for incidents causing damage or involving turbine-powered aircraft; this data feeds into the National Wildlife Strike Database for analysis. Certificated airports must conduct periodic wildlife hazard assessments to identify risks and implement management plans under 14 CFR Part 139. Internationally, the (ICAO) mandates that aerodromes develop and maintain a Wildlife Hazard Management Programme (WHMP) as outlined in Annex 14 and Airport Services Manual Doc 9137, encompassing site-specific evaluations, monitoring, and mitigation strategies. Airport zoning regulations further prohibit hazardous attractants, such as landfills, facilities, or operations, within separation distances typically ranging from 3 to 10 km of runways to deter bird foraging. In the , post-2020 updates include EASA's 2021 amendments to Certification Specifications for small (CS-27), introducing risk-based requirements to prevent windshield penetration from bird strikes and enhance occupant safety. Training protocols and data-sharing mechanisms support these regulations by fostering awareness and collaboration. Pilot training programs, endorsed by the FAA and ICAO, incorporate bird strike avoidance into recurrent curricula, teaching recognition of high-risk conditions, tactical maneuvers like shallow climbs, and post-strike checklists for engine and control assessments. Air traffic controllers receive specialized instruction to issue timely advisories on bird activity, often derived from real-time or ground reports. Global databases, including ICAO's Bird Strike Information System () and the FAA's National Wildlife Strike Database, facilitate international data exchange, enabling airports and operators to analyze trends, predict seasonal risks, and refine mitigation tactics. Compliance with these operational and regulatory approaches has demonstrated measurable effectiveness in reducing bird strike risks. Integrated wildlife management programs, including procedural adjustments and zoning enforcement, have achieved up to 99% prevention of potential strikes in airport departure scenarios through targeted interventions. Broader adherence correlates with 20-40% overall risk reductions in strike rates at managed facilities, as evidenced by longitudinal data analyses. Emerging regulations for unmanned aerial systems (UAS) and electric vertical takeoff and landing (eVTOL) vehicles are addressing unique vulnerabilities; for instance, the FAA and EASA are developing performance-based certification standards that incorporate bird impact testing, recognizing the lower-altitude operations of these aircraft amplify exposure.

Historical Context

Notable Aviation Events

The first recorded fatal bird strike in aviation history occurred on April 3, 1912, when pioneering aviator ' Wright Model B biplane collided with a while flying along the southern California coast near Long Beach; the bird became entangled in the control cables, causing the aircraft to crash and resulting in Rodgers' death. This incident highlighted the potential dangers of collisions even in the early days of powered flight, when aircraft were slow and propeller-driven. A more devastating event took place on October 4, 1960, involving Flight 375, a Lockheed L-188A Electra departing from Boston's ; seconds after takeoff, the aircraft ingested a large flock of starlings into engines 1, 2, and 4, leading to a loss of power and a crash into that killed 62 of the 72 people on board. This remains the deadliest bird strike in history until 2024, with investigations revealing that up to 20,000 starlings had been attracted to the airport area by nearby food sources. The accident prompted early U.S. regulatory efforts to address wildlife hazards at airports, including improved bird control measures. In the military sector, a notable case occurred on May 20, 1995, when a Norwegian Air Force F-16B fighter struck a approximately 45 seconds after takeoff from Rygge Air Station at an altitude of about 1,100 feet; the bird ingestion caused engine failure and the aircraft to crash, though both the instructor pilot and student ejected safely with minor injuries. Such military incidents underscored the risks to high-performance jets operating at low altitudes near coastal areas with abundant bird populations. A prominent modern commercial example is on January 15, 2009, when an Airbus A320 departing from New York LaGuardia Airport encountered a flock of Canada geese at about 2,800 feet, resulting in the ingestion of multiple birds into both CFM56 engines and causing a complete loss of thrust; Captain Chesley Sullenberger successfully ditched the aircraft in the , known as the "Miracle on the Hudson," with all 155 passengers and crew surviving. The (NTSB) investigation confirmed that the birds disabled both engines within seconds, emphasizing the vulnerability of turbofan engines to large bird strikes during critical climb phases. Since the 1980s, reported bird strikes in have trended upward, with the FAA documenting over 310,100 strikes in the U.S. from 1990 through December 2024, with s accounting for more than 90% of these events. This increase is driven by expanding populations of large birds like geese and the inherent vulnerabilities of high-bypass jet engines, which sustain more severe damage from bird ingestion due to their design for efficiency and quiet operation. Contributing factors include increased air traffic, low-altitude operations near airports, and changes that concentrate birds in flight paths. These trends have amplified safety risks, particularly during when aircraft are slowest and closest to the ground. NTSB investigations into major bird strike events have directly influenced design improvements; for instance, analyses following incidents like the 2009 Hudson ditching and 2023 bird strikes on aircraft with CFM LEAP-1B engines revealed risks of smoke entering the and cabin due to oil system failures post-, leading to urgent recommendations for modifications such as load reduction devices and improved oil containment to better withstand bird impacts. Earlier probes, including the 1960 Eastern Flight 375 crash, contributed to broader FAA guidelines on for bird tolerance, spurring iterative redesigns in technology to minimize power loss from collisions. A tragic recent example is the December 29, 2024, crash of Flight 7C2216, a 737-800 approaching in ; preliminary investigations confirmed bird strikes damaged both engines shortly before landing, contributing to the aircraft's , overrun, and collision with a concrete barrier, resulting in 179 fatalities out of 181 on board. This incident, the deadliest attributed to bird strikes in history, has prompted renewed global scrutiny on wildlife hazard management at airports.

Incidents in Other Sectors

Bird strikes extend beyond into ground transportation, where collisions with vehicles and trains pose significant risks to and infrastructure. In the United States, vehicle-bird collisions result in an estimated 89 to 340 million bird deaths annually, highlighting the scale of impacts on roadways. These incidents often involve birds or crossing paths with traffic, contributing to broader mortality patterns. For rail systems, while large mammals like deer are more commonly associated with , bird flocks on tracks have occasionally led to operational disruptions in since the 1970s, though specific cases remain rare and underdocumented compared to mammalian strikes. Infrastructure-related bird strikes have been particularly notable in installations and urban environments. At the Wind Resource Area in , wind turbines caused approximately 600 to 900 raptor deaths per year in the early , with numbers declining further after turbine repowering efforts, underscoring the hazards to from turbine blades. Similarly, building collisions in claim over 1 billion birds annually, primarily due to reflections and transparent surfaces in urban high-rises that disorient migrants. These events illustrate how static structures exacerbate collision risks in densely developed areas. Recent advancements in technology have introduced new collision vectors. Between 2020 and 2025, drone testing has reported isolated bird strikes, such as a 2024 incident where a Matrice 600 drone crashed into a after colliding mid-flight with a , damaging property and highlighting vulnerabilities in unmanned aerial systems. In solar farms, the "lake effect" attracts waterbirds and shorebirds to reflective photovoltaic panels, mistaking them for water bodies and increasing collision and entrapment risks. These incidents across sectors have prompted policy shifts emphasizing bird-friendly designs. In , reports advocate for avian-safe turbine placement and panel coatings to reduce reflections, influencing guidelines from organizations like the Audubon Society for transmission and projects. For rail and urban , emerging standards promote corridors and anti-collision glazing, fostering integrated approaches to mitigate non-aviation bird strikes while supporting sustainable development.

Insect and Debris Strikes

Insect strikes, often referred to as "bug strikes," involve collisions between and swarms of small flying , which differ from bird strikes primarily in scale and impact severity. While individual pose minimal risk due to their size, dense swarms can lead to engine fouling by accumulating in intake areas, potentially reducing airflow and causing temporary performance degradation. For instance, locust swarms in have been documented to enter engines and pitot tubes, leading to unreliable instrument readings and operational disruptions during takeoff or landing. These strikes are generally less catastrophic than bird encounters but exert cumulative effects over multiple flights, particularly through residue buildup on aerodynamic surfaces. Insect remains can roughen wing leading edges, accelerating boundary layer transition to turbulence and increasing drag by up to 4% in contaminated areas, which in turn elevates fuel consumption. Windshield abrasion from repeated impacts creates a hazy patina of micro-scratches, impairing pilot visibility during low-altitude operations like approach and landing. Debris strikes, classified by the (FAA) as (FOD), typically involve non-biological runway hazards such as loose gravel, tools, or tire fragments ingested during takeoff or landing. Unlike bird strikes, which are biological and airborne, FOD originates from ground operations and can cause immediate structural damage to engines or undercarriages, with annual global costs exceeding $4 billion in repairs and delays. Hybrid risks arise when birds collide with aircraft and generate secondary debris, such as feathers or tissue fragments, that exacerbate engine damage or contaminate control surfaces. Mitigation strategies for insect and debris strikes overlap with those for birds but require adaptations for smaller targets and ground-based threats. Radar systems effective against avian flocks can detect insect swarms, though their lower radar cross-section demands higher-resolution sensors; emerging insect-monitoring radars are being explored for airport perimeters. For engines, fine-mesh screens or electrostatic repellents are under development to prevent ingestion without impeding airflow, while routine cleaning addresses residue buildup. FOD prevention emphasizes airport sweeps and personnel training, reducing incidents by integrating automated detection tools. Biohazards, including insects and birds, contribute to a notable portion of propulsion anomalies, with wildlife-related events accounting for over 20% of reported engine incidents in some analyses. Climate change is amplifying these risks by driving erratic insect migrations, particularly for species, through altered rainfall patterns that foster breeding booms similar to shifts observed in timings. Increased swarm frequency in regions like and heightens the potential for encounters during critical flight phases, paralleling the unpredictable avian patterns exacerbated by warming temperatures.

Depictions in Media and Culture

Bird strikes have been portrayed in film and television as dramatic threats to , often emphasizing the sudden peril they pose to pilots and passengers. The 2016 biographical drama Sully, directed by and starring as Captain Chesley Sullenberger, centers on the 2009 incident, where a flock of Canada geese struck both engines shortly after takeoff from , forcing an emergency on the . This depiction highlights the pilots' quick decision-making amid engine failure, drawing from real NTSB investigations and Sullenberger's memoir to underscore the rarity and severity of such dual-engine bird strikes. Other films, such as (2022), include bird strike sequences during high-speed maneuvers, portraying the visceral impact on aircraft canopies and controls to heighten tension in narratives. Documentaries have further illuminated bird strikes through educational lenses, focusing on real events and mitigation efforts. The Smithsonian Channel's 2019 production Bird vs. Plane: Miracle on the Hudson recounts the Flight 1549 ditching while exploring the broader epidemiology of wildlife-aircraft collisions, including statistical trends from FAA databases. Similarly, the National Film Board of Canada's 1970 short Stop Bird Strikes uses footage of airport operations to demonstrate hazards like engine ingestion and the importance of habitat management, aiming to inform aviation personnel on proactive defenses. These works blend archival material with expert interviews to convey the $1.2 billion annual economic toll on from such incidents. In literature and news media, bird strikes feature as cautionary tales of technological vulnerability. Peter L. Kalafatas's 2015 narrative nonfiction book Bird Strike: The Crash of the Boston Electra details the 1960 Eastern Air Lines Flight 375 disaster, where a bird strike precipitated a crash-landing at Boston Logan Airport, killing 62 people; the author draws on eyewitness accounts and wreckage analysis to examine regulatory lapses in early jet-age safety. Media coverage often intensifies after high-profile events, as seen following the 2009 Hudson incident, which spurred FAA releases of strike data and widespread reporting on rising global occurrences. Wildlife strikes in the U.S. increased from 19,628 in 2023 to 22,372 in 2024 (a 14% rise), as reported by news outlets and the FAA, attributing increases to growing bird populations and air traffic; examples included an Iberia flight's emergency return from Madrid due to engine damage. A more recent tragedy, the December 29, 2024, crash of Flight 2216 in —which killed 179 of 181 on board after a strike caused dual engine failure—has drawn significant media scrutiny. Preliminary investigations confirmed bird remains in the engines, leading to extensive coverage in outlets like and Al Jazeera, documentaries exploring post-strike, and debates on airport wildlife management. This incident, one of the deadliest bird strike-related crashes, parallels earlier events in highlighting systemic vulnerabilities. Culturally, bird strikes symbolize the fraught intersection of human progress and natural forces, echoing longstanding where birds signal omens or disruptions. Alfred Hitchcock's 1963 thriller The Birds amplifies this by depicting mass avian assaults on a coastal , inspired by a 1961 real-life incident but transforming birds into harbingers of chaos, which has permeated public imagination of wildlife as unpredictable adversaries. In modern contexts, frequently features memes and anecdotes about bird strikes in pilot training or cockpit stories, reflecting aviation humor amid real risks. These representations have shifted public perception toward environmental debates, framing strikes as consequences of habitat loss and conservation successes that boost bird numbers near airports. Media portrayals have notably elevated awareness, influencing policy and research funding. The Sully film's release in 2016 aligned with peak media scrutiny, prompting airlines and regulators to prioritize bird hazard assessments and leading to enhanced FAA reporting protocols. Such coverage has driven conservation initiatives, with studies showing that heightened press on avian threats correlates with increased allocations for strike prevention technologies and programs.

References

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