Description

A wildlife strike is a collision between an animal and an aircraft which is in flight or on a take off or landing roll. The term to describe such events was initially bird strike since this was the most common scenario. However, the increased number of flights and airfields used resulted, among other things, in the increase of collisions between aircraft and animals other than birds.

Wildlife strikes may occur during any phase of flight but are most likely during the take-off, initial climb, approach and landing phases. The reason is that most birds fly at lower levels and other animals (except bats) can only hit an aircraft while on the ground.

The specific aspects of wildlife strikes are discussed in the dedicated articles Bird Strike and Non Avian Wildlife Hazards to Aircraft.

Effects

Wildlife strikes can be a significant threat to safety of aircraft. The impact of wildlife strike has been experienced to cause:

• Cracked or broken windshield and consequently, depressurization and possibly pilot injury.
• Engine failure due to ingestion, resulting in aborted take-off or emergency landing.
• Structural damage to the fuselage, control surfaces or landing gear which could potentially lead to e.g. depressurization, Loss of Control or emergency landing.
• Other effects, for example blockage of Pitot Static System air intakes which can cause dependent instrument readings to become erroneous.

The damage caused depends on a number of factors:

• Aircraft size - smaller aircraft can withstand less damage before the safety of flight is compromised and are generally more vulnerable.
• Animal size and weight. The weight of an animal is directly proportional to the energy to be absorbed in an impact.
• Speed during impact - the kinetic energy to be absorbed is proportional to the square of the relative speed of the two objects. Normally the aircraft is much faster and therefore the animal speed can be disregarded.

Defences

The defences against animal strike include measures to:

• Prevent the event from happening. This includes perimeter fencing to make the aerodrome inaccessible to non-flying animals as well as measures to make it less attractive to birds, e.g. reduction of plants that may provide food or shelter, grass management, employment of bird scaring techniques, etc. More detail can be found in the article on Airport Bird Hazard Management.
• Mitigate the effect of a strike on the aircraft. This is done by establishing relevant airworthiness requirements. The article on Aircraft Certification for Bird Strike Risk provides more detail on this subject.
• Observation of the manoeuvring area for birds and other animals and provision of information to flight crews. Detection can be visual (by the controller or dedicated checks by aerodrome personnel) or by using technical aids. Information may be passed by the controller or using ATIS or BIRDTAM.
• Tactical defences against hazardous bird strikes for those who operate and fly transport aircraft are reviewed in the article Operators Checklist for Bird Strike Hazard Management

Accidents and Incidents

For a list of accidents and incidents involving Wildlife Strike, see the separate article: "Accident and Serious Incident Reports: Wildlife Strike"

Further Reading

ICAO

• ICAO Doc 9137: Airport Services Manual Part 3 - Wildlife Control and Reduction, 4th edition, 2012.
• ICAO Annex 14 (Aerodromes)
• ICAO Electronic Bulletin: 2008 - 2015 Wildlife Strike Analyses, 2017

FAA

• AC 150/5200-33C: Hazardous Wildlife Attractants on or near Airports, FAA, 21 Feb. 2020.
• FAA "Lessons Learned from Transport Airplane Accidents": Bird Hazards
• Wildlife strike database
• Wildlife Hazard Mitigation website
• Wildlife Strikes to Civil Aircraft in the United States, 1990-2022, FAA and U.S. Department of Agriculture Wildlife Services, June 2023.
• Some Significant Wildlife Strikes to Civil Aircraft in the United States, January 1990 - March 2022, FAA Strike Database and U.S. Department of Agriculture, April 2022.

Others

• UK CAA CAP 772 - Wildlife hazard management at aerodromes;
• Wildlife Hazards, Bureau d’Enquêtes et d’Analyses - France
• "Sharing the Skies", An Aviation Guide to the Management of Wildlife Hazards - Transport Canada (TC 13549) on-line version.
• Airbus Flight Operations Briefing Note - Birdstrike Threat Awareness;
• ACRP Report 145: Applying an SMS Approach to Wildlife Hazard Management, R. DeFusco et al. (Transportation Research Board, US), 2015.
• ACRP Report 32: Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports by E. C. Cleary & A. Dickey, Transportation Research Board, US, 2010.
• Standards For Aerodrome Bird/Wildlife Control, by the International Birdstrike Committee, October 2006