What is a bird strike?
A bird strike is a collision between an airborne animal (usually a bird or a bat) and a man-made vehicle, especially aircraft (2009)1.
Bird strikes are a common problem throughout the world at all airports and along most aircraft flight routes and so it is a common threat to air and flight safety. Although there have been quite a few incidents over the years, major accidents involving civil aircraft are quite low and it has been estimated that there is only about 1 accident resulting in human death in one billion flying hours (2009)1. Most of the bird strikes (65%) cause little damage to the aircraft with most accidents occurring when the bird hits the windscreen or flies into the engines (2009)1.
Bird strikes is very expensive and post a threat to safe flight. It was found that over $600 million in damage to the U.S. civil and miltary aviation industry annually by bird strikes. These strikes not only put the lives of air crew members and their passengers at risk they are responsible for over 219 peoples being killed worldwide as a result of wildlife strikes since 1988 (2009)2. Birds strike can be lethal depending on the size and the place it strike on the aircraft. The most dangerous area is the striking directly in the engine where it may cause engine malfunction inflight or cause structural damage when the impact is huge.
|Damage sustained from aircraft collision with a single turkey vulture. (image embedded from HoverWorld on 20 August 2009)||(Video embedded from YouTube on 2 September 2009)|
The Bird Strike Committee USA (2009)2 have found some interesting facts about bird strikes:
Did u know that…
- Over 219 people have been killed world-wide as a result of bird strikes since 1988.
- Over 7,600 bird and other wildlife strikes were reported for USA civil aircraft in 2007 (over 5000 of them were bird strikes)
- Waterfowl (31%), gulls (26%), and raptors (18%) represented 75% of the reported bird strikes causing damage to USA civil aircraft from 1990-2007.
- Bird strikes are very common in fact over 56,000 bird strikes to civil aircraft in the US were reported to the Federal Aviation Administration (FAA) from 1990-2004.
- Large commercial aircraft are constructed to be able to withstand an impact of a 4-lb bird, even if the aircraft has sustained substantial and costly damage, and even if one of the engines has shut down. However, there are a lot of birds that weigh more than 4-lb and most travel in flocks increasing the level of damage to the aircraft. Even smaller bird flocks e.g. starlings and blackbirds, and some individual medium sized birds like that of gulls, ducks and hawks can cause engine failure and damage to aircraft.
- Large aircraft can still operate if one of their engines stops working and they can still land safely, although as birds travel in flocks there is always a possibility that birds will be ingested into multiple engines.
- For any aircraft, even a small amount of damage can lead to significant costs. For example, if as the result of a bird strike the aircraft has to have new fan blades put onto the aircraft, then the airline has to not only source a new part and someone to fit it, but also they have to deal with the indirect costs of keeping the aircraft out of revenue service and redirecting passengers.
- Bird strikes on aircraft can not only have an effect on human life but they can also effect the environment. For example, as a result of a bird strike that disabled an engine on a B-747 departing Los Angeles International Airport (LAX) in August 2000, the pilot had to dump 83 tonnes of fuel over the Pacific Ocean before he could land again safely (2009)2.
- Although most bird strikes can occur at low levels (less then 500 feet above ground level) while the aircraft is still on the ground during take-off or landing. Over 1,300 strikes were reported from 1990-2003. There was also a world height record for a strike at 37,000 feet as an aircraft collided with a Ruppell’s Vulture over the Côte d’Ivoire (2009)2.
The Cause of Bird Strike
The video link will show a compliation of accidents in general aviation that how our life and safety are put on the stake of birds. Thus it is important that the airport to manage birds with consistent measures such as bird watch periodically to scare bird off by different means. These means will be covered in the later part of the articles.
Bird strike prevention.
There are many airports around the world that are using different bird prevention methods to try and cut down on the number of bird strikes in the local area. Although these airports may choose to adopt similar or some very different methods, there has not been one specific method that will work every where to stop all bird strikes altogether. With this being said the main ways that airports are using to try and minimise the risk of bird strikes depend on the habitat; species; aircraft movements; public attitudes regarding the problem species and control methodologies; cost; and integration of techniques (2004)3.
There are three ways to reduce the effect of bird strikes:
- the aircrafts can be designed to be bird resistant,
- the birds can be moved out of the way of the aircraft,
- the aircraft can be moved out of the way of the bird.
1. Aircraft Design
Most large aircraft engines include a design feature that allows them to shut down after ingesting a foreign object or a bird. Modern aircraft structure must be able to withstand one 4 pound bird collision; the tail of the aircraft must withstand one 8 pound collision; and cockpit windows must withstand one 4 pound collision without yielding or fragmenting (2009)1.
- Chicken Guns (containing a dead chicken) are used as part of the design phase to test the strength of vulnerable areas such as aircraft windshields and safety of aircraft engines by simulating high speed bird impacts on these areas from a compressed air cannon. (2009)4
Videos below depict the effects of a bird strike testing on aircraft.
|(Video embedded from YouTube on 8 Oct 2009)||(Video embedded from YouTube on 8 Oct 2009)|
2. Bird Management
- Habitat Management
- Birds require food, water and security. Removing or depriving the birds of these necessities must form the core of the strategy in making the airfield unattractive to them.
- The availability of insects and unconsumed food not properly disposed off is a good source of food for birds. It is important that a system for the proper disposal of unconsumed food is put in place. Restricting food to designated areas with proper disposal facilities is one way of curbing the presence of birds.
- The proper use of insecticide and pesticide is recommended if it has been assessed that insects are the cause for the presence of birds.
- Stagnant water not only provides the drinking needs of the birds, it also supports the presence of larvae and tadpoles which are sources of food for the birds. Clogged drainage must be cleared and ponded areas filled.
- Roosting and nesting areas must be disrupted by physically removing their nest and pruning trees.
- Bird Dispersion Methods
- Chemical Bird Repellent. These are chemicals that are contained in special dispensers and are activated via sensors. It works by irritating the birds’ eyes and mucous membranes of the nose and mouth. It also settles on the birds’ feather and irritates them again when they preen.
- Bio-Acoustics Distress Device. These are hand-held or vehicle mounted loudhailers, which broadcast sounds of birds in distress. A variety of different birds’ distress calls can be recorded. The effect is greatly enhanced when used in conjunction with pyrotechnics.
- Pyrotechnics. These are flares, which are fired and set off two loud bangs to scare the birds away. The effect of pyrotechnics is enhanced when used in conjunction with the bio-acoustics distress device described above. However, users must also note that overuse of either methods can also lead to desensitisation, resulting in the birds becoming accustomed to the effects.
- Bird shooting. Several shooters are trained to operate the shotgun to fire at the birds. However, this method must be used with discretion. Special care must be taken not to cull protected bird species, or to endanger human lives and properties.
- Thermal Fogging. This is used over grass patches to reduce the insect population using pesticides. These insects serve as a rich food source for swallows.
- Soil Treatment. This is a treatment carried out for the control of insect nests on the grass patch of the airfield. These nests would be flooded with insecticide to eradicate the colony. (2009)1.
3. Flight Path
- As pilots are not given any specific training into how to avoid wildlife, they should be aware of the possibility that a bird strike can occur. With this in mind pilots should not takeoff or land in the presence of wildlife, avoid migratory routes, wildlife reserves, estuaries and other sites where birds are found
- On a similar note, steps can also be taken in identifying the areas outside the vicinity of the airfield, i.e. the departure/arrival routes which pictorially using geographical information services depicting where birdstrikes have occurred. With this information aircrew can either plan to avoid high threat areas or maintain a high vigilance while flying in the area.
- Aerodromes can also install a Bird Hazard Warning System. This system forewarns all aircrew of the presence of birds in and around the airfield, or in the vicinity of aircraft operating in the area by classifying the intensity of bird activity into different bird hazard states. (2009)1.
Incidents involving bird strikes.
- In the fall of 2006 the USAF lost a twin engine T-38 trainer to a bird strike and in October 2007 the US Navy lost a T-45 jet trainer in a collision with a bird (2009)1.
- On November 10, 2008, a Ryanair flight FR4102 Boeing 737 made an emergency landing after multiple bird strikes put both engines out of commission. After touchdown, the left main landing gear collapsed, and the aircraft briefly veered off the runway before the crew regained control, Three passengers and two crew members were injured, none seriously (2009)1.
- On January 15, 2009, US Airways Flight 1549 from LaGuardia Airport to Charlotte/Douglas International Airport ditched into the Hudson River after it was suspected that the engine failure was caused by a flock of geese. All of the passengers and crew managed to get out to safety (2009)1.
For a more comprehensive overview of this incident, please refer to US1549 Bird Strike
- In February 2009, a Air New Zealand A320 flying from Melbourne to Christchurch was struck on the wing by a bird which left it with a fist size hole.
Bird Strike Committees
As there have been a number of bird strike incidents over the years with a growing cost of well over $600 million in damage to US civil and military aircraft which put not only the air crew but also the passengers at risk, there became a need to have some sort of committee to try and gather together ideas of how to combat the bird strike problem. The committee that was formed out of this was the International Bird Strike Committee (IBSC) which is “a voluntary association of representatives from organisations who aim to improve commercial, military, and private aviation flight safety, by sharing knowledge and understanding concerning the reduction of the frequency and risk of collisions between aircraft, birds and other wildlife”(2009)5.
In America the Bird Strike Committee consists of 2-3 members each from the Federal Aviation Administration, Department of Defence, U.S. Department of Agriculture, aviation industry/airlines, and airports (2009)2. They meet annually to discuss a range of different topics to do with bird strikes. Such topics include (2009)2:
- Wildlife strike reporting/statistics in relation to safety management systems
- Bird management and control techniques
- Research on new technologies to reduce wildlife hazards
- Training in wildlife management on airports
- Military concerns of wildlife hazards
- Aircraft engines’components performance and standards related to wildlife hazards
- Policies/standards for airports and aircraft operations related to wildlife hazards
- Land use and environmental issues concerning airports
- Avian migration, behaviour and sensory capabilities related to aviation
- Remote sensing/modelling to detect and predict bird numbers and movements
Want to know more?
- Bird Strike Committee (USA)
- This webpage offers more detailed information about the Bird Strike Committee USA.
- International Bird Strike Committee
- This webpage offers more detailed information on the International Bird Strike Committee and what they do.