BIRD HAZARDS IN BANGLADESH AIRFIELDS BY GM, BFCC, BANGLADESH BIMAN 36TH COMMAND SAFETY CONFERENCE Prelude: Probably it is the right of the birds to say that airplanes are a hazard to their life. In the name of ‘Bird Hazard’ we have culled a number of species of birds worldwide. Yet we cannot help take action about birds that poise a high risk to aircraft flying up to about 4000ft. Commercial Flights in terminal area and general aviation flying are most susceptible to bird hazards but air force flights may also face the hazard. The cute and innocuous birds that make many animal rights activists, naturists, poets and watchers wonder in amazement are nothing but a foreign object that can damage an aircraft. Depending on the point of impact and the size the damage can even cause fatal accidents. The following extract from International Bird Strike committee in 2009 is a clear picture of the seriousness of the hazard. Quote: - It is now believed that the total number of fatal bird strike accidents is 54, killing 276 people and destroying 108 aircraft. These additional accidents are briefly detailed in the Paper so that the totals are now: Airliners and Executive Jets – 15 fatal accidents killing 188 and destroying 42 aircraft. Aeroplanes 5,700 kg and below – 32 fatal accidents killing 70 and destroying 56 aircraft. Helicopters – 7 fatal accidents killing 18 people and destroying 9 helicopters. -Unquote The above data says how serious the innocuous birds are! The accident data does not give the full picture. Because, most bird strikes do not culminate in accidents, they are just incidents or minor occurrences. Yet they cost lots of money in repair and maintenance of the affected aircraft. Bangladesh bird habitats: Bangladesh is a temperate deltaic basin of three major river systems. The soil is very fertile and produces lots of grains and fruits. As a result it has a large population of indigenous birds. Besides the permanent residents, there are many migratory birds visiting Bangladesh during their journey from Siberia to the wormer lands and back. The shady trees with perch-able branches make ideal resting place for perching birds. The abundance of water bodies and marshes make habitat for fishing birds water fowls; and the mangroves make habitat for wild fowls and insect eating tree dweller birds. The small birds that pick grains and ground insects and their birds of prey are the greatest hazards in the airports of Bangladesh. They flock in number when the grass covered plains in/near the airfield are mowed and the cultivable lands are ploughed. In large city airports the scavenger birds poise threat too. Birds related incidents and accidents: Bird strikes that hit the fuselage do not cause fatal accidents. Strikes in the engines and the wings have the potential to cause loss of power and loss of controllability and may lead to accidents. In the case of helicopters and props, the rotors and propellers are the vulnerable parts. Engines do not present a large frontal area; but due to their suction effects, they draw the passing birds in and get damaged. The high speed fan blades, like the rotors and props may be easily damaged by bird strike. The blades after being
deformed by the impact cause further engine damage due to vibration and imbalance. Bird remains reaching the turbine section is extremely rare. The modern jet engines are now tested by throwing actual bird carcasses into the running engine on the test bed. Bird strikes in the electronic bay below the cockpit have been known to cause electrical failures. Bird strikes in the wings and empennages can cause control problems by way of cable/hydraulic/drive failures. Where and when the bird strike occur: Most bird strikes occur on or near the ground, highlighting the need for wildlife management on airport grounds and in the vicinity. About 85% of all bird-strikes have occurred below 200ft of flight altitude. The birds soaring at high altitudes are gifted with good sights, have high maneuvering ability and therefore can avoid collision with aircraft. The high birds move individually. Single or multiple large birds, relatively small numbers of medium-size birds, and large flocks of relatively small birds are all problematic and have resulted in accidents. In Bangladesh, a list of birds most hazardous to flight has been identified: large flocking waterfowl (mostly migratory); gulls; pigeons and doves; blackbirds, starlings, and sparrows; and raptors (kites). The city garbage dump, when located near an airport can create hazards from scavenger birds. Mowing of the greens and scouring the meadows expose the insects. The birds are attracted by the ready food and gather in numbers. Traditional fishing in the water bodies near a Bangladeshi airport causes shells and small fish to be left behind on the bank and attract birds. Domestic and free pigeons reared near an airport can be accountable too. Seaside airports can receive flux of sea gulls especially in the mid day when they tend to stay away from the sun. The mating season of the resident birds are normally in March and the breeding season is in the next three months. During this time the birds move chaotically and may hit the aircraft in unpredictable manner. Birds can be attracted by littered food particles and packaging, by insects flying towards lights and by perching spots. Birds nesting sites may be in cracks, shelves and shelters created by wrongly designed buildings. Prevention and control of Bird Strikes Before we discuss how we can prevent or control the bird strikes we must give a thought about the stake holders. The aircraft operators are the major parties affected by bird strikes. The second party stake holders are the insurance agencies, the maintenance agencies, the safety agencies and the Public. Unfortunately, in Bangladesh neither the primary nor the secondary stake holders are consulted by the people who engage in bird strike prevention. That is probably the reason why after lots of cry from the stake holders not much has be achieved in the sphere. To perform the job of prevention of bird strikes the following studies have to be conducted. 1. Evaluate aircraft risks by identifying and analyzing the types, frequency of movement, flight paths and generic phases of flight of the aircraft that arrive, depart and operate in the vicinity of the airport; 2. Determine bird hazards by identifying and analyzing the resident and migratory bird species that could pose a risk to aircraft operations; 3. Employing information from 1 and 2, categorize relative risk by aircraft type and phase of flight, and chart this information;
4. Employing information from 1 and 2, determine high-risk bird species and the land uses that may attract them, and chart this information; and 5. Employing information derived from 3 and 4, plot bird hazard zones by category of severity and land use. After the above studies, a plan of action has to be decided to re-locate bird habitats and movements, revise the departure and arrival tracks, reduce the attractiveness of the airfield in the view of the birds and finally use deterrent and scare measures to drive the remaining species of birds. The process of birds control must be scientific, environmentally justified and acceptable not only to aviation but also to wild life agencies. Birds versus airplanes Birds Soared the air before Airplanes : The birds may say they have rights of the airspace over planes So, who has the right to airspace? : Probably it is the right of the birds to say that airplanes are a hazard to their life Many of us have seen the Alfred Hitchcock Movie ‘Birds’. Just imagine……………… We cannot help take action about birds that poise a high risk to aircraft It is now believed that the total number of fatal bird strike accidents is 54, killing 276 people and destroying 108 aircraft This is what a bird can do to a general aviation aircraft : The small, light General Aviation aircraft are very vulnerable to bird hit. Piston engine propeller aircraft can hardly withstand a bird hit in the critical areas Helicopters are also very vulnerable Birds in Bangladesh : Bangladesh is very fertile and fruits and seeds are found in abundance. The trees provide fruits and perching branches. This support many perching native birds. Rivers and fresh water lakes provide food for water fouls and fishing birds, Temperate winter attracts migratory birds from the cold north, Sea birds are found in the coastal areas, Birds of prey and scavenger birds are also plenty Most vulnerable parts of and aircraft : The engines, the windshield, the wings and the nose areas receive most of the strike, The engines are the most vulnerable, For the props and helicopters, propellers and rotors are the most vulnerable, The bird strike may cause fatal accidents due to loss of power or controllability When Bird strike is likely : 85% of bird strikes have occurred below 200 ft flight altitude, Most bird strikes occur in the airport control zone, Day time has ten times more probability of bird strike then night time, In Bangladesh winter season bird strikes are more common than summer Bird strike is directly related to bird density: Who will do it : In Bangladesh the CAAB performs the bird hazard mitigation in all airfields. But the number of bird strikes are on the rise, Commercial aircraft operators, the general aviation operators and the military aircraft agencies are suffering from bird hit, CAAB loses nothing, the operators bear the losses from the bird strike. This is a conflict of interest Solution:
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