February 16: Aviation experts in Mumbai have expressed scepticism over the claim of the Airports Authority of India (AAI) that bird strikes to aircraft at Mumbai airport have decreased following various measures taken to prevent accumulation of garbage in and around the airport area.About 150 acres of airport land just outside the perimeter wall at the Kurla end of the runway is encroached upon by unauthorised slums, and the area resembles a dumping ground for garbage and other obnoxious wastes. Nearly 50-odd unauthorised slaughterhouses in this area don't have any carcass-disposal facility, and the approach path of aircraft has become a permanent habitat for predatory birds, they maintain.The slums around the airport were targeted under the Brihanmumbai Municipal Corporation's (BMC) cleanliness drive, and action was taken against slumdwellers at Jarimari, Ambedkar Nagar and Bail Bazaar by imposing fines, but in vain. The flowing of the vast Mithi river nallah along the airport's perimeter wall hasonly worsened the situation.The Federation of Indian Pilots (FIP), a body of professionals engaged in enhancing flight safety in India, has said the decrease in bird hits could be merely coincidental. ``Although the airport and civic authorities have taken some measures, the area still remains a feeding source for birds. If concrete steps aren't taken to either relocate the slums or clean up the area, we'll only invite more trouble in future,'' FIP chairman Capt Ayodh Kapoor said.``It's not the speed with which the bird flies that makes it a live cannon ball, but the relative velocity with which it strikes the aircraft. For instance, a 15 lbs bird striking the windscreen of an airplane flying at a speed of 250 knots has a relative impact of 15 tonnes. A 30 lbs goose striking the windscreen of a plane flying at 200 knots (in circuit speed) creates a relative impact of 20 tonnes, which could cause serious damage to aircraft and pose a risk to lives of passengers,'' Capt Kapoor said.Studies revealthat 90 per cent of bird hit incidents occur up to a level of 3,000 feet. Of these, 60 per cent occur up to a level of 1,000 feet, when chances of remedial action by a pilot are almost nil.The Aircraft Act, 1934, and the International Civil Aviation Organisation (ICAO) regulations prohibit the slaughtering and flaying of animals, and deposition of rubbish and filth within a radius of 10 kms of the Aerodrome Reference Point. ``But in case of Mumbai airport, these rules apparently don't exist. The bird hazard begins for an approaching aircraft miles away from the airport over the Deonar dumping ground, and chances of a bird hit increase drastically just metres away from the runway,'' Capt Kapoor pointed out. ``While collisions between birds and airplanes will perhaps never be eliminated, it's the responsibility of the regulatory authorities to take effective steps to minimise the potential of a life-threatening encounter. But precious little has been done in this regard,'' he said.
