At least three collisions between birds and airplanes have happened at Shanghai's Pudong airport since July, forcing three airlines to change their flight schedules and leaving passengers worried.
On Tuesday, United Airlines canceled its UA858 flight to San Francisco due to a bird strike at the Shanghai Pudong International Airport.
The bird hit the engine during taxiing before the Boeing 747 took off. It was the third similar accident at the airport since July.
On Aug 18, an outbound Spring Airlines flight was forced to make an emergency landing at the Pudong airport after colliding with a bird a few minutes after it took off. One of the plane's two engines was damaged.
Spring Airlines said that the plane, which was flying to Hong Kong, returned to the airport at 11:26 am. No passengers were injured, and they boarded another plane after a four-hour delay.
The Shanghai Airport Authority declined to comment when contacted by China Daily.
Typhoons blamed
But according to a report in local newspaper Oriental Morning Post, the airport authority attributed the bird strikes to frequent typhoons this summer, saying that the natural disasters have hit many areas near the airport where the birds have nests, prompting some birds to move closer to the airport.
The report also said that the airport has boosted the inspection of runways and is using various methods to keep the birds away.
Some of the collisions are proving costly to the airlines.
"In some cases, we are not able to repair some serious damage caused by the bird strikes and have to return the damaged planes to the manufacturers. The birds can get stuck in the engine and may damage internal parts, which we can't see with a naked eye," said Hu Xu, an aircraft maintenance worker with Shanghai Airlines.
Hu said that every plane has to pass a "bird strike test", also known as an engine impact resistance test, before delivery. However, some of his work still involves repairing damage caused by bird strikes or by lightning.
The airport's bird control team has been busy in the last few days.
"They fire bird bombs into the sky to scare the birds away," said Tong Hao, an employee at the Pudong airport.
Bird bombs are pyrotechnic devices used by the aviation industry to deter birds without harming them.
According to Yuan Xiao, deputy director of the Shanghai Wildlife Conservation Station, the reason egrets are often seen near Pudong airport these days is because the airport was built next to a wetland by the seaside where the birds live.
"May is egret breeding season and now is the time when young birds are learning to fly and are heading all the way to the sea for food," he said.
Because airports are often in areas with low population next to water, wetlands or lawns, the birds' migratory routes sometimes overlap with airport airspaces.
"Shanghai is located along central coastlines, which means basically that the airport has to partly overlap with migratory routes wherever it is built," said Lei Jinyu, project coordinator with the Wuhan office of the World Wide Fund for Nature China.
Different methods
To address the problem, almost every airport in China has tried a variety of methods to disperse birds, including using other breeds of predator birds, scaring them off with the voice of their avian enemies or firing bird bombs.
Located along birds' migratory routes and in an area that is home to 142 types of birds, the Nanjing Lukou International Airport in Jiangsu province is often threatened by bird attacks, especially from July to October.
"Thousands of egrets have been gathering in forests southwest of the airport since July," said the director of the airport authority surnamed Shen. The airport's priority now is to fix the protective screening damaged by the recent typhoon Haikui.
Sometimes gas guns are also used to disperse the birds. Airports set up high-precision launch systems where guns with an 80-meter range aim at the birds from all directions.
However, bird experts suggest that ecological methods could prove more helpful than simply driving birds away with loud noises.
For Sui Guohui, one of the workers in charge of bird population control at the Beijing Capital International Airport, Lukou airport's methods are still at a primitive stage.
With about 30 of his colleagues, he follows the ecological chain of birds to drive them away from the airport rather than scare them away.
Since 1999, Sui and his colleagues have been mowing grass and using herbicides to control the growth of grass, keeping the height to less than 20 centimeters so that rats and other pests, which are food for the birds, will not breed in nearby forests.
"It's a much slower way to reduce the number of birds but it's also a more effective way," said Sui.
Copyright ©1999-2011 Chinanews.com. All rights reserved.
Reproduction in whole or in part without permission is prohibited.