Flying into trouble

By Liu Sheng Source:Global Times Published: 2013-6-27 17:53:01

Workers at Hongqiao International Airport use specially-equipped vehicles that broadcast the sounds of predatory birds to frighten other birds away. Photo: Courtesy of Hongqiao International Airport

Workers at Hongqiao International Airport use specially-equipped vehicles that broadcast the sounds of predatory birds to frighten other birds away. Photo: Courtesy of Hongqiao International Airport


When a 500-gram bird hits an aircraft flying at 370 kilometers per hour, the impact is the same as if the aircraft was hit with 3-ton weight. It's like a small bomb hitting a plane and can smash a windscreen, break propellers, wreck engines and, at worst, cause pilots to lose control. A bird strike like this is reportedly two or three times above the engineering design standards for impacts on aircraft. 

The Civil Aviation Administration of China (CAAC) reports that bird strikes cost the commercial aviation industry 1.2 billion yuan ($195.21 million) a year. Since 1960, bird strikes have caused 400 accidents and been blamed for the deaths of 370 passengers worldwide. 

The last thing a pilot wants to see ahead of him is a bird. In 2009, A United Airlines flight took off from LaGuardia Airport in New York City with 150 passengers and five crew on board. As it gained height it flew into a huge flock of birds. The engines lost power suddenly but the pilot managed to bring the plane down to a spectacular landing in the Hudson River in Manhattan where all aboard were rescued by boats.

But for the five passengers whose plane took off from a small airport in Oklahoma in 2008, the bird strike was fatal. Their plane hit a white pelican, one of the largest bird species in North America, and it crashed near Wiley Post Airport. No one survived. The Wiley Post Airport was located between two big lakes, a natural habitat for wild birds.

Big losses

In 2011, airports and airline companies on the Chinese mainland reported 1,538 bird strikes, which cost 113.3 million yuan in financial losses. The Fédération Aéronautique Internationale, the body that supervises air sports, has listed bird strikes as an A-class aviation fatality.

In China last year, 127 of the strikes caused aviation accidents, accounting for 58.5 percent of all aviation accidents, according to the China Academy of Civil Aviation Science and Technology.

Alongside all major international airports, the Shanghai Airport Authority is battling the birds as it tries to keep the skies around the city safe for travellers. "The frequency of bird strikes increases during summer when birds fly more, but they're not that common in other seasons," said Tian Lu, the press officer with the authority.

But keeping nature at bay while at the same time trying to improve the environment is not easy task. With more green areas in the city, there are more birds attracted here and this can cause problems when they intersect with aircraft.

Shanghai's Hongqiao International Airport has a bird team which works on estimating bird populations around the airport and patrolling the airport to keep the birds away from aircraft that are taking off or landing. The team uses a variety of methods to keep the birds away from flight paths including visual deterrents, sounds and ecological management.

The visual deterrents include the "scary eyes," large electronic boards that show giant red eyes and spin reminding birds of owls or other predators. The bird team also uses iridescent foil ribbons and strobe lighting.

"Birds have got used to traditional scarecrows and the sound of firecrackers," one member of the Hangzhou Xiaoshan International Airport bird management team told media. Large colored spinning wheels have also helped keep birds away.

It's certainly not all quiet on the airport front for the Shanghai Airport Authority which has been broadcasting bird calls from vehicles roving around the runways and setting off mid-air explosives. Airport staff use specially-equipped vehicles that broadcast particular bird calls (the calls of predatory birds usually) around Hongqiao airport before takeoffs and landings. The vehicles broadcast bird calls at frequencies outside the normal range of human hearing over 24 hours a day. The team reports that this has proved quite effective in keeping birds away.

To drive off more determined birds that intrude on airspace, the bird teams can fire devices into the air which explode loudly and produce a thick cloud of smoke.  

"Our battle with the birds never stops," said Tian Bin, the deputy manager of runway management at Hangzhou Xiaoshan International Airport. "We have seven professionals in the bird management team and they work from 6:30 am till dark."

Tian said they patrolled in two vehicles setting off the sounds whenever they spotted birds. Sometimes, though, the teams had to revert to firing blank bullet rounds to scare birds away.

Very loud

The bird call vehicles can reproduce more than 30 kinds of bird sounds and they broadcast them infrasonically. Although humans cannot hear the calls, they apparently sound very loud to the birds in the area.

Every year the team spends about 500,000 yuan scaring birds away. "Birds can adapt quite easily to these tactics so we have to keep changing the techniques and locations," Tian said.

Zhao Xinru, a bird expert and professor at Beijing Normal University, told the Global Times that the science of bird scaring was still in its infancy. "At present we lack enough information to tell which piece of equipment is the most effective at keeping birds away. Sometimes we as humans think a device should be effective because it sounds frightening to us but we have to test this to see if it actually works on the birds.

"Although birds tend to be more active during spring, summer and fall, preventative measures have to be carried out all year long because there's no method yet of keeping them away for good," Zhao said.

It's not all blasts, loud noises and large attacking creatures involved in the battle with the birds. At Hongqiao airport, team members mow the grassy areas around the runways regularly to control the insect population which attracts birds. "The grass has to be trimmed to less than 20 centimeters so that birds cannot use it to hide there and feed on insects," Tian Bin said.

 The team also lays rat poison - some larger birds prey on rats for food - and sprays pesticide around the runways every five to six days to keep the insects down.

At Hongqiao airport, pigeons, night herons and sparrows are common all year round, while egrets, swallows and skylarks are more often found in summer. Summer typhoons can also cause a jump in the bird population. When nests are swept away by storms, birds from surrounding areas search for new, open and flat places to nest in and airports are attractive, flat and open, the Shanghai Airport Authority has noted. The areas along the coast of the East China Sea and the southern estuary of the Yangtze River are especially hospitable to birds.

Numbers falling

"Hongqiao airport has seen fewer birds in 2012 than the year before, and we are now recording less than 1,000 birds a day," Chen Jiang, the general manager of the airport's airfield management department, told Shanghai media.

Domestic aviation regulations put a limit of less than three bird strikes per 100,000 flights for airports. Pudong International Airport sees more than 20,000 flights taking off or landing every month. It employs similar methods to keep birds under control.

Keeping the balance between flight safety and nature can be difficult. "The preventative measures, including bird nets, visual and sound effects, can harm some birds," said Yao Li, the secretary-general of the Wild Bird Society of Shanghai. 

But in a controlled situation and if the measures are kept to a reasonable limit, there should be no harm to a species as such. "These measures are temporary, just to scare them away and they are necessary - a human life is much more important."



Posted in: Metro Shanghai

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