The number of bird strikes--birds colliding with aircraft--at Haneda Airport in 2011 increased to 237, according to the Land, Infrastructure, Transport and Tourism Ministry, 1.4 times higher than the previous year.
Airport officials said the increase was partly because all four runways at the airport started full-scale operations in October 2010.
This spring, the ministry began a trial of the world's first bird-detection equipment at an airport. The system uses a combination of radar and cameras, but its effectiveness is unclear as there have been instances where the equipment has failed to detect birds or made erroneous detections.
Ministry data shows the total number of bird strikes nationwide in 2011 was 1,599, with Haneda Airport accounting for about 15 percent.
Bird species around Haneda Airport include gulls, kites, sparrows and little terns--a migrant bird species.
The airport's arrivals and departures increased from about 300,000 to 390,000 after the fourth runway began operating in October 2010.
Bird strikes rose from 143 instances in 2009, to 171 in 2010, and increased by 66 in 2011.
The airport plans to expand its arrivals and departures to about 450,000 by the end of fiscal 2013.
Because operation troubles at Haneda Airport affect other airports nationwide, reducing bird strikes is an urgent task that is necessary for securing air traffic safety.
The airport has implemented an around-the-clock patrol to detect birds.
However, patrol cars are sometimes unable to locate the birds and prevent a bird strike. Some birds flee after they are detected by the patrols, but then return to the areas, creating a cat-and-mouse routine.
The ministry spent 930 million yen by the end of fiscal 2010 to create the advanced equipment detection system. It uses radar to detect birds approaching the runways at all times of the day, and cameras that automatically take pictures in all directions.
The cameras were placed in three locations at the airport so that all four runways can be watched.
The system detects birds with the radar and then uses the cameras to identify the species.
While the system can detect birds, workers are then needed to drive them away.
In test operations, airport officials used blanks and fireworks to scare away birds after they were detected.
But the system has had errors, such as when the radar mistakenly recognized sea waves as birds and failed to detect birds that flew in complicated patterns.
Airport officials said the system's method of using the radar and cameras needs to be improved.
During bird strike incidents, birds hit the bodies of aircraft or are sucked into the engines, which could lead to an accident if the plane is damaged.
In 2009, a U.S. Airways plane made an emergency landing on the Hudson River in New York, and the accident highlighted the danger of bird strikes.
In May, a Japan Airlines plane was forced to return to Haneda Airport after a bird hit its engine.