Commercial airline crews reported more than two dozen emergency landings, aborted takeoffs or other hair-raising incidents due to collisions with birds in the past two years, according to a confidential database managed by NASA.
An Associated Press review of reports filed voluntarily with NASA's Aviation Safety Reporting System show that bird-airliner encounters happen frequently, though none as dramatic as the one involving a US Airways jet that ditched safely into the Hudson River on Jan. 15 because a run-in with birds took out both of its engines.
Since January 2007, at least 26 serious birdstrikes were reported. In some of them, the aircraft's brakes caught fire or cabins and cockpits filled with smoke and the stench of burning birds. Engines failed and fan blades broke. In one case, a birdstrike left a 12-inch hole in the wing of a Boeing 757-200.
The NASA data does not include details such as the names of crews, airlines, and in many cases, the airports involved — confidentiality designed to encourage greater reporting.
"That's only touching the tip of the iceberg," said former National Transportation Safety Board member John Goglia. "Clearly, we don't have knowledge of the full width and breadth of this problem."
From 1990 to 2007, there were nearly 80,000 reported incidents of birds striking nonmilitary aircraft, about one strike for every 10,000 flights, according to the Federal Aviation Administration and the Agriculture Department. But those numbers also are based on voluntary reports, which aviation safety experts say almost certainly underestimates the size of the problem and fails to convey the severity of some incidents.
In some cases reported to the NASA database, crews said they could smell birds burning in the engines — "a toxic smell like burning toast (or) popcorn" wrote a flight attendant on an MD-80 airliner that had just taken off last March. After returning to the airport for an emergency landing, it was discovered the aircraft had suffered a birdstrike on a previous landing that had gone undetected.
The pilot of a Boeing 767-200 reported aborting a takeoff after the cockpit "filled with the smell of cooking bird." The plane had "ingested" birds in the right engine on a prior landing, but mechanics had thought the birds had passed through the engine and had given the flight the go-ahead to takeoff again.
Among other cases detailed in the NASA database:
_In March 2007, the pilot of a Boeing 777-200, a wide-bodied airliner that typically seats over 280 passengers, reported a birdstrike in the right engine shortly after a takeoff, causing strong engine vibrations. The pilot shut down the engine and asked to divert to another airport for an emergency landing, dumping as much of the plane's 160,000 pounds of fuel as possible to reduce the plane's landing weight and cut its risk of breaking apart.
_In June 2007, a Boeing 757-200 at Denver International Airport was forced to abort a takeoff at between 150 mph and 160 mph after a flock of birds the size of grapefruit flew into the path of the plane. Some birds were sucked into both engines, the pilot reported.
_In July 2008, the pilot of a Boeing 737-300 in the midst of a 139-mph takeoff roll spotted a hawk with a 4-foot wing span on the runway. As the bird flew past the left side of the plane, the crew heard a "very loud bang" and there was engine surge. The pilot aborted the takeoff at great strain to the aircraft's brakes, which caught fire. Fire trucks doused the flames. No one was hurt.
_In May 2008, the pilot of a regional airliner reported that he arrived at his plane to get ready for a flight and found the windshield "covered in blood, guts and feathers from an obvious birdstrike" during a previous flight. When he complained to the airline's maintenance department, he said, he was told the previous flight crew was responsible for reporting the incident or cleaning up the mess themselves. "At no time should an aircraft ever be left with obvious birdstrike debris and no indication that someone has taken the necessary steps to ensure that the aircraft is safe to operate," the pilot's complaint said.
More common than aborted takeoffs are reports of planes that had to circle back to their departure airports or divert to other fields for emergency landings because a bird had damaged an engine shortly after takeoff.
Former NTSB Chairman Jim Hall said the safety board has been warning for decades that birds "are a significant safety problem." The board sent a series of bird-related safety recommendations to the FAA in 1999, including required reporting of birdstrikes by airlines and the development of a radar system that can detect birds near airports.
A decade later, reporting is still voluntary and there is no bird-detecting radar except limited testing at a handful of airports.
FAA spokeswoman Laura Brown said developing a reliable bird-detecting radar has proved difficult. Some of the systems tested by the agency picked up insects as well as birds.
"We've been working on this," Brown said, "and haven't developed a system yet we feel we can make operational in a commercial aviation environment that's going to give us the kind of solid, reliable data we're looking for."
Brown said the FAA decided nearly 20 years ago on a voluntary birdstrike reporting system to encourage greater cooperation. She said the agency also agreed not to make airport-specific birdstrike data public because it didn't want to discourage airports from reporting incidents. She said an airport that was diligent about reporting incidents might look like it had a greater bird problem than an airport that wasn't as thorough.