Avoiding Plane Crashes By Crunching Numbers

By Del Quentin Wilber
Washington Post Staff Writer
Sunday, January 13, 2008

PHOENIX -- For decades, aviation authorities played the role of homicide detectives. When an airliner went down, they scoured the crash site and flight recorders for clues that often showed how to avert future accidents.

But with so few crashes in recent years, air carriers and regulators have been trying to find other ways to identify potentially dangerous trends. Instead of digging through debris, they now spend far more time combing through computer records, including data downloaded from thousands of daily flights and scores of pilot incident reports.

The information is stored on banks of computers, such as the server housed in a windowless office of a US Airways hangar here. Like its counterparts at other carriers, a small team of pilots and analysts sift through thousands of records daily looking for the seeds of the next big air crash.

In recent years, the team has uncovered such potential safety problems as unsafe landing and takeoff practices and difficult landing approaches. The data have helped pinpoint areas that pose an increased risk of midair or ground collisions and have led to the discovery of a large bulge in the runway of a Vermont airport. Even after threats have been reduced, US Airways' executives and pilots say they keep monitoring the data to ensure that their new procedures work.

"We have improved our safety so much from having this data," said US Airways pilot Matt Merillat, who works on the database. "There is no doubt that by using this data we have prevented an accident."

Pilots and executives at 16 other airlines have similar data-monitoring initiatives approved by the Federal Aviation Administration that are known as flight operations quality assurance programs. The carriers scour the flight data, which is often combined with pilot reports, to identify potential "precursors," a buzzword in aviation circles used to describe events that often go unnoticed until they lead to an accident. The data are amazingly detailed -- small onboard memory discs (not the "black boxes") capture hundreds of parameters that include airspeed, pitch angles, engine temperatures and movements.

Such data initiatives have grown so extensive in recent years that the FAA has launched its own effort to mine the information in search of precursors. Seven carriers have signed on to the initiative, which began in October. The FAA, which already combs government safety databases looking for precursors, thinks the flight data will be a powerful tool when combined with other information, including pilot reports and radar plots.

More carriers are expected to join by year-end, FAA and industry officials said.

"We can use this tool to find the beginnings of a new safety threat that we don't even perceive," said Jay Pardee, director of the FAA's office of aviation safety analysis.

Outside experts and FAA officials say that such data mining is part of a new era in the industry, which is enjoying its safest stretch in history. The last major U.S. commercial aircraft crash was in August 2006.

One reason the system has become so safe is because investigators, regulators and industry executives got so good at learning from past accidents. Flights that crashed into mountains, the ground or into other airplanes led to computer warning systems that alert pilots to the dangers in enough time to take action. Crashes caused by obstinate pilots led to better cockpit communication.

"Historically, we have always taken a forensic approach to aviation safety, looking at past accidents and learning all we could," said Terry McVenes, a pilot and executive air safety chairman of the Air Line Pilots Association. "Because we don't have many accidents to analyze anymore, if we want to continue to lower the accident rate, we have to look at precursors, the near misses."

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