By ANDY PASZTOR
An American Airlines plane that careened off a slick Jamaican runway last year while trying to land has prompted transportation-safety investigators to reassess how well some jetliner braking systems perform in rainy conditions, people familiar with the details say.
American Flight 331 was en route from Miami to Kingston in stormy weather when it landed nearly halfway down the runway on Dec. 22. The pilots used maximum braking power but the Boeing 737 still slid off the end of the strip, ending up with a collapsed landing gear and the fuselage cracked in two places.
The crash, according to these people, has led the U.S. National Transportation Safety Board investigators to challenge longstanding airline practices and technical assumptions regarding braking capabilities on wet runways. By those criteria, the advanced Boeing 737-800 should have been able to stop safely on the strip.
Investigators don't believe there was a significant pool of water on the runway, though the crew was battling a stiff tail wind as well as some malfunctioning runway and approach lights, these people said. The crash, which didn't result in any fatalities, left several of the 154 people aboard hospitalized.
Preliminary information gathered by investigators indicates the two-engine jet started to slow down, but then failed to decelerate as quickly as it should have and actually picked up speed slightly for a brief period. Even after maximum manual braking was applied, these people said, the deceleration rate never reached levels projected by earlier flight tests and engineering calculations for the apparent runway conditions that night.
Safety board investigators are now moving to draft recommendations to reassess, and in some cases tighten, current safety margins for landing on wet runways, according to people familiar with the continuing investigation.
Safety Board investigators and a spokeswoman for AMR Corp.'s American Airlines unit declined to comment, citing the continuing probe formally led by Jamaican authorities. A spokeswoman for the Federal Aviation Administration, which previously has issued advisories and regulations alerting pilots about the hazards of landing on wet or slushy runways, didn't have any immediate comment.
Runway overruns have become the most frequent category of accident for commercial aircraft world-wide. From 1995 to 2008, roughly 30% of all commercial-aircraft accidents involved so-called runway excursions, often in rain or snowy conditions, according to the Flight Safety Foundation, an industry-supported group based in Alexandria, Va.
Any action by regulators is likely months away, and the preliminary conclusions could change. But if regulators in the U.S. and elsewhere embrace more stringent rules, the result could be greater operational constraints on airlines planning to land on relatively short or outmoded runways when they are wet. The Kingston strip lacks grooves intended to help increase friction between a jet's tires and the runway's surface. Like many other airports in the region and some in the U.S., it also doesn't have special materials installed to stop aircraft that may veer off the end of the runway.
Jamaican officials have maintained that the Kingston runway meets all international safety standards.
In recent years, regulators, airlines, safety-equipment manufacturers and independent experts have tended to focus on ways to reduce pilot mistakes or lapses in judgment that lead to overruns. They have emphasized enhanced training, improved pilot discipline and more sophisticated cockpit hardware to prevent crews from approaching runways too fast, touching down too far down strips or failing to use proper braking or engine commands.
Other experts have been working on ways to determine more precisely the extent of water, slush and snow on runways. Today, pilots to a large extent depend on subjective radio reports from crews on planes that landed previously, rating braking action as good, fair or poor.
But now, in the wake of the Kingston accident, the U.S. safety board is shifting a major part of its effort to analyze whether brakes installed on various aircraft models are performing as reliably or effectively as pilots have come to believe, particularly under challenging conditions.
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