Boeing Issues Reminder After Netherlands Crash
Instrument showed doomed plane was closer to ground than it actually was.
March 4, 2009— -- Boeing Co. today reminded airline pilots who operate the world's most popular commercial plane to monitor their flight altitude instrumentation after Dutch investigators announced that a faulty altimeter played a role in last week's crash of a 737 in Amsterdam.
Boeing asked operators of the world's nearly 6,000 737 airplanes "to carefully monitor primary flight instruments during critical phases of flight." The Turkish Airways plane that crashed one week ago in the Netherlands had a faulty altimeter that indicated the aircraft was much lower to the ground than it actually was, according to a report released today by Dutch investigators.
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The Dutch Safety Board today said the altimeter was a factor in the crash that killed nine of the 135 passengers and crew onboard. The Boeing 737-800 plane crashed Feb. 25, within a mile of the runway, while trying to land at Amsterdam's Polderbaan of Schiphol Airport. Another 80 were injured in the accident.
Boeing's reminder applies to all the 737 planes it manufactured, not just the kind involved in the crash.
Events of the flight's final moments became clearer today, with the release of the preliminary accident report.
At 1,950 feet above the ground, the altimeter showed the plane to be at negative-8 feet instead, according to safety board chairman Pieter van Vollenhoven.
As a result, the plane's automatic pilot system responded as though the plane were landing, reducing power the way it would if it were nearing the ground. The crew apparently failed to notice that the airspeed was dropping dramatically, according to the report. The plane's ability to fly continued to deteriorate for more than a minute and a half without the pilots taking action.
Today ABC News aviation consultant John Nance said he was surprised by that chain of events.
"You can hear it, and you can feel it," Nance said. "It's rather astounding that this crew was so fixated on running a check list or whatever else they were doing that they did not pick this up. They were not aware of it."
"The actions of the crew here bespeak a cockpit culture, at least at this point, that really is substandard with what we know of how to get a good result out of every single landing," Nance added.
The airspeed dropped 46 mph below the appropriate speed. At 450 feet above the ground, the plane's systems warned of an imminent stall, prompting the pilots to apply full power, according to the report. But there was too little time to correct the situation.
"When the crew of the Turkish Airlines noticed what was going on, it was already too late to intervene effectively," today's news release from the Hague said.
The Dutch Safety Board, in turn, issued a warning to Boeing, alerting it to possible problems with the radio altimeters on its 737-800 planes.
Boeing said today in a statement provided to ABC News that "erroneous radio altimeter readings are detectable and recoverable. Should a radio altimeter failure occur, anomalous readings would be detected by monitoring systems or be apparent through flight deck effects."
The plane's black box, which stored eight flight recordings, showed the altimeter had the same problem twice before, van Vollenhoven said.
Despite the findings, Boeing said that today's developments "should not be construed as a final conclusion or outcome of the investigation."
The company added that the Dutch Safety Board was "in the early stages of this complex investigation," adding, "We cannot comment publicly on the findings of an open investigation."
Meantime, Nance said passengers have no reason to be worried about flying on 737s, saying it's easy to alert airlines and crews to the problem.
"We can make sure that overnight, everybody who operates that airplane knows how to get past that and it therefore is not a problem any longer," Nance said.
"I wouldn't hesitate for a second to climb on, or have my family climb on, a 737 today," he added later.
ABC News' Matt Hosford and Miguel Marquez contributed to this story.