Boeing Max failed to apply safety lesson from deadly 2009 crash
A fatal airplane crash a decade ago prompted a life-saving fix across thousands of Boeing 737 cockpits. So why wasn’t the same lesson applied to the design of the 737 Max, an upgraded version on which 346 people died in recent disasters? Investigators of the 2009 crash of a Turkish Airlines jet identified a faulty altitude sensor that thought the plane was closer to the ground than it was and triggered the engines to idle. The plane’s second radio altimeter displayed the correct elevation, but it didn’t matter: the automatic throttle was tied to the first gauge. The Amsterdam-bound plane crashed into a field, killing nine people and injuring 120. Boeing ended up changing that throttle system to prevent one erroneous altitude reading from cascading into tragedy, changes the US FAA subsequently made mandatory. Yet when the Max debuted in 2017 with a new flight-control feature to help pilots avoid a stall, it was designed to react to only one of the plane’s two “angle of attack” sensors that measure the jet’s incline. That proved deadly when malfunctioning sensors on jets operated by Lion Air and Ethiopian Airlines automatically commanded the noses of the planes down over and over, even though the other sensor showed it wasn’t necessary. “When I read that the planes had two angle-of-attack sensors, I couldn’t think of a reason why they wouldn’t use both,” said Robert Canfield, an aeronautical engineering professor and technical director of the Virginia Tech Airworthiness Center. A software fix for the 737 Max that is now in testing will do just that, and multiple investigations of two crashes, the first in October and the second in March, are probing why it wasn’t incorporated into the original design. Boeing says the Max disasters shouldn’t be compared to the Turkish Airlines crash and no evidence has emerged to indicate that the altitude sensor, known as a radio altimeter, failed on the Lion Air or Ethiopian planes. “These incidents address fundamentally different system inputs and phases of flight,” Charles Bickers, a Boeing spokesman, said in an email.<br/>
https://portal.staralliance.com/cms/news/hot-topics/2019-05-07/general/boeing-max-failed-to-apply-safety-lesson-from-deadly-2009-crash
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Boeing Max failed to apply safety lesson from deadly 2009 crash
A fatal airplane crash a decade ago prompted a life-saving fix across thousands of Boeing 737 cockpits. So why wasn’t the same lesson applied to the design of the 737 Max, an upgraded version on which 346 people died in recent disasters? Investigators of the 2009 crash of a Turkish Airlines jet identified a faulty altitude sensor that thought the plane was closer to the ground than it was and triggered the engines to idle. The plane’s second radio altimeter displayed the correct elevation, but it didn’t matter: the automatic throttle was tied to the first gauge. The Amsterdam-bound plane crashed into a field, killing nine people and injuring 120. Boeing ended up changing that throttle system to prevent one erroneous altitude reading from cascading into tragedy, changes the US FAA subsequently made mandatory. Yet when the Max debuted in 2017 with a new flight-control feature to help pilots avoid a stall, it was designed to react to only one of the plane’s two “angle of attack” sensors that measure the jet’s incline. That proved deadly when malfunctioning sensors on jets operated by Lion Air and Ethiopian Airlines automatically commanded the noses of the planes down over and over, even though the other sensor showed it wasn’t necessary. “When I read that the planes had two angle-of-attack sensors, I couldn’t think of a reason why they wouldn’t use both,” said Robert Canfield, an aeronautical engineering professor and technical director of the Virginia Tech Airworthiness Center. A software fix for the 737 Max that is now in testing will do just that, and multiple investigations of two crashes, the first in October and the second in March, are probing why it wasn’t incorporated into the original design. Boeing says the Max disasters shouldn’t be compared to the Turkish Airlines crash and no evidence has emerged to indicate that the altitude sensor, known as a radio altimeter, failed on the Lion Air or Ethiopian planes. “These incidents address fundamentally different system inputs and phases of flight,” Charles Bickers, a Boeing spokesman, said in an email.<br/>
