Boeing Co. on Monday said certain safety alerts on its 737 Max jets didn’t operate as airlines would have anticipated because of a previously undisclosed error on its part.
Boeing’s BA, -0.46% statement came a day after The Wall Street Journal reported the company hadn’t told airlines flying 737 Max jets that certain safety alerts wouldn’t function as expected. The issue of nonfunctioning alerts came to light after the crash of a Lion Air jet in October in Indonesia, but there were no indications since then that it stemmed from a mistake on the part of the plane maker.
The alerts offer an extra safeguard for pilots in the event a separate stall-prevention system called MCAS, suspected in the deadly Lion Air crash and the crash of an Ethiopian Airlines 737 Max in March, may be on the verge of misfiring. The two crashes took a total of 346 lives, leading regulators around the world to ground the 737 Max fleet.
The Monday statement suggests Boeing engineers and management, as well as U.S. air-safety regulators, either missed or overlooked one more software design problem when the model was certified two years ago. Before Monday, neither Boeing nor the Federal Aviation Administration had disclosed that an additional software glitch — rather than an intentional plan by the plane maker — rendered so-called angle of attack alerts inoperable on most Max aircraft. The alerts warn pilots when there is a disagreement between two separate sensors measuring the angle of a plane’s nose.
An expanded version of this report appears on WSJ.com.
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