CHICAGO ¨C Boeing Co. knew months before a deadly 737 Max crash that a cockpit alert wasn¡¯t working the way the company had represented to buyers of the jetliner.
But the planemaker didn¡¯t tell airlines or the Federal Aviation Administration of the problem with the warning light until after a Lion Air plane went down off the coast of Indonesia in October, according to a Boeing statement Sunday. The accident occurred after an erroneous reading by a single angle-of-attack sensor triggered software that pushed the jet¡¯s nose down until pilots lost control.
The faulty cockpit indicator was supposed to flash when the plane¡¯s angle-of-attack vanes, which measure the position of the plane¡¯s nose against the oncoming air stream, send conflicting signals. Boeing had told airlines that the so-called AOA disagree alert was standard across the Max fleet, as it had been on a previous generation of 737 aircraft.
But the alert was only working on planes that had a separate angle-of-attack indicator on the cockpit display, the manufacturer said. The additional feature cost extra.
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