(CMR) A U.S. aviation regulator plans to mandate that airlines follow an advisory issued by Boeing Co. on how pilots should handle false readings from a plane sensor that authorities say occurred on a 737 MAX jet that crashed off the Indonesian coast last week.
The Federal Aviation Administration on Wednesday issued a statement saying it plans to issue an airworthiness directive on the issue and “will take further appropriate actions depending on the results of the investigation.” The FAA also notified other regulatory agencies around the world, which typically follow the U.S. agency’s lead on safety matters.
The operations-manual bulletin was issued Tuesday, Boeing said in a statement posted to Twitter, and tells flight crews to use existing guidelines when dealing with erroneous inputs from the so-called angle of attack sensor. That sensor is intended to maintain air flow over a plane’s wings but if it malfunctions it can cause the plane’s computers to erroneously think it is in a aerodynamic stall — which can then cause aircraft to abruptly dive.
Bloomberg News earlier reported that Boeing was said to be preparing to issue an alert to operators of the 737 MAX jet in response to the investigation into the Oct. 29 crash of the Lion Air plane, which saw 189 people killed.
The bulletin is based on preliminary findings from the Lion Air disaster. Under some circumstances, such as when pilots are flying manually, the MAX jets will automatically try to push down the nose if they detect that an aerodynamic stall is possible, a person familiar with the matter said. One of the critical ways a plane determines if a stall is imminent is the angle of attack measurement.
Boeing shares rose less than one percent to $368.11 in premarket trading Wednesday in New York. The stock had climbed 24 percent this year through Tuesday.