Nov. 13 (UPI) -- Airline safety experts and pilots' groups say Boeing did not disclose information about a new flight-control feature on its 737 MAX 8 that may have played a role in the crash of a Lion Air commercial airliner last month.
Boeing issued a global safety bulletin last week after a 737 MAX 8 jet crashed into the Java Sea after departing Jakarta, killing 189 passengers and crew.
The cause has not been determined, but investigators are looking at the possibility of faulty sensors. Boeing warned in its bulletin the plane's automated stall-prevention system, which is supposed to help pilots avoid raising the nose too high, could actually push it down unexpectedly, The Wall Street Journal reported.
That news stunned pilot unions and other experts who said they had no idea an automatic stall-prevention system was even added to the new 737 model, and never knew about the potentially fatal problem.
"The companies and the pilots should have been informed," Jon Weaks, president of the Southwest Airlines Pilots Association, said in a report by Bloomberg. "It makes us question, 'Is that everything, guys?' I would hope there are no more surprises out there."
The Allied Pilots Association, the union that represents 15,000 professional pilots who fly for American Airlines, issued a bulletin saying the presence of the system was never included in the documentation that came with the plane.
"This is the first description you, as 737 pilots, have seen," the bulletin stated.
Boeing declined to directly address the issue Monday, but did address the aircraft's overall safety.
"We are taking every measure to fully understand all aspects of this incident, working closely with the investigating team and all regulatory authorities involved," the company said in a statement. "We are confident in the safety of the 737 MAX."