Transcript for FAA warns airlines about sensor issue in Boeing's fastest-selling jet

the new warning from the FAA tonight, issuing an emergency derekive after that deadly crash in Indonesia. ABC's David Kerley on this again tonight. Reporter: That emergency FAA directive tonight, warning airlines about a sensor in Boeing's fastest selling jet ever. The 737 max-8. Indonesian investigators say the lion air jet that crashed 13 minutes into its flight, killing all 189 onboard, had a sensor malfunction, which could have sent the jet into an aggressive nose dive. That sensor aimed at preventing a dangerous stall had been replaced two fights earlier, but the problems per sipsed. Still, experts say this apparent first-ever occurrence in the popular plane should not cause a crash. It's extremely rare, but crews are trained to be able to handle it. And so, one of the questions that comes in, if that was what was involved in lion air, did the crew respond incorrectly? Reporter: The FAA order requires airlines make sure pilots are aware of procedures in the jet's manual on how to disengage the safety system. Southwest and American airlines the two U.S. Carriers flying the max-8, say they already have procedures in place that cover this emergency airworthiness directive. David? David Kerley, thank you. And a midterm election

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