AILSA CHANG, HOST:
Boeing is updating its 737 Max planes in the aftermath of two deadly crashes, but the aircraft maker also maintains the planes were fine to begin with. That is not sitting well with some people, as NPR's Camila Domonoske reports.
CAMILA DOMONOSKE, BYLINE: A system designed to make the 737 Max safer called MCAS malfunctioned in both the crash in Indonesia in October and in Ethiopia in March. After receiving faulty data, the system aimed the planes repeatedly toward the ground, and pilots tried and failed to steer the planes back up. Boeing is improving the software, but when Boeing's CEO, Dennis Muilenburg, spoke to investors yesterday, he said the Boeing still stands by the original design.
(SOUNDBITE OF ARCHIVED RECORDING)
DENNIS MUILENBURG: We've done deep assessments of our airplane and the design, and we've confirmed that the MCAS system as originally designed did meet our design and safety analysis criteria.
DOMONOSKE: Muilenburg pointed to the actions taken by the pilots, noting there's a checklist to follow when things go wrong.
(SOUNDBITE OF ARCHIVED RECORDING)
MUILENBURG: And in some cases, those procedures were not completely followed.
DOMONOSKE: The initial investigation into the Ethiopian Airlines crash found the pilots did follow the prescribed checklist, although there is some debate about this. And investigations are ongoing. So Christine Negroni, the author of "The Crash Detectives" about aviation disasters, was surprised that Muilenburg would comment on causes at all.
CHRISTINE NEGRONI: That's just not their role during an investigation.
DOMONOSKE: And she was very surprised to hear him point a finger toward the pilots.
NEGRONI: At least two sets of pilots, if he is correct, didn't do it right and the consequence is a lot of dead people. Everyone makes mistakes. But what you have to do in air safety is make sure that mistakes don't lead to disaster.
DOMONOSKE: Boeing is getting a lot of scrutiny over how it handled the rollout of MCAS. It was introduced without telling or training pilots because it wasn't supposed to change the way the plane handled. And this is where it gets technical. The plane had two sensors that could have fed into MCAS, but the software only listened to one. That made it vulnerable if one of the sensors malfunctioned.
Now we've learned the planes should have been warning pilots if one of those sensors seemed to be faulty. But a warning light that was supposed to be standard was unintentionally tied to a set of optional features that airlines had to pay extra for. If you didn't pay, you wouldn't see the warning. Boeing has gotten flak for having optional features like this in the first place. Transportation safety analyst Ashley Nunes says that's not quite fair.
ASHLEY NUNES: There's no shortage of features, additional features, that Boeing, Airbus, et cetera, charge for.
DOMONOSKE: But in this case, the light wasn't even supposed to be optional. As a result, airlines like Southwest were flying planes without a functional warning light even though pilots thought they worked. This is not just a PR disaster for Boeing. The manufacturer faces a number of lawsuits. Multiple victims' families have sued accusing Boeing of putting profits over safety. And at the same time, a group of shareholders have sued. Reed Kathrein is a lawyer on that case.
REED KATHREIN: It's on behalf of investors who invested during the time that Boeing didn't disclose that they had withheld safety features from the airplanes.
DOMONOSKE: And there could be long-term business fallout. On Monday, the chairman of flydubai said he's considering talking to Airbus, Boeing's rival, about buying their planes. That would be a big change for an airline that until now has only flown Boeing's. Camila Domonoske, NPR News. Transcript provided by NPR, Copyright NPR.