Just when did the airlines know that they had to pay extra for a key warning system on the Boeing 737 Max? The Wall Street Journal reported last night that it wasn’t at the point of sale. Until a crash in Ethiopia last October, Southwest Airlines thought the system came standard with the platform — so much so that their operating manuals included them.

Somehow, the news that the safety feature was an upgrade didn’t get mentioned to the FAA, either:

Boeing Co. didn’t tell Southwest Airlines Co. and other carriers when they began flying its 737 MAX jets that a safety feature found on earlier models that warns pilots about malfunctioning sensors had been deactivated, according to government and industry officials.

Federal Aviation Administration safety inspectors and supervisors responsible for monitoring Southwest, the largest 737 MAX customer, also were unaware of the change, the officials said. …

Southwest’s management and cockpit crews didn’t know about the lack of the warning system for more than a year after the planes went into service in 2017, industry and government officials said. They and most other airlines operating the MAX learned about it only after the Lion Air crash in October led to scrutiny of the plane’s revised design.

“Southwest’s own manuals were wrong” about the availability of the alerts, said the Southwest pilots union president, Jon Weaks. Since Boeing hadn’t communicated the modification to the carrier, the manuals reflected incorrect information, he said.

After the Lion Air crash, Southwest discovered the deactivation and apparently bought the upgrade. How did the FAA react when they found out that Boeing had made this system optional? Both the WSJ and AFP report that the FAA considered grounding the plane in December to review the change — but instead opted to let it go:

US regulators considered grounding some Boeing 737 MAX planes last year after learning of a problem with a system that is now the main suspect in two deadly crashes, a source close to the matter said.

Investigators in the Lion Air crash in October off the coast of Indonesia and the Ethiopia Airlines disaster in March have zeroed in on the planes’ anti-stall system, called the Maneuvering Characteristics Augmentation System, or MCAS.

Last year, inspectors with the Federal Aviation Administration discovered Boeing de-activated a signal designed to advise the cockpit crew of a malfunctioning of the MCAS system, the source said. …

They considered recommending grounding the planes as they explored whether pilots flying the aircraft needed additional training about the alerts, said the source.

They decided against that — but never passed details of the discussions to higher-ranking officials in the FAA, the source said, confirming a story in The Wall Street Journal.

After Boeing started reactivating the systems, both report, questions got asked internally as to whether to ground the platform while pilots received additional training. The FAA again opted against grounding the aircraft. Not until a second crash occurred this year did the FAA take action on the 737 Max.

This might explain why the expected delay on the platform has been extended into August. The FAA has some explaining to do, but in the meantime they want to demonstrate the kind of scrutiny that didn’t get applied to the 737 Max in the past. They will have to carefully parse through all of the changes to the platform from the previous iteration of the 737 and make sure they know what is standard and what is optional on the plane. Having been caught with their pants down once, now they want to make sure it doesn’t happen again.

Boeing has more questions to answer. Did they originally submit the whole 737 Max package to the FAA as standard and later decide to make parts of it optional? Or did they just not inform the FAA and the airlines which were which? Both reports make it clear that Southwest thought they had bought the whole system up front and got blindsided by the deactivation of the safety system. Did the same happen with American Airlines, Boeing’s other major domestic 737 Max customer? Or did American buy the full package from the start? If so, how did they know and Southwest didn’t?

At the very least, it’s become clear that two fatal crashes and over 300 deaths resulted from confusion (at the least) over Boeing’s product. We’re lucky more didn’t take place. And while air travel continues to be the safest mode of transportation, it’s tough to feel anywhere near as confident in it after the actions and inactions of Boeing and the FAA involving this platform.