It was a bad enough look for Boeing when reporters uncovered the company's decision to make some safety features optional on its 737 MAX 8s. Worse still that this decision was only made public after the deadly crash of Ethiopian Airlines Flight 302 just minutes after takeoff on March 10 - the second deadly crash involving the plane in six months, which spurred regulators around the world to ground the planes, erasing billions of dollars of Boeing market cap.

But a report in the Wall Street Journal published on Sunday that neither Southwest Airlines nor the FAA (Boeing's primary federal regulator) were aware that a safety feature intended to alert pilots to a potentially malfunctioning 'angle of attack' sensor - in other words, a feature that might have prevented both the crash of ET302 and the Oct. 29 crash of a 737 owned by Lion Air - had been disabled on the new 737s is simply staggering.

Not only did Boeing disable the alerts, which would notify pilots when the two sensors on the new 737 MAX 8s were reporting dramatically different data, and make them part of a new 'premium' package of safety features, but the manufacturer somehow neglected to tell the airline and its regulator that the alerts had been disabled. The result was that Southwest never updated its safety manuals for pilots to reflect the fact that the alerts had been disabled.

This is particularly egregious because the 737 MAX 8s featured the new MCAS anti-stall software which could be inadvertently triggered by erroneous data being reported by a malfunctioning sensor. Indeed, the preliminary findings from the investigation of the crash of Ethiopian Airlines flight 302 found that the misfire of the MCAS system effectively doomed all 157 people on board that day.

Pilots at Southwest and regulators at the FAA didn't learn that the alerts had been disabled until after the crash of the Lion Air flight, more than a year after the new jets had gone into service.

Plane maker Boeing Co. didn’t tell Southwest Airlines Co. when the carrier began flying 737 MAX jets in 2017 that a standard safety feature, found on earlier models and designed to warn pilots about malfunctioning sensors, had been deactivated. Federal Aviation Administration safety inspectors and supervisors responsible for monitoring Southwest, the largest MAX customer, were also unaware of the change, according to government and industry officials. Boeing had turned off the alerts which, in previous versions of the 737, informed pilots if a sensor known as an “angle-of-attack vane” was transmitting errant data about the pitch of a plane’s nose. In the MAX, which featured a new automated stall-prevention system called MCAS, Boeing made those alerts optional; they would be operative only if carriers bought additional safety features. Southwest’s cockpit crews and management didn’t know about the change for more than a year after the planes went into service. They and most other airlines operating the MAX globally learned about it only after the fatal Lion Air crash last year led to scrutiny of the plane’s revised design. The FAA office’s lack of knowledge about Boeing’s move hasn’t been previously reported. "Southwest’s own manuals were wrong" about the status of the alerts, said Southwest pilots union president, Jon Weaks. Since Boeing hadn’t communicated the modification to the carrier, the manuals still reflected incorrect information.

Perhaps most stunning of all, once the FAA and Southwest learned that the feature had been disabled, it set off a furor at the FAA that nearly pushed it to recommend that all 737 MAX 8s be grounded until the alerts had been turned back on. If the regulator had followed through, it's possible that the crash of ET302 might have been averted.

Following the Lion Air crash, Southwest asked Boeing to reactivate the alerts on planes already in its fleet. This move, along with questions about why they had been turned off, prompted FAA inspectors overseeing Southwest to consider recommending that the airline’s MAX fleet be grounded while they assessed whether pilots needed additional training about the alerts. Those internal FAA discussions, however, were brief and didn’t go up the chain, according to documents reviewed by The Wall Street Journal. […] Less than a month after the Lion Air jet went down, one FAA official wrote that AOA-related issues on 737 MAX jetliners “may be masking a larger systems problem that could recreate a Lion Air-type scenario." Roughly two weeks later, other internal emails referred to a “hypothetical question” of restricting MAX operations with one message explicitly stating: “It would be irresponsible to have MAX aircraft operating with the AOA Disagree Warning system inoperative.” The same message alluded to the FAA’s power: “We need to discuss grounding [Southwest’s] MAX fleet until the AOA Warning System is fixed and pilots have been trained” on it and related displays. The email discussions, previously unreported, were fleeting red flags raised by a small group of front-line FAA inspectors months before the Ethiopian jet nose-dived last month. The concerns raised by the FAA inspectors never progressed up the agency. Within days, they were dismissed by some involved in the discussions who concluded that the alerts provided supplemental pilot aids rather than primary safety information, and therefore no additional training was necessary. During that stretch and beyond, Boeing and the FAA continued to publicly vouch for the aircraft’s safety.

Boeing has never explained exactly why it decided to make these features optional. In the wake of the second crash, the company apologized profusely for this decision, and said that all safety features would be made available on all jets once it finished the software update to make MCAS less powerful, widely seen as an important prerequisite for FAA and other regulators to lift their grounding order.

Without a doubt, Sunday's report is the most damning news about the federal oversight of Boeing since reports that surfaced immediately after the March 10 crash revealed just how much of the approval process for the 737 MAX 8 had been delegated to Boeing itself.

But will either the FAA or Boeing be held accountable for this neglect? That remains to be seen...