Boeing has bigger problems than the FAA in dealing with its troubles involving the 737 Max 8 and Max 9. The FBI has opened a criminal investigation into the matter, specifically focusing on how Boeing won approval for its jets from the FAA, CNN reported overnight. Prosecutors have already sent out subpoenas that also touch on training and marketing for the new model after two deadly crashes finally grounded almost all of them:

US Justice Department prosecutors have issued multiple subpoenas as part of an investigation into Boeing’s Federal Aviation Administration certification and marketing of 737 Max planes, sources briefed on the matter told CNN.

The criminal investigation, which is in its early stages, began after the October 2018 crash of a 737 Max aircraft operated by Lion Air in Indonesia, the sources said. Transportation Secretary Elaine Chao on Tuesday asked the agency’s inspector general to investigate the Max certification.

Criminal investigators have sought information from Boeing on safety and certification procedures, including training manuals for pilots, along with how the company marketed the new aircraft, the sources said.

Boeing insists that the planes are safe but that a software patch will be issued to deal with autopilot issues. One attorney representing victims dismissed this as nothing more than a PR effort. Boeing self-certified the planes under the FAA’s authority, Mary Schiavo tells Will Ripley, which means both entities have lots of incentive to sweep this under the rug. Who’s left to ensure that the new software will make the plane safe for commercial travel?

As the US Justice Dept. issues multiple subpoenas in a criminal probe of the FAA & Boeing — @MarySchiavo doubts whether a software patch will fix the problems with the Boeing 737 Max 8: "It makes no sense. It's utterly ridiculous. Because no one will trust the FAA certification" pic.twitter.com/u7GPpTUpN4

— Will Ripley (@willripleyCNN) March 21, 2019

CBS reports that at least one subpoena is directly aimed at Boeing’s relationship with the FAA:

After last week’s crash of Ethiopian Airlines Flight #302, a Boeing employee received a subpoena to retain records relating to the approval of the 737 Max. Department of Transportation inspector general agents told employees at the FAA’s Seattle office to do the same.

“What did the FAA and Boeing know? When did they know it? And did they tell anybody about it or did they hide that?” said David Gomez, a retired FBI executive with experience in crash investigations.

The probe is focused on the process to certify the 737 Max as safe and airworthy, a process that by design allows the manufacturer to certify much of the plane itself.

“If there is any kind of documentation that indicates that they knew there was a problem and either didn’t resolve it to the satisfaction of the FAA or didn’t reveal that, that could put them in jeopardy in terms of a possible criminal violation,” Gomez said.

That might put the FAA in a tough position too. If they found this issue and didn’t follow up to ensure its resolution, then their allowance of the plane to operate commercially would be just as criminal — at least in a moral sense. If they didn’t find it, then their testing would appear to be horribly deficient, or at the very least that their trust in Boeing was horribly misplaced. And once again, one would have to ask why.

That’s what the FBI and DoJ want to know. And that might raise questions about what else the FAA may have overlooked when it comes to approvals.

Update: Plane manufacturers have lots of luxury upgrades to sell when manufacturing these planes. The New York Times reports that Boeing sold safety features that might have stopped these crashes as extras, too:

As the pilots of the doomed Boeing jets in Ethiopia and Indonesia fought to control their planes, they lacked two notable safety features in their cockpits.

One reason: Boeing charged extra for them. …

Boeing’s optional safety features, in part, could have helped the pilots detect any erroneous readings. One of the optional upgrades, the angle of attack indicator, displays the readings of the two sensors. The other, called a disagree light, is activated if those sensors are at odds with one another.

Boeing will soon update the MCAS software, and will also make the disagree light standard on all new 737 Max planes, according to a person familiar with the changes, who spoke on condition of anonymity because they have not been made public. The angle of attack indicator will remain an option that airlines can buy.

Airlines might consider other airplanes an option they can buy too. This assumes that these two options would have helped, which isn’t necessarily obvious. The problems in both crashes seemed to have come from the autopilot rather than pilots overcorrecting on their own. Still, it’s not a great look for Boeing to leave one of these as an expensive add-on.