> If he wanted to save lives, there's a very clear path to alerting the FAA.

Is there? I doubt you can just call up the FAA and be like, "hey, my former employer is going to get people killed." The FAA will naturally call the employer and the employer will naturally defend themselves, calling the ex-employee a kook.

You probably need to generate awareness of the issues in public and show the FAA you're not the only engineer who thinks those practices are unsafe. Then, and only then when you have some accredited clout behind your accusation, can you start holding the FAA's feet to the fire for inaction. And after that, maybe they will investigate.