From today's NYT:
Boeing Believed a 737 Max Warning Light Was Standard. It Wasn’t.
When Boeing began delivering its 737 Max to customers in 2017, the company believed that a key cockpit warning light was a standard feature in all of the new jets.
But months after the planes were flying, company engineers realized that the warning light worked only on planes whose customers had bought a different, optional indicator.
In essence, that meant a safety feature that Boeing thought was standard was actually a premium add-on.
Boeing detailed its initial confusion about the warning light in a statement released on Sunday, adding new details to what was already known about the flawed design and introduction of the 737 Max, its best-selling jetliner.
AOA disagree, of course. Sheesh.