That's not what those lights mean. The warning was for a malfunction of one of the triple-redundant pressure control systems.
> Homendy said investigators have learned that before the Friday flight, the “auto-depressurization” warning light came on during or after three previous flights, at least one time while the aircraft was in the air, and once while it was on the ground. Each time, the light was checked out, and Alaska Airlines reported the light turning on was a “benign” issue.
Homendy's remarks were obviously wrong and premature (sadly expected of the "chair" who is an administrator, not the qualified engineer.) The Alaska Air 1282 plane experience 3 different warnings. The system is "semi" triple redundant in that there is a primary system, a secondary system, and a manual system. In this case, the primary system was "failing", and the plane switched over to the secondary system. Alaska has not explained itself here.
However, the most obvious speculation, is that the plane was leaking (badly) and the primary system was probably keeping up with the leak (which is why the problem was intermittent.) But that primary system was likely have to "run all the time" (because it had to keep up with the leak) - and one of two (or both) things likely happened. Either sometimes it could NOT keep up (based on elevation, pressure, and temperature variations), or else the pressure pump was actually overheating (from constantly having to run to keep up with the leak), and occasionally failing. When this happened, the plane control systems would automatically switch to the secondary pump, and light the WARNING LAMP. Given that the problem happened twice in the prior 3 days, the problem was getting worse.
AlaskaAir's response was totally inappropriate, and NOT safety focused. They did not ROOT CAUSE the issue, HOPED it was the lamp, or lamp electricals, replaced those parts, and called it good. And the 4th time was the charm, when the plug failed entirely, there having been 3 prior warnings of an issue in pressurization. In my opinion, inexcusable, and the reason I am no longer flying on AlaskaAir. Though I would further speculate that Boeing's inspection procedure instructions probably do not include inspecting the exit door seals, the door plug seal, or the rear pressure cone. Inspecting those things would be much more expensive than just checking the warning light, and the pump operation. (The pressure pumps operating just fine, and the LAMP just fine as well.)
So Homendy's statement is almost certainly expected to be shown to be misplaced and premature. I was incredibly surprised that she made the statement.
> Homendy said investigators have learned that before the Friday flight, the “auto-depressurization” warning light came on during or after three previous flights, at least one time while the aircraft was in the air, and once while it was on the ground. Each time, the light was checked out, and Alaska Airlines reported the light turning on was a “benign” issue.
Homendy addresses this in the media brief: https://www.youtube.com/watch?v=0jeO5fwRXLo&t=257s