The new information in the article (buried in the last part of it!) is that apparently the warning message just didn't work on the ground at all, even with the

The new information in the article (buried in the last part of it!) is that apparently the warning message just didn't work on the ground at all, even with the already non-functioning sensors, and even if that option was paid for; read it again: "We were told that if the A.O.A. vane, like on Lion Air, was in a massive difference, we would receive an alert on the ground" ... "But in the last several weeks, Boeing has been saying something different. Mr. Tajer said the company recently told American pilots that the system would not alert pilots about any sensor disagreement until the aircraft is 400 feet above the ground."