Originally Posted by
DaveReidUK
...what are the two independent failures ...
https://www.bloomberg.com/news/artic...lure-data-showA review of public databases by Bloomberg News reveals the potential hazards of relying on the devices, which are mounted on the fuselage near the plane’s nose and are vulnerable to damage. There are at least 140 instances since the early 1990s of sensors on U.S. planes being damaged by jetways and other equipment on the ground or hitting birds in flight. In at least 25 cases in the U.S., Canada and Europe, the damage triggered cockpit alerts or emergencies.