Originally Posted by
B-757
.. 8000+fpm descend from 2200ft and recover by 800ft..?? Impossible in a B777. . Any pilot could tell that something doesn’t add up here.
Vertical rate (RoD/RoC) is a second-order ADS-B parameter and should be treated with caution in any regime other than a uniform climb/descent.
That said, the elapsed time for the upset from 2200 feet, down to 775 feet and back to 2200 was approximately 28 seconds, so unless doubt is being cast on the instantaneous height values or timestamps, that does indeed appear to be what happened.