Colvale wrote on Mar 1^st, 2019 at 8:57am:

Is it any wonder, when you have selected a V/S speed of initially -800 fpm descent then all of a sudden you increase it to -2600fpm descent? Naturally the IAS will shoot up because the aircraft is pithing down at ridiculous  ::)

I think you missed what I said...I intervened at the 0:14 mark. I turned VNAV off, which switches V/S mode on automatically. Whatever the current decent rate is at that moment is selected as the V/S fpm.

At 0:48, I attempt to re-engage VNAV but it again blows through the speed restrictions.

At 0:57, I intervene again because it's pushing the throttles all the way forward. Turning off VNAV switches V/S on again.

On my next flight, I'll get a video of it's attempts to push through the sound barrier with VNAV on (without my intervention), if that's what you'd like.