Originally Posted by pattern is full
I believe the request was for an altitude change of 1600 feet, not a descent RATE of 1600 fpm. Losing 1600 feet in, say, 25 seconds, takes a descent RATE of 3840 fpm.
And since the A319 was in climb, a change to a descent would have involved a total V/S change larger than simply descending from level flight. Say, a climb of 2000 fpm converting rapidly to a descent of 3840 fpm = net V/S change of 5840 fpm. Mild "vomit comet" maneuver.
Hold it. TCAS doesn't try to achieve any set altitude difference. It simply asks for a change to the flight path to miss the offending aircraft. Ms Cory doesn't know what she is talking about.
The 3840 is a red herring, as is adding 2000ft/min to it. If the TCAS gave over 2000ft/min change (ie a smooth pitch change of around 3-4° max) I'd be very very surprised.
I'll also wager that the continuing reduction in stick time (because of more use of the AP) will see more of these types of incidents. If you're not used to handflying, suddenly grabbing the stick and smoothly, gently but positively following the TCAS commands is difficult. A couple of practices twice a year in the SIM when you know it's coming isn't enough. No wonder Airbus is investigating the AP itself following the TCAS command without pilot intervention...