p51guy;
It wasn't very hard to lower their climb rate however. I would be interested to know what the RA green arc showed as the minimum they needed to lower their nose to satisfy it.
The suggested pitch change for a TCAS II RA response under 200KIAS is 5 to 7degrees, an expected IVSI of 1500fpm (flying to the green should result in this
initial rate) or an altitude change from an assigned altitude of between 300 and 500ft from an assigned altitude. Any increase or reversal TCAS command requires only a 1/3g maneuver executed within 2.5 seconds of the command.
The only reason they got the alert was an aircraft passing behind them so with future RA alerts they will fix that.
TCAS II is '
tau'-activated which means it is based upon time to the
CPA - Closest Point of Approach and not distance. I don't think TCAS II would issue an RA for an aircraft that was just 'passing behind' unless of course that aircraft was overtaking the one ahead; not the case here.
The
TCAS II Version 7.0 is an excellent document from the FAA.
PJ2