Cessna Citation Sovereign (C680)
Flight Crew Air Transport Pilot (ATP)
ATC Issue All Types; Conflict NMAC
Air Traffic Control Issued New Clearance; Flight Crew FLC complied w / Automation / Advisory; Flight Crew Took Evasive Action
Human Factors
We departed HPN Runway 16 on the WESTCHESTER 4 SID. As we reached 800 FT and initiated the turn to 320 we got a TA. ATC amended our instructions and were given runway heading maintain 2;000 FT. We both visually acquired the traffic and it continued to turn and climb into our flight path prompting an RA of 'monitor vertical speed.'  The First Officer informed the Tower of the RA as traffic passed beneath us with the TCAS displaying 200 FT on the target. We were then issued a climb to 3;000 FT and the turn to 320. We were given a number to call back in HPN. Upon arrival I notified the Assistant Chief Pilot (ACP) of our incident and then called HPN Tower. The Controller I spoke with explained that the traffic was a VFR departure off of Runway 11 before we departed 16. He further explained that the traffic was supposed depart straight out or make a left turn out from that runway.
A Citation Sovereign departing HPN Runway 16 on the WESTCHESTER SID experienced an NMAC with a departure off Runway 11 that had failed to comply with Tower's departure instructions.