EMB ERJ 145 ER/LR
Conflict Airborne Conflict; Deviation - Altitude Excursion From Assigned Altitude
Air Traffic Control Issued Advisory / Alert; Flight Crew Took Evasive Action
Airspace Structure; Human Factors; Procedure
We were on downwind being vectored with New York Approach to Runway 4R in EWR. ATC called out traffic at our 11 o'clock at 4;500 FT (we were at 5;000 FT) doing aerial survey work and were advised that the traffic was under their control. The weather was clear and we searched for the traffic. Traffic showed on our TCAS screen as closing but only 200 FT below not the 500 FT reported by the Controller. We were on the latest and current EWR altimeter setting. We then were issued a TA by the TCAS system. Shortly after we were issued a RA TCAS climb. Almost simultaneously ATC recommended a climb to 5;500 FT. I used the TCS button to override the autopilot and commence the TCAS climb of about 2;000 FT/minute as directed by the VSI. We advised ATC that we were in a TCAS climb. The RA ended near 5;500 FT and the flight continued normally.It is possible that the survey traffic either was not on the current altimeter setting or was not maintaining 4;500 FT as directed by ATC. ATC said that the traffic was under their control but we never heard them issue any instructions to that traffic to avoid us or to even point us out to them.
Air carrier First Officer is advised by ATC of VFR traffic ahead maintaining a 500 FT lower altitude. TCAS indicates a 200 FT separation and issues a climb RA; which is complied with.