EMB ERJ 145 ER/LR
Flight Crew Air Transport Pilot (ATP)
Conflict Airborne Conflict; Deviation - Altitude Excursion From Assigned Altitude
Flight Crew Took Evasive Action
Airspace Structure; Human Factors; Procedure
We were in level cruise flight and were at 11;000 feet. ATC issued a descent clearance to another airplane; to stop his descent at 11;500 from 12;500 and issued a traffic report to us and them. The other pilot acknowledged the clearance to stop his descent at 11;500. We reported we were looking for traffic; but he was right above us so we never saw him at all. Soon after we got an RA to monitor vertical speed. The First Officer disconnected the autopilot and pushed the nose down to follow the RA. The airplane above us continued his descent and the RA wanted full down VS; at which time I took the controls and pushed down further. I advised the Controller of this and then continued back up to 11;000 feet when we were clear of traffic. I told the Controller that the airplane came within 200 feet vertical (was in red 02= within 200 ft) of us. The other pilot said in a not so nice way that we were wrong and that our TCAS was wrong. I asked for an 800 number to call. I called and talked to a Controller; who had talked to the Controller handling our flight. He said the Controller had turned away from his screen and that the other pilot continued his descent through 11;500 into our altitude.
EMB145 Captain at 11;000 feet reports and airborne conflict with VFR traffic instructed by ATC to stop descent at 11;500 feet. The VFR traffic continues descent causing a descend RA for the EMB145 crew.