Flight Crew Air Transport Pilot (ATP)
Communication Breakdown; Situational Awareness
ATC Issue All Types; Conflict NMAC; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural FAR
Flight Crew Took Evasive Action
Human Factors; Procedure
On approach to OKC; Tower asked us to switch to Runway 17R for helicopter traffic over the interstate. We complied and were established by 1;000 feet. We saw one helicopter we avoided. Then we got an RA to descend at around 700 feet AGL. We complied. I flew the RA guidance after a momentary hesitation to descend below GS. We never saw the aircraft. The Captain saw the traffic on our TCAS [and] it showed 0 feet separation on top of us. The event was in Tower's airspace. They did not point out the traffic to us. We also did not hear them give any advisories to the helicopters. The level of safety they provided was unacceptable.Tower should have kept the helicopters away from our final approach course and advised us more exactly of their location.
ERJ-170 First Officer reported an NMAC with a helicopter on final approach to OKC that featured an RA command to descend below the glideslope at 700 feet AGL.