B737-800
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 247; Flight Crew Type 13500
Situational Awareness; Communication Breakdown
ATC Issue All Types; Conflict Airborne Conflict; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Flight Crew Took Evasive Action
Human Factors
While climbing out of RDU; we had several intermediate level offs. The last clearance was to climb to FL310. Shortly after leveling at FL310; we got a TA for an aircraft coming from the opposite direction at FL310. Atlanta Center asked us to verify that we were level at FL300; and we replied 'negative; level at FL310'. We then got an RA; and responded by disconnecting the autopilot and climbing. Atlanta Center also directed us to turn right to 360 degrees and climb to FL340. We entered the turn while still climbing. We saw the other aircraft pass maybe a mile away (he was descending in response to his RA); and after we were clear; Atlanta Center cleared us back on course. We discussed it with the Controller; and he was not sure whether he had cleared us to FL300 or FL310.I believe the Controller made an error by assigning us FL310 when he meant FL300. The TCAS procedures worked well.
After going over what had just happened; we both thought we heard cleared to FL310.
B737-800 flight crew reported responding to an RA from opposite direction traffic at FL310.