Large Transport
Flight Crew Air Transport Pilot (ATP)
ATC Issue All Types; Conflict Airborne Conflict; Inflight Event / Encounter Other / Unknown
Air Traffic Control Issued New Clearance; Flight Crew Executed Go Around / Missed Approach
Airspace Structure; Procedure
Air Traffic vectoring for RWY 16L and 16R visual approaches DEN caused two Go-arounds due to TCAS RA. They were vectoring to place our aircraft wing tip to wing tip on final; instead of staggering. The RA would not allow me to descend on the Glide Slope on both RA events. Even when Clear of Conflict was announced by the TCAS system the red zone was still displayed below and the system prevented a further descent until it placed our aircraft too high for a normal descent to the runway. We broke off the approach in both cases and returned for an additional approach. The third time we were being vectored for the approach I asked that we not have any side-by partners for the approach. The third approach was successful. I called the facility on the ground; had a discussion with the supervisor on duty and then gave him my contact information as he suggested I have the same conversation with the Airspace manager. This event is due; in my opinion; to incorrect or insufficient ATC procedures at DEN approach facility for closely spaced runway operations as well as the limitations of our current TCAS software and its inherent pressure altitude sensitivity application. ATC placing aircraft in close proximity (wing tip to wing tip) is the root cause. Staggered; to the minimum amount; should be the operational process for this runway spacing. Turning the TCAS to TA only should not be an approved operation as the floor of the Class B in that area is 7000 feet and the aircraft are at approximately 8000 feet outside of any FAF or FAP. Just too much open airspace below to disregard the protections.
Air Carrier Captain reported that two go-arounds had to be initiated at DEN while being vectored for visual approaches to Runways 16L and 16R due to side-by-side placement of aircraft resulting in TCAS RAs.