Narrative:

Inbound on the final approach for ILS runway 35L; we received a TCAS RA to climb. I disengaged the autopilot and autothrottle and hand flew the aircraft. When the first officer told ATC we were climbing for an RA; the controller responded; 'the ATIS is advertising parallel approaches.' the aircraft was reconfigured for the go-around and we climbed to our assigned altitude of 10000 ft. When we leveled at 10000 ft; and I reduced the power; the stick shaker activated. During the recovery; the aircraft settled. While we were climbing back to our assigned altitude; the controller said; 'I really need you at 10000 ft.' the first officer responded; 'we picked up ice and lost some altitude.' the stick shaker was probably activated due to a large accumulation of ice on the airframe and possibly erroneous engine indications due to ice on the engine P/T probes. There were numerous PIREPS for mixed icing in the area at approach altitudes. Engine anti-ice was on; however; the wing anti-ice was not on during the first approach; as ice accumulation was minimal. During the RA climb/go-around; we flew into additional icing and had not yet activated the wing anti-ice due to managing the leveloff. The wing anti-ice was selected on after stick shaker recovery. During postflight; the first officer removed ice from the engine P/T probes. At least 2 inches of mixed ice was still adhering to the leading edge of the horizontal and vertical stabilizers; and fist-sized balls of ice were on the windshield wiper posts. There was also ice adhering to the landing gear struts. While the primary focus of this report is the above; I would like to also address den approach control procedures. Recently; prior to this event; a company pilot had related a very similar TCAS RA/go-around while on approach to den. He felt that the RA was a result of being crowded behind the preceding aircraft on the parallel approach. I believe our RA was caused by the same scenario. In both cases; the controller's attitude seemed to be; 'well; we are conducting parallel approaches.' pilots have no leeway when responding to a TCAS RA. The threat aircraft may or may not be the preceding aircraft on the parallel approach. In both cases cited; the pilots believed it was. For den approach to run operations in a manner that actually triggers TCAS tas is not acceptable.

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Original NASA ASRS Text

Title: An air carrier pilot executed a go-around on an ILS to DEN 35L after receiving a TCAS RA climb command while conducting a parallel approach. In the climb ice was accumulated leading to a stick shaker and loss of altitude.

Narrative: Inbound on the final approach for ILS Runway 35L; we received a TCAS RA to climb. I disengaged the autopilot and autothrottle and hand flew the aircraft. When the First Officer told ATC we were climbing for an RA; the Controller responded; 'The ATIS IS advertising parallel approaches.' The aircraft was reconfigured for the go-around and we climbed to our assigned altitude of 10000 ft. When we leveled at 10000 ft; and I reduced the power; the stick shaker activated. During the recovery; the aircraft settled. While we were climbing back to our assigned altitude; the Controller said; 'I really need you at 10000 ft.' The First Officer responded; 'We picked up ice and lost some altitude.' The stick shaker was probably activated due to a large accumulation of ice on the airframe and possibly erroneous engine indications due to ice on the engine P/T probes. There were numerous PIREPS for mixed icing in the area at approach altitudes. Engine anti-ice was on; however; the wing anti-ice was not on during the first approach; as ice accumulation was minimal. During the RA climb/go-around; we flew into additional icing and had not yet activated the wing anti-ice due to managing the leveloff. The wing anti-ice was selected on after stick shaker recovery. During postflight; the First Officer removed ice from the engine P/T probes. At least 2 inches of mixed ice was still adhering to the leading edge of the horizontal and vertical stabilizers; and fist-sized balls of ice were on the windshield wiper posts. There was also ice adhering to the landing gear struts. While the primary focus of this report is the above; I would like to also address DEN Approach Control procedures. Recently; prior to this event; a company pilot had related a very similar TCAS RA/go-around while on approach to DEN. He felt that the RA was a result of being crowded behind the preceding aircraft on the parallel approach. I believe our RA was caused by the same scenario. In both cases; the Controller's attitude seemed to be; 'Well; we ARE conducting parallel approaches.' Pilots have no leeway when responding to a TCAS RA. The threat aircraft may or may not be the preceding aircraft on the parallel approach. In both cases cited; the pilots believed it was. For DEN Approach to run operations in a manner that actually triggers TCAS TAs is not acceptable.

Data retrieved from NASA's ASRS site as of May 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.