Narrative:

The weather in the denver area was very gusty and turbulent this morning; and I was in and out of rain once I arrived in the terminal area. On approach into apa; I was cleared while on downwind for a visual approach to runway 17L while at 8;000 ft. When I was on a (roughly) 4 mile base leg into apa; tower reported that the winds were now 300 at 08 KTS; favoring runway 35. I requested runway 35R; and was switched back over to denver approach control (after a small delay) for the ensuing vectors around the west side of the airport to runway 35R. Once back on with denver approach; I was given a climb to 9;000 ft; then we were vectored approximately 7 miles south of apa; I was given 8;000 ft and was then cleared for the visual approach to runway 35R. During this time; my aircraft was being buffeted by large downdrafts; and very gusty winds. After configuring my aircraft for landing; the wind report from tower indicated that the winds were now above 35 KTS out of the west (270?); favoring runway 28. Runway 28 is too short for my aircraft; so I decided to go around and divert to denver international. (3 different runway assignments; while close in; and all in roughly 5 minutes.) two to three seconds after I discontinued the approach to 35R; I witnessed a sustained loss of approximately 25 KTS airspeed due to windshear; and the left wing of the aircraft dropped approximately 15 degrees; coupled with moderate turbulence. During my windshear recovery/go around procedure; I simultaneously initiated a climb; and powered up. During the windshear/go around procedure; apa tower controller said 'fly the localizer'. As I was cleared for a visual approach; I was not using or set up for the localizer; so I maintained runway heading. When [I] asked tower if I should contact approach control; I heard an unintelligible sound from tower that sounded like 'hang on...'. I continued on the northerly runway heading gaining airspeed and altitude and waiting for tower to switch me off to approach. By the time apa tower switched me to approach control; I had begun leveling at 9;500 ft from my windshear recovery/go around. Approach control pointed out traffic at our 1 o'clock position (an airbus); which I had seen on TCAS; and had visual contact with; before approach pointed them out. My windshear recovery had caused a resolution advisory to occur in the air carrier aircraft. I descended to 9;000 ft and was given heading instructions and a runway assignment into denver international; where I eventually landed. In hindsight; the delay of the tower controller on the go around was what eventually led to the loss of separation when coupled with our windshear recovery. We were expecting immediate heading/altitude instructions from the tower on the missed approach; as tower controllers are usually very good at giving. We had been given a visual approach; so there is no altitude for the missed; until specified by the controller. When we asked the tower to be switched to approach; were were told 'hold on...'. We could have also stated the reason for our missed approach; and why we were climbing so aggressively; but the speed at which the event occurred; in conjunction with the delayed communication from the tower; made it very difficult to communicate all but the most necessary of readbacks. Another factor affecting this situation was the rapidly changing weather conditions. As stated above; apa went from using runway 17L; to runway 35R; to runway 28 in roughly 4 minutes. I know that apa is a training facility for new controllers; and speculate that this could have been the reason for the slow communications from tower. My thought is that when weather conditions indicate that a go around might occur; (gusty winds; windshear etc..) having prearranged missed approach instructions for pilots is imperative to the safety of flight. I learned to ask for visual missed approach instructions from the tower; even if they do not give them to you; and even when you do not think a go around is imminent. Having this information in hand before initiating a go around would have prevented this loss of separation from occurring.

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Original NASA ASRS Text

Title: A Premier pilot and an ATC Local Controller Instructor describe the same weather-driven windshear go around; subsequent diversion and airborne conflict from their own perspectives.

Narrative: The weather in the Denver area was VERY gusty and turbulent this morning; and I was in and out of rain once I arrived in the terminal area. On approach into APA; I was cleared while on downwind for a VISUAL approach to Runway 17L while at 8;000 FT. When I was on a (roughly) 4 mile base leg into APA; Tower reported that the winds were now 300 at 08 KTS; favoring Runway 35. I requested Runway 35R; and was switched back over to Denver Approach Control (after a small delay) for the ensuing vectors around the west side of the airport to Runway 35R. Once back on with Denver Approach; I was given a climb to 9;000 FT; then we were vectored approximately 7 miles south of APA; I was given 8;000 FT and was then cleared for the visual approach to Runway 35R. During this time; my aircraft was being buffeted by large downdrafts; and VERY GUSTY winds. After configuring my aircraft for landing; the wind report from Tower indicated that the winds were now above 35 KTS out of the west (270?); favoring Runway 28. Runway 28 is too short for my aircraft; so I decided to go around and divert to Denver International. (3 different runway assignments; while close in; and all in roughly 5 minutes.) Two to three seconds after I discontinued the approach to 35R; I witnessed a sustained loss of approximately 25 KTS airspeed due to windshear; and the left wing of the aircraft dropped approximately 15 degrees; coupled with moderate turbulence. During my windshear recovery/go around procedure; I simultaneously initiated a climb; and powered up. During the windshear/go around procedure; APA Tower Controller said 'Fly the localizer'. As I was cleared for a visual approach; I was not using or set up for the localizer; so I maintained runway heading. When [I] asked Tower if I should contact Approach Control; I heard an unintelligible sound from Tower that sounded like 'HANG ON...'. I continued on the northerly runway heading gaining airspeed and altitude and waiting for Tower to switch me off to Approach. By the time APA Tower switched me to Approach Control; I had begun leveling at 9;500 FT from my windshear recovery/go around. Approach Control pointed out traffic at our 1 o'clock position (an Airbus); which I had seen on TCAS; and had visual contact with; before Approach pointed them out. My windshear recovery had caused a Resolution Advisory to occur in the air carrier aircraft. I descended to 9;000 FT and was given heading instructions and a runway assignment into Denver International; where I eventually landed. In hindsight; the delay of the Tower Controller on the go around was what eventually led to the loss of separation when coupled with our windshear recovery. We were expecting immediate heading/altitude instructions from the Tower on the missed approach; as Tower Controllers are usually VERY good at giving. We had been given a visual approach; so there is no altitude for the missed; until specified by the Controller. When we asked the Tower to be switched to Approach; were were told 'HOLD ON...'. We could have also stated the reason for our missed approach; and why we were climbing so aggressively; but the speed at which the event occurred; in conjunction with the delayed communication from the Tower; made it very difficult to communicate all but the most necessary of readbacks. Another factor affecting this situation was the rapidly changing weather conditions. As stated above; APA went from using Runway 17L; to Runway 35R; to Runway 28 in roughly 4 minutes. I know that APA is a training facility for new controllers; and speculate that this could have been the reason for the slow communications from Tower. My thought is that when weather conditions indicate that a go around might occur; (gusty winds; windshear etc..) having prearranged missed approach instructions for pilots is imperative to the safety of flight. I learned to ask for visual missed approach instructions from the Tower; even if they do not give them to you; and even when you do not think a go around is imminent. Having this information in hand before initiating a go around would have prevented this loss of separation from occurring.

Data retrieved from NASA's ASRS site as of April 2012 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.