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.
Synopsis
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.
Second reporter narrative
I was training on Local Control. A direction was given by his supervisor that we needed to 'burn' his hours because he was ready for checkout and the mentality is that no one can check out at APA unless they have at least 70% of their hours complete; regardless of their ability. The Trainee is a CPC-IT who transferred in to us. With that in mind; I asked if we could work the Local and Ground positions combined because 1) the traffic was light and 2) he would be expected to do this on his own if he was checked out. My intention was to let him work the position with very little interference so that I can document if he was truly ready for checkout. When we first started working the position; the winds were light out of the south and we were landing Runway 17L which is when we first encountered [the Premier]. After The Trainee cleared him to land; the winds shifted to out of the northwest around 8-10 KTS and were forecast to gust even higher shortly. I had to prompt the Trainee to give the new winds to the [Premier] and he asked if he could land Runway 35R instead. At this point [the Premier] was on the left downwind Runway 17L. The Trainee decided to call D01 and inform them first that we were changing configuration to Runway 35R; and second; could they please put the next arrival (Citation) on Runway 35R and finally he was going to give [the Premier] back to them and they said fine. The Trainee proceeded to ship [the Premier] back to approach without an altitude or heading. He remained at 8;000 on a northerly heading and was eventually turned westbound and climbed to 9;000 by D01. We discussed this at length both during and after the training session.....NEED AN ALTITUDE AND HEADING!!! The third aircraft that we were working was an SR22 that was inbound from the south who was requesting to fly the approach on his own to Runway 35R and then circle to Runway 28 due to the winds. The last and 4th aircraft was a VFR helicopter that was southbound; east of the approach course to Runway 35R around 6;700 FT. The Citation was #1 to Runway 35R; The SR22 was #2 and the Premier was west of the field southbound at 9;000; being vectored for the approach to Runway 35R. The Trainee worried about [the Premier] catching the SR22; the Trainee turned him off of the approach by telling him to fly northeast bound....right at the helicopter. The Trainee did not issue traffic. The targets merged but they passed by 500 FT and I saw them visually out the window. We discussed this as well. By this time; the Citation is attempting to land; the winds are gusting out of the west/northwest up to 27 KTS and he goes around. The Trainee quickly jumps on the line and informs D01 that the Citation is going around and he is going to give him back to them but I stop the Trainee and tell him to tell D01 that we will keep him; which he does. We have already cleared the SR22 to land Runway 28. At this point [the Premier] is checking on and he hears the winds that were given to the Citation which are now 280 at 27G35 and he says 'Hang On; that won't work. What do you want us to do?' The Trainee was about to push the D01 line and I prompted him to tell [the Premier] to continue on the Localizer because; in my mind; a 350 heading and the strong west winds would push him to the east side of the airport and possible conflict with the Citation. He states he's not on the localizer but he will continue toward the runway. To me; perfect. forces him to known VFR point on the airport and gives me a few seconds to coordinate with D01 for [the Premier] to overfly the airport and enter a right downwind for Runway 28 to follow the Citation. Flight Data is open and assisting us in trying to coordinate with D01. While we are working out our sequence and coordination; [the Premier] states that Runway 28 is too short and he needs to go to DEN. At that point; I noticed that [the Premier] is now out of 9;500 FT and I prompted the Trainee to descend him back down to 8;000 FT which he does. I never would have expected him to climb; let alone climb higher than 9;000 FT which was the last level altitude he was flying on the downwind before being cleared for the approach. The lowest altitude I observed was about 8;300 FT when we jumped on the D01 line. Apparently [the Premier] conflicted with an air carrier aircraft that climbed; thanks to TCAS; but separation was never lost. When I left work that day; I was informed that everything was fine. 1) We need to fix the training program at APA. We need to stop 'burning' trainees hours just for the heck of it. We need to put them on when there is meaningful traffic; or as in this case; increase the complexity to see if they can handle the extra load and unusual situations. Had I not been led to believe that he was ready for checkout; I would have overrode the frequency and land line coordination instead of letting him dig his hole and see how he crawls out of it. The Trainee was truly not ready to handle even the simplest of unusual situations. Had the trainees actually completed the allocated classroom time in the beginning of their training; maybe they would know what kind of coordination is required. Some Ground Control classes; for example; have been completed in 1-2 hours. Another trainee wasn't even shown the strip markings. Local Control classes are not much better. 2) The pilot should have never climbed out of 9;000 FT; which is the highest altitude even mentioned on the approach charts. 3) I should have never assumed the pilot was competent. When I say continue on the approach; and the pilot understands that I have to coordinate with the Radar Controller; I always expected and they have complied; that they would either level off or continue to slowly descend toward the airport. He knew that we were circling aircraft to Runway 28 due to the high winds. 4) We need to update our SOP or LOA which states that the go-around gets runway heading and 8;000 FT. As I mentioned in the brief; if runway heading and 8;000 FT were given to [the Premier]; he would have drifted to 1-2 east of the airport due to the high winds and possibly conflict with the Citation though I would have maintained visual; but I just didn't trust [the Premier].....and now I know why. Runway heading is good when the aircraft is close to or at the airport. If he's outside the outer marker; not a great idea especially on days when D01 gives us some departure headings such as 140 degrees or 190 degrees. I never liked those 2 especially when we are IFR.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.