Narrative:

I was working the local control #4 position, responsible for arrival traffic on runways 16L&right, and departing traffic on runway 25. The winds initially were out of the south around 6-8 KTS. Traffic was moderate at the time. I started to notice the winds shifting to the north, initially at 5-7 KTS. This was expected to have happened earlier based on WX forecasts. I notified the traffic management coordinator and tower supervisor of the changing winds. Winds then hit 10 KTS. Winds starting picking up to 12 KTS, then 14 KTS, then 15 KTS. I repeatedly notified the traffic management coordinator and supervisor. I overheard the traffic management coordinator attempting to contact the TRACON with no luck after repeated calls. Finally, he succeeded. By this time, the winds had picked up to around 17 KTS. I again reminded them that we would soon be having go around's due to the tailwinds. At 20 KTS, all of the aircraft on final were starting to go around. We were running visual approachs at the time, so many aircraft were side-by-side of each other on final to runways 16L&right. There were probably 10-12 missed approachs since the TRACON kept sending aircraft to me on final for runways 16L&right. The wind eventually peaked at around 24 KTS out of the north. Due to the last few aircraft departing runway 25, I could not immediately turn the aircraft on runway 16R to the west. Nor could I turn the aircraft on runway 16L to the east due to departures off runways 8 and 17L&right by the local #1 and local #2 controllers. I stopped any further departures off runway 25, while the local #2 controller stopped all of his departures off runways 17L&right. I then coordination with him the use of his departure airspace. Even though it was quite hectic at the time, I could overhear in the backgnd the traffic management coordinator attempting to initiate a runway change to start landing north. He then told me we would be landing north soon. However, I still had numerous aircraft going around off runways 16L&right, that I had to take a couple of mi south before I could turn due to an eagles nest restr area that we are not allowed to fly through. In some cases, when I could not turn immediately, I would climb one missed approach to 8000 ft and the other to 9000 ft to get vertical separation. I immediately got visual separation on all of the missed approachs. Eventually, I was able to start turning the aircraft to diverging heading and hand them back off to approach for re-sequencing them back to the airport. At one point I looked at the radar and noticed an air carrier X jet at 8000 ft about 5 mi in front of air carrier Y (one of the missed approachs off runway 16L) that I had assigned 8000 ft and a coordination heading of 155 degrees. I then noticed that air carrier X was not a departure heading south, but an arrival heading north to land on runway 35L. I immediately yelled to the traffic management coordinator and supervisor for them to tell the TRACON to get air carrier X out of there as he was head-on to my missed approach at the same altitude (8000 ft), only 5 mi apart. Talk about an adrenaline rush! Just prior to seeing that, I had shipped air carrier Y to departure for re-sequence. I was still busy trying to separate the other missed approachs on runways 16L&right. The TRACON then called and asked me to climb air carrier Y. I told the traffic management coordinator that I had already shipped him to approach. Eventually, they descended air carrier X and turned him out of the path of air carrier Y. At what point they lost separation is unknown to me. However, I am sure we probably did. However, I was never informed that there would be an investigation of that since someone made the call that no separation was lost. Several things were striking about this event. First, was the trouble the tower traffic management coordinator had in contacting the TRACON to initiate a runway change, before events turned sour. In addition, when they did change the runway, the TRACON starting vectoring aircraft into runway 35L before I released the airspace that was full of missed approachs. This was exacerbated by the fact that we have a restr area (with no eagles in it) that we cannot fly through without a fine to the controllers, thus making us fly aircraft side-by-side to each other for an inordinately long period of time. Additionally, even after they were told that every aircraft on final to runways 16L&right would be going around due to the 20+ KT tailwind, thetracon kept vectoring aircraft to those runways while starting to vector aircraft to runways 35L&right. Also, the conflict alert never went off between air carrier X and air carrier Y. Had I not seen this and brought it to everyone's attention, the outcome could have been much worse. I do not know why it never went off. I am sure the TCASII was definitely going off in the cockpits of both aircraft. It also disturbed me that facility management did not even attempt to investigate how and why this happened. I am a 22 yr veteran and have never experienced an incident as close as this, and never want to experience it again. While it always appears easy for the TRACON to stop departures when being overloaded, it should be just as important to stop vectoring arrs to runways that aircraft cannot land on. It should also be noted that too many people who are not talking to aircraft and/or are not responsible for delegated airspace are giving that airspace up without coordinating with the person responsible. While we are grateful this incident ended with a positive outcome, it should be a wake-up call about timeliness and changing out of confign before the wind forces it. We have too much good equipment that gives us notice of pending events. It is too common in denver to force aircraft to land with tailwinds when we have too many options that other airports only dream of.

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Original NASA ASRS Text

Title: DEN TWR CTLR DESCRIBES QUICKLY CHANGING WX FACTORS REQUIRING RWY CHANGE, MULTIPLE GAR'S, UNTIMELY COORD BTWN TWR AND TRACON CTLRS AND A POSSIBLE LOSS OF SEPARATION BTWN AN ARR ON APCH FREQ AND A DEP WORKED BY THE TWR.

Narrative: I WAS WORKING THE LCL CTL #4 POS, RESPONSIBLE FOR ARR TFC ON RWYS 16L&R, AND DEPARTING TFC ON RWY 25. THE WINDS INITIALLY WERE OUT OF THE S AROUND 6-8 KTS. TFC WAS MODERATE AT THE TIME. I STARTED TO NOTICE THE WINDS SHIFTING TO THE N, INITIALLY AT 5-7 KTS. THIS WAS EXPECTED TO HAVE HAPPENED EARLIER BASED ON WX FORECASTS. I NOTIFIED THE TFC MGMNT COORDINATOR AND TWR SUPVR OF THE CHANGING WINDS. WINDS THEN HIT 10 KTS. WINDS STARTING PICKING UP TO 12 KTS, THEN 14 KTS, THEN 15 KTS. I REPEATEDLY NOTIFIED THE TFC MGMNT COORDINATOR AND SUPVR. I OVERHEARD THE TFC MGMNT COORDINATOR ATTEMPTING TO CONTACT THE TRACON WITH NO LUCK AFTER REPEATED CALLS. FINALLY, HE SUCCEEDED. BY THIS TIME, THE WINDS HAD PICKED UP TO AROUND 17 KTS. I AGAIN REMINDED THEM THAT WE WOULD SOON BE HAVING GAR'S DUE TO THE TAILWINDS. AT 20 KTS, ALL OF THE ACFT ON FINAL WERE STARTING TO GO AROUND. WE WERE RUNNING VISUAL APCHS AT THE TIME, SO MANY ACFT WERE SIDE-BY-SIDE OF EACH OTHER ON FINAL TO RWYS 16L&R. THERE WERE PROBABLY 10-12 MISSED APCHS SINCE THE TRACON KEPT SENDING ACFT TO ME ON FINAL FOR RWYS 16L&R. THE WIND EVENTUALLY PEAKED AT AROUND 24 KTS OUT OF THE N. DUE TO THE LAST FEW ACFT DEPARTING RWY 25, I COULD NOT IMMEDIATELY TURN THE ACFT ON RWY 16R TO THE W. NOR COULD I TURN THE ACFT ON RWY 16L TO THE E DUE TO DEPS OFF RWYS 8 AND 17L&R BY THE LCL #1 AND LCL #2 CTLRS. I STOPPED ANY FURTHER DEPS OFF RWY 25, WHILE THE LCL #2 CTLR STOPPED ALL OF HIS DEPS OFF RWYS 17L&R. I THEN COORD WITH HIM THE USE OF HIS DEP AIRSPACE. EVEN THOUGH IT WAS QUITE HECTIC AT THE TIME, I COULD OVERHEAR IN THE BACKGND THE TFC MGMNT COORDINATOR ATTEMPTING TO INITIATE A RWY CHANGE TO START LNDG N. HE THEN TOLD ME WE WOULD BE LNDG N SOON. HOWEVER, I STILL HAD NUMEROUS ACFT GOING AROUND OFF RWYS 16L&R, THAT I HAD TO TAKE A COUPLE OF MI S BEFORE I COULD TURN DUE TO AN EAGLES NEST RESTR AREA THAT WE ARE NOT ALLOWED TO FLY THROUGH. IN SOME CASES, WHEN I COULD NOT TURN IMMEDIATELY, I WOULD CLB ONE MISSED APCH TO 8000 FT AND THE OTHER TO 9000 FT TO GET VERT SEPARATION. I IMMEDIATELY GOT VISUAL SEPARATION ON ALL OF THE MISSED APCHS. EVENTUALLY, I WAS ABLE TO START TURNING THE ACFT TO DIVERGING HDG AND HAND THEM BACK OFF TO APCH FOR RE-SEQUENCING THEM BACK TO THE ARPT. AT ONE POINT I LOOKED AT THE RADAR AND NOTICED AN ACR X JET AT 8000 FT ABOUT 5 MI IN FRONT OF ACR Y (ONE OF THE MISSED APCHS OFF RWY 16L) THAT I HAD ASSIGNED 8000 FT AND A COORD HDG OF 155 DEGS. I THEN NOTICED THAT ACR X WAS NOT A DEP HDG S, BUT AN ARR HDG N TO LAND ON RWY 35L. I IMMEDIATELY YELLED TO THE TFC MGMNT COORDINATOR AND SUPVR FOR THEM TO TELL THE TRACON TO GET ACR X OUT OF THERE AS HE WAS HEAD-ON TO MY MISSED APCH AT THE SAME ALT (8000 FT), ONLY 5 MI APART. TALK ABOUT AN ADRENALINE RUSH! JUST PRIOR TO SEEING THAT, I HAD SHIPPED ACR Y TO DEP FOR RE-SEQUENCE. I WAS STILL BUSY TRYING TO SEPARATE THE OTHER MISSED APCHS ON RWYS 16L&R. THE TRACON THEN CALLED AND ASKED ME TO CLB ACR Y. I TOLD THE TFC MGMNT COORDINATOR THAT I HAD ALREADY SHIPPED HIM TO APCH. EVENTUALLY, THEY DSNDED ACR X AND TURNED HIM OUT OF THE PATH OF ACR Y. AT WHAT POINT THEY LOST SEPARATION IS UNKNOWN TO ME. HOWEVER, I AM SURE WE PROBABLY DID. HOWEVER, I WAS NEVER INFORMED THAT THERE WOULD BE AN INVESTIGATION OF THAT SINCE SOMEONE MADE THE CALL THAT NO SEPARATION WAS LOST. SEVERAL THINGS WERE STRIKING ABOUT THIS EVENT. FIRST, WAS THE TROUBLE THE TWR TFC MGMNT COORDINATOR HAD IN CONTACTING THE TRACON TO INITIATE A RWY CHANGE, BEFORE EVENTS TURNED SOUR. IN ADDITION, WHEN THEY DID CHANGE THE RWY, THE TRACON STARTING VECTORING ACFT INTO RWY 35L BEFORE I RELEASED THE AIRSPACE THAT WAS FULL OF MISSED APCHS. THIS WAS EXACERBATED BY THE FACT THAT WE HAVE A RESTR AREA (WITH NO EAGLES IN IT) THAT WE CANNOT FLY THROUGH WITHOUT A FINE TO THE CTLRS, THUS MAKING US FLY ACFT SIDE-BY-SIDE TO EACH OTHER FOR AN INORDINATELY LONG PERIOD OF TIME. ADDITIONALLY, EVEN AFTER THEY WERE TOLD THAT EVERY ACFT ON FINAL TO RWYS 16L&R WOULD BE GOING AROUND DUE TO THE 20+ KT TAILWIND, THETRACON KEPT VECTORING ACFT TO THOSE RWYS WHILE STARTING TO VECTOR ACFT TO RWYS 35L&R. ALSO, THE CONFLICT ALERT NEVER WENT OFF BTWN ACR X AND ACR Y. HAD I NOT SEEN THIS AND BROUGHT IT TO EVERYONE'S ATTN, THE OUTCOME COULD HAVE BEEN MUCH WORSE. I DO NOT KNOW WHY IT NEVER WENT OFF. I AM SURE THE TCASII WAS DEFINITELY GOING OFF IN THE COCKPITS OF BOTH ACFT. IT ALSO DISTURBED ME THAT FACILITY MGMNT DID NOT EVEN ATTEMPT TO INVESTIGATE HOW AND WHY THIS HAPPENED. I AM A 22 YR VETERAN AND HAVE NEVER EXPERIENCED AN INCIDENT AS CLOSE AS THIS, AND NEVER WANT TO EXPERIENCE IT AGAIN. WHILE IT ALWAYS APPEARS EASY FOR THE TRACON TO STOP DEPS WHEN BEING OVERLOADED, IT SHOULD BE JUST AS IMPORTANT TO STOP VECTORING ARRS TO RWYS THAT ACFT CANNOT LAND ON. IT SHOULD ALSO BE NOTED THAT TOO MANY PEOPLE WHO ARE NOT TALKING TO ACFT AND/OR ARE NOT RESPONSIBLE FOR DELEGATED AIRSPACE ARE GIVING THAT AIRSPACE UP WITHOUT COORDINATING WITH THE PERSON RESPONSIBLE. WHILE WE ARE GRATEFUL THIS INCIDENT ENDED WITH A POSITIVE OUTCOME, IT SHOULD BE A WAKE-UP CALL ABOUT TIMELINESS AND CHANGING OUT OF CONFIGN BEFORE THE WIND FORCES IT. WE HAVE TOO MUCH GOOD EQUIP THAT GIVES US NOTICE OF PENDING EVENTS. IT IS TOO COMMON IN DENVER TO FORCE ACFT TO LAND WITH TAILWINDS WHEN WE HAVE TOO MANY OPTIONS THAT OTHER ARPTS ONLY DREAM OF.

Data retrieved from NASA's ASRS site as of July 2007 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.