|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1201 To 1800|
|Locale Reference||airport : den|
|Altitude||agl bound lower : 1500|
agl bound upper : 1500
|Controlling Facilities||tower : den|
|Operator||common carrier : air carrier|
|Make Model Name||Medium Large Transport, Low Wing, 2 Turbojet Eng|
|Navigation In Use||Other|
|Flight Phase||descent : approach|
landing : go around
|Affiliation||company : air carrier|
|Function||flight crew : first officer|
|Qualification||pilot : commercial|
pilot : flight engineer
pilot : instrument
|Experience||flight time last 90 days : 220|
flight time total : 2800
flight time type : 1400
|Function||flight crew : captain|
oversight : pic
|Qualification||pilot : atp|
|Anomaly||inflight encounter : weather|
|Independent Detector||other flight crewa|
|Air Traffic Incident||other|
Preflight and en route WX reports all reported low level wind shear alerts, cumulus and virga all quadrants. When we broke out below the overcast, virga was seen as well as blowing dust due north of downtown denver, approximately 4 mi west of den. At this time I was busy trying to avoid virga latitude, get clearance below the virga, slow the aircraft while configuring for approach and landing. We were switched to tower while intercepting 6-7 mi final. We were cleared to land and advised that the aircraft ahead of us had experienced a 40 KT decrease in airspeed at 3 mi and also a 10 KT decrease at 20' AGL. Due to conditions already seen, I had set approach speed 20 KTS above reference. I decided to maintain current airspeed of 50 KTS above reference. Conditions encountered were identical to that in our simulator windshear training. To maintain descent I was having to retard the throttles, but didn't come back 1.12 EPR. As we flew under virga over the approach course, airspeed dropped to reference and our go around was initiated. We could feel the airplane being pushed down, but were soon climbing and out of danger. We turned downwind and landed 26R uneventfully. In questioning myself as to why the runway 17R approach was even attempted, I concluded that others were landing just ahead and could discern no change in WX condition between us and the airport. I had no indication that the aircraft ahead had gone around until we were entering the shear conditions and heard tower ask if that aircraft wanted to change runways and land runway 26R. Having experienced simulated windshear in training, I was able to recognize the entry into the shear conditions and react properly in a timely manner. In retrospect, I should have discontinued the approach when advised of 40 KT speed loss, but continued assuming the aircraft ahead had encountered it far enough on approach and landed. Therefore, I should be able to land--an assumption I won't make again.
Original NASA ASRS Text
Title: MLG ENCOUNTERED SEVERE WIND SHEAR AND DOWNDRAFT ON APCH AT DEN.
Narrative: PREFLT AND ENRTE WX RPTS ALL RPTED LOW LEVEL WIND SHEAR ALERTS, CUMULUS AND VIRGA ALL QUADRANTS. WHEN WE BROKE OUT BELOW THE OVCST, VIRGA WAS SEEN AS WELL AS BLOWING DUST DUE N OF DOWNTOWN DENVER, APPROX 4 MI W OF DEN. AT THIS TIME I WAS BUSY TRYING TO AVOID VIRGA LAT, GET CLRNC BELOW THE VIRGA, SLOW THE ACFT WHILE CONFIGURING FOR APCH AND LNDG. WE WERE SWITCHED TO TWR WHILE INTERCEPTING 6-7 MI FINAL. WE WERE CLRED TO LAND AND ADVISED THAT THE ACFT AHEAD OF US HAD EXPERIENCED A 40 KT DECREASE IN AIRSPD AT 3 MI AND ALSO A 10 KT DECREASE AT 20' AGL. DUE TO CONDITIONS ALREADY SEEN, I HAD SET APCH SPD 20 KTS ABOVE REF. I DECIDED TO MAINTAIN CURRENT AIRSPD OF 50 KTS ABOVE REF. CONDITIONS ENCOUNTERED WERE IDENTICAL TO THAT IN OUR SIMULATOR WINDSHEAR TRNING. TO MAINTAIN DSCNT I WAS HAVING TO RETARD THE THROTTLES, BUT DIDN'T COME BACK 1.12 EPR. AS WE FLEW UNDER VIRGA OVER THE APCH COURSE, AIRSPD DROPPED TO REF AND OUR GO AROUND WAS INITIATED. WE COULD FEEL THE AIRPLANE BEING PUSHED DOWN, BUT WERE SOON CLBING AND OUT OF DANGER. WE TURNED DOWNWIND AND LANDED 26R UNEVENTFULLY. IN QUESTIONING MYSELF AS TO WHY THE RWY 17R APCH WAS EVEN ATTEMPTED, I CONCLUDED THAT OTHERS WERE LNDG JUST AHEAD AND COULD DISCERN NO CHANGE IN WX CONDITION BTWN US AND THE ARPT. I HAD NO INDICATION THAT THE ACFT AHEAD HAD GONE AROUND UNTIL WE WERE ENTERING THE SHEAR CONDITIONS AND HEARD TWR ASK IF THAT ACFT WANTED TO CHANGE RWYS AND LAND RWY 26R. HAVING EXPERIENCED SIMULATED WINDSHEAR IN TRNING, I WAS ABLE TO RECOGNIZE THE ENTRY INTO THE SHEAR CONDITIONS AND REACT PROPERLY IN A TIMELY MANNER. IN RETROSPECT, I SHOULD HAVE DISCONTINUED THE APCH WHEN ADVISED OF 40 KT SPD LOSS, BUT CONTINUED ASSUMING THE ACFT AHEAD HAD ENCOUNTERED IT FAR ENOUGH ON APCH AND LANDED. THEREFORE, I SHOULD BE ABLE TO LAND--AN ASSUMPTION I WON'T MAKE AGAIN.
Data retrieved from NASA's ASRS site as of August 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.