Narrative:

Aircraft was on a visual approach to runway 16 at den. At approximately XA55Z and 6800 ft MSL, aircraft experienced decreasing performance in airspeed, vertical speed and substantial requirement for increased fuel flow to maintain GS and airspeed. Almost immediately thereafter, windshear aural and visual alerts were displayed in the cockpit. Aircraft throttles were advanced to mechanical stops in a windshear escape maneuver. Aircraft performance initially continued to decrease for approximately 5 seconds. Recovery and escape immediately followed. Go around was made. This was an actual windshear encounter and escape, crew attention was focused on pitch attitude, airspeed, and vertical speed indications. Prior to initiating our initial approach to runway 16, there were no indications of windshear, microburst, broad temperature dewpoint spreads, or strong or gusty surface winds. There were no alerts forwarded to crew by ATIS, or ZDC, in reference to windshear, microburst, or strong surface winds. Within 5 seconds of our escape maneuver, den tower immediately began issuing windshear alerts for runway 16. We decided to attempt a vector for runway 17L after a short delay, as there were no adverse conditions reported on that runway. Prior to reaching the final approach course for runway 17L, conditions deteriorated. Runway 17R became the next option, that deteriorated as well. Finally runway 16 became an option again, and then deteriorated. On departing the runway 16 final approach course, decreasing performance was again experienced. The conditions continued to deteriorate at den and the decision was made to proceed to cos, the nearest suitable alternate based on distance, mechanical considerations, WX, and time. Dispatch was notified of our decision.

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Original NASA ASRS Text

Title: AN ACR FLC FLYING A B727 AT DEN RWY 16 EXPERIENCES WINDSHEAR ON FINAL APCH AND EXECUTES A MISSED APCH.

Narrative: ACFT WAS ON A VISUAL APCH TO RWY 16 AT DEN. AT APPROX XA55Z AND 6800 FT MSL, ACFT EXPERIENCED DECREASING PERFORMANCE IN AIRSPD, VERT SPD AND SUBSTANTIAL REQUIREMENT FOR INCREASED FUEL FLOW TO MAINTAIN GS AND AIRSPD. ALMOST IMMEDIATELY THEREAFTER, WINDSHEAR AURAL AND VISUAL ALERTS WERE DISPLAYED IN THE COCKPIT. ACFT THROTTLES WERE ADVANCED TO MECHANICAL STOPS IN A WINDSHEAR ESCAPE MANEUVER. ACFT PERFORMANCE INITIALLY CONTINUED TO DECREASE FOR APPROX 5 SECONDS. RECOVERY AND ESCAPE IMMEDIATELY FOLLOWED. GAR WAS MADE. THIS WAS AN ACTUAL WINDSHEAR ENCOUNTER AND ESCAPE, CREW ATTN WAS FOCUSED ON PITCH ATTITUDE, AIRSPD, AND VERT SPD INDICATIONS. PRIOR TO INITIATING OUR INITIAL APCH TO RWY 16, THERE WERE NO INDICATIONS OF WINDSHEAR, MICROBURST, BROAD TEMP DEWPOINT SPREADS, OR STRONG OR GUSTY SURFACE WINDS. THERE WERE NO ALERTS FORWARDED TO CREW BY ATIS, OR ZDC, IN REF TO WINDSHEAR, MICROBURST, OR STRONG SURFACE WINDS. WITHIN 5 SECONDS OF OUR ESCAPE MANEUVER, DEN TWR IMMEDIATELY BEGAN ISSUING WINDSHEAR ALERTS FOR RWY 16. WE DECIDED TO ATTEMPT A VECTOR FOR RWY 17L AFTER A SHORT DELAY, AS THERE WERE NO ADVERSE CONDITIONS RPTED ON THAT RWY. PRIOR TO REACHING THE FINAL APCH COURSE FOR RWY 17L, CONDITIONS DETERIORATED. RWY 17R BECAME THE NEXT OPTION, THAT DETERIORATED AS WELL. FINALLY RWY 16 BECAME AN OPTION AGAIN, AND THEN DETERIORATED. ON DEPARTING THE RWY 16 FINAL APCH COURSE, DECREASING PERFORMANCE WAS AGAIN EXPERIENCED. THE CONDITIONS CONTINUED TO DETERIORATE AT DEN AND THE DECISION WAS MADE TO PROCEED TO COS, THE NEAREST SUITABLE ALTERNATE BASED ON DISTANCE, MECHANICAL CONSIDERATIONS, WX, AND TIME. DISPATCH WAS NOTIFIED OF OUR DECISION.

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.