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TRACON approach control concerned with the operational effectiveness of terminal doppler WX radar (tdwr) equipment. Approach controller observed numerous go around due to windshear without tdwr equipment alerts. Controller met with maintenance management to discuss equipment parameters.
| Attributes | |
| ACN | 419439 |
| Time | |
| Date | 199811 |
| Day | Tue |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | airport : mke |
| State Reference | WI |
| Altitude | agl bound lower : 100 agl bound upper : 100 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | DC-9 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | landing other |
| Route In Use | approach : visual arrival other |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air carrier |
| Make Model Name | DC-9 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | climbout : takeoff |
| Route In Use | departure other departure sid : sid |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : local |
| Experience | controller non radar : 5 controller radar : 10 |
| ASRS Report | 419439 |
| Person 2 | |
| Affiliation | government : faa |
| Function | oversight : supervisor |
| Events | |
| Anomaly | inflight encounter : weather other anomaly other |
| Independent Detector | other controllera other flight crewa |
| Resolutory Action | other |
| Consequence | faa : investigated |
| Supplementary | |
| Air Traffic Incident | Intra Facility Coordination Failure other |
| Situations | |
| ATC Facility | procedure or policy : unspecified |
| Airport | other physical facility |
| Navigational Aid | Unspecified |
Narrative:
While working at mke tower on the afternoon and evening of nov/tue/98, we were experiencing extremely high winds at milwaukee as was most of the midwestern united states. In my 9 hour shift I observed more gars (7) due to windshear than I have in the rest of my 15 yr ATC career combined. Pilots were reporting gains and losses to 30 KTS on arrival and departure and continuous severe turbulence on the approach. Yet our tdwr (terminal doppler WX radar) equipment (finally up and running after yrs of problems) never once indicated a windshear condition. While O'hare airport in chicago 90 mi to our south was virtually shut down for 3-4 hours due to microburst alerts and windshear alerts, we had none. When I questioned as to whether the equipment was working properly I was told that it was working fine. I subsequently filed an unsafe condition report stating my belief that our tdwr (terminal doppler WX radar) equipment was not accurately reporting our windshear conditions. As a result of this, I was called into a meeting with our assistant manager, a union representative, and airway facilities manager. I was informed at this meeting that the parameters of our tdwr (terminal doppler WX radar) equipment were such that it would not detect windshear below 500 ft AGL. Despite this fact, our old low level windshear equipment was decommissioned because it was supposed to be replaced by tdwr (terminal doppler WX radar). I don't consider this an adequate replacement. We now have no way of giving pilots advance warning or low level windshear at mke. I consider this a dangerous and unacceptable situation. If the new equipment isn't as good as the old, why replace it? I am curious if the air carrier pilots flying into airports with tdwr (terminal doppler WX radar) know its' limitations. I am submitting this report in the hope that more will now be aware of this suspect equipment.
Original NASA ASRS Text
Title: TRACON APCH CTL CONCERNED WITH THE OPERATIONAL EFFECTIVENESS OF TERMINAL DOPPLER WX RADAR (TDWR) EQUIP. APCH CTLR OBSERVED NUMEROUS GAR DUE TO WINDSHEAR WITHOUT TDWR EQUIP ALERTS. CTLR MET WITH MAINT MGMNT TO DISCUSS EQUIP PARAMETERS.
Narrative: WHILE WORKING AT MKE TWR ON THE AFTERNOON AND EVENING OF NOV/TUE/98, WE WERE EXPERIENCING EXTREMELY HIGH WINDS AT MILWAUKEE AS WAS MOST OF THE MIDWESTERN UNITED STATES. IN MY 9 HR SHIFT I OBSERVED MORE GARS (7) DUE TO WINDSHEAR THAN I HAVE IN THE REST OF MY 15 YR ATC CAREER COMBINED. PLTS WERE RPTING GAINS AND LOSSES TO 30 KTS ON ARR AND DEP AND CONTINUOUS SEVERE TURB ON THE APCH. YET OUR TDWR (TERMINAL DOPPLER WX RADAR) EQUIP (FINALLY UP AND RUNNING AFTER YRS OF PROBS) NEVER ONCE INDICATED A WINDSHEAR CONDITION. WHILE O'HARE ARPT IN CHICAGO 90 MI TO OUR S WAS VIRTUALLY SHUT DOWN FOR 3-4 HRS DUE TO MICROBURST ALERTS AND WINDSHEAR ALERTS, WE HAD NONE. WHEN I QUESTIONED AS TO WHETHER THE EQUIP WAS WORKING PROPERLY I WAS TOLD THAT IT WAS WORKING FINE. I SUBSEQUENTLY FILED AN UNSAFE CONDITION RPT STATING MY BELIEF THAT OUR TDWR (TERMINAL DOPPLER WX RADAR) EQUIP WAS NOT ACCURATELY RPTING OUR WINDSHEAR CONDITIONS. AS A RESULT OF THIS, I WAS CALLED INTO A MEETING WITH OUR ASSISTANT MGR, A UNION REPRESENTATIVE, AND AIRWAY FACILITIES MGR. I WAS INFORMED AT THIS MEETING THAT THE PARAMETERS OF OUR TDWR (TERMINAL DOPPLER WX RADAR) EQUIP WERE SUCH THAT IT WOULD NOT DETECT WINDSHEAR BELOW 500 FT AGL. DESPITE THIS FACT, OUR OLD LOW LEVEL WINDSHEAR EQUIP WAS DECOMMISSIONED BECAUSE IT WAS SUPPOSED TO BE REPLACED BY TDWR (TERMINAL DOPPLER WX RADAR). I DON'T CONSIDER THIS AN ADEQUATE REPLACEMENT. WE NOW HAVE NO WAY OF GIVING PLTS ADVANCE WARNING OR LOW LEVEL WINDSHEAR AT MKE. I CONSIDER THIS A DANGEROUS AND UNACCEPTABLE SIT. IF THE NEW EQUIP ISN'T AS GOOD AS THE OLD, WHY REPLACE IT? I AM CURIOUS IF THE ACR PLTS FLYING INTO ARPTS WITH TDWR (TERMINAL DOPPLER WX RADAR) KNOW ITS' LIMITATIONS. I AM SUBMITTING THIS RPT IN THE HOPE THAT MORE WILL NOW BE AWARE OF THIS SUSPECT EQUIP.
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.