Atx WX reporting equipment false microburst warning.

Attributes
ACN	294050
Time
Date	199501
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : mem
State Reference	TN
Environment
Flight Conditions	IMC
Light	Daylight
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Experience	controller radar : 5
ASRS Report	294050
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Experience	controller radar : 11 flight time total : 1200
ASRS Report	294049
Events
Anomaly	other anomaly other
Independent Detector	atc equipment other atc equipment : unspecified
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Supplementary
Air Traffic Incident	other

Narrative:

Microburst alert for 55 KT loss on final off the ribbon display tdwr equipment. No shear or microburst present. Supplemental information from acn 294049: just a little backgnd: north boundary sensor for the winds has been OTS for 12 months. On jan/xx/95 we had a wind shear alert that didn't make any sense. Runway 18L lsa 30K - 99999, runway 18R lsa 30K - 99999, center field winds calm. I brought this to the supervisor's attention and in turn he advised maintenance. This was logged. 4 days later it was removed from the log without being fixed. I am aware of at least 7 different occasions when this occurred. The actual display (CRT) showed nothing at all. I don't now why maintenance returned this to service. Today we were IFR and we had a microburst alert on runway 18L that read: runway 18L mba 55K - 99999, runway 18R 55K - 99999, cf 080 07. Aircraft went into holding for about 5 mins. Finally a SF340 made an approach and reported just a little bumpy ride. The supervisor then turned the ribbon display off. Maintenance was notified. As of PM35Z jan/yy/95 no log reports were made. I brought this to the supervisor's attention and it was logged. The problem might be the tdwr system itself.

Original NASA ASRS Text

Title: ATX WX RPTING EQUIP FALSE MICROBURST WARNING.

Narrative: MICROBURST ALERT FOR 55 KT LOSS ON FINAL OFF THE RIBBON DISPLAY TDWR EQUIP. NO SHEAR OR MICROBURST PRESENT. SUPPLEMENTAL INFO FROM ACN 294049: JUST A LITTLE BACKGND: N BOUNDARY SENSOR FOR THE WINDS HAS BEEN OTS FOR 12 MONTHS. ON JAN/XX/95 WE HAD A WIND SHEAR ALERT THAT DIDN'T MAKE ANY SENSE. RWY 18L LSA 30K - 99999, RWY 18R LSA 30K - 99999, CTR FIELD WINDS CALM. I BROUGHT THIS TO THE SUPVR'S ATTN AND IN TURN HE ADVISED MAINT. THIS WAS LOGGED. 4 DAYS LATER IT WAS REMOVED FROM THE LOG WITHOUT BEING FIXED. I AM AWARE OF AT LEAST 7 DIFFERENT OCCASIONS WHEN THIS OCCURRED. THE ACTUAL DISPLAY (CRT) SHOWED NOTHING AT ALL. I DON'T NOW WHY MAINT RETURNED THIS TO SVC. TODAY WE WERE IFR AND WE HAD A MICROBURST ALERT ON RWY 18L THAT READ: RWY 18L MBA 55K - 99999, RWY 18R 55K - 99999, CF 080 07. ACFT WENT INTO HOLDING FOR ABOUT 5 MINS. FINALLY A SF340 MADE AN APCH AND RPTED JUST A LITTLE BUMPY RIDE. THE SUPVR THEN TURNED THE RIBBON DISPLAY OFF. MAINT WAS NOTIFIED. AS OF PM35Z JAN/YY/95 NO LOG RPTS WERE MADE. I BROUGHT THIS TO THE SUPVR'S ATTN AND IT WAS LOGGED. THE PROB MIGHT BE THE TDWR SYS ITSELF.

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.