WX reporting equipment problem LLWAS gave no wind shear alerts.

Attributes
ACN	293456
Time
Date	199501
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : tys
State Reference	TN
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	IMC
Light	Dusk
Aircraft 1
Controlling Facilities	tracon : pit
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Experience	controller radar : 2
ASRS Report	293456
Person 2
Affiliation	government : faa
Function	controller : local
Qualification	controller : radar
Experience	controller radar : 6
ASRS Report	293063
Events
Anomaly	other anomaly other
Independent Detector	other controllera
Resolutory Action	none taken : anomaly accepted
Consequence	faa : investigated
Supplementary
Air Traffic Incident	other

Narrative:

At 3000 ft AGL winds reported 180 degrees at 75 KTS all LLWAS sensors indicated calm except southwest boundary which was at 120 degrees at 15-16 KTS. There was no alarm for wind shear. Supplemental information from acn 293063: with many reports of wind shears from pilots we observed the ctrfield wind to be calm on the LLWAS but the southwest boundary indicator showed wind at 120 degrees at 16 KTS. I feel this should have set off the low level wind shear alarms but it didn't. Af says this is normal. If so, they need new software!

Original NASA ASRS Text

Title: WX RPTING EQUIP PROB LLWAS GAVE NO WIND SHEAR ALERTS.

Narrative: AT 3000 FT AGL WINDS RPTED 180 DEGS AT 75 KTS ALL LLWAS SENSORS INDICATED CALM EXCEPT SW BOUNDARY WHICH WAS AT 120 DEGS AT 15-16 KTS. THERE WAS NO ALARM FOR WIND SHEAR. SUPPLEMENTAL INFO FROM ACN 293063: WITH MANY RPTS OF WIND SHEARS FROM PLTS WE OBSERVED THE CTRFIELD WIND TO BE CALM ON THE LLWAS BUT THE SW BOUNDARY INDICATOR SHOWED WIND AT 120 DEGS AT 16 KTS. I FEEL THIS SHOULD HAVE SET OFF THE LOW LEVEL WIND SHEAR ALARMS BUT IT DIDN'T. AF SAYS THIS IS NORMAL. IF SO, THEY NEED NEW SOFTWARE!

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.