WX reporting equipment problem LLWAS unreliable during tropical storm.

Attributes
ACN	296455
Time
Date	199502
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : mia
State Reference	FL
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : gfk
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Experience	controller military : 4 controller radar : 15 controller supervisory : 2
ASRS Report	296455
Person 2
Affiliation	government : faa
Function	other personnel other
Qualification	controller : radar
Events
Anomaly	other anomaly other
Independent Detector	other controllera
Resolutory Action	none taken : anomaly accepted
Consequence	faa : investigated
Supplementary
Air Traffic Incident	other

Narrative:

Low level wind shear alert system (LLWAS) inaccurate during heavy thunderstorm and wind shear situation. During this particular incident, the wind was so strong a B747 was actually moved and damaged, along with the jetway it was parked at. NWS reported winds of 54 KTS. A pilot reported winds in excess of 100 KTS, yet the LLWAS never registered a gust over 30 KTS. Wind information can be critical to aircraft operations, and the LLWAS at mia is unreliable. This situation has been ongoing for several months, but today was the worst incident. Callback conversation with reporter revealed the following information: mia facility operations officer stated they did have a problem with the mid field sensor of the LLWAS during a tropical storm. Sensor would not show gust above 30 KTS. Mid field sensor was logged OTS and fixed by maintenance several days later. LLWAS is working normally.

Original NASA ASRS Text

Title: WX RPTING EQUIP PROB LLWAS UNRELIABLE DURING TROPICAL STORM.

Narrative: LOW LEVEL WIND SHEAR ALERT SYS (LLWAS) INACCURATE DURING HVY TSTM AND WIND SHEAR SIT. DURING THIS PARTICULAR INCIDENT, THE WIND WAS SO STRONG A B747 WAS ACTUALLY MOVED AND DAMAGED, ALONG WITH THE JETWAY IT WAS PARKED AT. NWS RPTED WINDS OF 54 KTS. A PLT RPTED WINDS IN EXCESS OF 100 KTS, YET THE LLWAS NEVER REGISTERED A GUST OVER 30 KTS. WIND INFO CAN BE CRITICAL TO ACFT OPS, AND THE LLWAS AT MIA IS UNRELIABLE. THIS SIT HAS BEEN ONGOING FOR SEVERAL MONTHS, BUT TODAY WAS THE WORST INCIDENT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: MIA FACILITY OPS OFFICER STATED THEY DID HAVE A PROB WITH THE MID FIELD SENSOR OF THE LLWAS DURING A TROPICAL STORM. SENSOR WOULD NOT SHOW GUST ABOVE 30 KTS. MID FIELD SENSOR WAS LOGGED OTS AND FIXED BY MAINT SEVERAL DAYS LATER. LLWAS IS WORKING NORMALLY.

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.