Narrative:

LLWAS system is totally unreliable and unsafe. NWS winds on sa's will often show double the velocity of our LLWAS or maximum, and our LLWAS almost never indicates gust factors, even when NWS winds are indicating gusts over 30 KTS. We frequently receive pilot complaints of unsafe crosswind conditions (air carrier pilots) while our LLWAS is indicating 8-9 KTS velocity. Also, due to noise abatement procedures, we frequently operate with a tailwind component. Our procedures mandate no more than a 7 KT tailwind component, but we measure that with the LLWAS. Under these conditions, we not infrequently receive complaints from INS equipped aircraft of 15 KTS or more tailwinds near the surface. We have reported this to FAA with no results. This problem has existed for a long time, and I believe safety is significantly compromised. Callback conversation with reporter revealed the following information: reporter stated this has been an ongoing problem with LLWAS. 2 ucr's have been filed to no avail. Last week a thunderstorm past the airport and the equipment did not show gusting winds. Several aircraft made gars because of the wind.

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Original NASA ASRS Text

Title: EQUIP PROB WIND INSTS LLWAS UNRELIABLE.

Narrative: LLWAS SYS IS TOTALLY UNRELIABLE AND UNSAFE. NWS WINDS ON SA'S WILL OFTEN SHOW DOUBLE THE VELOCITY OF OUR LLWAS OR MAX, AND OUR LLWAS ALMOST NEVER INDICATES GUST FACTORS, EVEN WHEN NWS WINDS ARE INDICATING GUSTS OVER 30 KTS. WE FREQUENTLY RECEIVE PLT COMPLAINTS OF UNSAFE XWIND CONDITIONS (ACR PLTS) WHILE OUR LLWAS IS INDICATING 8-9 KTS VELOCITY. ALSO, DUE TO NOISE ABATEMENT PROCS, WE FREQUENTLY OPERATE WITH A TAILWIND COMPONENT. OUR PROCS MANDATE NO MORE THAN A 7 KT TAILWIND COMPONENT, BUT WE MEASURE THAT WITH THE LLWAS. UNDER THESE CONDITIONS, WE NOT INFREQUENTLY RECEIVE COMPLAINTS FROM INS EQUIPPED ACFT OF 15 KTS OR MORE TAILWINDS NEAR THE SURFACE. WE HAVE RPTED THIS TO FAA WITH NO RESULTS. THIS PROB HAS EXISTED FOR A LONG TIME, AND I BELIEVE SAFETY IS SIGNIFICANTLY COMPROMISED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THIS HAS BEEN AN ONGOING PROB WITH LLWAS. 2 UCR'S HAVE BEEN FILED TO NO AVAIL. LAST WK A TSTM PAST THE ARPT AND THE EQUIP DID NOT SHOW GUSTING WINDS. SEVERAL ACFT MADE GARS BECAUSE OF THE WIND.

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.