Narrative:

C402 on final to runway 18, B737 on final to runway 22L. LLWAS has been very unreliable. LLWAS indicated 270 degrees at 7 KTS. I noticed flags standing out straight from nnw (30 ft flag), looked at wind sock and concurred wind direction. Immediately notified C402 of winds estimated 320 degrees at 20 KTS. B737 stated winds short final 320 degrees at 25 KTS, gusting to 35 KTS. Numerous problems with this new generation LLWAS. Controller confidence in system does not exist. Maintenance works on system, tries to repair when another segment fails. Number of failures too many to count. No backup system available, no test bed to prove system works. Continues to fail with no relief in sight. Only a substandard system. Alarms do not work. 50 degree variation and 15 KT difference does not alarm. 20 degree variation and 5 KT difference alarms. System needs help before someone or something else does. Callback conversation with reporter revealed the following information: reporter indicated that the facility is attempting to have the problem resolved. Reporter stated that a suggestion was made for backup wind equipment and was told that with the backup, they would have to state the reported wind in conjunction with the LLWAS alleging this was for legal purposes. Reporter said that a design engineer from the manufacturer was at the facility to check the equipment and indicated that nothing was resolved to solve the problem. Reporter said that they have had nonstop repeated repairs on the equipment since it was installed 6 months ago. Reporter stated that recently the LLWAS was reporting wind out of the south, light and variable, when it was apparently out of the northeast at 15 KTS, gusting to 25 KTS, when an aircraft on short final pitched down due to the tailwind but was able to recover and go around between 5-10 ft above the runway. Reporter stated the 'bird' (sensor) is located about 50-75 ft from the approach end of the runway.

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Original NASA ASRS Text

Title: LLWAS RPTED TO BE UNRELIABLE. WIND DIRECTION RPTED BY LLWAS AS 270 DEGS WHEN ACTUAL WIND FROM 320 DEGS AS RPTED BY ACR B737. RPTR ALLEGES MAINT MAKES REPAIRS ON ONE SEGMENT AND ANOTHER FAILS. RPTED THAT NUMBER OF FAILURES TOO MANY TO COUNT. NO BACKUP SYS AVAILABLE. 50 DEG VARIATION AND 15 KTS DIFFERENCE DOES NOT ALARM.

Narrative: C402 ON FINAL TO RWY 18, B737 ON FINAL TO RWY 22L. LLWAS HAS BEEN VERY UNRELIABLE. LLWAS INDICATED 270 DEGS AT 7 KTS. I NOTICED FLAGS STANDING OUT STRAIGHT FROM NNW (30 FT FLAG), LOOKED AT WIND SOCK AND CONCURRED WIND DIRECTION. IMMEDIATELY NOTIFIED C402 OF WINDS ESTIMATED 320 DEGS AT 20 KTS. B737 STATED WINDS SHORT FINAL 320 DEGS AT 25 KTS, GUSTING TO 35 KTS. NUMEROUS PROBS WITH THIS NEW GENERATION LLWAS. CTLR CONFIDENCE IN SYS DOES NOT EXIST. MAINT WORKS ON SYS, TRIES TO REPAIR WHEN ANOTHER SEGMENT FAILS. NUMBER OF FAILURES TOO MANY TO COUNT. NO BACKUP SYS AVAILABLE, NO TEST BED TO PROVE SYS WORKS. CONTINUES TO FAIL WITH NO RELIEF IN SIGHT. ONLY A SUBSTANDARD SYS. ALARMS DO NOT WORK. 50 DEG VARIATION AND 15 KT DIFFERENCE DOES NOT ALARM. 20 DEG VARIATION AND 5 KT DIFFERENCE ALARMS. SYS NEEDS HELP BEFORE SOMEONE OR SOMETHING ELSE DOES. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR INDICATED THAT THE FACILITY IS ATTEMPTING TO HAVE THE PROB RESOLVED. RPTR STATED THAT A SUGGESTION WAS MADE FOR BACKUP WIND EQUIP AND WAS TOLD THAT WITH THE BACKUP, THEY WOULD HAVE TO STATE THE RPTED WIND IN CONJUNCTION WITH THE LLWAS ALLEGING THIS WAS FOR LEGAL PURPOSES. RPTR SAID THAT A DESIGN ENGINEER FROM THE MANUFACTURER WAS AT THE FACILITY TO CHK THE EQUIP AND INDICATED THAT NOTHING WAS RESOLVED TO SOLVE THE PROB. RPTR SAID THAT THEY HAVE HAD NONSTOP REPEATED REPAIRS ON THE EQUIP SINCE IT WAS INSTALLED 6 MONTHS AGO. RPTR STATED THAT RECENTLY THE LLWAS WAS RPTING WIND OUT OF THE S, LIGHT AND VARIABLE, WHEN IT WAS APPARENTLY OUT OF THE NE AT 15 KTS, GUSTING TO 25 KTS, WHEN AN ACFT ON SHORT FINAL PITCHED DOWN DUE TO THE TAILWIND BUT WAS ABLE TO RECOVER AND GAR BTWN 5-10 FT ABOVE THE RWY. RPTR STATED THE 'BIRD' (SENSOR) IS LOCATED ABOUT 50-75 FT FROM THE APCH END OF THE RWY.

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.