Narrative:

The low level wind shear alert system (LLWAS) at the nashville airport is very inaccurate. Numerous pilot reports complaining about the winds that are issued by the controllers at nashville can be substantiated by comparison to the wind sock and readings issued by aircraft that are EFIS equipped. The wind sensors indicate winds of only 3-4 KTS when it is closer to 20 KTS. The center field wind sensor has not been replaced after the new runway 2C was constructed. Even with all sensors operational the LLWAS does not give accurate winds. The winds displayed are an average over 2 mins. This average decreases the actual gusts that may be received. I believe that pilots would rather have a worst case scenario of a high instantaneous gust than an average of the winds. I have witnessed a BE55 nearly go off the runway when the wind sock was full but the LLWAS display only indicated 3-4 KTS. An FK100 also complained that he would have requested another runway if he knew the winds were actually that bad. Callback conversation with reporter revealed the following information: reporter stated after he informed management a NASA ASRS report had been filed the LLWAS was notamed OTS and the tower used estimated wind from the NWS. Another sensor was used and the LLWAS was restored. Reporter said he was informed a center field wind would be installed. No action has been forth coming on a center field sensor. Reporter feels they should have an analog wind indicator.

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Original NASA ASRS Text

Title: ATC EQUIP PROB WIND INDICATORS LLWAS INACCURATE.

Narrative: THE LOW LEVEL WIND SHEAR ALERT SYS (LLWAS) AT THE NASHVILLE ARPT IS VERY INACCURATE. NUMEROUS PLT RPTS COMPLAINING ABOUT THE WINDS THAT ARE ISSUED BY THE CTLRS AT NASHVILLE CAN BE SUBSTANTIATED BY COMPARISON TO THE WIND SOCK AND READINGS ISSUED BY ACFT THAT ARE EFIS EQUIPPED. THE WIND SENSORS INDICATE WINDS OF ONLY 3-4 KTS WHEN IT IS CLOSER TO 20 KTS. THE CTR FIELD WIND SENSOR HAS NOT BEEN REPLACED AFTER THE NEW RWY 2C WAS CONSTRUCTED. EVEN WITH ALL SENSORS OPERATIONAL THE LLWAS DOES NOT GIVE ACCURATE WINDS. THE WINDS DISPLAYED ARE AN AVERAGE OVER 2 MINS. THIS AVERAGE DECREASES THE ACTUAL GUSTS THAT MAY BE RECEIVED. I BELIEVE THAT PLTS WOULD RATHER HAVE A WORST CASE SCENARIO OF A HIGH INSTANTANEOUS GUST THAN AN AVERAGE OF THE WINDS. I HAVE WITNESSED A BE55 NEARLY GO OFF THE RWY WHEN THE WIND SOCK WAS FULL BUT THE LLWAS DISPLAY ONLY INDICATED 3-4 KTS. AN FK100 ALSO COMPLAINED THAT HE WOULD HAVE REQUESTED ANOTHER RWY IF HE KNEW THE WINDS WERE ACTUALLY THAT BAD. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED AFTER HE INFORMED MGMNT A NASA ASRS RPT HAD BEEN FILED THE LLWAS WAS NOTAMED OTS AND THE TWR USED ESTIMATED WIND FROM THE NWS. ANOTHER SENSOR WAS USED AND THE LLWAS WAS RESTORED. RPTR SAID HE WAS INFORMED A CTR FIELD WIND WOULD BE INSTALLED. NO ACTION HAS BEEN FORTH COMING ON A CTR FIELD SENSOR. RPTR FEELS THEY SHOULD HAVE AN ANALOG WIND INDICATOR.

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.