Narrative:

I am extremely concerned about the accuracy and reliability of the newly installed ASOS at the jackson international airport. In recent months the ASOS system routinely reports values that do not reflect the actual WX conditions prevailing at the time. In addition, the ASOS system consistently lags behind in reporting significant changes in the WX occurring at the airport. I feel that the inadequacies of this system result in an unacceptable means of determining the WX conditions at the jan airport. My greatest concern is the potential for a pilot to have grossly inaccurate WX reports during the landing phase of the flight. A 10-15 min delay in receiving correct WX is not compatible with aviation safety. This unacceptable condition is particularly troubling when coupled with the fact that pilots are executing catii and catiii instrument approachs at jan. It is absolutely imperative that pilots have timely, accurate WX information during these operations. I must report that the NWS at jan airport has been completely unresponsive when informed that the ASOS is reporting erroneous information. It was my understanding when the ASOS was installed that if erroneous information was suspected a manual observation would be performed. The WX service has been very resistant to making manual observations and in most cases has been unwilling to respond to our requests. WX service personnel seem to ignore our requests even when we make it clear that the ASOS inaccuracies are adversely affecting aviation operations. Callback conversation with reporter revealed the following information: reporter stated ASOS will not update current WX conditions at the airport during rapidly changing WX. When requested to take a special observations, NWS personnel say if there is no major change to WX they will not augment the system. Reporter has been told this is policy set down by NWS in washington headquarters.

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Original NASA ASRS Text

Title: INACCURATE WX RPTING BY ASOS.

Narrative: I AM EXTREMELY CONCERNED ABOUT THE ACCURACY AND RELIABILITY OF THE NEWLY INSTALLED ASOS AT THE JACKSON INTL ARPT. IN RECENT MONTHS THE ASOS SYS ROUTINELY RPTS VALUES THAT DO NOT REFLECT THE ACTUAL WX CONDITIONS PREVAILING AT THE TIME. IN ADDITION, THE ASOS SYS CONSISTENTLY LAGS BEHIND IN RPTING SIGNIFICANT CHANGES IN THE WX OCCURRING AT THE ARPT. I FEEL THAT THE INADEQUACIES OF THIS SYS RESULT IN AN UNACCEPTABLE MEANS OF DETERMINING THE WX CONDITIONS AT THE JAN ARPT. MY GREATEST CONCERN IS THE POTENTIAL FOR A PLT TO HAVE GROSSLY INACCURATE WX RPTS DURING THE LNDG PHASE OF THE FLT. A 10-15 MIN DELAY IN RECEIVING CORRECT WX IS NOT COMPATIBLE WITH AVIATION SAFETY. THIS UNACCEPTABLE CONDITION IS PARTICULARLY TROUBLING WHEN COUPLED WITH THE FACT THAT PLTS ARE EXECUTING CATII AND CATIII INST APCHS AT JAN. IT IS ABSOLUTELY IMPERATIVE THAT PLTS HAVE TIMELY, ACCURATE WX INFO DURING THESE OPS. I MUST RPT THAT THE NWS AT JAN ARPT HAS BEEN COMPLETELY UNRESPONSIVE WHEN INFORMED THAT THE ASOS IS RPTING ERRONEOUS INFO. IT WAS MY UNDERSTANDING WHEN THE ASOS WAS INSTALLED THAT IF ERRONEOUS INFO WAS SUSPECTED A MANUAL OBSERVATION WOULD BE PERFORMED. THE WX SVC HAS BEEN VERY RESISTANT TO MAKING MANUAL OBSERVATIONS AND IN MOST CASES HAS BEEN UNWILLING TO RESPOND TO OUR REQUESTS. WX SVC PERSONNEL SEEM TO IGNORE OUR REQUESTS EVEN WHEN WE MAKE IT CLR THAT THE ASOS INACCURACIES ARE ADVERSELY AFFECTING AVIATION OPS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED ASOS WILL NOT UPDATE CURRENT WX CONDITIONS AT THE ARPT DURING RAPIDLY CHANGING WX. WHEN REQUESTED TO TAKE A SPECIAL OBSERVATIONS, NWS PERSONNEL SAY IF THERE IS NO MAJOR CHANGE TO WX THEY WILL NOT AUGMENT THE SYS. RPTR HAS BEEN TOLD THIS IS POLICY SET DOWN BY NWS IN WASHINGTON HEADQUARTERS.

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.