WX reporting equipment ASOS reporting incorrect WX IFR versus VFR.

Attributes
ACN	254242
Time
Date	199310
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : ama
State Reference	TX
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : ama tower : lga
Person 1
Affiliation	government : faa
Function	controller : local
Qualification	controller : radar
Experience	controller non radar : 9 controller radar : 8
ASRS Report	254242
Events
Anomaly	other anomaly other
Independent Detector	other controllera
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Weather
Air Traffic Incident	other

Narrative:

Ama has an ASOS WX reporting system. Today's WX showed clear below 120, visibility plus 10, advertising visual approachs to runway 22. Numerous aircraft VFR inbound expecting VFR pattern to runway 22 as was the approach controller. Local control advised fog bank moving in from the northwest. We cannot change the ATIS to reflect the changing WX as we are not WX observers. After waiting for 5 mins a phone call was placed to the NWS to have them give an actual WX observation. Several aircraft had to divert because they were not IFR qualified. The ASOS has been shown to be ineffective and dangerous in changing WX sits. Under VFR conditions it works fine. The only real solution would be to remove the ASOS and have the NWS give the WX observations.

Original NASA ASRS Text

Title: WX RPTING EQUIP ASOS RPTING INCORRECT WX IFR VERSUS VFR.

Narrative: AMA HAS AN ASOS WX RPTING SYS. TODAY'S WX SHOWED CLR BELOW 120, VISIBILITY PLUS 10, ADVERTISING VISUAL APCHS TO RWY 22. NUMEROUS ACFT VFR INBOUND EXPECTING VFR PATTERN TO RWY 22 AS WAS THE APCH CTLR. LCL CTL ADVISED FOG BANK MOVING IN FROM THE NW. WE CANNOT CHANGE THE ATIS TO REFLECT THE CHANGING WX AS WE ARE NOT WX OBSERVERS. AFTER WAITING FOR 5 MINS A PHONE CALL WAS PLACED TO THE NWS TO HAVE THEM GIVE AN ACTUAL WX OBSERVATION. SEVERAL ACFT HAD TO DIVERT BECAUSE THEY WERE NOT IFR QUALIFIED. THE ASOS HAS BEEN SHOWN TO BE INEFFECTIVE AND DANGEROUS IN CHANGING WX SITS. UNDER VFR CONDITIONS IT WORKS FINE. THE ONLY REAL SOLUTION WOULD BE TO REMOVE THE ASOS AND HAVE THE NWS GIVE THE WX OBSERVATIONS.

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.