WX reporting equipment ASOS incorrect visibility. NWS observer refused to augment system.

Attributes
ACN	316944
Time
Date	199509
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : cha
State Reference	TN
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Person 1
Affiliation	government : faa
Function	controller : ground
Qualification	controller : radar
Experience	controller radar : 6
ASRS Report	316944
Events
Anomaly	other anomaly other
Independent Detector	other controllera
Resolutory Action	none taken : unable
Consequence	Other
Supplementary
Air Traffic Incident	other

Narrative:

The ASOS was reporting the visibility at 2 1/2 mi in fog. The tower visibility was greater than 10 mi. There is a mountain ridge 7 mi west of the airport that could be plainly seen. There were several contact approachs made to the airport. We notified the NWS several times advising them that the ASOS was in error, however, there was no change.

Original NASA ASRS Text

Title: WX RPTING EQUIP ASOS INCORRECT VISIBILITY. NWS OBSERVER REFUSED TO AUGMENT SYS.

Narrative: THE ASOS WAS RPTING THE VISIBILITY AT 2 1/2 MI IN FOG. THE TWR VISIBILITY WAS GREATER THAN 10 MI. THERE IS A MOUNTAIN RIDGE 7 MI W OF THE ARPT THAT COULD BE PLAINLY SEEN. THERE WERE SEVERAL CONTACT APCHS MADE TO THE ARPT. WE NOTIFIED THE NWS SEVERAL TIMES ADVISING THEM THAT THE ASOS WAS IN ERROR, HOWEVER, THERE WAS NO CHANGE.

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.