WX reporting equipment problem ASOS incorrect visibility aircraft delayed.

Attributes
ACN	307647
Time
Date	199506
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : dab
State Reference	FL
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : dab
Operator	common carrier : air carrier
Make Model Name	MD-88
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent : approach
Flight Plan	IFR
Aircraft 2
Operator	general aviation : personal
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	ground : holding
Flight Plan	VFR
Person 1
Affiliation	government : faa
Function	controller : local
Qualification	controller : radar
Experience	controller military : 9 controller non radar : 7 controller radar : 20 controller supervisory : 4
ASRS Report	307647
Person 2
Affiliation	government : faa
Function	controller : flight data
Qualification	controller : radar
Experience	controller radar : 8
ASRS Report	307648
Events
Anomaly	other anomaly other
Independent Detector	other controllera other flight crewa
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Supplementary
Air Traffic Incident	other

Narrative:

ASOS reported a special WX observation of 2 mi in haze. All pilots on frequency plus 3 controllers in the tower were observing no obstructions to visibility and visibility 10 plus. NWS was asked to issue an augmented observation and reported visibility more than 10 mi. MD88 landing runway 7L was vectored for an ILS thereby delaying his arrival due to the erroneous report. C172, a VFR departure, was delayed until an augmented VFR special WX observation could be taken. Recommend ASOS equipment be removed and WX personnel remain as official WX observers or tower personnel be authority/authorized to override erroneous ASOS reports. Supplemental information from acn 307648: ASOS reported visibility 1 1/2 mi haze, correct visibility was more than 10 mi, VFR aircraft were needlessly delayed -- ASOS discrepancies are almost an hourly occurrence -- this equipment is not suitable for the role that the FAA intends to use it in. No one at dab has any confidence in this equipment. In its present form, the ASOS equipment will never be an adequate substitute for manual observation.

Original NASA ASRS Text

Title: WX RPTING EQUIP PROB ASOS INCORRECT VISIBILITY ACFT DELAYED.

Narrative: ASOS RPTED A SPECIAL WX OBSERVATION OF 2 MI IN HAZE. ALL PLTS ON FREQ PLUS 3 CTLRS IN THE TWR WERE OBSERVING NO OBSTRUCTIONS TO VISIBILITY AND VISIBILITY 10 PLUS. NWS WAS ASKED TO ISSUE AN AUGMENTED OBSERVATION AND RPTED VISIBILITY MORE THAN 10 MI. MD88 LNDG RWY 7L WAS VECTORED FOR AN ILS THEREBY DELAYING HIS ARR DUE TO THE ERRONEOUS RPT. C172, A VFR DEP, WAS DELAYED UNTIL AN AUGMENTED VFR SPECIAL WX OBSERVATION COULD BE TAKEN. RECOMMEND ASOS EQUIP BE REMOVED AND WX PERSONNEL REMAIN AS OFFICIAL WX OBSERVERS OR TWR PERSONNEL BE AUTH TO OVERRIDE ERRONEOUS ASOS RPTS. SUPPLEMENTAL INFO FROM ACN 307648: ASOS RPTED VISIBILITY 1 1/2 MI HAZE, CORRECT VISIBILITY WAS MORE THAN 10 MI, VFR ACFT WERE NEEDLESSLY DELAYED -- ASOS DISCREPANCIES ARE ALMOST AN HRLY OCCURRENCE -- THIS EQUIP IS NOT SUITABLE FOR THE ROLE THAT THE FAA INTENDS TO USE IT IN. NO ONE AT DAB HAS ANY CONFIDENCE IN THIS EQUIP. IN ITS PRESENT FORM, THE ASOS EQUIP WILL NEVER BE AN ADEQUATE SUBSTITUTE FOR MANUAL OBSERVATION.

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.