WX reporting equipment problem AWOS.

Attributes
ACN	298652
Time
Date	199503
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : guc
State Reference	CO
Altitude	msl single value : 0
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdv tower : fra
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 11200 flight time type : 2500
ASRS Report	298652
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	inflight encounter : weather
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Supplementary
Air Traffic Incident	other

Narrative:

In an area like gunnison when high winds exist, blowing snow and snow squalls cause the AWOS ceiling and visibility to change on each cycle. That change coupled with the built-in time delay make it difficult to determine if minimums actually exist to continue an instrument approach. The solution at gunnison is already in place but is not used - a qualified national WX service observer. Air carrier, however, can only use AWOS as the official WX source. If the NWS observer could be used officially, his first-hand up-to-the-minute report would be a more realistic way to determine whether to attempt an approach. The alternative of continuous AWOS monitoring to determine a trend (nearly impossible in variable WX conditions with the time delay) can interfere with essential cockpit communications which can be especially critical on an approach in IMC in mountainous terrain. Suggestion: where available allow qualified NWS observer reports to be used as an official WX source. Callback conversation with reporter revealed the following information: anm 200 procedures specialist for guc stated a LOA has been set up between the airport and airlines for an enhanced unicom at gus. The unicom operator is observer qualified and can augment the AWOS. Reporter was called and advised of this fact and to have his company call FSDO procedures specialist for details.

Original NASA ASRS Text

Title: WX RPTING EQUIP PROB AWOS.

Narrative: IN AN AREA LIKE GUNNISON WHEN HIGH WINDS EXIST, BLOWING SNOW AND SNOW SQUALLS CAUSE THE AWOS CEILING AND VISIBILITY TO CHANGE ON EACH CYCLE. THAT CHANGE COUPLED WITH THE BUILT-IN TIME DELAY MAKE IT DIFFICULT TO DETERMINE IF MINIMUMS ACTUALLY EXIST TO CONTINUE AN INSTRUMENT APCH. THE SOLUTION AT GUNNISON IS ALREADY IN PLACE BUT IS NOT USED - A QUALIFIED NATIONAL WX SVC OBSERVER. ACR, HOWEVER, CAN ONLY USE AWOS AS THE OFFICIAL WX SOURCE. IF THE NWS OBSERVER COULD BE USED OFFICIALLY, HIS FIRST-HAND UP-TO-THE-MINUTE RPT WOULD BE A MORE REALISTIC WAY TO DETERMINE WHETHER TO ATTEMPT AN APCH. THE ALTERNATIVE OF CONTINUOUS AWOS MONITORING TO DETERMINE A TREND (NEARLY IMPOSSIBLE IN VARIABLE WX CONDITIONS WITH THE TIME DELAY) CAN INTERFERE WITH ESSENTIAL COCKPIT COMS WHICH CAN BE ESPECIALLY CRITICAL ON AN APCH IN IMC IN MOUNTAINOUS TERRAIN. SUGGESTION: WHERE AVAILABLE ALLOW QUALIFIED NWS OBSERVER RPTS TO BE USED AS AN OFFICIAL WX SOURCE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: ANM 200 PROCS SPECIALIST FOR GUC STATED A LOA HAS BEEN SET UP BTWN THE ARPT AND AIRLINES FOR AN ENHANCED UNICOM AT GUS. THE UNICOM OPERATOR IS OBSERVER QUALIFIED AND CAN AUGMENT THE AWOS. RPTR WAS CALLED AND ADVISED OF THIS FACT AND TO HAVE HIS COMPANY CALL FSDO PROCS SPECIALIST FOR DETAILS.

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.