Close proximity atx-amt GA-small aircraft at non tower airport. Both aircraft on approach.

Attributes
ACN	90733
Time
Date	198806
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : riw
State Reference	WY
Altitude	msl bound lower : 7300 msl bound upper : 7300
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air taxi
Make Model Name	Small Transport
Flight Phase	descent : approach
Route In Use	approach : circling
Flight Plan	None
Aircraft 2
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	descent : approach
Person 1
Affiliation	company : air taxi
Function	flight crew : first officer
Qualification	pilot : commercial
ASRS Report	90734
Person 2
Affiliation	company : air taxi
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : commercial
ASRS Report	90731
Events
Anomaly	conflict : nmac other spatial deviation
Independent Detector	other other : unspecified cockpit
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	unspecified : 40
Supplementary
Primary Problem	Flight Crew Human Performance

Narrative:

We were going VFR from casper to riverton direct at 8500' MSL. We turned left onto the 15 DME arc at riverton and reported same on 122.8. We turned onto the ILS localizer at 7700' MSL and again reported same on 122.8. We reported crossing the OM and started down the G/south. At about 7300' MSL we spotted a red and white high wing single engine aircraft slightly above and right of our flight path. We took evasive action by turning left and descending. He saw us soon after and turned left. We had heard no transmission from the other aircraft at any time. We continued our approach and landed west/O incident. This ILS approach was flown for familiarization only and was not flown for instrument practice or under the hood. It was flown VFR and not under the control of an ATC agency. Supplemental information from acn 90734: we were in level flight, heading into the sun. As the airplanes passed, the distance was less than 40'. We could hear the airplane pass from inside a closed cabin. The other airplane was descending for landing at riverton.

Original NASA ASRS Text

Title: CLOSE PROX ATX-AMT GA-SMA AT NON TWR ARPT. BOTH ACFT ON APCH.

Narrative: WE WERE GOING VFR FROM CASPER TO RIVERTON DIRECT AT 8500' MSL. WE TURNED LEFT ONTO THE 15 DME ARC AT RIVERTON AND RPTED SAME ON 122.8. WE TURNED ONTO THE ILS LOC AT 7700' MSL AND AGAIN RPTED SAME ON 122.8. WE RPTED XING THE OM AND STARTED DOWN THE G/S. AT ABOUT 7300' MSL WE SPOTTED A RED AND WHITE HIGH WING SINGLE ENG ACFT SLIGHTLY ABOVE AND RIGHT OF OUR FLT PATH. WE TOOK EVASIVE ACTION BY TURNING LEFT AND DSNDING. HE SAW US SOON AFTER AND TURNED LEFT. WE HAD HEARD NO XMISSION FROM THE OTHER ACFT AT ANY TIME. WE CONTINUED OUR APCH AND LANDED W/O INCIDENT. THIS ILS APCH WAS FLOWN FOR FAMILIARIZATION ONLY AND WAS NOT FLOWN FOR INSTRUMENT PRACTICE OR UNDER THE HOOD. IT WAS FLOWN VFR AND NOT UNDER THE CTL OF AN ATC AGENCY. SUPPLEMENTAL INFO FROM ACN 90734: WE WERE IN LEVEL FLT, HDG INTO THE SUN. AS THE AIRPLANES PASSED, THE DISTANCE WAS LESS THAN 40'. WE COULD HEAR THE AIRPLANE PASS FROM INSIDE A CLOSED CABIN. THE OTHER AIRPLANE WAS DSNDING FOR LNDG AT RIVERTON.

Data retrieved from NASA's ASRS site as of August 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.