A C172 pilot descended in IMC without a clearance mhe VOR.

Attributes
ACN	441256
Time
Date	199906
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : mhe.airport
State Reference	SD
Altitude	msl bound lower : 2000 msl bound upper : 4000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Navigation In Use	other
Flight Phase	descent : approach
Route In Use	arrival : vfr
Flight Plan	None
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : private
Experience	flight time last 90 days : 45 flight time total : 130 flight time type : 130
ASRS Report	441256
Person 2
Affiliation	other
Function	other personnel
Events
Anomaly	inflight encounter : vfr in imc non adherence : far
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted none taken : detected after the fact
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

After flying 2 hours (previous leg that morning was 3.6 hours), I continued to fly over a developing cloud layer. I observed large areas in the cloud layer several mi ahead. I monitored traffic below and estimated that there was a 2000 ft ceiling with the top of the layer about 2000 ft above that. I was also monitoring the WX at my next fuel stop and determined it would be best to stop early while I could penetrate the cloud layer. (Cruise at 9500 ft MSL, cloud layer below at 3500 ft MSL base and 5500 ft MSL top, a cloud layer above 12000 ft MSL with about 1/4 sky coverage.) upon descending to one of the large, hazy holes in the cloud layer, I discovered that the holes were actually shadows from the higher clouds. Rather than turn back (plenty of fuel), I picked an altitude below which I wouldn't continue descending. (I believe this judgement error was related to relatively little solo cross country and the flight duration. I made a decision and stuck with it.) I had current altimeter setting. Landing was made without mishap. Ceilings were as reported (2000 ft AGL).

Original NASA ASRS Text

Title: A C172 PLT DSNDED IN IMC WITHOUT A CLRNC MHE VOR.

Narrative: AFTER FLYING 2 HRS (PREVIOUS LEG THAT MORNING WAS 3.6 HRS), I CONTINUED TO FLY OVER A DEVELOPING CLOUD LAYER. I OBSERVED LARGE AREAS IN THE CLOUD LAYER SEVERAL MI AHEAD. I MONITORED TFC BELOW AND ESTIMATED THAT THERE WAS A 2000 FT CEILING WITH THE TOP OF THE LAYER ABOUT 2000 FT ABOVE THAT. I WAS ALSO MONITORING THE WX AT MY NEXT FUEL STOP AND DETERMINED IT WOULD BE BEST TO STOP EARLY WHILE I COULD PENETRATE THE CLOUD LAYER. (CRUISE AT 9500 FT MSL, CLOUD LAYER BELOW AT 3500 FT MSL BASE AND 5500 FT MSL TOP, A CLOUD LAYER ABOVE 12000 FT MSL WITH ABOUT 1/4 SKY COVERAGE.) UPON DSNDING TO ONE OF THE LARGE, HAZY HOLES IN THE CLOUD LAYER, I DISCOVERED THAT THE HOLES WERE ACTUALLY SHADOWS FROM THE HIGHER CLOUDS. RATHER THAN TURN BACK (PLENTY OF FUEL), I PICKED AN ALT BELOW WHICH I WOULDN'T CONTINUE DSNDING. (I BELIEVE THIS JUDGEMENT ERROR WAS RELATED TO RELATIVELY LITTLE SOLO XCOUNTRY AND THE FLT DURATION. I MADE A DECISION AND STUCK WITH IT.) I HAD CURRENT ALTIMETER SETTING. LNDG WAS MADE WITHOUT MISHAP. CEILINGS WERE AS RPTED (2000 FT AGL).

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.