C172 pilot has fuel starvation and lands off field.

Attributes
ACN	554860
Time
Date	200207
Day	Fri
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : tki.airport
State Reference	TX
Altitude	msl single value : 1700
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	None
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : private
Experience	flight time last 90 days : 15 flight time total : 435 flight time type : 330
ASRS Report	554860
Person 2
Affiliation	other
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : landed in emergency condition
Consequence	other
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Aircraft

Narrative:

I had been flying for approximately 1 hour. I was in straight and level cruise flight at about 1700 ft MSL when the engine began to run roughly, and then there was a loss of most of the engine power. I determined that I was too far away from the nearest airport (tki) to safely make it, so I chose a suitable pasture for an off-airport landing. The pasture was a fairly level vacant farm field in a rural area, perhaps 100 acres or so. I landed in the field without causing any damage to the property. My airplane had some scratches on the propeller from ground brush/weeds. I left the airplane in the pasture, and returned the next day with an a&P to find the cause of the engine roughness. The a&P determined that it was a blocked gas tank fuel vent line, that was causing gas starvation to the engine. The vent line blockage was cleared and the airplane ran fine again. The owner of the pasture was contacted and gave permission for me to fly the airplane out. The pasture had adequate length and there wasn't any problem in the 'grass runway' takeoff. I flew the airplane back to my home airport without any problems. My airplane has a vented fuel tank cap on 1 gas tank. The a&P suggested that a good prevention measure would be to have vented fuel tank caps installed on both tanks. Callback conversation with reporter revealed the following information: reporter stated he had both fuel tanks selected with the fuel selector valve. He did not notice his fuel quantity difference between the 2 tanks.

Original NASA ASRS Text

Title: C172 PLT HAS FUEL STARVATION AND LANDS OFF FIELD.

Narrative: I HAD BEEN FLYING FOR APPROX 1 HR. I WAS IN STRAIGHT AND LEVEL CRUISE FLT AT ABOUT 1700 FT MSL WHEN THE ENG BEGAN TO RUN ROUGHLY, AND THEN THERE WAS A LOSS OF MOST OF THE ENG PWR. I DETERMINED THAT I WAS TOO FAR AWAY FROM THE NEAREST ARPT (TKI) TO SAFELY MAKE IT, SO I CHOSE A SUITABLE PASTURE FOR AN OFF-ARPT LNDG. THE PASTURE WAS A FAIRLY LEVEL VACANT FARM FIELD IN A RURAL AREA, PERHAPS 100 ACRES OR SO. I LANDED IN THE FIELD WITHOUT CAUSING ANY DAMAGE TO THE PROPERTY. MY AIRPLANE HAD SOME SCRATCHES ON THE PROP FROM GND BRUSH/WEEDS. I LEFT THE AIRPLANE IN THE PASTURE, AND RETURNED THE NEXT DAY WITH AN A&P TO FIND THE CAUSE OF THE ENG ROUGHNESS. THE A&P DETERMINED THAT IT WAS A BLOCKED GAS TANK FUEL VENT LINE, THAT WAS CAUSING GAS STARVATION TO THE ENG. THE VENT LINE BLOCKAGE WAS CLRED AND THE AIRPLANE RAN FINE AGAIN. THE OWNER OF THE PASTURE WAS CONTACTED AND GAVE PERMISSION FOR ME TO FLY THE AIRPLANE OUT. THE PASTURE HAD ADEQUATE LENGTH AND THERE WASN'T ANY PROB IN THE 'GRASS RWY' TKOF. I FLEW THE AIRPLANE BACK TO MY HOME ARPT WITHOUT ANY PROBS. MY AIRPLANE HAS A VENTED FUEL TANK CAP ON 1 GAS TANK. THE A&P SUGGESTED THAT A GOOD PREVENTION MEASURE WOULD BE TO HAVE VENTED FUEL TANK CAPS INSTALLED ON BOTH TANKS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED HE HAD BOTH FUEL TANKS SELECTED WITH THE FUEL SELECTOR VALVE. HE DID NOT NOTICE HIS FUEL QUANTITY DIFFERENCE BTWN THE 2 TANKS.

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.