Engine became rough and pilot elected to land off airport.

Attributes
ACN	101187
Time
Date	198812
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : lit
State Reference	AR
Altitude	agl bound lower : 0 agl bound upper : 3000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : lit
Operator	general aviation : instructional
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other cruise other other
Flight Plan	VFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Experience	flight time last 90 days : 8 flight time total : 118 flight time type : 4
ASRS Report	101187
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : declared emergency none taken : unable
Consequence	other Other
Supplementary
Primary Problem	Aircraft

Narrative:

I took off out of olv in an small aircraft. The trip was approximately 115 SM. The winds were out of the southeast. I climbed to an altitude of 3000' and stayed around 3000-3500'. I checked the WX to lit and it wasn't anything serious, just a few scattered clouds and a little turbulence. My airspeed varied between 95 and 107 KTS, pending on the changing wind. It kept changing around from a tailwind to a crosswind. For the entire trip I heard a thumping noise on the aircraft. It wasn't the seat belts--the seat belts were the first I checked. The trip went rather well except for being a little off schedule. My RPM setting was between 2290 and 2350 and I calculated my fuel burn to be 4.7 and 5.7 per hour. The plane was topped before us, and was flown .8. Before we left the left tank was topped and the right was 3/4 full. With my calculations, I could definitely make the trip with 3 mins of fuel left. My mixture was lean all of the way. On our approach into lit the engine just started revving up and down. It never stopped completely. I used my best judgement and landed in a field about 10 mi outside of lit. The gas gauges read 1/4 full on each side and when I landed I could see fuel in both wings. I then went to FBO at adams field to see if more gas would help. We tried to put it in, but it blew mostly away with the wind. I tried to start it up again but the same thing happened. It started for about 3 mins and I taxied around. It then quit again and sank in the mud.

Original NASA ASRS Text

Title: ENGINE BECAME ROUGH AND PLT ELECTED TO LAND OFF ARPT.

Narrative: I TOOK OFF OUT OF OLV IN AN SMA. THE TRIP WAS APPROX 115 SM. THE WINDS WERE OUT OF THE SE. I CLBED TO AN ALT OF 3000' AND STAYED AROUND 3000-3500'. I CHKED THE WX TO LIT AND IT WASN'T ANYTHING SERIOUS, JUST A FEW SCATTERED CLOUDS AND A LITTLE TURB. MY AIRSPD VARIED BTWN 95 AND 107 KTS, PENDING ON THE CHANGING WIND. IT KEPT CHANGING AROUND FROM A TAILWIND TO A XWIND. FOR THE ENTIRE TRIP I HEARD A THUMPING NOISE ON THE ACFT. IT WASN'T THE SEAT BELTS--THE SEAT BELTS WERE THE FIRST I CHKED. THE TRIP WENT RATHER WELL EXCEPT FOR BEING A LITTLE OFF SCHEDULE. MY RPM SETTING WAS BETWEEN 2290 AND 2350 AND I CALCULATED MY FUEL BURN TO BE 4.7 AND 5.7 PER HR. THE PLANE WAS TOPPED BEFORE US, AND WAS FLOWN .8. BEFORE WE LEFT THE LEFT TANK WAS TOPPED AND THE RIGHT WAS 3/4 FULL. WITH MY CALCULATIONS, I COULD DEFINITELY MAKE THE TRIP WITH 3 MINS OF FUEL LEFT. MY MIXTURE WAS LEAN ALL OF THE WAY. ON OUR APCH INTO LIT THE ENG JUST STARTED REVVING UP AND DOWN. IT NEVER STOPPED COMPLETELY. I USED MY BEST JUDGEMENT AND LANDED IN A FIELD ABOUT 10 MI OUTSIDE OF LIT. THE GAS GAUGES READ 1/4 FULL ON EACH SIDE AND WHEN I LANDED I COULD SEE FUEL IN BOTH WINGS. I THEN WENT TO FBO AT ADAMS FIELD TO SEE IF MORE GAS WOULD HELP. WE TRIED TO PUT IT IN, BUT IT BLEW MOSTLY AWAY WITH THE WIND. I TRIED TO START IT UP AGAIN BUT THE SAME THING HAPPENED. IT STARTED FOR ABOUT 3 MINS AND I TAXIED AROUND. IT THEN QUIT AGAIN AND SANK IN THE MUD.

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.