Private pilot of an small aircraft made an off airport forced landing after the engine lost power.

Attributes
ACN	323750
Time
Date	199512
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : c17
State Reference	IA
Altitude	msl bound lower : 3000 msl bound upper : 3000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	cruise other other
Flight Plan	None
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Experience	flight time total : 105 flight time type : 105
ASRS Report	323750
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

Reached cruise altitude (3000 ft MSL) and noticed poor performance. Pulled on carburetor heat and engine slowed to approximately 500-700 RPM. Turned carburetor heat off and on and had no real change. Leaned engine and that helped some, but not enough to maintain altitude. Left carburetor heat on thinking carburetor had large ice buildup, but it was only making an already rich mixture richer, landed on gravel road. I think airport could have been made if carburetor heat was left off and mixture leaned. Mechanics stated mechanical problem relating to fuel intake and possible stuck intake valve. I remained calm entire time which I feel was the biggest factor in escaping injury and damage.

Original NASA ASRS Text

Title: PVT PLT OF AN SMA MADE AN OFF ARPT FORCED LNDG AFTER THE ENG LOST PWR.

Narrative: REACHED CRUISE ALT (3000 FT MSL) AND NOTICED POOR PERFORMANCE. PULLED ON CARB HEAT AND ENG SLOWED TO APPROX 500-700 RPM. TURNED CARB HEAT OFF AND ON AND HAD NO REAL CHANGE. LEANED ENG AND THAT HELPED SOME, BUT NOT ENOUGH TO MAINTAIN ALT. LEFT CARB HEAT ON THINKING CARB HAD LARGE ICE BUILDUP, BUT IT WAS ONLY MAKING AN ALREADY RICH MIXTURE RICHER, LANDED ON GRAVEL ROAD. I THINK ARPT COULD HAVE BEEN MADE IF CARB HEAT WAS LEFT OFF AND MIXTURE LEANED. MECHS STATED MECHANICAL PROB RELATING TO FUEL INTAKE AND POSSIBLE STUCK INTAKE VALVE. I REMAINED CALM ENTIRE TIME WHICH I FEEL WAS THE BIGGEST FACTOR IN ESCAPING INJURY AND DAMAGE.

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.