Small aircraft has engine surge and loss of RPM. Precautionary landing in field.

Attributes
ACN	179085
Time
Date	199109
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : fim airport : vny
State Reference	CA
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other descent other landing other
Flight Plan	VFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : cfi pilot : commercial
Experience	flight time last 90 days : 180 flight time total : 730 flight time type : 40
ASRS Report	179085
Person 2
Affiliation	government : faa
Function	other personnel other
Qualification	other other : other
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	other other : unspecified cockpit
Resolutory Action	flight crew : declared emergency other
Consequence	faa : investigated
Supplementary
Primary Problem	Aircraft

Narrative:

Having less than 20 hours of flight experience in this particular aircraft itself, following a series of short flts which included long taxi's, run-ups, touch and go's, takeoffs and climbs, I became more dependent on the fuel indicating system rather than performance tables and calculations. During the return portion to the home base, approximately 35 NM leg, the aircraft began running rough and the RPM started surging. After trouble shooting the engine, and not being able to keep altitude, the decision to make an emergency landing was made. An off airport sight was selected. The aircraft was landed west/O any injuries or damage. The official cause of engine malfunction is still to be determined. Callback conversation with reporter revealed the following: reporter states the engine was inspected and showed 2 fuel filters were clogged, partially cutting off fuel flow. FAA called reporter to office with log books and questioned reporter for several hours the day after the incident. Nothing has been done since. No contact whatsoever.

Original NASA ASRS Text

Title: SMA HAS ENGINE SURGE AND LOSS OF RPM. PRECAUTIONARY LNDG IN FIELD.

Narrative: HAVING LESS THAN 20 HRS OF FLT EXPERIENCE IN THIS PARTICULAR ACFT ITSELF, FOLLOWING A SERIES OF SHORT FLTS WHICH INCLUDED LONG TAXI'S, RUN-UPS, TOUCH AND GO'S, TKOFS AND CLBS, I BECAME MORE DEPENDENT ON THE FUEL INDICATING SYS RATHER THAN PERFORMANCE TABLES AND CALCULATIONS. DURING THE RETURN PORTION TO THE HOME BASE, APPROX 35 NM LEG, THE ACFT BEGAN RUNNING ROUGH AND THE RPM STARTED SURGING. AFTER TROUBLE SHOOTING THE ENG, AND NOT BEING ABLE TO KEEP ALT, THE DECISION TO MAKE AN EMER LNDG WAS MADE. AN OFF ARPT SIGHT WAS SELECTED. THE ACFT WAS LANDED W/O ANY INJURIES OR DAMAGE. THE OFFICIAL CAUSE OF ENG MALFUNCTION IS STILL TO BE DETERMINED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR STATES THE ENG WAS INSPECTED AND SHOWED 2 FUEL FILTERS WERE CLOGGED, PARTIALLY CUTTING OFF FUEL FLOW. FAA CALLED RPTR TO OFFICE WITH LOG BOOKS AND QUESTIONED RPTR FOR SEVERAL HRS THE DAY AFTER THE INCIDENT. NOTHING HAS BEEN DONE SINCE. NO CONTACT WHATSOEVER.

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.