An AA5A experienced engine problems and landed in a field incurring some aircraft damage.

Attributes
ACN	718957
Time
Date	200611
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	msl single value : 3500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Cheetah Tiger Traveler
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	VFR
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : private
Experience	flight time last 90 days : 65 flight time total : 200 flight time type : 65
ASRS Report	718957
Person 2
Function	observation : passenger
Events
Anomaly	aircraft equipment problem : critical maintenance problem : improper maintenance
Independent Detector	other flight crewa other flight crewb
Resolutory Action	other
Consequence	other
Supplementary
Problem Areas	Maintenance Human Performance Flight Crew Human Performance Aircraft
Primary Problem	Ambiguous

Narrative:

Departed ZZZ around XA30 after filling aircraft with fuel and adding a quart of oil; to fly under VFR conditions. Approximated distance is 90 mi. After approximately 20 mins into flight at cruise altitude; the engine began to vibrate and lose power. Both pilots tried all emergency procedures. The more experienced pilot; the passenger took over control of the airplane while the other pilot looked for safe places to possibly land. A successful off field landing was performed with no injuries occurred with damage to aircraft involving propeller; engine and nose gear. After discussions with mechanic who maintains aircraft he believes it to be a valve failure. Prevention of reoccurrence would be not to fly aircraft beyond recommended tbo.

Original NASA ASRS Text

Title: AN AA5A EXPERIENCED ENG PROBS AND LANDED IN A FIELD INCURRING SOME ACFT DAMAGE.

Narrative: DEPARTED ZZZ AROUND XA30 AFTER FILLING ACFT WITH FUEL AND ADDING A QUART OF OIL; TO FLY UNDER VFR CONDITIONS. APPROXIMATED DISTANCE IS 90 MI. AFTER APPROX 20 MINS INTO FLT AT CRUISE ALT; THE ENG BEGAN TO VIBRATE AND LOSE PWR. BOTH PLTS TRIED ALL EMER PROCS. THE MORE EXPERIENCED PLT; THE PAX TOOK OVER CTL OF THE AIRPLANE WHILE THE OTHER PLT LOOKED FOR SAFE PLACES TO POSSIBLY LAND. A SUCCESSFUL OFF FIELD LNDG WAS PERFORMED WITH NO INJURIES OCCURRED WITH DAMAGE TO ACFT INVOLVING PROP; ENG AND NOSE GEAR. AFTER DISCUSSIONS WITH MECH WHO MAINTAINS ACFT HE BELIEVES IT TO BE A VALVE FAILURE. PREVENTION OF REOCCURRENCE WOULD BE NOT TO FLY ACFT BEYOND RECOMMENDED TBO.

Data retrieved from NASA's ASRS site as of January 2009 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.