C152 TRAINEE HAD ENG FAILURE NEAR LXT.

Narrative

WHILE ON A HDG OF DUE N AT CRUISE SPD; ALT 2500 FT MSL; THE ENG IN MY ACFT (A C152) BEGAN RUNNING ROUGHLY. AT THE TIME; I WAS APPROX 8 MI SE OF LXT ARPT. I TURNED ON THE CARB HEAT. HOWEVER; THE ENG BECAME ROUGHER AND LOST RPM RAPIDLY. ABOUT 30 SECONDS AFTER THE FIRST INDICATION OF ENG PROBS; THE ENG FAILED AND IT WAS ELECTED TO PERFORM A FORCED LNDG OFF ARPT. I WAS ABLE TO LAND THE ACFT SAFELY IN A PLOWED FIELD. THERE WERE NO INJURIES; AND THE ACFT SUSTAINED NO STRUCTURAL DAMAGE. PRIOR TO TKOF; I NOTED 5 QUARTS OF OIL IN THE ENG DURING PREFLT INSPECTION; AND EACH FUEL TANK WAS APPROX 3/4 FULL BY VISUAL INSPECTION. A CHK OF MY INSTS ABOUT 1 MIN PRIOR TO THE ENG FAILURE SHOWED NORMAL OIL PRESSURE AND OIL TEMP. SUPPLEMENTAL INFO FROM ACN 493729: ENG DEVELOPED EXCESSIVE VIBRATIONS; LOST PWR; AND WAS FORCED TO LAND IN A FIELD E OF LEE'S SUMMIT ARPT. THE PLANE LANDED SUCCESSFULLY WITHOUT DAMAGE TO THE ACFT OR INJURY TO THE PLT. THE ONLY DAMAGE RESULTED FROM THE ENG CYLINDER STRIKING THE L SIDE OF THE COWLING; WHEN IT SEPARATED FROM THE ENG. ACCORDING TO THE STUDENT PLT; HE PERFORMED THE 'ENG FAILURE PROC' AS INSTRUCTED; THEREBY SUCCESSFULLY AND SAFELY LNDG THE ACFT. THE STUDENT DID A REMARKABLE JOB IN CTLING THE ACFT AND IS COMMENDED FOR HIS 'COOL HANDLING' OF THIS EMER. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: TRAINEE WAS ON HIS SECOND SOLO FLT. HE WAS FLYING AN FBO RENTAL ACFT. AN ENG CYLINDER DETACHED FROM THE ENG CASE. THE INSTRUCTOR ALSO FILED A RPT EVEN THOUGH HE WAS NOT ABOARD AT THE TIME. THE INSTRUCTOR DID NOT KNOW WHAT KIND OF ENG WAS IN THE ACFT.