DURING FORCED LNDG TRAINING; THE ACFT ENG FAILED TO RESPOND FOR SEVERAL SECONDS CAUSING A LOSS OF ALT NEAR TO THE GND.

Narrative

IN AN SMA DURING TRAINING FOR ENG OUT PROCS; THERE WAS A 5-10 SECOND LOSS OF PWR (POSSIBLY LOSS OF ENG; BUT UNSURE) WHERE THE PLANE DSNDED TO AN ESTIMATED 300 FT AGL. EARLIER IN THE DAY THERE HAD BEEN PROBS WITH ACHIEVING USUAL PWR. I BELIEVE IT WAS SPARK PLUG FOULING. AFTER A PRACTICE STALL RECOVERY; THE ENG TOOK AN UNUSUALLY LONG (3 SECOND) TIME TO REACH FULL PWR. THE REAL PROB AROSE WHEN A GAR WAS ATTEMPTED AFTER A SIMULATED ENG-OUT AT AN OFF-ARPT LOCATION. THE SIMULATED ENG-OUT HAD LASTED AN ESTIMATED 2 MINS. WHILE ON FINAL FOR A PLOWED FIELD; THE GAR WAS ATTEMPTED. THE ENG SUPPLIED NO PWR FOR 5-10 SECONDS. THEREFORE; THE DSCNT WAS CONTINUED FOR A POSSIBLE REAL EMER LNDG. ONCE PWR WAS REGAINED (BY NO ACTION ON OUR PART) WE SPIRALED UP; STAYING ABOVE THE FIELD TO 2000 FT AGL AND IMMEDIATELY RETURNED TO THE ARPT. WE WERE UNABLE TO DUPLICATE THE PROB ON THE GND. MECHS WERE INFORMED; BUT NOTHING WAS FOUND. POSSIBLE EXPLANATIONS INCLUDE: 1) FOULED SPARK PLUGS; 2) WATER IN TANKS (THEY WERE CHKED IN PRE-FLT); 3) NOT CLRING THE ENG DURING IDLE TIME.