What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
Pilot was conducting a maintenance flight check for an engine problem in N560PC. Take-off was normal, on climp out pilot noted the RPM was dropping from 2350. Pilot was turning downwind leg at 900' AGL and RPM continued to drop to 1800 RPM and he could not maintain altitude, had to lower nose to maintain airspeed. Declared emergency and was given any runway. Pilot determined he could not make it back to airport and attempted to make a private airfield north of Hillsboro but could not make the strip, pilot elected to land in wheat field. Pilot made a successfull off field landing resulting in no damage to aircraft or crew.
As the FAA filed it
PILOT WAS CONDUCTING A MAINTENANCE FLIGHT CHECK FOR AN ENGINE PROBLEM IN N560PC. TAKE-OFF WAS NORMAL, ON CLIMP OUT PILOT NOTED THE RPM WAS DROPPING FROM 2350. PILOT WAS TURNING DOWNWIND LEG AT 900' AGL AND RPM CONTINUED TO DROP TO 1800 RPM AND HE COULD NOT MAINTAIN ALTITUDE, HAD TO LOWER NOSE TO MAINTAIN AIRSPEED. DECLARED EMERGENCY AND WAS GIVEN ANY RUNWAY. PILOT DETERMINED HE COULD NOT MAKE IT BACK TO AIRPORT AND ATTEMPTED TO MAKE A PRIVATE AIRFIELD NORTH OF HILLSBORO BUT COULD NOT MAKE THE STRIP, PILOT ELECTED TO LAND IN WHEAT FIELD. PILOT MADE A SUCCESSFULL OFF FIELD LANDING RESULTING IN NO DAMAGE TO AIRCRAFT OR CREW.