This location is a group of small experimental field separated by alley, it is a bit rugged and therefore not adapted for landing and rolling a small aircraft.
As the F-BOZS is a tailwheel aircraft, it completed the approach into the field by a bump into one of the alley and then turned upside down (see following picture from the fire rescue departement).
The crew was safe but the instructor, who is a bit tall was more seriously injured than his student pilot due to this rollover.
As we can see on the above picture, fire and rescue departement arrived quickly and deployed substantial efforts in order to bring help to the crew and to avoid any fire breakout.
1- History of the flight
Back from a local VFR flight of about 40 minutes during which low speed flight has been practiced, student pilot starts his descent at the end of base leg in order to land on runway 29L.
The instructor asks the student pilot to “increase a little bit power” because he thinks that the aircraft is low on the approach plan.
Despite several actions on the thrust lever, the engine rpm doesn’t increase.
Instructor announces to ATC an engine failure. He takes control of the aircraft, check nominal position of engine controls and land into a high cereal field.
During rolling, the aircraft turns upside down.
Firefighters evacuate the crew stuck inside the aircraft.
2- Additional information
The 44 years old pilot, has an instructor rating since December 2013.
He had logged about 1000 hours of flight at the time the event occurred.
3.1- Information on the aircraft and the location
Firefighters has expanded some foam around the aircraft to avoid any fire breakout.
The pressure of the water hoses has compressed the air intake grid and lots of wastes have been pushed into the engine air intake pipe.
These wastes were found in the head of cylinders, from open valves, and also in the carburetor bowl.
Engine and its accessories have been contaminated by mud and organic waste.
Due to this contamination, it has not been possible to determine the origin of inability of the crew to increase engine power.
Collected fuel in the aircraft fuel pump’s bowl looked a bit greenish.
The result of the analysis of this sample indicates that the fuel, of type 100LL, has been polluted by organic elements.
However, the origin of the pollution couldn’t be determined as the container, used to collect and store the sample, wasn’t adapted.
Indeed, it is possible that the container would be the origin of the fuel pollution.
2.3 Estimated weather condition on the crash site
Wind was 10 knots from 290°, temperature was 18°C, dew point was 7°C and relative humidity was 49%.
The investigation couldn’t determine the reason for the lack of engine power rise.