THE PURPOSE OF THE FLIGHT WAS AERIAL OBSERVATION OF A WHEAT FIELD. WITNESSES OBSERVED THE AIRPLANE MANEUVERING AT LOW ALTITUDES (LESS THAN 100 FEET AGL), BEFORE IT PITCHED NOSE UP AND BANKED TO THE LEFT INTO THE GROUND. A POSTIMPACT FIRE ENSUED. POSTACCIDENT INVESTIGATION REVEALED NO EVIDENCE OF PREIMPACT MECHANICAL MALFUNCTION. RECORDS INDICATE THE PILOT HAD APPROXIMATELY 435 HOURS TOTAL FLIGHT TIME, OF WHICH ABOUT 390 HOURS WERE IN THE ACCIDENT AIRPLANE. THE AIRPLANE CO-OWNER STATED THE PILOT HAD FLOWN LESS THAN TWO HOURS IN THE PRECEDING EIGHT MONTHS.