Grumman Acft Eng Cor-Schweizer G-164B N6793K accident near Pleasant Grove, California

Probable cause

The pilot’s delayed recognition of the extent of the airplane’s increased takeoff roll. Contributing to the accident was the pilot’s lack of experience operating the airplane at a high gross weight.

NTSB analysis

The operator hired the pilot to reposition the turbopropeller-engine equipped airplane from the seller’s private airstrip to the job location. Although the pilot had experience flying reciprocating engine-equipped models of the airplane, he did not have any previous experience flying the turbopropeller-engine equipped model until he started preparing for the repositioning flight. His preparations included attending ground training and making four familiarization flights (about 2.5 hours total) in the accident airplane with progressively increased loading but at weights less than that of the loading for the accident flight.

For the accident flight, the pilot loaded the airplane to about 6,011 lbs, which was below the Civil Aeronautics Manual (CAM) Part 8 operational gross weight of 6,075 lbs listed in an exemplar Pilot’s Operating Handbook (POH) for the airplane model. The POH did not list performance data for the turbopropeller engine or provide performance charts for calculating required runway distances.

No performance charts for the turbo-propeller equipped Ag Cat were available to the pilot; however, the ground/flight instructor was confident that the airplane could take off from the 2,100 ft asphalt runway. The pilot’s pretakeoff checks revealed normal operation of the engine. During the takeoff roll, the airplane accelerated at a significantly lower rate than during the pilot’s previous flights in it. Once the tailwheel came up, the pilot saw that most of the runway had been used. The pilot elected to continue the takeoff and pulled back on the control stick to climb. The airplane climbed slowly but struck a gate and then a pickup truck before impacting terrain, which substantially damage the fuselage, wings, and empennage. Any advantage to braking, rather than electing to takeoff, could not be determined due to the lack of performance charts.

Postaccident examination of the airframe and engine revealed no mechanical malfunction or anomaly that would have precluded normal operation. An anomaly identified in the fuel control bellows would not have reduced engine power.

Text from the NTSB. Open the NTSB docket for WPR24LA214 for the full record.