Grumman Acft Eng Cor-Schweizer G-164B N8834H accident near Lockport, Louisiana

Probable cause

The pilot’s inadequate planning for the high density altitude conditions which resulted in reduced airplane performance, climb capability, and subsequent forced landing.

NTSB analysis

The pilot reported that on the morning of the accident he flew two previous aerial application flights in the airplane without issue. The outside air temperature and humidity had increased since his first two flights, and he estimated that the temperature at the time of the accident was 93°F. The pilot sprayed a few fields while enroute to the final field and estimated that the airplane had about 35 gallons (210 lbs) of fuel and about 160 gallons (1,334 lbs) of liquid applicant in the hopper before arriving to the final field. He descended into the target field and completed one spray pass. As the airplane approached the end of the field, he increased airplane pitch but “noticed the plane not climbing as normal” despite all the engine gauges depicting normal indications. The airplane descended as it approached a highway, but the pilot did not want to dump the hopper over the highway or the adjacent bayou. The airplane cleared a set of powerlines next to the highway, landed hard in a field, and then nosed over. The airplane substantial damage to the fuselage, empennage, wings, and engine mount.

Postaccident examination of the airplane did not reveal any mechanical malfunctions or failures that would have precluded normal operation. Since there were no anomalies found during the examination and the pilot confirmed that the engine gauges depicted normal indications during the flight, it is likely that the engine was operating normally at the time of the accident. Based on available information, the airplane’s weight at the time of the accident was likely near the airplane’s maximum gross weight limitation.

The calculated density altitude for the accident flight was about 2,353 ft, which would have further degraded the airplane’s climb performance and ability to maintain altitude.

Text from the NTSB. Open the NTSB docket for CEN25LA231 for the full record.