Gulfstream-Schweizer A/C Corp GULFSTREAM AM G 164B N8402K accident near Delaplaine, Arkansas

Probable cause

The pilot’s failure to establish a proper airspeed and angle-of attack during takeoff in elevated density altitude and light tailwind conditions, which resulted in an aerodynamic stall.

NTSB analysis

The commercial pilot was conducting an agricultural application flight. The pilot reported that the airplane had been refueled before the preceding flight, which was about 15 minutes long and was completed without incident, and that the fertilizer load was about the same on the accident flight as it was on the preceding flight. He added that the accident takeoff ground run was longer than for the previous takeoff and that, after he became aware of the extended ground run, the airplane was already past his predetermined takeoff "commitment" (go/no go) point. The airplane became airborne but did not climb. The tailwheel subsequently impacted a rice levee, and the airplane then settled into the field and came to rest inverted. The pilot noted that he never actually lost control of the airplane and that he did not perceive any issues with the airframe or the engine during the accident takeoff.

A postaccident examination of the engine and airframe did not reveal any preimpact mechanical failures or malfunctions. An engine teardown examination revealed evidence consistent with engine operation at impact. The examination also revealed that the torsion shaft had failed due to torsional overload as a result of a sudden stoppage of the engine at impact.

The density altitude was calculated to be about 1,680 ft, and a light tailwind existed at the time of the accident. The airplane was likely operating at or near its maximum gross weight, which, combined with the effects of the elevated density altitude and light tailwind conditions, resulted in the airplane becoming airborne at an airspeed that could not be maintained outside of ground effect. The pilot subsequently failed to maintain the proper angle-of-attack as he attempted to climb the airplane out of ground effect, which resulted in an aerodynamic stall.

Text from the NTSB. Open the NTSB docket for CEN15LA259 for the full record.