Bell UH-1H N72297 accident near Coalinga, California

Probable cause

The pilot’s loss of situational awareness for reasons that could not be determined given the available evidence, which led to controlled flight into terrain. Contributing to the accident was the pilot’s decision to operate the helicopter while ill and fatigued.

NTSB analysis

The pilot departed the operator’s ramp for five nighttime aerial application operations. He was supported by three ground crewmembers, who described normal interactions with the pilot during the landings to the truck. About 2.5 hours later, while at the third job site, the pilot indicated that the wind had increased and that he was having difficulty lining up the helicopter with the support truck (for landing). The pilot also reported that the helicopter’s heater was not working and that he was cold, even though he was dressed for the outside conditions. The pilot also exhibited confusion and difficulty with communicating with the ground crew. The pilot subsequently canceled the third and fourth jobs, directed the ground crew to the fifth job site, and then departed the fourth jobsite with chemicals still in the helicopter’s tanks and without stating his intentions—two actions that were reportedly not typical for the pilot. The helicopter was last seen heading south above a large set of power lines that were about 100 ft high and close to the fourth job site. The last location of the helicopter was also near an airstrip that the pilot commonly used when taking breaks.

The helicopter impacted terrain in a nose-low left bank. Postaccident examination of the recovered airframe and engine revealed no evidence of any mechanical anomalies that would have precluded normal operation.

Before the accident, the pilot had told two family members that he had tested positive for COVID-19. Hydroxychloroquine and ibuprofen were found in the debris field, and acetaminophen was found in one of the pilot’s specimens. His postmortem COVID-19 test was negative. A low level of ethanol was detected in a single specimen from the pilot but not in two others, which indicated that the source was not from ingestion and thus was not a factor in the accident.

Given the evidence of the pilot’s conversations about COVID-19, the medicines found at the accident site, and the reported change in the pilot’s normal behavior pattern as the night progressed suggested that the pilot might have reported to work ill and was experiencing worsening symptoms or fatigue.

The location of the accident is consistent with the pilot deciding to fly to the airstrip with the intentions of taking a break. The full moon and clear night would have provided ample illumination for a transition to the airstrip, which was parallel with the power distribution lines in the area. Even though the pilot was likely operating the helicopter at 500 ft above ground level, the altitude that the pilot used for ferry flights, the pilot likely lost situational awareness and descended the helicopter into the terrain while enroute to the airstrip.

Text from the NTSB. Open the NTSB docket for WPR22FA098 for the full record.