Schweizer Aircraft CORP G-164B accident near Tracy, California, July 30, 2021

The NTSB's narrative final · quoted from the NTSB record

The pilot reported that he was performing a low-level agricultural pesticide application on a hay field when the engine suddenly lost all power. Although the airplane was at a high airspeed at the time, the pilot was unable to climb due to the presence of high-tension powerlines above him in his flightpath. During the subsequent descent, he flew beneath a set of powerlines, turned, and landed in a field after his airspeed had decreased. During the landing, the airplane contacted the ground and trees, which resulted in substantial damage to the fuselage and wings. Postaccident examination of the engine and accessories did not reveal any mechanical anomalies that could have precluded normal operation. Evidence of rotational scoring and metal spray deposits in the engine indicate that it was operating at the time of impact. The fuel solenoid shutoff valve was in the CLOSED position, which would have prevented fuel flow to the engine. However, due to the overwhelming evidence that the engine was rotating at the time of impact, it is likely that the shutoff valve moved to the CLOSED position as a result of the impact. Propeller signatures indicated that the blades impacted the ground while rotating at low power. An examination of the propeller did not reveal any visible discrepancies that would have affected performance prior to impact. The damage to the start lock brackets, start lock plates, and a contact mark on the internal surface of the piston suggest the propeller was on or below the start lock angle at impact. This was likely the result of impact forces, as the pilot stated that he did not reduce throttle input or attempt to feather blades before impact. Previous maintenance indicated that the blade radius was properly set. The pilot did not recall the power lever position at the time of the power loss and the investigation did not reveal any evidence of preimpact mechanical malfunctions or failures. Therefore, the reason for the pilot’s reported loss of power could not be determined.

The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.

Other NTSB records under N3629F the same tail number, which may have belonged to a different aircraft at the time