WPR24FA123 · Ayres Corporation S2R-G10

On the morning of the accident, the pilot departed from the operator’s base and flew the airplane about 174 miles northeast, to an airstrip near a rice farm. About 1230, after performing multiple flights to drop wild rice in the paddies near the airstrip, the pilot asked the fuel truck operators to fuel the airplane until the tanks were 3/4 full and subsequently departed the airstrip to continue spreading rice. When the pilot returned to the airstrip about 1400, he said he was not feeling well and was going to apply one last load of rice before leaving work. The pilot declined to have more fuel added to the fuel tanks. The pilot was seen with his safety harnesses fastened when he last departed. About 1444, witnesses near the rice farm heard the airplane crash and saw it inverted and partially submerged in the rice paddy. When they opened the airplane’s canopy, they found the pilot unbuckled from the safety harness, unresponsive. Examination of the airplane revealed an unusable amount of fuel (less than 2 gallons) in the fuel system, and no fuel sheen was observed in the water. No preaccident mechanical failures or malfunctions that would have precluded normal operation were found. The propeller blade damage signatures at the accident site were consistent with low rotational energy at impact. The airplane’s fuel system was intact, and there was no evidence of fuel leakage. After the pilot departed the operator’s facility, he had texted the mechanic stating the airplane’s fuel gauge was inoperative and that the airplane’s fuel gauge was slower to respond to fuel quantity changes than other airplanes. The mechanic explained that the gauge did not read fuel quantities greater than 82 gallons per tank; additionally, the cockpit fuel gauge noted that fuel quantities above 82 gallons were “ungageable.” Postaccident testing of the airplane’s fuel gauge and level senders indicated that they were operating to the manufacturer’s specifications. Fuel consumption calculations indicate that, with the reported fuel load, the airplane would have had an endurance of 2.1 to 2.9 hours. Although the airplane sustained substantial damage, the accident appeared to be survivable. The pilot’s autopsy identified no obvious fatal traumatic injuries, and the cause of death was determined to be hypertensive and atherosclerotic cardiovascular disease. However, the accident circumstances provide no clear evidence of in-flight pilot incapacitation, and it is unlikely that the pilot’s cardiovascular disease contributed to the accident. Additionally, severe acute mental or physical stress may be a trigger for cardiac events in individuals with underlying heart disease. It is possible that the airplane’s impact with the water of the rice paddy, followed by it becoming partially submerged and inverted, could have resulted in such a cardiac event in the setting of the pilot’s preexisting heart disease. The lack of fuel at the accident site and onboard the airplane during postaccident examination is consistent with fuel exhaustion, which resulted in the airplane’s impact with terrain. Though the pilot reported he was feeling unwell in the hours before the accident, available evidence is insufficient to determine what specific symptoms he was experiencing, or whether his symptoms contributed to the accident.

Verbatim NTSB analysis and probable cause from the NTSB dataset