Accident Overview
On January 30, 2017, at approximately 1000 central standard time, the pilot of a Zenith CH750 STOL (registration N1971C) conducted a forced landing in a field about 3 miles east of Jennings, Louisiana. The engine had lost power during the approach. The pilot, who was the sole occupant, received minor injuries, and the aircraft sustained substantial damage. The flight was operated under 14 CFR Part 91 for personal purposes, and visual meteorological conditions prevailed at the time. No flight plan was filed.
Background
The pilot had recently completed building the aircraft and logged about 10 flight hours. He had experienced fuel flow issues; specifically, fuel did not flow evenly from the wing tanks. The Zenith CH750 is a high-wing design with 15-gallon fuel tanks in each wing, feeding the carburetor via gravity. Early tests showed a flow rate of 2.5 gallons per minute by gravity and 1.5 gallons per minute with the auxiliary fuel pump on. The vented fuel caps were connected via a T-fitting above and behind the pilot seats. Fuel passed through an ON/OFF selector valve, a gascolator, an in-line fuel filter, an auxiliary fuel pump, then to the carburetor. On the ground, the fuel levels in both tanks equalized to within a quarter gallon within minutes.
To address uneven fuel flows, the aircraft kit manufacturer (Zenith) recommended adding snorkels to each vented cap. After installation, a test flight revealed fuel being pushed out of one tank and draining from the opposite tank. The pilot tried various configurations and eventually flew with the vented caps closed and only snorkels in use.
Accident Flight
On the morning of the accident, the pilot departed Jennings Airport (3R7) at about 0900 with 7 gallons of fuel in the left tank and 8 gallons in the right. He flew for approximately one hour, performing several full-power climbs as part of Phase 1 certification. While returning to the airport, the left tank fuel gauge indicated a low level, while the right tank indicated a high level. The pilot had been advised by Zenith that when one tank reached 1 to 2 gallons, the other tank would continue to supply fuel.
While on a 3-mile final approach at an altitude of 1,800 feet and aligned with the runway, the engine lost power. The pilot determined he could not glide to the airport and faced a fence line with trees and power lines. He chose to make a forced landing in a field. Upon touchdown, the nose gear dug into soft ground, causing the aircraft to nose over.
Cause
The pilot reported that the cause of the crash was fuel starvation due to the left tank running empty and the right tank not flowing to the engine.