Overview
On September 28, 2020, at about 1352 central daylight time, a Beech A36 airplane, registration N104RK, sustained substantial damage in an accident near Lago Vista, Texas. The pilot and one passenger were seriously injured, while another passenger received minor injuries. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal flight.
Fueling History
The airplane was fueled on the evening of September 24, 2020, at Rusty Allen Airport (RYW) in Lago Vista, in preparation for a cross-country flight the following afternoon. The pilot used the self-serve fuel pump, preselecting 20 gallons. The right main tank was filled to overflowing, but the pump shut off before the left tank was completely full. Analog fuel quantity gauges for both main tanks indicated full. Wingtip auxiliary tanks were empty at departure.
Outbound Flight to Brownsville
On September 25, 2020, the pilot departed RYW for South Padre Island International Airport (BRO) in Brownsville, Texas. Due to thunderstorm activity, he made an intermediate landing at Cameron County Airport (PIL) in Port Isabel, Texas. ADS-B data showed the flight from RYW to PIL took about 1.8 hours. After waiting for weather improvement, he flew the remaining leg from PIL to BRO, which took about 0.2 hours. The pilot stated that only the right main fuel tank was used during both legs, with a combined flight time of about 2 hours.
Return Flight and Accident
On September 28, before departing BRO for the return to RYW, the pilot asked the fixed-base operator to add 10 gallons of fuel to the right main tank, which was "slightly below half." The left main tank remained nearly full from the initial fueling. The pilot estimated 56 gallons of fuel were available, but did not directly verify the quantities. The wingtip auxiliary tanks remained empty. The fuel selector was positioned to the left main tank for departure and remained there until the loss of engine power.
During the approach to RYW, the pilot executed a go-around from the first approach to runway 33 and entered left traffic for a second attempt. While on a left base leg, a loss of engine power occurred. The propeller windmilled, but there was no indication of engine operation. The pilot attempted to restore power by switching the fuel selector to the right main tank, verifying the mixture was full rich, and selecting each magneto separately before returning to BOTH, all without success. Shortly after hearing the stall horn, the airplane rolled right and entered an aerodynamic stall at low altitude. The pilot could not recall the final moments before impact.
Impact and Wreckage Examination
The airplane impacted vegetation and terrain in a nose-low attitude, coming to rest inverted with the fuselage suspended above ground against vegetation. Both wings and the fuselage sustained substantial damage.
ADS-B data indicated the airplane cruised at altitudes between 8,500 and 10,500 feet mean sea level, with an enroute time of about 1 hour 57 minutes. The final data point at 1351:47 showed the airplane about 50 feet above ground level and 78 feet west of the accident site.
An onsite examination on September 28-29 by an FAA airworthiness inspector found the fuel selector valve positioned to the right main tank. First responders reported fuel leaking from the damaged right wing. No fuel was found in the fuel lines connected to the selector valve, forward of the firewall, fuel strainer, engine-driven fuel pump, fuel manifold valve, or injector lines. About half a tablespoon of fuel was recovered from the fuel metering assembly. The engine-driven fuel pump drive coupler was intact.
A second examination on January 7, 2021, before wreckage recovery, revealed no fuel in the main or auxiliary tip tanks. Flight control cable continuity was confirmed; landing gear and flaps were extended. The fuel selector valve functioned as designed during an operational test. The engine was upside down, partially attached through control cables; the propeller had separated at the crankshaft flange, with all blades attached and exhibiting polishing and minor leading-edge damage. Upper spark plugs showed normal operation. Internal engine continuity and valve train continuity were confirmed; cylinder compression was felt by finger test. Both magnetos produced spark when rotated. No fuel was present in engine fuel lines or related components.
Fuel System and Performance Data
The airplane was equipped with two 40-gallon main fuel tanks (37 gallons usable each) and two 15-gallon wingtip auxiliary tanks. At 75% engine power, the expected fuel consumption rate was 13.5 to 15.2 gallons per hour. However, the exact fuel used could not be calculated because the airplane lacked an engine monitor or fuel flow meter with data recording. Additionally, the distribution of fuel between the main tanks at departure could not be determined with accuracy, despite the pilot's estimate of 56 gallons total. The Pilot Operating Handbook's Before Landing Checklist requires selecting the fullest main fuel tank before landing.