N104RKBeech A36 · 1979

On September 28, 2020, about 1352 central daylight time, a Beech A36 airplane, N104RK, was substantially damaged when it was involved in an accident near Lago Vista, Texas. The pilot and one passenger were seriously injured, and another passenger sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.

The pilot reported that the airplane was fueled on the evening of September 24, 2020, at Rusty Allen Airport (RYW), Lago Vista, Texas, in preparation for a cross-country flight the following afternoon from RYW to South Padre Island International Airport (BRO), Brownsville, Texas. The pilot fueled the airplane using the self-serve fuel pump at RYW and the airplane was not flown again before he departed for BRO on the afternoon of September 25, 2020. The pilot stated that he preselected 20 gallons to be dispensed at the self-serve fuel pump; that the right tank was filled to the point of overflowing, but the self-serve pump shutoff before left tank was completely full. The airplane’s analog fuel tank quantity gauges for both main fuel tanks indicated “full” before he departed on the outbound flight to BRO. The pilot reported that the wingtip auxiliary tanks were empty at departure.

The pilot reported that after departing RYW he made an intermediate landing at Cameron County Airport (PIL), Port Isabel, Texas, due to thunderstorm activity along his planned route-of-flight to BRO. According to automatic dependent surveillance-broadcast (ADS-B) track data, about 1.8 hours of flight time elapsed during the flight from RYW to PIL. The pilot stated that he waited for the weather to improve before he departed PIL and continued toward BRO. According to ADS-B track data, about 0.2 hours of flight time elapsed during the second flight leg from PIL to BRO. The pilot stated that he only used fuel from the right main fuel tank during both flight legs from RYW to BRO. The combined flight time for both flight legs was about 2 hours.

On September 28, 2020, before he departed BRO for the return flight to RYW, he asked the fixed-base operator to add 10 gallons of fuel to the right main tank that was “slightly below half.” The pilot noted that he did not use fuel from the left main fuel tank during the flight legs from RYW to BRO and, as such, the left main fuel tank remained “nearly full” from the previous fueling on September 24, 2020. Based on his flight planning, the pilot estimated that he departed on the accident flight with 56 gallons of fuel; however, he did not directly ascertain how many gallons of fuel were in the main fuel tanks before departure. The wingtip auxiliary tanks remained empty. The pilot stated that the flight departed with the fuel selector positioned on the left main fuel tank where it remained until the airplane lost engine power while in the traffic pattern at RYW.

The pilot reported that the cross-country flight was uneventful until the landing approach at RYW. He stated that the airplane was not stabilized on his first landing approach to runway 33 at RYW, so he made a go-around and entered left traffic for a second landing attempt. The airplane had a loss of engine power while the airplane was on a left base leg to runway 33. The propeller continued to windmill after the loss of engine power, but there was no indication that the engine was operating. The pilot was unable to restore engine power by switching fuel tanks (from the left main fuel tank to the right main fuel tank), verifying that the mixture control was full rich, and selecting each magneto separately before returning the ignition switch to BOTH. As he prepared his passengers for a forced landing, the pilot heard the airplane’s stall horn shortly before the airplane rolled right. The pilot does not recall the final moments of the flight after the airplane entered an aerodynamic stall at a low altitude.

The airplane impacted vegetation and terrain in a nose low attitude. The airplane came to rest inverted, with the fuselage suspended above the ground, against vegetation. The airplane sustained substantial damage to both wings and the fuselage.

According to ADS-B track data, the airplane flew at various cruise altitudes between 8,500 and 10,500 ft mean sea level, and the elapsed time enroute was about 1 hour 57 minutes. At 1351:47, the final ADS-B track datapoint was about 50 ft above ground level and about 78 ft west of the accident site.

On September 28-29, 2020, an onsite examination completed by a Federal Aviation Administration (FAA) airworthiness inspector revealed that the airplane came to rest nose down and inverted in a wooded area. The fuel selector valve was positioned to use fuel from the right main fuel tank. First responders to the accident site reported that there was fuel leaking from the damaged right wing. There was no evidence of fuel in the fuel lines connected at the fuel selector valve, in the fuel lines forward of the firewall, fuel strainer assembly, engine-driven fuel pump, fuel manifold valve, or the fuel injector lines. About ½ tablespoon of fuel was recovered from the fuel metering assembly. A disassembly of the engine-driven fuel pump confirmed the drive coupler remained intact.

On January 7, 2021, before the wreckage was recovered, an additional onsite examination was completed by a FAA airworthiness inspector with the assistance of an airframe manufacturer investigator. The fuselage and both wings exhibited impact related damage. There was flight control cable continuity between the individual flight control surfaces and their respective cockpit controls. The landing gear and flaps were found fully extended. There was no evidence of fuel in the main fuel tanks or the auxiliary tip tanks. The fuel selector valve functioned as designed during an operational test.

The engine was found upside down and partially attached to the airframe through control cables. The propeller separated from the engine at the crankshaft flange. All blades remained attached to the hub and exhibited polishing and some minor leading-edge damage. The upper spark plugs exhibited features consistent with normal engine operation. Internal engine continuity and valve train continuity were confirmed while the crankshaft was rotated. Cylinder compression was confirmed by placing a finger over the open spark plug holes and feeling suction and expelled air from each cylinder while the crankshaft was rotated. Both magnetos provided spark when rotated by hand. There was no evidence of fuel in the engine fuel lines or fuel-related engine components.

The airplane was equipped with two 40-gallon (37 gallon usable) main fuel tanks and two 15-gallon wingtip auxiliary tanks. Based on available performance data for the cruise altitudes flown during the flight, the expected fuel consumption rate at 75% engine power is 13.5-15.2 gallons per hour (gph). However, the amount of fuel used during the flight could not be calculated with an appreciable level of accuracy because the airplane was not equipped with an engine monitor or fuel flow meter with data recording capability. Additionally, although the pilot estimated the airplane had about 56 gallons of fuel available at departure, the investigation could not determine with an appreciable level of accuracy how that fuel was distributed between main fuel tanks. According to the airplane’s Pilot Operating Handbook, the Before Landing Checklist requires pilots to select the fullest main fuel tank before landing.