N94694Ercoupe 415-C · 1947

On January 28, 2017, about 1014 mountain standard time, an Ercoupe 415-C airplane, N94694, sustained substantial damage during a forced landing after a loss of engine power during cruise flight near Butterfield, Texas. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.The pilot reported that he was flying the airplane from Cypress, Texas, to Fullerton, California, for the current owner who had recently purchased the airplane. On January 26, 2017, the pilot completed 4 flight legs before he landed at Cavern City Air Terminal (CNM), Carlsbad, New Mexico. According to flight track data and fueling information provided by the pilot, the airplane had an average fuel consumption rate between 5.25 and 6.25 gallons per hour. The pilot reported that after landing at CNM he topped-off the airplane's 24-gallon fuel system with 8.3 gallons of fuel.

On January 28, 2017, the pilot departed CNM about 0901 with the intended destination of Deming Municipal Airport (DMN), Deming, New Mexico. According to flight tracking data, the airplane had a total loss of engine power about 1 hour 13 minutes after takeoff. The pilot stated that the wing fuel tank gauge indicated above ¾ full, and that the header tank quantity sight gauge appeared "unchanged" from where it had been at departure.

The pilot's corrective actions were unsuccessful in restoring engine power and a forced landing was made to a dirt road. The pilot reported that during landing roll the airplane's left wing struck a small Yucca tree, which spun the airplane 180° into a berm alongside the road. He switched off the magnetos, master electrical switch, and the main fuel valve on the lower left side of instrument panel. The pilot reported that the header fuel tank was empty after the accident, and each wing fuel tank contained about 7-8 gallons of fuel. The airplane's left wing and twin vertical stabilizers were substantially damaged during the accident.

The pilot then walked to a nearby ranch to ask for assistance. A ranch employee drove the pilot back to the accident site to retrieve his personal belongings. The ranch employee stated that while they were at the accident site the pilot showed him that the header tank was empty and that the right wing tank was ¾ full and not leaking. The ranch employee does not recall the pilot showing him the fuel level in the left wing tank. The ranch employee and pilot then drove to El Paso, Texas, where the pilot purchased a commercial airline ticket.

A representative from the wreckage recovery company reported that the fuel tanks were void of any fuel when he arrived to retrieve the airplane from the dirt road. However, comparing photos taken shortly after the accident and when the airplane was recovered revealed that the airplane had been rotated and pushed off the dirt road by unknown individuals. Additionally, the same ranch employee who had assisted the pilot after the accident stated that there is a fair amount of illegal vehicle traffic on the road throughout the night and it is likely that someone had moved the airplane and drained the remaining fuel from the fuel tanks.

The airplane's 24-gallon fuel system consisted of a 6-gallon header tank and two 9-gallon wing tanks. The wing tanks were interconnected by fuel lines and could not be individually selected. A main fuel shutoff valve controls fuel flow from the header tank to the engine. The main shutoff valve is located behind the instrument panel and halfway between the brake handle and the left control wheel shaft. A second fuel shutoff valve located on the right side wall, forward of the passenger seat, controls fuel flow from the interconnected wing tanks to the engine driven fuel pump. The engine driven fuel pump then pumps the fuel to the header tank. The engine driven fuel pump transfers fuel from the right wing fuel tank to the header tank, where it is gravity fed to the engine. The header tank has an overflow line that drains excess fuel from the header tank back into the right wing fuel tank. The amount of fuel in the header tank is indicated by a float-equipped sight gauge. When the float gauge is at its highest position it corresponds to a full header tank (about 60 minutes at cruise power). When the float is at its lowest position there is about 1 gallon of fuel remaining in the header tank (about 10 minutes at cruise power). The interconnected wing fuel tanks shared a common fuel gauge. The airplane was not equipped with an electric fuel pump. In the event of an engine driven fuel pump failure or an obstructed fuel transfer line, the only fuel accessible to the engine is from the header tank.

The airplane was examined by a Federal Aviation Administration (FAA) airworthiness inspector after it was recovered from the accident site. The inspector stated that a visual inspection of the left wing fuel tank revealed significant pitting of the aluminum skins and that there were areas of peeling tank sealant. A visual inspection of the right wing fuel tank revealed similar pitting of the aluminum tank skins. The right fuel tank also contained a 2-inch long crack in the outboard lower tank skin. It is unknown if the crack was from impact-related accident damage or when the airplane had been pushed off the road by unknown individuals. Additionally, the right wing fuel tank strainer valve was found open. The vented fuel caps were installed correctly on both wing fuel tanks. The vents were clear and functioned as designed. The cork float for the header tank sight gauge appeared to be covered in an unknown sealant. A functional test of the header tank sight gauge revealed the float would stick in the full up position, and that it would remain stuck in the full up position despite vigorous shaking of the assembly by hand. The FAA inspector stated that the main fuel shutoff valve was found turned off, and that the wing tank fuel shutoff valve was found turned on and secured by a rubber hose.

One gallon of fuel was added to the header tank in order to facilitate an engine test run. The engine started and ran normally for about 5 minutes before it was shut down manually. Two additional gallons of fuel were added to the right wing fuel tank and the engine was restarted to verify if the engine driven fuel pump was functional. After the engine ran for about 5 minutes, the fuel line from the engine driven fuel pump to the header tank was disconnected to confirm fuel flow from the pump. The disconnected line sprayed fuel indicating that the engine driven fuel pump was functional and pumping fuel from the right wing tank to the header tank. The engine was then shut down manually. There was no evidence of an obstruction of the fuel lines when compressed air was blown through the fuel lines. The engine was then restarted and run for an additional 10 minutes before it was shut down manually. There were no fuel leaks observed during the 3 engine test runs; however, after the third engine test a small amount of fuel was observed to seep from the screen bowl on top of the engine driven fuel pump. The fuel pump was removed from the engine and examined. The screen bowl had not been adequately torqued and fuel lube had been applied to the gasket. The pump discharged fuel when the activation lever was moved by hand. The 90° fuel line fitting on the fuel pump could be rotated by hand, but there was no evidence of a fuel leak. The right fuel tank was removed from the wing for additional examination. There were no finger screens installed in the tank. There was no evidence of particulate contamination in the fuel tank or in the remaining fuel that had been added before the engine tests.