Accident Summary
On January 28, 2017, at about 1014 mountain standard time, an Ercoupe 415-C airplane, registration N94694, experienced a total loss of engine power during cruise flight and subsequently made a forced landing on a dirt road near Butterfield, Texas. The airplane sustained substantial damage. The pilot, who was the sole occupant, reported no injuries. The flight was conducted as a personal flight under Title 14 Code of Federal Regulations Part 91.
Pilot Actions
The pilot had departed earlier that day from Cavern City Air Terminal (CNM) in Carlsbad, New Mexico, at about 0901, with the intended destination of Deming Municipal Airport (DMN) in Deming, New Mexico. The flight was part of a trip from Cypress, Texas, to Fullerton, California, for the new owner of the airplane. Two days prior, on January 26, the pilot completed four flight legs before landing at CNM, where he topped off the 24-gallon fuel system with 8.3 gallons of fuel. According to flight tracking data, the engine power loss occurred about 1 hour 13 minutes after departure. The pilot reported that the wing fuel tank gauge indicated above ¾ full and the header tank quantity sight gauge appeared unchanged from departure. His attempts to restore engine power were unsuccessful.
During the forced landing, the airplane’s left wing struck a small yucca tree, causing the airplane to spin 180 degrees into a berm alongside the road. The pilot then shut off the magnetos, master electrical switch, and main fuel valve. After the accident, the header tank was empty, while each wing fuel tank contained about 7–8 gallons of fuel. The left wing and twin vertical stabilizers were substantially damaged.
Fuel System Details
The Ercoupe 415-C fuel system consisted of a 6-gallon header tank and two 9-gallon wing tanks interconnected by fuel lines; the wing tanks could not be individually selected. A main fuel shutoff valve located behind the instrument panel controlled fuel flow from the header tank to the engine. A second shutoff valve on the right side wall, forward of the passenger seat, controlled fuel flow from the interconnected wing tanks to the engine-driven fuel pump. The engine-driven fuel pump transferred fuel from the right wing tank to the header tank, which then gravity-fed the engine. An overflow line drained excess fuel from the header tank back into the right wing tank. The header tank quantity was indicated by a float-equipped sight gauge; at full, it provided about 60 minutes of cruise power, and at the lowest position, about 1 gallon (10 minutes). The interconnected wing tanks shared a common fuel gauge. The airplane had no electric fuel pump.
Post-Accident Examination
A ranch employee who assisted the pilot after the accident reported that the pilot showed him the header tank was empty and the right wing tank was ¾ full and not leaking. The employee did not recall seeing the left wing tank fuel level. The pilot later purchased a commercial airline ticket in El Paso, Texas. A representative from the wreckage recovery company stated that the fuel tanks were void of fuel when he arrived, but photos indicated the airplane had been rotated and pushed off the road by unknown individuals. The same ranch employee noted frequent illegal vehicle traffic on the road and suggested that someone may have moved the airplane and drained the remaining fuel.
An FAA airworthiness inspector examined the recovered airplane. The left wing fuel tank showed significant pitting of the aluminum skins and areas of peeling tank sealant. The right wing tank had similar pitting and a 2-inch-long crack in the outboard lower tank skin; it was unclear if the crack was from impact or from being moved. The right wing fuel tank strainer valve was found open. The vented fuel caps were installed correctly and functional. The cork float for the header tank sight gauge was covered in an unknown sealant, and a functional test revealed the float would stick in the full-up position, even with vigorous shaking. The main fuel shutoff valve was found turned off, while the wing tank shutoff valve was turned on and secured by a rubber hose.
Engine Testing
One gallon of fuel was added to the header tank, and the engine started and ran normally for about 5 minutes before manual shutdown. Two additional gallons were added to the right wing tank; after restarting, the fuel line from the engine-driven fuel pump to the header tank was disconnected and sprayed fuel, confirming pump function. Compressed air blown through the fuel lines showed no obstruction. The engine ran for an additional 10 minutes. No fuel leaks were observed during the three test runs, though after the third run, a small amount of fuel seeped from the screen bowl on top of the engine-driven fuel pump. The pump was removed 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-degree fuel line fitting could be rotated by hand but showed no evidence of leakage. The right fuel tank was removed; no finger screens were installed, and no particulate contamination was found in the tank or in the fuel added for testing.