Accident Sequence
On January 14, 2010, at 1441 Pacific standard time, an Ercoupe 415-D, registration N2332H, lost engine power shortly after takeoff from Napa County Airport, Napa, California. The commercial pilot, the sole occupant, was uninjured, and the airplane sustained substantial damage. The flight was conducted under Title 14 Code of Federal Regulations Part 91 in visual meteorological conditions; no flight plan was filed.
The pilot reported that before departure, both wing fuel tanks were full and the engine run-up was normal. Almost immediately after takeoff, at about 100 feet above ground level, the engine began losing power, surged twice, and then lost all power. The pilot landed in an open field off the departure end of runway 36R. During the landing roll, the nose wheel sank into soft ground and collapsed.
Aircraft and Pilot Information
The two-seat, low-wing, fixed-gear Ercoupe 415-D (serial number 2957) was manufactured in 1946. It was powered by a Teledyne Continental Motors O-200 100-horsepower engine equipped with a McCauley fixed-pitch propeller. The total airframe time was 1,608 hours. An overhauled O-200 engine had been installed on August 1, 2009, with zero time since overhaul per a supplemental type certificate; however, the required electric fuel pump was not installed—the airplane retained the original engine-driven mechanical fuel pump. A new tachometer and hobbs meter (1,608.83 hours) were installed.
The fuel system comprised a nine-gallon tank in each wing and a six-gallon fuselage tank. The engine-driven pump moved fuel from the wing tanks to the fuselage tank; excess fuel drained back to the wing tanks. Fuel was gravity-fed from the fuselage tank to the engine through a two-position main fuel valve (on/off). According to the flight manual, the valve should be located halfway between the brake handle and the left yoke control wheel, but in this airplane it was mounted on the bottom far left side of the instrument panel, about two inches from the left cockpit wall.
The 23-year-old pilot held a commercial pilot certificate with single-engine, multi-engine, and instrument ratings, issued April 30, 2008. He had 410 total flight hours, with 13 hours in the Ercoupe, and a third-class medical certificate dated May 16, 2008.
Wreckage and Examination
The airplane came to rest about one-quarter mile north of the departure end of runway 36R, in a grass field, nose-down with the tail angled 30 degrees up. The nose wheel had collapsed into the underside. Photographs showed the main fuel valve positioned at about the 2 o'clock position; the fuel valve plate indicated "fuel on" at 12 o'clock and "fuel off" at 9 o'clock.
Post-accident examination on February 3, 2010, revealed the fuselage fuel tank sight gauge was at the bottom, with about an inch of liquid remaining. The intake manifold was fractured above the carburetor mounting pad. Blue fluid smelling of aviation fuel was drained from the gascolator and wing sumps. The carburetor was reattached with a replacement manifold.
Functional tests showed that the main fuel valve lacked positive stops in either the on or off positions. When the valve was at the 12 o'clock position, fuel flow was steady; moving it to either side (9-10 o'clock or 2-4 o'clock) restricted flow to a dribble. During an engine run with the valve at 12 o'clock, the engine operated normally up to 2,500 rpm. However, when the operator inadvertently moved his left knee to the left, it shifted the valve lever to the 2 o'clock position; after about one minute, engine rpm dropped to 1,700-1,800, accompanied by sputtering and backfiring. Reducing throttle to idle smoothed the engine before shutdown.