Accident Details
On May 2, 2018, at approximately 1620 central daylight time, an experimental amateur-built Laminar Lancair 360 (registration N92WL) experienced a total loss of engine power while in cruise flight. The airplane subsequently impacted terrain during a forced landing to a field about half a mile from Woodward Municipal Airport (WWR) in Woodward, Oklahoma. The pilot and a pilot-rated passenger were not injured, and the airplane sustained substantial damage. The flight, operated under Title 14 Code of Federal Regulations Part 91, departed Lee Summit Municipal Airport (LXT) in Lee's Summit, Missouri, around 1416, en route to Dalhart Municipal Airport, Texas. Visual meteorological conditions prevailed, and an instrument flight plan was filed.
Pilot and Passenger Accounts
The pilot reported that while cruising at 8,000 feet, he requested 10,000 feet to stay clear of clouds. As the airplane reached 10,000 feet, it encountered moderate to severe turbulence for a few seconds. Shortly after, the engine stopped producing power without prior indications such as sputtering. The pilot initiated a descent, activated the fuel boost pump and fuel transfer pumps, and adjusted throttle and mixture settings in an attempt to restart the engine, but without success. The pilot-rated passenger declared a MAYDAY and identified WWR, about 12 nautical miles southeast, as the nearest airport. The pilot flew the airplane at best glide airspeed with the propeller lever set to the coarsest pitch, resulting in a glide ratio with a 1,000 to 1,100 feet-per-minute rate of descent. At about 5,700 feet mean sea level (msl), the pilot deemed it unlikely to reach the airport, so he pushed the propeller forward and attempted another restart. The rate of descent increased to 1,800 to 2,000 fpm, and the engine did not restart. The pilot then aimed for a road but, seeing power lines and trees, chose a pasture instead. He lowered the landing gear (the flaps were found retracted). Upon landing in the pasture, sagebrush caused the gear to collapse; the airplane bounced and skidded to a stop.
Post-accident, the pilot examined the airplane and noted that the main fuel cutoff valve, hidden in the co-pilot's foot well, was partially moved. He was uncertain whether the valve moved during the turbulence or while bouncing across the pasture. The pilot-rated passenger stated he could not see the valve, located on the right side of the center console under the instrument panel. He speculated whether his knee hit the valve handle during turbulence, shutting off fuel flow from the header tank to the engine. The fuel valve handle was found about a quarter of the way from the horizontal (on) to vertical (off) position, and the handle moved without much resistance.
Aircraft Information
The airplane's builder reported using two similar stainless steel, Teflon-coated ball valves with 3/8-inch lines. One valve, with an orange handle, was located on the left side of the center console for the pilot—an emergency gear dump valve. The other orange-handled valve, the emergency fuel shutoff valve, was on the right side (passenger side) and could not be seen by the pilot. This valve shut off fuel from the header tank to the engine. In normal operations, the handle was horizontal; turning it vertical cut off fuel.
Flight Data and Examination
The airplane was equipped with a Garmin EFIS that recorded flight and engine data. The SD card data showed the airplane at about 10,000 feet msl when it experienced a 2g vertical acceleration. Engine data indicated a rapid decrease in fuel flow within 20 seconds of that acceleration, coinciding with decreases in exhaust gas temperatures (EGTs) and fuel pressure. The wreckage was transported to a recovery facility, where about 30 gallons of fuel was drained—the header tank was nearly full, and the rest came from wing tanks.
An examination and engine run were conducted by the National Transportation Safety Board. The engine, a 180-horsepower Lycoming IO-360-C1E6, started and ran at various power settings. Magneto drop was high but similar between left and right magnetos. The engine performed satisfactorily, and no reason for the lost power was found. A second test assessed the emergency fuel shutoff valve. With the engine running at 2,090 rpm and 18.3 inches of manifold pressure, the valve was slowly moved from horizontal to vertical. There was no power loss until the handle reached full vertical, then the engine stopped within about 10 seconds.