N653TBeech H35 · 1957

On June 3, 2014, about 1055 central daylight time, a Beech H35 airplane, N653T, impacted a parking lot following a total loss of engine power near Monroe, Louisiana. The commercial pilot was seriously injured and the airplane was substantially damaged. The airplane was registered to WFO Flying Services, and operated by a private individual under the provisions of 14 Code of Federal Regulations Part 91 as a maintenance test flight. Visual meteorological conditions prevailed for the flight, which operated with a flight plan. The local flight originated from Monroe Regional Airport (KMLU), Monroe, Louisiana, about 1020.The airplane was co-owned by the accident commercial pilot and another pilot. They acquired the airplane in March 2013. Months prior to the accident, the airplane had been mistakenly fueled with Jet-A by the other pilot. Data obtained from the onboard JPI engine data monitoring (EDM) system found that on November 1, 2013, the engines cylinder head temperatures (CHT) increased about 460° F several times during the flight. The airplane landed at KMLU and it was repaired. An invoice from the repair facility stated that the fuel tanks were drained and mechanics "flushed 5 gallons through fuels to clear them of contamination." The engine was removed, repaired, and reinstalled on the airplane. The engine's fuel hoses were also replaced. Work was completed on the airplane on June 2, 2014.

On the day of the accident, the airplane departed KMLU for a maintenance test flight flown by the accident commercial pilot/co-owner. The pilot reported an unspecified fuel malfunction before the engine experienced a total loss of engine power. During the forced landing, the airplane collided with a tree and impacted a parking lot. The cockpit was distorted and crushed aft. The airplane's right wing sustained more damage when compared to the left wing. The outboard portion of the right wing was torn outboard of the landing light. The fuselage was wrinkled and distorted. At the accident site, fuel was drained from each tank and from a fuel line leading to the engine. The fuel pulled from the fuel line leading to the engine was light orange in color. The fuel samples pulled from the fuel tanks appeared in color and clarity with 100 low lead fuel. The orange colored fuel was sent for fuel testing.

Gas chromatograph mass spectrometer testing was conducted on the orange colored fuel sample. The testing's certificate of analysis noted "if heavier compounds or polymers are present these were not seen on the gas chromatograph mass spectrometer. Testing found the presence of silicon in the quantity of 12.9 mg/kg.

An examination of the airframe and engine was conducted at a salvage facility. No preimpact anomalies were detected with the airframe or the fuel tanks. The fuel lines and fuel screens were all found clear and unobstructed. The engine examination did not detect any preimpact anomalies. No silica or white powdery deposits were noted in the fuel divider, cylinders, or spark plugs.

Data obtained from the JPI EDM, found that on the day of the accident, data for the accident flight began at a JPI EDM time of 1437:44. At 1517:20 EDM time, the engine's CHTs averaged 373° F and the exhaust gas temperatures (EGTs) averaged 1412° F. Within 6 seconds the EGTs averaged 780° F and continued to decay. About 2 minutes later, the EDM recorded "NA" values for several values.

Reliable scientific data does not exist to determine a level of silicon contamination prior to obstruction of an airplane's engine performance.