Pilot Debrief

177MF LLC PITTS MODEL 12 near Bluffdale, UT — 2014-05-04

Final reportWPR14LA185
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Date
2014-05-04
Location
Bluffdale, UT, USA
Aircraft
177MF LLC PITTS MODEL 12
Registration
N177MF
Category
Airplane
Highest injury
Minor
Fatalities
0
Phase of flight
Descent

Probable cause

A complete loss of engine power for reasons that could not be determined because of insufficient evidence.

NTSB narrative

The private pilot had recently purchased the experimental airplane, and the flight was the second leg of his cross-country trip to fly the airplane home from the purchase location. After the first leg, the pilot topped off the main and auxiliary (wing) fuel tanks, which, according to the pilot's operating handbook (POH) for the airplane, provided a total usable fuel quantity of 53 gallons. After flying about 3.5 hours, when the airplane was about 20 miles short of the planned destination, the engine lost total power, and the pilot was unable to restart it. During a forced landing in a field, the airplane nosed over and came to rest inverted. When the airplane was righted during recovery, about 4 to 5 gallons of fluid drained from the area where the main fuel tank and the smoke oil tank were mounted; however, it was not determined whether the fluid was fuel or a mixture of fuel and smoke oil. The auxiliary tank was breached, and no determination of its postimpact fuel quantity could be made. The engine was a highly modified aftermarket version of one of two different models produced by the original engine manufacturer, a 360-horsepower (hp) model and a 400-hp model, and no specific fuel burn chart for the modified engine had been developed. The pilot's flight planning, which was based on fuel burn rates for a 360-hp engine, indicated that the flight would consume about 45 gallons of fuel. Calculations using the POH fuel burn rates, which were for a 400-hp engine, indicated that the flight would consume between 51 and 58 gallons, depending on the power setting. Because the auxiliary fuel tank was not equipped with any quantity indication system, and the main tank fuel quantity indicator was difficult for the pilot to see, the pilot used an engine information system (EIS) to determine the fuel state of the airplane. The EIS used a pilot-entered initial fuel quantity and a sensed fuel flow rate to calculate the fuel remaining. Although the pilot reported that the EIS indicated that about 11 gallons of fuel was on board at the time of the power loss, the investigation was unable to determine the accuracy of that EIS-calculated quantity. Based on the available information, the power loss was likely the result of either an ignition or fuel problem. However, due to damage to the airplane that precluded a complete examination of the ignition and fuel systems, a lack of design and construction information, and the inability to accurately determine the airplane's postimpact fuel quantity, the reason for the loss of engine power could not be determined.

Analysis

Primary failure mode
Fuel management
First missed decision gate
Pilot could have better managed fuel selection before power loss.

NTSB coding

Evidence available

  • 22 docket documents
View NTSB final reportView NTSB docket

Docket documents22

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