WPR24LA114 · Mooney Aircraft CORP. M20K

The pilot reported that he intended to service the airplane with fuel at the destination airport, which had cheaper fuel and was a short distance away. During the preflight inspection he observed that the low fuel indicator was illuminated for one tank, and the panel gauge for the other indicated it was ¼ full, which he estimated would equate to about 20 about gallons. He cross-checked the levels with the airplanes fuel totalizer system, which indicated 20 gallons of fuel remained. While enroute, the pilot noticed the fuel gauge level dropping faster than he anticipated, and a short time later the engine lost all power due to fuel exhaustion. The pilot performed a forced landing onto a dirt road in farmland, after maneuvering the airplane under a power line. The airplane struck fence on roll-out and sustained substantial damage to both wings. The pilot and passenger were not injured. The pilot reported there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. The airplanes low fuel indicators illuminate when about 2 ½ gallons of fuel remain in their respective tanks. Each tank holds about 9 gallons of fuel when ¼ full, rather than the 20 gallons the pilot had estimated. The pilot stated that he had mistakenly used the airplanes total fuel capacity of about 76 gallons when making that calculation, rather than half the value that a single tank could hold. He also stated that he may not have properly adjusted the totalizer the last time he serviced the airplane with fuel, hence its reading was not accurate. He stated that because the totalizer and fuel tank gauge readings were similar, due to confirmation bias he concluded that sufficient fuel remained. The pilot stated that he is risk averse, and conservative in nature and has never departed with the low fuel light on before but, he surmised, the cheaper fuel at the destination likely influenced his decision to proceed with the flight.

Verbatim NTSB analysis and probable cause from the NTSB dataset