Mcdonnell Douglas Heli Co 369FF N530KD accident near Decorah, Iowa

Probable cause

The pilot's failure to properly manage the helicopter's available fuel supply, which led to a total loss of engine power due to fuel exhaustion. Contributing to the accident was the improper calibration of the fuel gauge and the fuel-low warning light.

NTSB analysis

The pilot and his passenger were repositioning the helicopter and stopped twice to refuel. Each time they stopped the pilot topped off the fuel tank. During the second stop, the pilot used the airplane for personal reasons and flew for just over an hour. Before continuing on with the repositioning flight, the pilot added 15 gallons of fuel. Since this was not enough fuel to top off the tank, he referenced the fuel guage, which indicated 305-310 pounds of fuel on board. The pilot and passenger then departed on the next leg of their flight. About 58 minutes after they departed, the fuel-low caution light illuminated, indicating there was 35 pounds of fuel remaining. The pilot continued with the flight since he was within a few miles of the destination airport. About three minutes after the fuel-low caution light illuminated, the engine quit. The pilot made an autorotation to a mature corn field. The helicopter bounced upon touch down and rolled over on to its left side, which damaged the tail boom. Examination of the helicopter revealed only two drops of fuel were drained from the fuel sump and a 1/4-cup of fuel was drained from the fuel tank. Further examination revealed no mechancal deficiencies with the fuel system; however, when the fuel gauge and low-fuel caution light were tested they were found to not be calibrated correctly. The fuel gauge indicated a higher fuel total then what was actually in the fuel tank and the fuel-low caution light came on when there was only 19 pounds of fuel in the fuel tank versus 35 pounds. According to the operator, the low fuel-low caution light was inspected several months before the accident as part of a normal maintenance inspection. From the time this inspection was completed to the time of the accident, no other maintenance was performed on the fuel quantity sensor system.

Text from the NTSB. Open the NTSB docket for CEN12LA667 for the full record.