NTSB Identification: CEN12LA667
14 CFR Part 91: General Aviation
Accident occurred Sunday, September 30, 2012 in Decorah, IA
Probable Cause Approval Date: 01/13/2014
Aircraft: MCDONNELL DOUGLAS HELI CO 369FF, registration: N530KD
Injuries: 2 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

The pilot and passenger were repositioning the helicopter and stopped twice to refuel. Each time they stopped, the pilot filled the fuel tank. Following the second stop, the pilot flew the helicopter for just more than 1 hour for personal reasons. Before continuing on the repositioning flight, the pilot added 15 gallons of fuel. Because this was not enough fuel to top off the fuel tank, the pilot referenced the fuel gauge, which he said indicated 305 to 310 pounds of fuel on board. According to the pilot, the helicopter burned about 240 pounds of fuel per hour. The pilot and passenger then departed on the next leg of their flight with an estimated time en route of 1 hour. About 58 minutes after they departed, the fuel-low caution light illuminated, indicating the helicopter had 35 pounds of fuel remaining. The pilot continued the flight because he was within a few miles of the destination airport. However, about 3 minutes after the fuel-low caution light illuminated, the engine lost total power. The pilot made an autorotation to a mature corn field, and the helicopter bounced on touchdown and rolled over on its left side, which damaged the tail boom.

Examination of the helicopter revealed minimal fuel remained in the fuel sump and 1/4-cup of fuel remained in the fuel tank. Further examination revealed no mechanical 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-than-actual fuel tank quantity, and the fuel-low caution light illuminated when only 19 pounds of fuel remained in the fuel tank, instead of 35 pounds, as designed. According to the operator, the fuel quantity sensor system, including the low fuel-low caution light, was inspected during a normal maintenance inspection about 7 months before the accident, and no discrepancies were noted. No subsequent maintenance had been performed on the fuel quantity sensor system.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

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.

Full narrative available

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