Accident Summary
On April 16, 2019, about 1126 Hawaii time, a McDonnell Douglas 369E helicopter (registration N593C) was substantially damaged when it was involved in an accident near Hauula, Hawaii. The pilot and three passengers were not injured. The helicopter was operating under Title 14 Code of Federal Regulations Part 135.
Flight Details
The pilot conducted the fifth flight of the day. While flying at about 1,700 ft mean sea level over mountainous terrain, he noted the engine-out warning beeping, the engine-out light, and the re-ignition warning light. The FUEL LEVEL LOW caution light did not illuminate during the flight. The pilot entered an autorotation, descended toward a more level area, made a mayday call, and executed a “full down” autorotation through the tree canopy. The helicopter rolled to the right before coming to rest upside down. All four occupants evacuated without assistance.
Pilot Report
The pilot reported that after arriving at the “Turtle Bay” staging area for the first flight, he performed a preflight inspection, fueled the helicopter with 64 gallons of fuel, and configured it for five flights. The first four flights occurred between 0750 and 1045, transporting passengers and cargo to different landing zones. The engine was not shut down between the fourth and fifth flights. The pilot noted about 200 lbs of fuel on the gauge before lifting off about 1050. He then flew three passengers to three landing zones to deploy equipment before heading toward the staging area to refuel. The fuel gauge indicated 100 lbs of fuel when he lifted off from the final landing to fly about 5 minutes to the staging area. Total flight time was calculated at about 2 hours and 36 minutes, with 30 minutes of shutdown time. The pilot stated, “it seems apparent to me that fuel exhaustion was the cause of the engine flaming out and this accident.” He explained he planned for enough fuel but did not keep a running track of actual flight time and relied solely on the fuel gauge.
Fuel System Examination
A Federal Aviation Administration (FAA) inspector examined the wreckage and the FUEL LEVEL LOW warning system. The FUEL LOW LEVEL light illuminated when the PRESS TO TEST button was depressed but did not illuminate when the float arm was lowered to simulate low fuel. The fuel gauge responded appropriately when the float arm was moved. Examination of the circuit board revealed a disconnected/broken and corroded wire on one end of a resistor. According to the helicopter manufacturer, the FUEL LEVEL LOW light normally illuminates with about 35 pounds of fuel remaining (about 22.5 pounds usable, equating to 3.3 gallons). At a fuel burn of about 35 gallons per hour, the engine would operate about 5 minutes after the light illumination.