Accident Overview
A twin-engine helicopter on a positioning flight to pick up a medical patient suffered a complete loss of power in both engines while cruising at 2,000 feet. The pilot initiated an autorotation toward a field, but the helicopter struck trees and came to rest on its right side.
Pilot Observations
The pilot reported no warning lights illuminated immediately before or during the power loss. Post-accident examination revealed that the variable resistor control for the pilot and console lights was in the ON position, which dims the master caution and annunciator panel lights. The NTSB investigator-in-charge noted that these caution and annunciator lights were not visible in daylight with that setting.
Fuel System Examination
Although the two fuel transfer pump switches were found in the ON position after the accident, evidence indicated they had not been ON for the majority of the flight. The supply lines to the engines were empty, with nominal fuel found in the fuel filters. The fuel quantity indicator showed 4 gallons in the #1 supply tank, 0 gallons in the #2 supply tank, and 15 gallons in the forward main tank.
The fuel transfer pumps are designed to move fuel from the forward main tank to the two supply tanks. During post-accident testing, turning on the switches caused fuel to flow into the supply tanks, and the fuel transfer pump caution lights (which illuminate when pumps are off) extinguished.
Engine Testing
Both engines were placed in a test cell and operated without anomalies.
Normal Operating Checklist
The standard checklist requires the pilot to set instrument lights as needed, test the annunciator panel for operation, and turn on the transfer pumps after engine start.