What happened
A night VFR cross-country navigation instruction flight was being conducted for a student pilot. While flying over an en route airport, the certified flight instructor and the student discussed the low fuel status of the helicopter. Although they identified the low fuel condition, they elected not to refuel because neither pilot possessed a credit card.
Shortly after this decision, the aircraft's amber low fuel warning light illuminated. A few minutes later, the engine suffered a total loss of power. The crew performed an autorotation, during which the aircraft impacted trees and experienced a hard landing. There were no fatalities reported in the accident.
The investigation
The investigation examined the flight planning and fuel management procedures. The instructor stated that a flight navigation log sheet was not utilized for this flight. During preflight planning, the instructor had estimated a fuel burn rate of 10 gallons per hour based on a cruise airspeed of 85 knots, with an estimated total flight time of 90 minutes. However, an FAA inspector determined that the normal planned cruise airspeed for this aircraft type is 70 knots.