Background
The purpose of the flight was to provide night visual flight rules (VFR) cross-country navigation instruction to a student pilot. The flight was conducted under the supervision of a certified flight instructor (CFI).
Flight Planning and Fuel Status
During preflight planning, the CFI estimated the fuel burn rate at 10 gallons per hour at a cruise airspeed of 85 knots, with a planned total flight time of 90 minutes. Notably, the CFI did not use a flight navigation log sheet during the flight. According to an FAA inspector, the normal planned cruise airspeed for this helicopter model is 70 knots.
In-Flight Events
While overflying one of the en route airports, the CFI and student discussed the low fuel status. However, they elected not to refuel because neither pilot had a credit card. Subsequently, the helicopter's amber-colored low fuel warning light illuminated. A few minutes later, the engine experienced a total loss of power.
Forced Landing
An autorotation was performed in response to the power loss. During the autorotation, the helicopter impacted trees and landed hard. The CFI provided an account of the events to investigators.