Narrative:

I picked up a helicopter from ZZZ and was taking it to ZZZ1. I performed all preflight checks; including turning the master switch on; and checking the low fuel light warning system; which worked. I observed that the gauges indicated I had sufficient fuel in both tanks for the 10 minute flight. The auxiliary fuel gauge registered at half; and the main fuel gauge registered just under half. Based on the R22 B11 consumption rate; there was more than enough indicated fuel to complete the flight with the required 20 minutes extra fuel. I picked the helicopter up into a hover; checked the pad for residual fluids; checked my gauges; got the clearance and departed ZZZ to the east. Roughly 3 minutes into the flight I saw the main gauge drop to empty and the low fuel light flickered; at the same time the auxiliary gauge showed a little over half. After approximately another minute the auxiliary gauge then dropped to empty and the fuel light remained on full alert. At this point I was already in contact with ZZZ1. Due to the erratic fuel gauge; fuel light; and clutch light flicker: I decided to make a precautionary landing on a golf driving range just off the charted VFR helicopter approach route. I contacted the tower again; informed them of my decision and executed a safe off field landing under full power. After meeting with fire; police; and FAA officials; a mechanic inspected the fuel system and after adding fuel and signing the log book; I flew the helicopter back to ZZZ1. During this flight the auxiliary fuel gauge again registered just under half; which was impossible as not enough fuel was added to the fuel system for the auxiliary gauge to register that amount. I have contacted the a&P mechanics for further inspection.callback conversation with reporter revealed the following information: the reporter states that this aircraft had sat idle for two to three days prior to this event. Because the gauges indicated more than sufficient fuel for a ten minute flight the reporter did not feel the necessity to visually check the tank quantity. A visual inspection of the fuel tanks is suggested but is not required. After this event he learned that similar events have occurred with this aircraft type after a period of non flight. After the aircraft was returned to the airport and the tanks filled the quantity was again accurate. Maintenance could find nothing wrong with the fuel system.

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Original NASA ASRS Text

Title: An R22 B11 departed with the electronic fuel quantity indicators showing half full tanks. Approximately three minutes into the flight both tank gauges indicated low fuel. A precautionary off airport landing was completed. Inaccurate fuel guages are suspected.

Narrative: I picked up a helicopter from ZZZ and was taking it to ZZZ1. I performed all preflight checks; including turning the master switch on; and checking the low fuel light warning system; which worked. I observed that the gauges indicated I had sufficient fuel in both tanks for the 10 minute flight. The AUX fuel gauge registered at half; and the main fuel gauge registered just under half. Based on the R22 B11 consumption rate; there was more than enough indicated fuel to complete the flight with the required 20 minutes extra fuel. I picked the helicopter up into a hover; checked the pad for residual fluids; checked my gauges; got the clearance and departed ZZZ to the East. Roughly 3 minutes into the flight I saw the main gauge drop to empty and the low fuel light flickered; at the same time the AUX gauge showed a little over half. After approximately another minute the AUX gauge then dropped to empty and the fuel light remained on full alert. At this point I was already in contact with ZZZ1. Due to the erratic fuel gauge; fuel light; and clutch light flicker: I decided to make a precautionary landing on a golf driving range just off the charted VFR helicopter approach route. I contacted the tower again; informed them of my decision and executed a safe off field landing under full power. After meeting with fire; police; and FAA officials; a mechanic inspected the fuel system and after adding fuel and signing the log book; I flew the helicopter back to ZZZ1. During this flight the AUX fuel gauge again registered just under half; which was impossible as not enough fuel was added to the fuel system for the AUX gauge to register that amount. I have contacted the A&P mechanics for further inspection.Callback conversation with reporter revealed the following information: The reporter states that this aircraft had sat idle for two to three days prior to this event. Because the gauges indicated more than sufficient fuel for a ten minute flight the reporter did not feel the necessity to visually check the tank quantity. A visual inspection of the fuel tanks is suggested but is not required. After this event he learned that similar events have occurred with this aircraft type after a period of non flight. After the aircraft was returned to the airport and the tanks filled the quantity was again accurate. Maintenance could find nothing wrong with the fuel system.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.