Narrative:

We departed las in VMC on an IFR flight to bur. Just after liftoff from runway 19R, the tower advised us that we appeared to be venting fuel and asked our intentions. We informed the tower that we would be returning to land. We flew a visual pattern and landed on runway 19R. The tower had the fire safety equipment standing by. A normal landing was made after which we taxied the aircraft to the FBO ramp to investigate the problem. The aircraft had been fueled that morning prior to departure using the conventional single point pressure refueling system. All caps, valves and switches had been checked after fueling and prior to departure. Upon returning to the ramp, another inspection verified that all caps, valves and switches were in their proper position. It appeared that fuel had vented through the left wing fuel tank vent line pressure relief valve. This valve is opened during pressure refueling to allow air pressure to escape during fueling. It is then closed after fueling. The valve switches were verified to be in the proper position prior to takeoff. We also confirmed this after returning to the FBO after landing. A call to our maintenance confirmed our suspicion that the valve had somehow stuck partially open allowing fuel to escape as the aircraft departed. The valves were then function tested as per maintenance instructions and performed normally. The flight then departed las, landed in bur, and returned to las without any further irregularities. After discussions with fellow pilots who experienced similar circumstances only a week earlier after fueling at the same FBO in las, our maintenance feels that the fuel trucks may be pumping at too high a pressure. We feel that this could have caused the valve to not close properly. The indicated pressure on the truck was high but within limits. Several flts have been made since then, and we have experienced no additional problems. Callback conversation with reporter revealed the following information: the reporter indicated that others in his company have had problems with fueling at this particular station in this aircraft as well as a lear and citation. The fueling pressure used is 50 psi on the truck which is within the acceptable limits for the aircraft. The valve in question was not removed and has operated normally since the incident.

Related reports:

Google
 

Original NASA ASRS Text

Title: A FALCON 20 EXPERIENCES FUEL VENTING FROM FUEL TANK VENT LINE AFTER TKOF.

Narrative: WE DEPARTED LAS IN VMC ON AN IFR FLT TO BUR. JUST AFTER LIFTOFF FROM RWY 19R, THE TWR ADVISED US THAT WE APPEARED TO BE VENTING FUEL AND ASKED OUR INTENTIONS. WE INFORMED THE TWR THAT WE WOULD BE RETURNING TO LAND. WE FLEW A VISUAL PATTERN AND LANDED ON RWY 19R. THE TWR HAD THE FIRE SAFETY EQUIP STANDING BY. A NORMAL LNDG WAS MADE AFTER WHICH WE TAXIED THE ACFT TO THE FBO RAMP TO INVESTIGATE THE PROB. THE ACFT HAD BEEN FUELED THAT MORNING PRIOR TO DEP USING THE CONVENTIONAL SINGLE POINT PRESSURE REFUELING SYS. ALL CAPS, VALVES AND SWITCHES HAD BEEN CHKED AFTER FUELING AND PRIOR TO DEP. UPON RETURNING TO THE RAMP, ANOTHER INSPECTION VERIFIED THAT ALL CAPS, VALVES AND SWITCHES WERE IN THEIR PROPER POS. IT APPEARED THAT FUEL HAD VENTED THROUGH THE L WING FUEL TANK VENT LINE PRESSURE RELIEF VALVE. THIS VALVE IS OPENED DURING PRESSURE REFUELING TO ALLOW AIR PRESSURE TO ESCAPE DURING FUELING. IT IS THEN CLOSED AFTER FUELING. THE VALVE SWITCHES WERE VERIFIED TO BE IN THE PROPER POS PRIOR TO TKOF. WE ALSO CONFIRMED THIS AFTER RETURNING TO THE FBO AFTER LNDG. A CALL TO OUR MAINT CONFIRMED OUR SUSPICION THAT THE VALVE HAD SOMEHOW STUCK PARTIALLY OPEN ALLOWING FUEL TO ESCAPE AS THE ACFT DEPARTED. THE VALVES WERE THEN FUNCTION TESTED AS PER MAINT INSTRUCTIONS AND PERFORMED NORMALLY. THE FLT THEN DEPARTED LAS, LANDED IN BUR, AND RETURNED TO LAS WITHOUT ANY FURTHER IRREGULARITIES. AFTER DISCUSSIONS WITH FELLOW PLTS WHO EXPERIENCED SIMILAR CIRCUMSTANCES ONLY A WK EARLIER AFTER FUELING AT THE SAME FBO IN LAS, OUR MAINT FEELS THAT THE FUEL TRUCKS MAY BE PUMPING AT TOO HIGH A PRESSURE. WE FEEL THAT THIS COULD HAVE CAUSED THE VALVE TO NOT CLOSE PROPERLY. THE INDICATED PRESSURE ON THE TRUCK WAS HIGH BUT WITHIN LIMITS. SEVERAL FLTS HAVE BEEN MADE SINCE THEN, AND WE HAVE EXPERIENCED NO ADDITIONAL PROBS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR INDICATED THAT OTHERS IN HIS COMPANY HAVE HAD PROBS WITH FUELING AT THIS PARTICULAR STATION IN THIS ACFT AS WELL AS A LEAR AND CITATION. THE FUELING PRESSURE USED IS 50 PSI ON THE TRUCK WHICH IS WITHIN THE ACCEPTABLE LIMITS FOR THE ACFT. THE VALVE IN QUESTION WAS NOT REMOVED AND HAS OPERATED NORMALLY SINCE THE INCIDENT.

Data retrieved from NASA's ASRS site as of July 2007 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.