Narrative:

While pushing aircraft into hangar, fuel poured from fuel inlet area drain. I turned all fuel selector handles off. Fuel still siphoned from auxiliary tank to main. I am told this is a common occurrence. The cap to main tank should be placarded, 'keep tightly sealed when lower than auxiliary tank level.'

Google
 

Original NASA ASRS Text

Title: FUEL OVERFLOWED FROM FUEL INLET AREA WHEN MOVING ACFT INTO HANGAR.

Narrative: WHILE PUSHING ACFT INTO HANGAR, FUEL POURED FROM FUEL INLET AREA DRAIN. I TURNED ALL FUEL SELECTOR HANDLES OFF. FUEL STILL SIPHONED FROM AUX TANK TO MAIN. I AM TOLD THIS IS A COMMON OCCURRENCE. THE CAP TO MAIN TANK SHOULD BE PLACARDED, 'KEEP TIGHTLY SEALED WHEN LOWER THAN AUX TANK LEVEL.'

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.