Narrative:

I parked at osh for the annual event. I secured the completed fueling card to the propeller as per the fueling card instructions. A fueler was not present at this time as there were many; many (think hundreds) other arriving aircraft also seeking to be fueled. I returned to my aircraft mid morning a week later and discovered that my fuel caps were not properly installed after being refueled. They were not flush or centered as they should have been. I was unable to open the fueling caps with just my fingers; which is the way I should have been able to accomplish this task. Instead; it required the mechanical advantage of a tire iron (no kidding) to unlock the caps and remove them. It had rained on several occasions at the airport during the week. Upon preflighting the fuel system I discovered water in all three drain locations. I alerted a fueling employee of the improper replacement of the fuel caps on my aircraft and requested a supervisor to witness the event. Once again; there were thousands of aircraft that were also trying to depart osh that morning. So I began the process of draining the water out of the fuel tanks on my aircraft. I also took photographs and videos of the water that was appearing during the draining process. After ninety minutes of almost constant fuel sampling a fueling manager arrived and I related the events to him. He then assisted by completing the remaining draining of the water. His efforts only took another fifteen or twenty minutes and he then added 1.3 gallons of fuel to the aircraft to return it to full tanks. Subsequent engine starts and flights were normal. I feel that the fueler of the aircraft was probably overwhelmed by the sheer numbers of different airplanes he had to fuel and improperly replaced the fuel caps on my aircraft. I have flown this aircraft to osh before and I have always been present for the fueling. I also do not know when it was fueled during the week. This time I was not present. Fortunately; my routine preflight was sufficient to catch this error.

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Original NASA ASRS Text

Title: A pilot departing OSH discovered his fuel tank caps on incorrectly and upon removing them found rain water had entered all the fuel tanks.

Narrative: I parked at OSH for the annual event. I secured the completed fueling card to the propeller as per the Fueling Card instructions. A fueler was not present at this time as there were many; many (think hundreds) other arriving aircraft also seeking to be fueled. I returned to my aircraft mid morning a week later and discovered that my fuel caps were not properly installed after being refueled. They were not flush or centered as they should have been. I was unable to open the fueling caps with just my fingers; which is the way I should have been able to accomplish this task. Instead; it required the mechanical advantage of a tire iron (no kidding) to unlock the caps and remove them. It had rained on several occasions at the airport during the week. Upon preflighting the fuel system I discovered water in all three drain locations. I alerted a Fueling employee of the improper replacement of the fuel caps on my aircraft and requested a supervisor to witness the event. Once again; there were thousands of aircraft that were also trying to depart OSH that morning. So I began the process of draining the water out of the fuel tanks on my aircraft. I also took photographs and videos of the water that was appearing during the draining process. After ninety minutes of almost constant fuel sampling a fueling manager arrived and I related the events to him. He then assisted by completing the remaining draining of the water. His efforts only took another fifteen or twenty minutes and he then added 1.3 gallons of fuel to the aircraft to return it to full tanks. Subsequent engine starts and flights were normal. I feel that the fueler of the aircraft was probably overwhelmed by the sheer numbers of different airplanes he had to fuel and improperly replaced the fuel caps on my aircraft. I have flown this aircraft to OSH before and I have always been present for the fueling. I also do not know when it was fueled during the week. This time I was not present. Fortunately; my routine preflight was sufficient to catch this error.

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.