On August 2, 2003, a Mooney M20B (registration N33EM) operated by Ronald Shields was involved in an aviation accident near Leonardtown, MD. Investigators recorded the probable cause as: A loss of engine power due to water contamination of the fuel. A factor was the fuel cap not being secured to the tank. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
Shortly after takeoff, an airplane's engine surged and lost power at 150 ft AGL. The pilot performed a forced landing. Investigation revealed water in the fuel system and a mis-seated fuel filler cap.
Event
Shortly after takeoff, while climbing through about 150 feet above ground level, the airplane's engine surged and then lost complete power. The pilot initiated an immediate left turn and executed a forced landing to a field.
Examination
Post-accident examination of the airplane revealed that the left wing fuel filler cap did not seat correctly into its fuel tank fitting. A sample of fuel from the left tank contained "several ounces" of water. Samples taken from the carburetor bowl and the engine-driven fuel pump also contained water, and corrosion was noted on the pump.
Weather Context
A review of recorded precipitation totals from an airport located 7 miles east of where the airplane was based, covering the two-week period prior to the accident, indicated that 2.3 inches of rain had fallen in the area.