CEN24LA316 · Cessna A185E

The pilot reported that the float-equipped airplane had a total loss of engine power shortly after takeoff from a lake. The pilot conducted a forced landing to an open area of grass on the lake shoreline. The pilot reported that the airplane touched down very hard with the wings level and skidded upright about 150 ft. The airplane sustained substantial damage to the fuselage during the hard forced landing. The pilot stated that a few weeks before the accident the airplane was exposed to a significant rain event. He stated he drained fuel and checked for water before the flight, but did not observe any water contamination. The left- and right-wing fuel cap seals exhibited deterioration and discoloration around the outer surface but were otherwise pliable. The fuel cap sealing surfaces on both wings were corroded. Examination of the fuel that was collected at the accident scene revealed about 1 gallon of water in the bottom of the collection tank. Based on the airframe examination, it is likely that rainwater entered the fuel tanks due to the poor condition of the fuel caps and their respective wing sealing surfaces. A postaccident engine run was conducted, and the engine started, idled, and accelerated without hesitation. In the absence of a mechanical engine malfunction, the total loss of engine power was likely due to water contamination ingested by the engine shortly after takeoff.

Verbatim NTSB analysis and probable cause from the NTSB dataset