The pilot was performing a full stop landing at an airport. He landed the airplane on a grass strip and reported that the airplane “started sliding off the runway to the left.” The pilot was unable to regain control of the airplane and the airplane departed the side of the runway and came to rest in a field. The left main landing gear had collapsed, and substantial damage was sustained to the left wing. Inspectors from the Federal Aviation Administration documented the accident scene and reported that marks in the grass strip were consistent with the airplane landing in a crab, with the nose of the airplane pointed towards the right side of the strip. Tracks made by the landing gear showed the airplane’s ground roll shifted towards the left and continued as the airplane departed the side of the runway. The pilot stated that the ground was soft and wet.