On October 5, 1993, at 1650 Pacific daylight time, a tailwheel equipped Cessna 150E, registered to Jerry M. Meng, ground looped and impacted terrain after landing at the Sandy River Airstrip, Sandy, Oregon. There was no flight plan filed for the local personal flight that departed Troutdale, Oregon, at 1545, October 5, 1993. The ATP pilot and the private certificated owner were not injured in the accident. The aircraft was substantially damaged. There was no fire. The ATP certificated pilot reported he initiated a landing on the grass airstrip during the local proficiency flight and lost directional control during landing roll. He stated that the airstrip is grass, which is not completely level across the width of the airstrip. There is a gravel road across the airport about midway, and there is a berm or small downhill grade on one side of the airstrip. He said the airstrip is not well marked and it is hard to differentiate between the runway and taxiway. He said he apparently landed long beyond the road and on the downhill grade. The airplane started to groundloop shortly after touchdown.