On January 29, 1997, about 1004 eastern standard time, a Cessna 152, N67898, was destroyed when it experienced a partial loss of engine power and struck trees, while on approach to the Lawrence Airport (LWN), North Andover, Massachusetts. The certificated private pilot and passenger were not injured. Visual meteorological conditions prevailed for the personal flight which originated from Bedford, Massachusetts, about 0940. No flight plan had been filed for the flight which was conducted under 14 CFR Part 91. In a written statement, the pilot said he flew a final approach to runway 32 at LWN. He further stated: "...Shortly after starting a two mile final, the engine started to lose power. At this point I believe we were about 1,300 MSL, 2,000-2,100 rpm, carb heat on, mixture full rich, 80 KIAS...As we tried all combinations of more/less throttle, more/less mixture, more/less carb heat, the engine lost even more power - it would occasionally reach 1,200-1,300 rpm but was mostly at about 1,000 rpm...." The pilot was unable to restore full engine power, and could not maintain altitude. The airplane struck trees about 50 feet above the ground, and then settled through the trees and came to rest with its nose on the ground. The pilot also reported that during his preflight inspection, the right wing tank fuel drain was frozen and had to be heated. After heating, the first fuel sample revealed a small amount of water, but the third and fourth samples were clear. The left tank drain was not frozen, and contained a small amount of water in the first sample. There was no water detected in the filter drain sample. Examination of the wreckage, by a Federal Aviation Administration (FAA) Inspector, while the ambient temperature was below freezing, revealed a small amount of water and contaminants in the carburetor bowl, and the fuel drain. When the fuel caps were removed, the sound of air rushing into the tank was heard. Sounds of the tanks expanding from the in-rushing air was also heard. After the wings were removed and placed in a heated hanger, approximately 1 cup of dirty water was found in the fuel tanks. The engine was test run satisfactorily by an FAA Inspector using a temporary fuel connection. This was the third occurrence of a power loss with one of several airplanes owned by the operator within a 5 day period. The operator was using automobile gasoline purchased at a local service station. The airplanes were refueled from a tank placed on the back of a pickup truck. The operator reported that fuel filters were changed once a month. At the time of the accident the outside air temperature was about 20 degrees Fahrenheit, and had been below freezing for at least 24 hours.