On December 4, 2002, approximately 1115 Pacific standard time, a Canadian registered Luscombe 8A, C-FIIF, collided with trees during low-level cruise flight about 3 miles north of Tekoa, Washington. The pilot, who holds a Canadian Airline Transport Pilot license, and who was the sole occupant of the aircraft, received serious injuries. The airplane, which is owned and operated by the pilot, sustained substantial damage. The 14 CFR Part 91 personal pleasure flight, which departed Walla Walla Regional Airport, Walla Walla, Washington, at 0916, was operating in an area of rain showers, freezing temperatures, and visibility reduced by haze. No flight plan had been filed. The ELT, which was activated by the accident sequence, and aided in the location of the wreckage, was turned off at the scene. According to the pilot, as he was heading north in cruise flight in an area where the indicated outside air temperature was one degree centigrade, he passed through a rain shower that produced an ice coating on his windshield about three-eights of an inch thick. Because he was unable to see clearly out the windshield, he attempted to control the aircraft by reference to the limited instrumentation present in the 62 year old no-electrical, non-IFR equipped aircraft. He then used his portable Global Positioning System (GPS) for directional guidance as he tried to fly a direct course to Willard Field, which is located about 18 miles east of where the windshield iced over. As he proceeded toward Willard Field, he attempted to take a look at his Sectional Aeronautical Chart in order to confirm the terrain clearance, but he found the aircraft "difficult and unstable" to fly on instruments, and was unable to get a "good look" at the map. He therefore was not aware that the only high terrain within ten miles of Willard Field was directly between his position and the airport. Ultimately, when the aircraft reached a point approximately four miles west of Willard field, it flew into a stand of trees on the westerly slope of Tekoa Mountain. During his attempt to reach Willard Field, the pilot elected not to climb higher, as the area was covered by a 1,000 foot overcast, within which additional icing would be expected. When the aircraft was located by search teams several hours after the accident, a coating of ice still remained on portions of the windshield, the leading edges of the wings and horizontal stabilizer, and the leading edge of the wing lift struts. According to the pilot, there was no indication that there had been any malfunction of the aircraft's engine or flight controls.