On August 13, 1997, at 1427 hours Pacific daylight time, a Cessna 140, N76233, registered to Barbara L. Baker, and being flown by a private pilot, was substantially damaged during a loss of control during landing at the Portland- Hillsboro airport, Hillsboro, Oregon. The pilot and his wife were uninjured. Visual meteorological conditions existed at the time and a VFR flight plan had been filed for the flight. The flight, which was personal, was to have been operated under 14CFR91, and had departed Eugene, Oregon, at 1230 on the day of the accident. The pilot reported that upon arrival in the Hillsboro area the "wind advisory from both flight following and (the) tower were winds calm, 30 in use." He entered a left base for runway 30, was cleared to land and executed a "normal 3 point landing @ ~ 45 mph" during which a "wind gust blew hard to the left." The pilot further reported that he "tried (sic) to stay on (the) runway" and then "entered a ground loop leaving (the) runway to (the) left." Aviation surface weather observations taken at the Hillsboro airport reported winds as follows: TIME WINDS 1547 calm 1455 calm 1432 calm 1350 variable at 4 knots 1250 variable at 5 knots 1155 calm 1047 calm 949 calm 855 calm 753 calm An Inspector assigned to the Federal Aviation Administration (FAA) Flight Standards District Office at the Hillsboro airport, and who was on site at the time of the accident reported the weather conditions as a "sultry day" with calm winds. The pilot reported that there was no mechanical malfunction with the aircraft.