On October 29, 1994, at 1200 hours Pacific daylight time, a Champion 7ECA, N7MM, ground looped and dragged its right wing during the landing roll on runway 26 at Mariposa-Yosemite Airport, Mariposa, California. The pilot was completing a visual flight rules personal flight. The airplane, registered to and operated by the pilot, sustained substantial damage. Neither the noncertificated student pilot nor his passenger was injured. Visual meteorological conditions prevailed. The flight originated at Mariposa-Yosemite Airport at 1100 hours. National Transportation Safety Board investigators obtained a telephone statement from the pilot on November 1, 1994. The pilot said that he was taking his fiancee on a birthday flight. On landing, he inadvertently applied uneven brake pressure during the landing rollout. The airplane then ground looped. The pilot also said that his third-class medical/student pilot certificate had lapsed. The Federal Aviation Administration (FAA) Airman's Records Section, Oklahoma City, Oklahoma, show that the pilot was issued a third-class medical/student pilot certificate on June 25, 1991; the certificate was valid until June 30, 1993.