On July 28, 1995, at 1710 hours Pacific daylight time, a Cessna 305A, N65067, ground looped while landing at the Hemet-Ryan Airport, Hemet, California. The aircraft sustained substantial damage, but the pilot and his aerial observer were not injured. The public-use aircraft was being operated as an aerial observation flight by the Riverside County Sheriff's Department when the accident occurred. The flight originated in Hemet at 1530 on the day of the accident as a patrol of the western section of the County. Visual meteorological conditions prevailed at the time and no flight plan was filed. The pilot stated that at 1705 he was in the traffic pattern at the Hemet-Ryan airport in preparation for landing. While on approach he observed the wind sock and noted a slight crosswind, but reported that conditions were smooth otherwise. Touchdown and initial rollout were uneventful; however, about 5 to 8 seconds after touchdown, the aircraft suddenly swerved to the right and ran off the right side of runway 23. The pilot added power and turned left back toward the runway, but as the aircraft reached the pavement the right main landing gear collapsed. The aircraft slid across the runway, coming to rest near the runway centerline. According to sheriff's investigators, the pilot told them he had lowered one notch of flaps (30 degrees) and said that he had intended to make a wheel landing. He touched down 1,500 feet from the approach end of runway 23 and bounced slightly. The observer onboard the aircraft reported after touchdown the aircraft rolled straight down the runway for a short distance and the suddenly swerved to the right and ran off the right side of the runway. He said the pilot added power in an effort, he thought, to become airborne again. He said he thought they had become airborne again, but then the aircraft decelerated and they settled onto the grass, heading back toward the runway. Upon reaching the runway, the aircraft "tipped" to the right and then skidded to a stop. A postaccident inspection of the aircraft revealed the right wing had buckled upward outboard of the wing strut upper attachment point. The right main landing gear had separated at the fuselage attachment point and the left wing had buckled inboard of the wing strut upper attachment point. There was skin damage to both wings, both elevators, the cowling and airbox, and the right side of the fuselage. The tailwheel attachment bracket was bent and there were "S" bends in both propeller blades. The aircraft operator's manual provided by the original manufacturer does not address demonstrated crosswind capabilities. The pilot reported that he had logged about 1,000 hours in conventional geared aircraft with 50 hours in the Cessna 305A/L-19. Prior to assuming pilot responsibilities in the aircraft, he had received a "two-hour check ride" conducted by Hemet-Ryan Aerobatic School in a school-owned Cessna 305A/L-19 followed by a second check ride in the county-owned aircraft. When interviewed by a Safety Board investigator, the pilot did not know the demonstrated crosswind capability of the aircraft, and also stated that he did not specifically recall performing crosswind landings during his initial checkout. He did report that crosswind landing techniques were discussed and that wheel landings under crosswind conditions were not considered appropriate. He stated that he felt his training was adequate and that he had felt confident in his ability to perform his flying duties. He was unable to explain with a degree of certainty what he believed had occurred. He concluded that the aircraft had been caught by a sudden gust of wind; however, he stated that the approach and landing had required only minimal crosswind correction. March AFB is 16 miles northwest of the Hemet-Ryan airport. At 1655 PDT, the winds at March AFB were from 310 degrees at 10 knots. The runway alignment at Hemet-Ryan airport is 05-23 and 04-22. The pilot reported that he had not obtained a weather briefing prior to his flight and that the Hemet-Ryan CTAF advisory had closed prior to his arrival. The surface winds immediately after the accident were reported as from the north at 10 knots.