On April 4, 1999, at 1245 hours Pacific daylight time, a Cessna U206G, N756CF, collided with the ground short of runway 27 while landing at the Ramona, California, airport. The aircraft was operated by Pinnacle Aviation of Carlsbad, California, and rented by the private pilot for a local area personal flight under the provisions of 14 CFR Part 91 of the Federal Aviation Regulations. Visual meteorological conditions prevailed the time and no flight plan was filed. The aircraft sustained substantial damage. One passenger sustained minor injuries and the pilot and one other passenger were not injured. The flight originated at the Carlsbad airport on the day of the accident at 1200. In a telephone interview with a Safety Board investigator, the pilot said he flew to Ramona to practice takeoffs and landings. During the accident sequence, the aircraft was on short final and configured with full flaps at a normal approach speed when a very high sink rate suddenly developed. The pilot said he was unable to arrest the descent before colliding with the ground. He further stated that during the prior landings, the winds had been variable 10 degrees or more on either side of the runway heading and he believed he encountered a wind shear. The aviation surface weather observation (METAR) at Ramona taken 11 minutes after the accident reported winds from 260 at 7 knots, variable from 230 to 290 degrees.