On June 23, 1996, about 1935 eastern daylight time, a Cessna 172C, N1665Y, was substantially damaged when it overran the runway and nosed over during takeoff at the Block Island State Airport, Block Island, Rhode Island. The private pilot and passenger were seriously injured. Visual meteorological conditions prevailed for the personal flight destined for the Hartford-Brainard Airport, Hartford, Connecticut. No flight plan was filed for the flight conducted under 14 CFR Part 91. In a written statement submitted by the pilot, he stated: "As a background, my wife. . .and I departed Hartford-Brainard Airport about [1330]. . .for Block Island. The aircraft was owned by The Civil Air Patrol Flying Association Inc. of which I am a member. The flight to Block Island was uneventful. . . .Sometime shortly after [1900], we returned to the airplane, completed the prefight, and taxied to the end of runway 28 for the runup. During the take-off roll, I only recall that: 1) at normal rotation speed, I noticed that the control wheel would not travel aft and I did not understand why it would not travel further; 2) as I approached the end of runway, I realized we would not clear and I attempted to select a path of minimum obstruction ahead of the aircraft. . . ." Examination of the wreckage by a Federal Aviation Administration Inspector revealed no evidence of malfunctions, nor did the pilot report any. Also, the control lock was observed to be installed. Following the wreckage examination, a telephone interview was conducted with the pilot. During the interview, the pilot was asked if he was aware that the control lock was found installed at the accident site. He stated that he had been aware of the finding and stated, "that would explain it." According to the Cessna 172 Pilot Operating Handbook, for preflight inspection, it stated to remove the control lock.