On July 17, 1997, at 1810 hours Pacific daylight time, a Cessna 182N, N9099G, porpoised down runway 22L on takeoff from Sacramento Mather Airport, Sacramento, California, and collapsed the nose landing gear. The airplane sustained substantial damage, and the pilot/owner, the sole occupant, was not injured. Visual meteorological conditions existed for the personal flight to the Rio Vista, California, airport. No flight plan was filed. The pilot reported that new seat locks and an avionics system had been installed, and that some additional problems had arisen while the mechanics were working on the aircraft. When the mechanics had shown the seat locks to the pilot, he noted that they would not slide and would jam on the rail. The aircraft was moved back into the maintenance hangar to be repaired. During the repair, the pilot performed a preliminary walk around, and noted that the trim tab was in an elevated position. He also found that the he was unable to remove the dipstick. He informed maintenance personnel, who repositioned the dipstick tube. The pilot stated that after the work was completed, the aircraft was moved out of the hangar. He started the engine and remembered that the trim tab was in an up position. The pilot stated that he rolled the trim wheel down into the takeoff position, and attempted to make a radio transmission, but was unable to do so. He shut the aircraft down and found the mechanic who had worked on the aircraft. The mechanic discovered that one of the wire connections for the radio was in the wrong opening. The pilot reported that he started the aircraft and transmitted his intentions to taxi to runway 22L without further incident. The pilot said that once the aircraft reached 60-65 knots, he applied back pressure to the yoke to lift the nose off the ground and the yoke felt heavier than what he was used to. As the nose came off the ground he released some of the back pressure on the yoke to gain airspeed. Once the aircraft became airborne it bounced back onto the runway. The pilot reported that he ". . .pulled the yoke back and then it bounced higher and harder." He realized something was different than a previous experience and compensated by reducing the power after the second bounce. The aircraft came down nose wheel first, collapsed the nose wheel, and the propeller struck the runway. The pilot further reported that he is certain that the trim indicator did not provide a ". . .true reading of the trim position." A Federal Aviation Administration (FAA) inspector from the Sacramento Flight Standards District Office inspected the airplane. Flight control continuity could not be established due to cockpit floor area impact damage. The inspector noted that in the trim tab travel "up" direction the stop occurred at 25 degrees tab deflection. Cessna specification states that the "up" stop is at 25 degrees plus/minus 2. In the trim travel "down" direction, the stop was at 10 degrees, with the Cessna specification as 15 degrees plus/minus 1. The "down" limit was limited by "trim cable stop." The FAA Aircraft Type Certificate Data Sheet notes that the total stop-to-stop trim tab travel should be 43 degrees, including the plus/minus degrees. The inspector found that the total trim available in the aircraft was 35 degrees. The inspector reported that "while the total trim travel was favoring the trim tab travel up/nose down attitude, it was off-centered by only 5 degrees." The inspector did note that when the trim was set to the takeoff position inside the aircraft, the trim tab was measured at an approximate 30-degree tab up or nose down position. He further noted that the trim indicator pointer "slipped easily from one trim wheel groove into another while actuating the trim wheel was moved with normal force." The inspector reported that this would have allowed an erratic trim tab position indication. The inspector stated that there was also noticeable deformation to the trim wheel pointer assembly that was not postcrash related. The Safety Board conducted a review of the maintenance records. On June 27, 1997 an entry on a squawk sheet was made where the pitch trim wire had jumped its groove. The corrective action was to reposition the pitch trim indicator to center travel in the window. This repair was made by the same facility that had worked on the aircraft the day of the accident.