On January 8, 2006, about 0015 Pacific standard time, a Cessna T206H, N531HP, collided with multiple airport objects during the landing flare to runway 31 at Palo Alto Airport, Palo Alto, California. The California Highway Patrol (CHP) was operating the public-use airplane under the provisions of 14 CFR Part 91. The commercial pilot and three passengers were not injured; the airplane sustained substantial damage. The cross-country flight departed Santa Maria, California, about 2245. The flight was destined for Palo Alto. Night visual meteorological conditions prevailed, and no flight plan had been filed. In a written statement to the National Transportation Safety Board, the Chief Airplane Pilot for the CHP stated the pilot was landing at the destination airport at the time of the accident. The purpose of the flight was to transport family members of an East Palo Alto police officer who had been killed earlier that day. On approach, the pilot was unable to lower the flaps. He entered the traffic pattern and positioned the airplane for landing on runway 31. He flared for landing, lost sight of the runway, and the airplane drifted to the west side of the runway. The airplane's left elevator, right horizontal stabilizer, rudder, tail cone, and rear bottom fuselage were damaged after colliding with a runway directional sign and two runway edge lights. The pilot believed that he had a flat tire and decided to go-around. He was unable to ascertain the damage to the airplane and elected to divert to San Jose International Airport (SJC), San Jose, California, due to the longer and wider runways. The pilot made a successful no flap landing at SJC. Following the accident, CHP maintenance personnel performed a functional test on the flap system and determined it was operational. In addition, they reported that the right rear passenger side door is equipped with a door/flap limit switch. The switch deactivates the flaps when the door is slightly ajar to fully open, thus preventing the flaps from being lowered. Maintenance personnel determined that the right rear passenger was leaning "heavily" against the door and deactivated the door/flap limit switch, which prevented the flaps from lowering. The CHP stated there were no mechanical malfunctions or failures with the airplane prior to the accident.