On February 28, 1999, about 1845 eastern standard time, a Piper PA-23-250, N2313Z, registered to Stuart Jet Center, Inc., experienced a hard landing at the Witham Field Airport, Stuart, Florida. Visual meteorological conditions prevailed at the time and no flight plan was filed for the 14 CFR Part 135, nonscheduled, domestic, passenger flight. The airplane was substantially damaged and the commercial-rated pilot and three passengers were not injured. The flight originated about 1815 from the St. Lucie County International Airport, Fort Pierce, Florida. The pilot stated that while driving to the airport, he called the Miami Automated Flight Service Station to "check on weather" and to file Defense Visual Flight Rules (DVFR) flight plans for the departure and arrival flights from and to the U.S., respectively. He was advised that the weather condition from the airport closest to his destination airport in the Bahamas indicated that the wind was from 250 degrees at 15 knots. The flight departed on the first leg to Freeport, Bahamas, and as reported by the pilot, it was windy and turbulent but uneventful. The flight cleared customs then departed on the second leg which was also uneventful to pick up the passengers. The passengers were loaded and the flight departed arriving uneventfully in Fort Pierce, Florida, where the flight cleared customs, then departed for the final flight. Review of a certified copy of the communications tape and a transcription of communications revealed that at 1827.18, the pilot contacted the Air Traffic Control Tower (ATCT), and advised that the flight was 15 miles to the north, inbound for a full stop landing. The controller advised the pilot that the wind was from 250 degrees at 18 knots with gusts to 25 knots. The pilot acknowledged that transmission and at 1832.53, the controller cleared the flight to land and advised the pilot that the wind was from 250 degrees gusting to 25 knots. At 1835.08 and 1835.32, the tower controller broadcast on the tower frequency that the wind was from 240 degrees at 24 knots and 250 degrees at 15 knots, respectively. The pilot later reported that while on final approach, there was light to moderate turbulence and that he was not aware that earlier, there was windshear in the area. While on final approach with the flaps fully extended, the flight condition was "pretty bumpy" but not uncomfortable. The flight continued and during final approach, he was able to maintain his airspeed, but during the flare about 3-5 feet above the runway, the nose of the airplane pitched up. The pilot corrected but the airplane then touched down first on the nose landing gear and bounced, remaining in a nose high attitude. At 1836.13, the pilot advised the controller that the flight was "gonna go around." The controller acknowledged this then cleared the flight to land again on runway 25. The pilot requested that he perform a low pass by the tower and the controller advised the pilot that all gears appeared to be down and locked. The flight was cleared again to land on runway 25. The flight returned for landing and again with the flaps fully extended, the airplane was landed on all three landing gears. About 600-800 feet into the landing roll, a sound was heard from the nose landing gear. The pilot confirmed in the inspection mirror that the nose landing gear tire was flat and secured the airplane on the runway. The airplane was later removed from the runway and examined by an FAA airworthiness inspector. Examination of the airplane revealed damage to the left wing main spar, entry door frame, a wrinkle in skin beneath the pilots window, and the nose landing gear tire balance weight was noted to be separated. Damage to the structure in the avionics bay was noted, and the copilot seat back lock was broken. According to Martin J. Heischberg, the tower controller at the St. Lucie County International Airport who was in contact with the accident pilot during the flight, the wind at the time of the occurrence was variable from 230 to 270 degrees at 17 knots with gusts to 30 knots. Additionally, there were no reports of windshear in the previous 1.5 hours before the accident.