On February 10, 1997, about 0500 eastern standard time, a Cessna 210L, N115WL, registered to Flight Express Inc., was substantially damaged during a forced landing, near Weston, Florida. The commercial-rated pilot was not injured. Instrument meteorological conditions (IMC) prevailed in the vicinity, and an IFR flight plan had been filed. The on-demand, cargo flight was being conducted in accordance with Title 14 CFR Part 135. The flight had departed Opa-Locka, Florida, en route to Tampa, when the pilot heard noises coming from the engine, and elected to make a forced landing, in foggy weather conditions, and impacted in a swampy area. The pilot stated that before departure he performed a preflight inspection. He noted "47 gallons" total fuel onboard, with "22 gallons" in the left wing fuel tank and "25 gallons" in the right wing fuel tank. He stated, "when I found out that the FBO [fixed base operator]...ran out of fuel, I decided to refuel in Tampa since I had plenty of reserve." The flight departed about 0436, and at a location about 25 miles northwest of Opa-Locka, at an altitude of 5,000 to 6,000 feet the pilot said he heard a "thud." He said, "...I realized that I was experiencing a mechanical problem...it seemed at first that I lost a cylinder." He turned southeast, and notified ATC that he was having engine problems. The pilot stated, "my gauges were showing normal indications: 23 inches of manifold pressure, 2500 RPM, 120 pounds of fuel flow." He then attempted to "restart," by "switch[ing] fuel to the left side, turned on [the] fuel pump to prime lines, checked the magnetos on left and right, verified mixture rich, with no re-start successful." On February 18, 1997, the engine from N115WL was test run at the facilities of Certified Engines Inc., Opa-Locka, Florida, under the supervision of the NTSB. The engine was run with all the parts that were on the engine at the time of the accident, with the exception, of the magnetos, and no discrepancies were noted. On March 4, 1997, both magnetos from N115WL's were examined at Continental Motors, Magneto Division, Atlanta, Georgia, under the supervision of the FAA. The magnetos were tested through 3500 rpm, with no discrepancies observed.