ERA13LA094

About 1 month before the accident flight, the pilot added about 17 gallons of fuel to the airplane's bottom fuel tank. About 25 minutes into the accident flight, the engine experienced a total loss of engine power. The pilot ditched the airplane in the Gulf of Mexico, and it sank. A postaccident examination of the wreckage after recovery revealed no mechanical malfunctions or failures that would have precluded normal operation. The examination also revealed that the fuel tank contained 4 gallons of seawater and no fuel and that the fuel system had only trace amounts of fuel at the gascolator. According to the pilot and local authorities, no evidence of fuel leakage was found in the water. According to fuel records and the pilot's statement, it is likely that the airplane had a total of about 23 gallons of fuel on board at the last refueling; however, 6 gallons of the fuel were in the top tank and used during taxi and run-up operations. Therefore, considering the airplane's lowest fuel consumption rate of about 7.2 gallons per hour, the airplane would have been able to operate for 3.2 total hours. At the time of the accident, it had flown a total of 3.3 flight hours. Therefore, the pilot began the flight with an insufficient amount of fuel and did not monitor its quantity during the flight.

On December 19, 2012, about 1420 eastern standard time, an experimental amateur-built Skybolt, N328GW, was substantially damaged following a forced landing into the Gulf of Mexico near Sarasota, Florida. The private pilot was not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the personal flight, which was conducted under the provisions of Title 14 Code of Federal Regulations Part 91. The local flight originated at Venice Municipal Airport (VNC), Venice, Florida, about 1355. According to the pilot, he performed a preflight inspection, departed the airport, and flew north over the Gulf of Mexico. He flew the airplane for about thirty minutes and had just turned around in order to fly back to VNC when the engine began to surge. He unsuccessfully attempted to restore the engine to full power and turned the airplane toward the beach in order to perform a forced landing. The engine experienced a total loss of power; the airplane descended, impacted the water, and subsequently sank just off shore. The pilot egressed and swam to shore. A Federal Aviation Administration (FAA) inspector responded to the accident site and examined the wreckage. The inspector confirmed substantial damage to the right lower wing spar, the left upper wing spar, and all lower wing leading edges exhibited impact damage. In addition, there was no oil or fuel spill reported by the pilot, the life guards, nor local law enforcement. The wreckage was recovered to a storage facility where a subsequent examination of the engine and airframe was performed. All engine cowlings and the upper spark plugs were removed. Compression was confirmed on all cylinders. The fuel system was examined from the fuselage tank through the selector valve to the engine, which was selected to the fuselage tank. No blockage was noted throughout the fuel system and a small amount of fuel was present in the gascolator bowl. About 4 gallons of fluid was drained from the fuselage tank into a clean bucket. The fluid was similar in color and smell as sea water and there was no evidence of any fuel. According to the pilot, the most recent refueling was accomplished in late November and there had been three previous flights totaling 2.9 hours of flight time in addition to the accident flight since that refueling. A fuel receipt dated November 24, 2012 indicated that the pilot had purchased 17 gallons of 100 LL aviation fuel. The pilot stated to the FAA inspector that the top tank was used for taxi and run up operations and contained approximately 6 gallons of fuel at the last refueling. The bottom, or fuselage, tank was utilized exclusively in flight. During a phone interview with an NTSB investigator, the pilot reported that the engine was "steady at 2400 [rpm] prior to the engine sputtering." According to excerpts from the Textron Lycoming "Operator's Manual" for the IO-360 series engine, at 2400 rpm, the fuel consumption, depending on the mixture setting would be between43 and 82 pounds per hour.