On May 8, 2006, about 0800 eastern daylight time, a twin-engine Cessna 421B, N988GM, operated by BCL, LLC, Pompano Beach, Florida, impacted in a canal following an aborted landing at The Florida Keys Marathon Airport, Marathon, Florida. Visual meteorological conditions prevailed, and an Instrument flight rules (IFR) flight plan was filed for the Title 14, CFR Part 91, corporate flight. The airplane sustained substantial damage, and the commercial pilot and sole pilot-rated passenger were seriously injured. The flight originated about 0720, from Pompano Beach Airpark, Pompano Beach. According to witnesses on the airport, the airplane was observed near the midfield of runway 07/25, flying eastbound approximately 20 feet above ground level (agl), with the landing gear retracted. One witness who recently witnessed a gear-up landing, but was not looking towards the runway, reported hearing the sound of a twin engine airplane approaching with the engines at reduced power as if for landing. He then heard a scraping noise similar to the recent gear-up landing he had witnessed. He said he looked toward the runway, and the accident airplane was at midfield, left of the runway centerline, and he saw a cloud of dust and heard what he thought was full engine power being applied. He reported the airplane climbed to about 100 feet agl, then disappeared from his view to the east. Another witness with a portable VHF radio, reported hearing on the unicom frequency, "gulf mike doing emergency go around." The airplane descended striking utility poles, and impacted in a saltwater canal about one mile east of the airport . An on-site investigation commenced on May 11. In attendance were representatives of the airplane and engine manufacturers. The airport runway revealed a set of parallel propeller strike marks near the area of the dust cloud observed by the witnesses. The left and right sets of marks were 109 and 113 feet long respectively, and the 16 feet,10-inch center-to-center measurement is consistent with the engine centerline-to-centerline measurement for the Cessna 421 series airplane. There were no landing gear marks present. An examination of the airplane's six propeller blades showed that all six blades had extensive torsional twisting and bending. All of the propeller blades had extensive chord-wise scratching and abrasion. Several of the blades had fractured or missing tips. An examination of the airplane's cockpit showed the landing gear retraction/extension handle was in the up/retracted position during the final impact. The landing gear extension warning horn circuit breaker was in the pulled/tripped position. The landing gear emergency extension handle was in the stowed position. During the final impact the nose landing gear was severely damaged and was not functional. At the impact site, both the left and right main landing gear were stowed in the up-and-locked/retracted position. The landing gear were released/unlocked and operated with the emergency extension handle. The main landing gear functioned appropriately. An examination of the left and right main landing gear showed no damage to the wheel doors, leg doors, wheels, or tires. All linkages and locking devices were undamaged, and appeared to function normally.