On August 11, 1999, about 0930 eastern daylight time, an Arnet Pereyra Aero Design Aventura II, N303SQ, registered to Sky Quest, Inc., operating as a Title 14 CFR Part 91 personal flight, crashed on takeoff from Rockledge Airpark, Rockledge, Florida. Visual meteorological conditions prevailed and no flight plan was filed. The homebuilt amphibian airplane received substantial damage, the private-rated pilot was seriously injured, and a passenger, (German pilot-rated) was fatally injured. The flight was originating at the time of the accident. According to a business acquaintance of both occupants, they were German nationals who were in this country to reassemble the airplane, having been disassembled and shipped from Austria to an address at the Rockledge Airpark, and register it in the name of a newly formed Florida corporation. Having accomplished that, both occupants were planning to deliver the dual controlled airplane to the Dominican Republic in the near future, and were familiarizing themselves with its flight characteristics. An eyewitness stated that the airplane was attempting to take off from the grass adjacent to the east edge of the airpark's runway 18, a standard procedure. The airplane had attained an altitude of 20 to 25 feet and appeared to be at a slower airspeed and was climbing slower than he remembered for that type airplane. The airplane drifted left of runway centerline, ("left wing tip was 2 feet lower than right"), scraped the end wall of the hangar where he was standing, and collided with the next door two-story building at its roof line. He stated the engine sounded, "wide open" but the airplane appeared to act, "sluggish". He stated it appeared the flaps were full down. Postcrash, the airplane slid down the building wall and came to rest in the 8 foot wide alleyway between the two buildings, nose down. He stated his first impression was that the pilot was intending to "buzz" the hangar until he saw their facial expressions. Responding EMT workers hosed down the site with foam due to leaking fuel. They had to cut the wings off the airframe in their rescue attempt. Personal articles removed from the wreckage and stored by Sheriff Department personnel were, (1) knapsack containing personal property, (2) cell phone, (3) camera and lens, and (4) a zipper folder. The total weight was estimated at 15 pounds. They were unable to estimate the amount of fuel spillage. The pilot was air lifted and admitted to Holmes Regional Hospital, Melborne, Florida, with skull and rib fractures, pelvic trauma, and multiple abrasions and lacerations. Subsequent examination of the wreckage by an FAA inspector revealed the flap actuator was found in the flaps-fully-extended position. The left and right flap surfaces are connected by a common torque tube that was found intact. Flaps on the airplane were electrically driven and any position between up and full down, (40 degrees) can be selected. This particular airplane had two separate selector switches for the flaps; (1) a toggle switch on the instrument panel as supplied by the factory and, (2) a "coolie hat" switch atop a military fighter type stick grip. The aircraft was equipped with a cockpit installed flap position indicator. Estimate of fuel aboard could not be determined, and the pilot stated he could not remember. A factory test pilot who had flown familiarization flights with both occupants in the accident airplane four days before the accident, stated he demonstrated and used the optimum flap setting of 15 degrees for takeoff on those occasions. He did not demonstrate the 40-degree flap setting, and stated that he discouraged its use because of its resultant dramatic nose down attitude change. According to factory specifications, the maximum gross takeoff weight of the airplane is 1,350 pounds at sea level, standard atmospheric conditions. Standard atmospheric conditions did not exist at the time of the accident; in fact, the density altitude was 1,849 feet. According to the factory test pilot, this aircraft's operating empty weight was 900 pounds. The pilot weighed 242 pounds and the passenger weighed 235 pounds. The airplane was equipped with the optional 18-gallon fuel tank. With no fuel loaded, the takeoff weight was 1,392 pounds, or 42 pounds over maximum gross takeoff weight. Postmortem examination of the passenger was conducted by Dr. Paulino O. Vassallo, M.D., District Medical Examiner, District 18, Brevard County, Florida. The cause of death was attributed to multiple blunt force injuries. Toxicological testing of specimens from both occupants was conducted by the Federal Aviation Administration Research Laboratory, Oklahoma City, Oklahoma. No findings that could be considered causal were noted in either the postmortem or the toxicological tests. The pilot was discharged on September 3, 1999, whereby he returned to Germany. Numerous attempts to contact the pilot finally resulted in the enclosed statement made to the German Federal Bureau of Accident Investigation and forwarded to the NTSB.