On June 16, 2007, at 1100 eastern daylight time, an amateur-built experimental light sport aircraft (E-LSA), Northwing Design Apache Quest, N425DW, was substantially damaged after takeoff from the Hartness State Airport (VSF), Springfield, Vermont. The non-certificated pilot was seriously injured. Visual meteorological conditions prevailed and no flight plan was filed for the local test flight conducted under 14 Code of Federal Regulations Part 91. According to a Federal Aviation Administration (FAA) inspector, the pilot was a co-owner of the aircraft kit manufacturing company; however, he was not a certificated pilot. On the day of the accident, he planned to test an alternate wing design, which was to be sold in an aircraft kit to a new customer. The pilot did not have a fuselage available to test the wing, so he asked the owner of the accident airplane to fly to VSF, and assist him with testing the alternate wing on his fuselage. The owner of the airplane agreed, flew to VSF, and assisted the accident pilot in securing the alternate wing to the fuselage of his airplane. The pilot then departed from VSF, and shortly after takeoff, witnesses observed the airplane nose over and impact a lake. The pilot was unable to release his seatbelt, and was pulled from the airplane by witnesses, prior to it sinking in the lake. Examination of the airplane by the FAA inspector revealed the wing was "defective," and not compatible with the fuselage. Substantial damage was observed to fuselage. Weather reported at VSF, at 1054, included wind from 160 degrees at 5 knots, 10 miles visibility, clear skies, temperature 23 degrees Celsius (C), dew point 14 degrees C, and an altimeter setting of 29.98 inches of mercury.