On April 27, 1997 at 1033 eastern daylight time (edt), a Acro Sport II, N52260, was substantially damaged near Monon, Indiana. The pilot was reported to be flying at low altitude when witnesses reported the airplane sustained a loss of power. One witness believed that the airplane was less than 200 feet above the ground when the loss of power occurred. After the loss of power the airplane contacted trees, and collided with the terrain during an uncontrolled descent. The commercial rated pilot, and passenger were seriously injured in the accident. The 14 CFR Part 91 flight was operating in visual meteorological conditions, and no flight plan had been filed. A post flight examination of the airplane was conducted by a representative from the Federal Aviation Administration (FAA). The representative reported that at least two witnesses to the accident reported that the engine sustained a loss of power prior to impact. The representative reported that the airplane's propeller blades were both straight, and showed no signs of chordwise scratching. The representative stated that one witnesses went up to the airplane following the accident and used dirt to plug a fuel line which was leaking fuel. No flight control abnormalities were reported by the FAA representative. The airplane was removed from the accident site and was stored at a private airstrip. Before the airplane's engine was examined by a representative of the FAA or the IIC the aircraft wreckage was released to the son of the pilot of the airplane, who removed the airplane and engine from the private airstrip. The IIC left messages on the sons answering machine, and sent certified letters requesting an inspection of the aircraft's engine. No correspondence was received by the IIC from the son of the pilot.