On June 22, 2019, about 1030 eastern daylight time, a Waco YMF airplane, N63WC, sustained substantial damage when it was involved in an accident near Bar Harbor, Maine. The pilot and two passengers sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 air tour flight. The flight departed for a 25-minute sightseeing tour of Acadia National Park. The pilot reported that the flight was normal until he heard a loud "crack/bang" from the front of the airplane, followed by a steady noise for about 10 seconds that sounded "similar to a helicopter," and the propeller subsequently stopped turning. The pilot conducted a forced landing to wet, marshy terrain, during which the left wing impacted a tree and the airplane nosed over and came to rest inverted, resulting in substantial damage to the upper and lower wings. The airplane owner reported that one of the engine cylinders was fractured at the barrel head joint. The airplane was operated without engine cowling installed. According to the airplane’s owner, the cowling assists with engine cooling in vintage radial engines.