Air Boss Informed The Announcer And Ground Crew That He Thought The Engine Was Running Rough And To Prepare For A Possible Precautionary Landing

Location: Rhinebeck, NY Accident Number: ERA25LA002
Date & Time: October 5, 2024, 14:56 Local Registration: N94100
Aircraft: Fokker D VIII Replica Injuries: 1 Fatal
Flight Conducted Under: Part 91: General aviation - Air race/show

On October 5, 2024, about 1456 eastern daylight time, an experimental amateur-built Coughlin Fokker D-VIII Replica, N94100, was destroyed when it was involved in an accident near Old Rhinebeck Airport (NY94), Rhinebeck, New York. The commercial pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 airshow flight. The purpose of the flight was to perform a single ship demonstration routine for an airshow at NY94. The planned flight duration was 10 minutes from engine start to shutdown. Several witnessed captured video of the flight, with one of the videos depicting the flight from takeoff until just before impact with terrain.

Witness statements from two individuals associated with the airshow, along with review of the recorded video, revealed that the airplane departed from NY94 about 1453. The airplane took off to the north, then made a right turn and passed along the airshow line flying in a southerly direction. During that southerly pass one witness, who was the Director of Maintenance for Rhinebeck Aerodrome Museum and the air boss for the airshow with considerable flight experience flying airplanes equipped with the same Gnome 9N engine, heard a noticeable engine roughness that was not present moments before. The airplane continued past the runway and then began a 270° left turn. During that turn, or about 1 minute 5 seconds into the routine, the air boss informed the announcer and ground crew that he thought the engine was running rough and to prepare for a possible precautionary landing. 

The pilot completed the 270° turn and approached the airport, then upon reaching the show line, the pilot began a right 90° turn. At the start of the turn, or about 1 minute 24 seconds into the routine, the air boss noted that the sound emanating from the engine operating at full power was poor enough that he thought the pilot would enter the airport traffic pattern for landing. The pilot completed the turn and continued in a northerly direction along the show line and then made a 180° right turn proceeding in a southerly direction along show line. At about the end of the 180° turn the air boss reported that the engine was clearly not firing on all cylinders, though it was operating at full power.

The airplane continued in a southerly direction along show line, and about 2 minutes 16 seconds into the routine, when the airplane was near the end of the downwind leg, the air boss reported that the engine lost total power and the airplane began descending. About that time, the video became blurry but the airplane continued descending. At about 2 minutes 17 seconds into the routine, a prominent fire was noted in the front portion of the airplane. The airplane continued descending while the fire increased in intensity, eventually obscuring nearly the entire fuselage. The video also captured parts separating from the airplane. The airplane then appeared to pitch downward and descended steeply and out of view behind trees. The airplane impacted in a wooded area. Multiple personnel from the airport responded and attempted to extinguish the fire.

Preliminary postaccident examination of the Gnome 9N engine revealed that cylinders for the Nos. 6 and 7 positions were separated. The separated cylinders were subsequently recovered. The engine crankcase displayed a wide crack between the threaded mounting bosses of the separated cylinders.

The wreckage was retained for further examination.

FMI: www.ntsb.gov