ERA24LA343 · Yakovlev YAK-55M

The non-certificated pilot had just purchased the high-performance, aerobatic, tailwheel-equipped airplane and was returning home when the engine began to run rough about 40 minutes into the flight. He said that he adjusted the throttle, and found a “sweet spot” with the engine where he could make a precautionary landing at a nearby tower-controlled airport. An air traffic controller advised the pilot of the wind and active runway; however, he was given the option to land straight in on another runway with a 14-knot quartering tailwind. The pilot elected to land straight in; however, he did not have any recollection of what happened after the airplane touched down on the runway. The controller said the airplane bounced on landing, ground looped, and collided with runway lighting. The controller further described that the pilot appeared to overcorrect the airplane and both wing tips struck the ground before the airplane nosed over and came to rest inverted. This resulted in substantial damage to the right wing, empennage and tail section. Postaccident examination of the 9-cylinder radial engine found several fouled spark plugs including both spark plugs on the No. 4 cylinder. However, it was not determined if the fouling was preexisting or from the engine being inverted. Further examination of the engine revealed that its crankshaft rotated freely and compression was confirmed on each cylinder. No obvious mechanical deficiencies were observed that would have precluded normal operation. The person who sold the airplane to the pilot said the pilot fueled the airplane before he departed. He also performed several run-ups of the engine and performed some high-speed taxi maneuvers to get a feel for the airplane. The seller said the pilot was overcontrolling the airplane at first but started to get more comfortable. The pilot then departed without performing any takeoffs or landings. A review of excerpts of the pilot’s flight logbook revealed that the accident flight was his first flight in the accident airplane. There was no record he had any previous experience in a tailwheel-equipped airplane. Though the pilot reported a rough running engine, possibly due to fouled spark plugs, he was able to reach an airport to make a safe precautionary landing. However, due to his lack of experience in the airplane and decision to land with a quartering tailwind, he lost directional control on landing.

Verbatim NTSB analysis and probable cause from the NTSB dataset