ERA12FA565 · Yakovlev YAK 52

During a fly-in, the private pilot was participating in a three-airplane formation aerobatics demonstration with a student pilot-rated passenger onboard. Several witnesses observed the three airplanes flying from west to east in trailing formation, each slightly lower than the one in front. The first two airplanes in the formation performed a barrel roll. The third airplane, which was being flown by the private pilot, then entered a barrel roll; however the nose of the airplane "dropped" into an extremely low attitude as it came through the inverted arc of the roll. The roll then stopped, but the airplane was almost full nose-down in a vertical descent. The airplane then appeared to immediately begin pitching up, and the airplane's pitch attitude decreased to about 45 degrees nose-low. The pitch attitude continued to decrease, but the airplane began to oscillate rapidly about the roll and pitch axis. A few seconds later, the airplane's heading changed about 180 degrees while the airplane continued descending at a 30- to 45-degree nose-low attitude and continued to oscillate about the roll and pitch axis until it was lost from sight behind. The sound of impact was then heard and smoke rose from behind the trees.

Examination of the accident site, airplane, and engine, did not reveal any evidence of any preimpact failure or malfunction that would have prevented normal operation of the airplane.

During a barrel roll maneuver, it is critical to raise the nose high enough during the first 45 degrees of turn. Not doing so could result in a corresponding nose-low attitude and proportionally high airspeed when recovery is made. Insufficient back pressure could then result in a "dish out" (the airplane falling out of the maneuver) during the inverted portion of the roll.

The pilot of the accident airplane was an experienced aerobatic pilot, but the co-owner of the airplane advised that, like all such pilots, he got rusty after long periods of inactivity. A few weeks before the accident, the pilot had commented to the co-owner that he would like for him to ride in the back cockpit and help him "brush up" on his barrel rolls. The co-owner agreed to ride with him, but they did not set aside a specific time to do that, and it was never accomplished.

During the formation sortie, at first the accident pilot's rolls were crisp and tight, but the pilot fell farther and farther behind and his rolls were getting slower. The airplane's co-owner observed that the final barrel roll "dished out very badly" (the airplane fell out of the maneuver), which resulted in an extremely nose-low attitude followed by an accelerated stall. It is likely that the pilot recognized his position in relationship to the ground and aggressively applied aft stick in an effort to recover from the nose-low attitude, which resulted in the stall.

On the day of the accident, the pilot had flown several formation sorties. The day was hot, and the formation activities were demanding. The accident flight was relatively long, and the co-owner of the airplane guessed it was about 45 minutes long. Most formation sorties were 30 minutes or less. The accident pilot was in his early 70s and was by far the oldest member of the flight. Due to the pilot's age, the demanding schedule, and the length of the formation sorties, fatigue could have been a factor, although it could not be conclusively determined.

Verbatim NTSB analysis and probable cause from the NTSB dataset