N2207X

HISTORY OF FLIGHTOn September 16, 2012, about 1515 central daylight time, a, Yakovlev Yak-52, N2207X, registered to Matrushka LLC and operated by an individual, was substantially damaged when it impacted terrain after a loss of control at Moontown Airport (3M5), Brownsboro, Alabama. The pilot and the student pilot rated passenger were fatally injured. Visual meteorological conditions prevailed, and no flight plan was filed for the Title 14 Code of Federal Regulations (CFR), Part 91, personal flight.

The accident occurred on the last day of the "Moontown Airport Annual Grass Strip Fly In" which was organized by Experimental Aircraft Association, Chapter 190, and the Moontown Airport. Several witnesses observed three Yak-52 airplanes flying from west to east in trailing formation, each slightly lower than the one in front. When they were southeast of the airport, the lead airplane performed a barrel roll, followed by the second airplane in the formation which also performed a barrel roll. The third airplane 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 approximately 180 degrees (from west to east) 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 trees that separated an open field from the airport's grass runway. The sound of impact was then heard and smoke was observed to rise from behind the trees. PERSONNEL INFORMATIONAccording to Federal Aviation Administration (FAA) records, the pilot held a private pilot certificate with ratings for airplane single-engine land, and instrument airplane. His most recent FAA second-class medical certificate was issued on February 29, 2012. He had accrued 6,150 total hours of flight experience.

According to FAA and pilot records, the student pilot rated passenger held a student pilot certificate with third-class medical which was issued on November 21, 2011. At the time of the examination he reported that he had accrued 12 total hours of flight experience. AIRCRAFT INFORMATIONThe accident aircraft was a low wing, two seat monoplane of conventional metal construction. It was equipped with retractable landing gear and wing flaps, and was powered by 9-cylinder, 360 horsepower radial engine equipped with a two-bladed, counter-clockwise rotating, variable pitch, wood and fiberglass, laminated propeller. It was capable of performing all of the aerobatic maneuvers in the Aresti catalog up to a positive load of 7 Gs and a negative load of 5 Gs.

According to FAA and airplane maintenance records, the airplane was manufactured in 1982 and was issued a special airworthiness certificate in the exhibition category on November 19, 1999.

The airplane's most recent conditional inspection was completed on August 31, 2012. At the time of the inspection, the airplane had accrued approximately 1,575.7 total hours of operation. The engine had accrued 1008.1 total hours of operation and had accrued 384.4 hours of operation since its last major overhaul which had occurred on April 11, 2006. METEOROLOGICAL INFORMATIONThe recorded weather at Madison County Executive Airport (MDQ), Huntsville, Alabama, located approximately 8 nautical miles northwest of the accident site, at 1415, included: winds calm, visibility 10 miles; broken clouds at 4,900 feet, temperature 28 degrees C, dew point 17 degrees C, and an altimeter setting of 30.03 inches of mercury. AIRPORT INFORMATIONThe accident aircraft was a low wing, two seat monoplane of conventional metal construction. It was equipped with retractable landing gear and wing flaps, and was powered by 9-cylinder, 360 horsepower radial engine equipped with a two-bladed, counter-clockwise rotating, variable pitch, wood and fiberglass, laminated propeller. It was capable of performing all of the aerobatic maneuvers in the Aresti catalog up to a positive load of 7 Gs and a negative load of 5 Gs.

According to FAA and airplane maintenance records, the airplane was manufactured in 1982 and was issued a special airworthiness certificate in the exhibition category on November 19, 1999.

The airplane's most recent conditional inspection was completed on August 31, 2012. At the time of the inspection, the airplane had accrued approximately 1,575.7 total hours of operation. The engine had accrued 1008.1 total hours of operation and had accrued 384.4 hours of operation since its last major overhaul which had occurred on April 11, 2006. WRECKAGE AND IMPACT INFORMATIONAccident Site and Airplane Wreckage Examination

Examination of the accident site, and wreckage revealed no evidence of any preimpact malfunctions or failures which would have precluded normal operation of the airplane.

The airplane's energy path at the accident site was on an approximate 90-degree heading. The airplane's initial collision point was with the ground occurred at an elevation of 686 feet above mean sea level and was marked by an approximately 3 foot diameter crater about 2 feet deep. One of the two wooden propeller blades was also imbedded into the ground at that location.

The engine, along with its cowling was separated from the airframe and had come to rest about 50 feet along the energy path from the crater. The propeller hub assembly had remained attached to the engine minus the propeller blades.

A section of the left outboard wing was located about 90 feet along the energy path from the crater. The main wreckage came to rest about 150 feet from the crater on an estimated 290-degree heading. Remnants of wing's flight control surfaces, engine parts, nose gear, right main gear, and canopy debris were located along the energy path leading up to the main wreckage which consisted of the fuselage, wings, and empennage with its flight control surfaces.

The engine firewall to the rear cockpit area had sustained thermal damage from the post impact fire which had ensued. Some instrument panel components and the wing's cross spar beam were discernible among the melted metal, and the front seat to rear seat flight control connecting tube was visible. Examination of the tube revealed that it was fractured at the rivet holes at the connection to the rod end clevis fitting. Examination of the mating fracture sides of the control tube revealed however, that the fractures were oriented at an approximately 45 degree angle through the wall thickness which was consistent with overstress separation.

The right wing was intact with impact damage to the leading edge and thermal damage near the wing root area. The left wing was separated from the wing root area and bent back to the fuselage. The left main gear remained attached to the wing. The empennage areas sustained impact damage and the fabric covered flight control surfaces had thermal damage.

Engine Examination

Examination of the engine did not reveal evidence of any preimpact failures or malfunctions which would have precluded normal operation of the engine.

The engine was intact, but due to impact damage, the drivetrain could not be rotated. Continuity of the drive train was able to be established however from the propeller hub to the back of the engine by removal of the cylinders for internal examination.

Examination of spark plugs from each cylinder revealed that they were normal in appearance.

Examination of the intake and exhaust valves revealed that they appeared normal and there were no obstructions discovered in the intake system.

Examination of the carburetor revealed that it had remained attached to the engine. No anomalies were discovered, and all of its linkages were still intact and connected.

The magnetos were still attached and secured. ADDITIONAL INFORMATIONAirplane Co-owner's Statement

According to the co-owner of the airplane, the pilot of the accident airplane was an experienced aerobatic pilot but, he advised that like all such pilots, he got rusty after long periods of inactivity. Many times he had watched him practice and any errors he observed were minor (mainly errors of style) and within the realm of safety.

A few weeks before the accident the pilot had commented to him that he would like for him to ride in the back cockpit and help him "brush up" on his barrel rolls. He said that he had lately developed a tendency to "dish out." According to the Co-owner, a dish-out is not normally a dangerous error if enough altitude is available for recovery and he advised that the pilot always practiced aerobatics with plenty of extra altitude. 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.

On the day of the accident, the pilot had flown several formation sorties. The day was hot and the formation activities were demanding. All of the planes in the 4-ship flight were alike except for one, a Nanchang CJ-6, but the Nanchang was very similar to the Yak-52. All the pilots knew each other and were very experienced in formation flight. All were current and qualified Red Star Pilots Association Formation and Safety Team (FAST) members. Several formation flights were launched the day of the accident by this same group and all of the flights were briefed and debriefed. The co-owner had sat in on most of the briefings and debriefings and had also flown four formation sorties in the accident aircraft with the same pilots the prior day.

The accident flight was a relatively long one, and the co-owner guessed it was about 45 minutes long. Most formation sorties ...