N6868YAerostar S A YAK-52

**This reported was modified on 11/7/2011; the accident date was corrected from May 27 to May 15, 2010.**

On May 15, 2010, at 1145 eastern daylight time, an Aerostar Yak-52, N6868Y, was substantially damaged near Jensen Beach, Florida, after it impacted water while maneuvering. The certificated private pilot and his passenger were fatally injured. Visual meteorological conditions prevailed, and no flight plan was filed for the local, personal flight conducted under Title 14 Code of Federal Regulations Part 91, which departed from Witham Field Airport (SUA), Stuart, Florida.

According to the Federal Aviation Administration (FAA) the accident airplane departed SUA at 1140 eastern daylight time. The airplane was then observed by witnesses flying along the beach about 100 yards offshore, descending from approximately 300 feet to approximately 50 feet above the water, in a northerly direction. It next entered a "very abrupt and steep turn" to the northeast, and then went "straight up" while continuing to turn, until it rolled out on a westerly heading towards a cluster of condominiums that lined the beach. It once again made a "sharp turn" to the right (northbound), then pitched up "sharply", until it was "on its back" (upside down). It then pitched down, rolled about its longitudinal axis, and impacted the water nose first.

According to a Palm Beach County Sheriff's officer, who also observed the event while flying at 500 feet above mean sea level in a helicopter, the airplane (which was below them), initially made a climbing right turn towards the west (towards the beach). The airplane then continued the climbing right turn in a "very nose high attitude", then almost did a "wingover" while still turning to the right. The nose of the airplane then began to "fall through the turn", almost like the pilot was going to attempt a "partial loop". The airplane than "almost rolled wings level, nose down". About this time, The Sheriff's deputy that was observing the accident airplane, realized that the pilot did not have enough room to recover and commented to the other Sheriff's deputy that was flying with him that, "there is no way he is going to make it". Almost as soon as he completed his comment, he heard a voice on the radio say "OH", and then observed the airplane contact the water and sink immediately.

According to FAA and pilot records, the pilot held a Private Pilot certificate with ratings for airplane single-engine land, and instrument airplane. His most recent application for an FAA third-class medical certificate was dated August 13, 2008. He had accrued approximately 442 total hours of flight experience.

The accident aircraft was a fully aerobatic two seat monoplane of conventional construction. It was powered by a 360 horsepower 9-cylinder radial engine which drove a two-bladed counter-clockwise rotating, variable pitch, wood and fiberglass laminate propeller. It was equipped with retractable landing gear. Engine starting, landing gear operation, flap operation, and braking, were all pneumatically actuated. It was equipped with inverted fuel and oil systems which permitting inverted flight for up to two minutes. It was also stressed to 7 Gs positive and 5 Gs negative and was capable of producing roll rates of 180 degrees per second.

According to FAA records, the airplane was manufactured in 1980. The airplane’s most recent conditional inspection was completed on June 9, 2009. At the time of the inspection the airplane had accrued 1,015.4 total hours of operation.

A weather observation taken about 2 minutes after the accident, at SUA located approximately 5 nautical miles southwest of the accident site, recorded the wind as 100 degrees at 12 knots, gusting to 18 knots, visibility 10 miles, scattered clouds at 2,500 feet, broken clouds at 3,000 feet, temperature 28 degrees Celsius, dew point 20 degrees Celsius, and an altimeter setting of 30.19 inches of mercury.

All of the major pieces of the airplane with the exception of the outer wing panels were recovered from the waters off Jensen Beach. Examination of the wreckage by the NTSB revealed no evidence of preimpact malfunction or failure of the airplane or engine.

The airframe exhibited no evidence of inflight structural failure and control continuity was established from the flight controls to the breaks in the system which exhibited evidence of tensile overload. The landing gear was down and locked and the wing flaps were up.

Examination of the cockpit revealed that the attitude indicator indicated a 55 degree nose down pitch attitude and a 10 degree right bank. The airspeed indicator's needle was past the 250 knot mark and the accelerometer (G meter) was at its stop at – 6Gs.

The Kollsman window indicated 30.24 inches of mercury and the altimeter indicated 150 feet below sea level.

The throttle lever was full open, the propeller pitch control lever was in the midrange position, the friction lock lever was locked, and the "FIRE VALVE" (fuel cutoff) lever was open.

The cooling controls (cowl louvers and oil cooler flap) levers were fully forward (open) and the carburetor heat lever was in the "COLD" position.

The magneto switch was in the "1+2" (both) position. The battery switch and generator switch were in the "ON" position. The ignition switch was in the "1st COCKPIT" position.

The landing gear selector was in the neutral position and the gear down indicator's light bulb exhibited evidence of filament stretching. The landing gear emergency release valve was closed.

The flap lever was in the "UP" position.

The strobe lights switch was in the "ON" position. The navigation lights and transponder switches were in the "OFF" position. The oil scavenge switch was in the "OFF" position and the pitot and clock heaters switches were in the "OFF" position.

The instrument fault switches were safety wired in the "OFF" position.

Examination of the annunciator panels did not reveal evidence of filament stretching in the light bulbs for the Stall Warning, Approaching Stall, Low Airspeed, Excess G, or Metal Chip in Oil annunciator lights.

Examination of the engine revealed that its cowling had separated during impact and the oil tank was crushed. The propeller blades had severed at the hub. The planetary reduction drive was intact. Drive train continuity was confirmed visually and through partial rotation of the drive shaft. The top spark plugs were removed from the cylinders. They were light gray in color and their electrodes were intact. External and internal examination of the cylinders revealed no preimpact anomalies and oil was present in the rocker boxes. Internal examination of the engine's power section revealed the presence of a mixture of sand, water, and oil. Examination of the magnetos revealed that they could not be fired due to saltwater immersion. Visual examination of the magnetos however, did not reveal any evidence of preimpact malfunction.

An autopsy was performed on the pilot by the State of Florida, District 19, Medical Examiner. The cause of death was multiple blunt trauma injuries.

Toxicological testing of the pilot was conducted at the FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma. The specimens were negative for carbon monoxide, cyanide, basic, acidic, and neutral drugs.

Review of Photographs

Review of photographs provided to the NTSB by the St. Lucie Sherriff's Office and the FAA revealed that the airplane prior to the accident had been flying with the landing gear in the down position. Review of the Yak 52 Pilots Operating Handbook however, specified that after takeoff the pilot should "Retract the landing gear and climb away at 90 knots" and to "Check for gear up indication".

Additionally, a response to a query sent to the RedStar Pilots Association which is an organization composed of owners, pilots, and maintainers, who promote safe operation and display of aircraft designed and manufactured in current and former soviet block nations revealed that, they were unaware of any in-flight maneuvers that would require that the landing gear remain extended after takeoff.

Minimum Altitude for Aerobatics

According to the FAA, aerobatic flight is defined as an intentional maneuver involving an abrupt change in an aircraft’s attitude, an abnormal attitude, or abnormal acceleration, not necessary for normal flight.

According to the operating rules section of 14 CFR Part 91 which defines the restrictions on aerobatics, no person may operate an aircraft in aerobatic flight below an altitude of 1,500 feet above the surface.

Additionally, the International Aerobatic Club, Inc. which is a division of the Experimental Aircraft Association inc. and the National Aeronautic Association and is responsible for the administration, management, and promotion of the sport of aerobatics in the United States under the applicable regulations of the Federation Aeronautique Internationale also recommends that the" minimum altitude" for any aerobatic maneuver should be 1,500 feet above ground level.