NTSB Factual Report

"THIS CASE WAS MODIFIED MARCH 22, 2010"

HISTORY OF FLIGHT

On June 16, 2008, about 1330 central daylight time, an experimental amateur-built Acroduster II SA750, N363J, registered to and operated by a private individual, experienced a reported flight control malfunction during an aerobatic flight and crashed in a wooded area near Panama City, Florida. Visual meteorological conditions prevailed at the time and no flight plan was filed for the 14 Code of Federal Regulations (CFR) Part 91 personal, local flight from Panama City-Bay County International Airport (PFN), Panama City, Florida. The airplane was substantially damaged and the certificated private pilot was killed. A passenger parachuted from the airplane and was not injured. The flight originated about 1245, from PFN.

The passenger stated that the pilot-in-command (PIC) performed a thorough preflight inspection of the airplane. After takeoff, the flight proceeded to a practice area where the PIC performed aerobatic maneuvers. Before the last maneuver, the PIC asked the passenger if he wanted the PIC to perform what he believed was called a tail slide. The flight climbed to 3,500 feet and the pilot then initiated the maneuver. After "...falling for a few seconds, [the PIC] then attempted to bring the [airplane] out of the maneuver and it appeared that he was able to bring the nose of the [airplane] back to straight and level for a second with full power (not sure if it was full power but seemed like it). At that point, the [airplane] started rolling to the left, then to the right, up and down and I heard [the PIC] began loudly announcing that we had problems with the [airplane] which I believe he repeated 3 times. It was very difficult to hear with the speed we were at and with the [airplane] starting to lose control.”

The passenger further stated that the airplane seemed to be out of control, “…as it was going to the left, the right, towards the ground and I heard [the pilot]…” tell him to bail out of the airplane. The passenger released his restraints and bailed out beginning his free fall. He deployed his parachute and performed a quick search of the sky looking for the airplane or a parachute from the pilot. He did not see either, and landed in the tops of trees. While hanging in trees from his parachute he listened for sound from the airplane and looked for it, but did not hear or see it. He extracted himself from the parachute and trees, and walked to a house where he summoned help.

The airplane crashed during daylight conditions in a heavily wooded area.

PERSONNEL INFORMATION

The pilot, age 31, held a private pilot certificate with an airplane single-engine land rating, issued February 4, 2000. He also held a second-class medical certificate, with a limitation to wear corrective lenses, issued October 2, 2006. He listed a total flight time of 900 hours on the application for his last medical certificate.

The pilot’s father reported that his son told him approximately 2 weeks before the accident that he had passed the threshold of 1,000 hours total flight time. Review of excerpts from the pilot’s pilot logbook revealed that within the last 30 days, he logged a total of approximately 16 hours, of which approximately 7 hours were logged as PIC in the accident airplane.

AIRCRAFT INFORMATION

The two-seat bi-wing airplane was manufactured by a private individual in 1980, as model Acroduster II SA750, and was designated serial number 363. An excerpt of the plans submitted to the Federal Aviation Administration (FAA) indicate the airplane positive and negative limit loads were 6 g’s, and the positive and negative ultimate load limits were 9.0 g’s. It was powered by a Lycoming IO-360-A1B, 200-horsepower engine.

Review of the airworthiness file from the FAA revealed that on February 20, 1981, a Special Airworthiness Certificate was issued with an expiration date of February 20, 1982. The operating limitations associated with the issuance of the airworthiness certificate indicated in part that the airplane must be operated within a specific radius of the specified airport and that passenger carrying was prohibited. In a letter from the airplane builder to the FAA dated July 15, 1981, the builder requested release from the flight test area and advised that the airplane was controllable throughout its normal range of power settings and flight attitudes, and throughout all the specific maneuvers to be executed. The builder also advised that the airplane had not indicated any adverse or unusual, nor hazardous operating characteristics. A special airworthiness certificate was issued and the operating limitations associated with the issuance of the airworthiness certificate indicated in part that the aircraft was prohibited from aerobatic flight.

Further review of the airworthiness file revealed operating limitations dated August 21, 1995, indicate that the airplane was allowed to be flown in aerobatic flight, but aerobatic flight may not be accomplished until sufficient flight experience has been gained to establish that the airplane is satisfactorily controllable and the airplane has been demonstrated to be controllable. The limitations also specify that aerobatic maneuvers performed must be recorded in the aircraft logbook.

The pilot’s father purchased the airplane on July 17, 2000. At the time of purchase, the airplane total time was approximately 363 hours.

Review of the maintenance records revealed the airplane was last inspected in accordance with a conditional inspection on March 15, 2008; the airplane total time at that time was recorded to be 838.2 hours. Although the recording tachometer time at the time of the accident was not determined, the pilot’s father (airplane owner) reported the airplane had been operated between 20 and 25 hours since the last condition inspection.

According to an Internet posting dated December 29, 2002, by a person using the name of the accident pilot, he reported that while, “…practicing vertical torque rolls. On the fifth one I had a monster, rolling tail-slide and violent flop back toward the ground. After which I noticed that the stick was unusually stiff in roll and the aircraft was now out of trim in roll. I carefully returned to the airport and found that with the stick centered the [right] aileron was in the proper position and the [left] aileron was deflected [approximately] 3 inches up.” The individual reported that inspection of the aileron system revealed the left bellcrank inside the fuselage and an AN-5 bolt that secures the bellcrank were bent.

The pilot’s father reported that following the December 2002 event, new bellcranks were manufactured and installed. The maintenance records did not reveal an entry related to this maintenance. At that time, his son questioned whether the replacement bellcranks needed to be stronger, but concluded that if they strengthened the bellcranks, the failure would show up somewhere else in the system. Additionally, at that time his son noted that wood aileron stop blocks were installed on the aft side of the main spar of both lower wings. He also reported that his son had performed numerous aerobatic maneuvers since the 2002 event.

METEOROLOGICAL INFORMATION

A surface observation weather report taken at PFN at 1253, or approximately 37 minutes before the accident, indicates the wind was from 300 degrees at 7 knots, the visibility was 10 statute miles, clear skies existed. The temperature and dew point were 31 and 22 degrees Celsius respectively, and the altimeter setting was 29.93 inches of Mercury. The accident site was located approximately 24 degrees and 8.3 nautical miles from the center of PFN.

COMMUNICATIONS

The pilot was not in contact with any Federal Aviation Administration (FAA) air traffic control facility at the time of the accident.

WRECKAGE AND IMPACT INFORMATION

Examination of the accident site by an FAA inspector revealed the airplane crashed inverted in a wooded area. Flight control continuity was confirmed for pitch and yaw; however, the remote location precluded determination of continuity for roll. The wreckage was recovered for further examination.

Examination of the aileron flight control system, following recovery by an FAA airworthiness inspector, revealed continuity of control was verified on the lower wing ailerons, but impact damage to the upper wing aileron control tubes was noted. The FAA inspector further noted that the wooden aileron stop, attached to the main spar of each lower wing, appeared smaller than the stop depicted in a builders guide.

MEDICAL AND PATHOLOGICAL INFORMATION

A postmortem examination of the pilot was performed by the District Fourteen Medical Examiner’s Office, located in Panama City, Florida. The cause of death was listed as “Multiple Blunt Force Injuries.”

Forensic toxicology was performed on specimens of the pilot by the FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma. The toxicology report stated the results were negative for carbon monoxide, cyanide, volatiles, and tested drugs.

TESTS AND RESEARCH

Review of postaccident photographs of the forward spar of both lower wings, provided by the pilot’s father, revealed one wooden block attached to the aft side of the main spar of both lower wings. Each block was nearly perpendicular to the main spar and was supported on both sides at the base by a triangular shaped wedge. Further inspection of each block revealed parallel crush lines consistent by contact made with the upper and lower portions of each aileron outer bellcrank. Additionally, scrape damage to a drag truss associated with the left and right wing outer aileron bellcranks was noted in both lower wings. Another photograph provided by the pilot’s father revealed both inboard aileron bellcranks were bent slightly up.

Review of the builder’s guide revealed a note indicating that, in tail slides, it is quite easy to lose control of the stick and have the ailerons go violently stop to stop as the airplane slides backwards. In order to keep these high shock loads from traveling thru the entire control system, put blocks of wood on the front spar, placed so the aileron bell cranks will hit the wood stops at, or a fraction of an inch before, the stick hits the stops in the fuselage.” The illustration of the guide indicates a wood wedge attached to the aft side of the main spar; the shape of the wedge is parallel with the shape of the bellcrank at the point the bellcrank would contact the wedge. The illustration does not provide dimensions of the wedge; however, it clearly shows that both sides of the wedge are different thicknesses. The installed aileron stop blocks were not consistent with the shape or design of the wedge depicted in the builder’s guide.

NTSB Probable Cause

The pilot's inability to recover from an intentional aerobatic maneuver due to loss of aileron control. Contributing to the accident was the installation of an inadequate aileron secondary stop block against the main spar of both lower wings.