History of Flight
On January 16, 2008, at 2043 central standard time, a twin-engine Aero Commander 500-B, registration N712AT, was destroyed during an in-flight breakup and subsequent impact with terrain after a loss of control following takeoff from Runway 36L at Tulsa International Airport, Oklahoma. The commercial pilot, the sole occupant, was fatally injured. The aircraft, operated by Central Air Southwest, Inc., was conducting an on-demand cargo flight hauling canceled bank checks under 14 CFR Part 135. Dark night instrument meteorological conditions prevailed, and an instrument flight rules flight plan was filed for the 94-nautical mile flight to Wiley Post Airport, Oklahoma City.
Shortly after departure, the pilot reported gyro problems. Radar showed the aircraft turning right despite instructions to turn left. The aircraft completed two 360-degree turns in a steep right bank before disappearing from radar. Wreckage was located about 90 minutes later in Mohawk Park, approximately 1.75 miles north of the airport. There was no fire.
Injuries and Damage
The pilot sustained fatal injuries; no ground injuries occurred. The aircraft was destroyed by impact forces.
Pilot and Aircraft Information
The 31-year-old pilot held a commercial certificate with instrument and multi-engine ratings. He had accumulated 4,373 total flight hours, including 695 hours in the Aero Commander 500-B. The 1961-model Aero Commander 500-B (serial number 1118-68) had 17,888 flight hours at its last inspection on January 10, 2008. It was powered by two 290-horsepower Lycoming IO-540-B1A5 engines.
Meteorological Conditions
At the time of the accident, Tulsa International Airport reported a broken ceiling at 600 feet, overcast at 1,900 feet, visibility 3 miles in rain and snow, temperature 31°F, and wind from 300° at 18 knots gusting to 24 knots. The pilot received a weather briefing.
Communications and Radar Data
Forty-five seconds into the flight, air traffic control cleared the aircraft to 6,000 feet with a left turn to 250°. The pilot acknowledged. At 1 minute 59 seconds, the controller noted a right turn. At 2 minutes 55 seconds, the pilot reported, "I think I have lost my gyros, I'm trying to level out now." The controller informed him of a right 360. The pilot acknowledged further difficulty. At 3 minutes 54 seconds, the controller asked for altitude, but no response was received, and the aircraft disappeared from radar. Radar data showed a left turn after departure, then a gradual right turn that developed into a tight right spiral until impact, with a maximum recorded ground speed of 156 knots.
Wreckage and Impact Examination
The debris field extended over a wooded area. The outboard portion of the left wing was found first, followed by the outboard portion of the right wing, the empennage, and the fuselage. All fractures of wing and empennage structures were characteristic of ductile overload with no evidence of preexisting failures such as fatigue or stress corrosion. Deformation indicated positive loading upward on both wings. The empennage separated at the fuselage-empennage junction. The left horizontal stabilizer showed upward loading, and the right horizontal stabilizer showed downward loading, indicating a roll left to right, characteristic of an in-flight breakup with the right wing failing first.
The rudder control cable, a multi-strand spiral wound steel cable with protective coating, was failed approximately 8 inches from the rudder. The cable was uniformly rusted due to apparent failure of the protective coating in service; the protective strips were also rusted and the coating cracked. The failure mode could not be determined without advanced microscopy. The rudder itself was fractured and folded, with ductile overload fractures.
Both engines were examined and found to have continuity, compression, and no anomalies. Propellers were at low blade angles at impact, with no preexisting discrepancies. Vacuum pumps, fuel flow dividers, and vacuum system components were tested and showed no abnormalities.
Medical and Pathological Information
An autopsy determined the cause of death as blunt force trauma. Toxicological tests were negative.
Additional Information
The wreckage was released to the owner's representative after the investigation.