History of the Flight
On March 24, 2017, at 1924 eastern daylight time, a Cessna 500 (N8DX) collided with terrain in a residential neighborhood near Marietta, Georgia. The pilot was fatally injured, and the airplane was destroyed by impact forces and postcrash fire. The flight was a Title 14 Code of Federal Regulations Part 91 business flight operated by Shelter Charter Services Inc., originating from Cincinnati Airport–Lunken Field (LUK) about 1812 and destined for Fulton County Airport–Brown Field (FTY) in Atlanta, Georgia. Visual meteorological conditions existed near the accident site, and the flight operated under an instrument flight rules (IFR) flight plan.
The aircraft was equipped with a cockpit voice recorder (CVR) that began recording at 1853. Air traffic control (ATC) transcripts indicate that the pilot received routing amendments and subsequently expressed difficulty with the Garmin GTN 750 GPS unit. The pilot reported "steering problem" and "very little steering" during the descent, and stated he had his "autopilot back" at one point. The pilot eventually declared an emergency and asked for runway landing lights to be turned up. The last communication from the pilot occurred at 1923:44, when he reported lowering the landing gear. The CVR captured sounds of strain, the pilot saying "it's going down," autopilot disconnect tone, and Terrain Awareness and Warning System (TAWS) alerts of "sink rate" and "pull up."
Personnel and Aircraft Information
The pilot, aged 78, held a private pilot certificate with multiple ratings, including multiengine land and instrument airplane. He purchased the accident airplane in May 2001 and received a Cessna 500 type rating in 2002. His last FAA third-class medical certificate was issued on September 27, 2016, with a limitation for near/intermediate vision glasses. No logbooks were available, so overall currency and flight experience in the accident airplane could not be verified. A friend, who was a flight instructor and mechanic, stated that the pilot was "very confused" with the Garmin GTN 750 unit and was "very dependent on the autopilot." The friend also noted that the pilot did not trim the airplane before engaging the autopilot, leading to complaints of the airplane being uncontrollable.
The airplane was an eight-seat business jet powered by two Pratt & Whitney Canada JT15-1A turbofan engines, with a Sierra Industries Eagle wing modification and wing extension. It was retrofitted with a JetTech LLC Supplemental Type Certificate (STC) that upgraded the flight panel to a Garmin GTN 750 display, integrated with a Sperry (now Honeywell) SPZ-500C autopilot/flight director system. The autopilot provided automatic control in pitch, roll, and yaw. The airplane was also equipped with a Bendix/King KGP560 GA Enhanced Ground Proximity Warning System (EGPWS).
Witness Observations
Several witnesses observed the airplane before impact. A professional pilot described seeing the airplane flying level below the cloud layer, then making a complete 360-degree roll to the left, followed by a steep 90-degree bank to the left, similar to a "military high key turn." The airplane then rolled inverted and entered a sudden vertical nose-down dive. Another witness observed a "barrel roll" with the nose slightly elevated, then a second roll, after which the airplane slowed, nose pointed down, and it spiraled downward counterclockwise.
Wreckage and Impact Examination
On-scene examination revealed the airplane impacted the front yard of a home approximately 15 miles north of the destination airport. The wreckage indicated an upright, nose-level, wings-level attitude with little forward momentum. A postimpact fire consumed most of the cockpit, fuselage, left wing, and inboard portion of the right wing. Flight control continuity was established from each primary control system to the cockpit. The landing gear was extended. Both engines exhibited damage consistent with operation at impact. No preimpact anomalies were found that would have precluded normal operation. Examination of autopilot components showed no evidence of failure and no preimpact anomalies.
Available Recorded Data
The CVR recorded the entire accident sequence from 1853 to 1924. Data from the TAWS unit recorded two warnings: a Mode 1 Sinkrate warning at 4,000 ft with descent increasing to about 8,500 fpm, followed three seconds later by a Mode 1 Pull Up warning at 2,900 ft. The data ended approximately seven seconds later with a descent rate of nearly 12,000 fpm.
Meteorological Conditions
At Cobb County International Airport–McCollum Field, about three miles west of the accident site, the reported weather at 1947 included wind from 160° at 8 knots, visibility 10 statute miles, overcast ceiling at 5,500 feet, temperature 21°C, dew point 9°C, and altimeter setting 30.28 inches of mercury.