History of Flight
On November 17, 2018, about 1835 eastern standard time, an experimental amateur-built Lancair Legacy RG, registration N8448J, was substantially damaged when it struck tree tops and terrain during an approach to Lee Gilmer Memorial Airport (GVL) in Gainesville, Georgia. The private pilot owner of the airplane was fatally injured, and a flight instructor was seriously injured. The flight was conducted under 14 Code of Federal Regulations Part 91 as an instructional flight.
The accident occurred on the third flight of the day. The first flight was a local solo flight by the flight instructor, during which he performed three takeoffs and landings at GVL. The second flight, with both pilots aboard, departed GVL for Charleston Executive Airport (JZI) in South Carolina. The third flight departed JZI about 1728 and arrived in the vicinity of GVL at 1835, approximately one hour after sunset.
As the airplane approached GVL, the flight instructor requested clearance for a practice GPS approach to runway 23, which was approved by the air traffic controller. Runway 23 has an elevation of 1,276.9 ft mean sea level and is equipped with a two-light precision approach path indicator (PAPI) on the left side.
A witness, who was in an airplane waiting to take off from runway 23, observed the accident airplane approaching. He reported seeing the landing lights, which "became dim and they appeared to roll 180 degrees" before the accident. The flight instructor recalled that the pilot was flying the airplane on the approach when the airplane suddenly became inverted, but he did not recall further details.
Flight Data and Aircraft Performance
According to flight data recorded by the airplane's primary flight display (PFD), while at 3,500 ft msl with the autopilot engaged, the airplane arrived at the initial approach fix from the southeast and turned left onto the inbound course. About 12 seconds before reaching the final approach fix, the autopilot vertical mode changed from altitude hold to glidepath mode. Just after passing the final approach fix at an indicated airspeed of 165 knots, the flaps were extended to 17°. The pitch attitude changed from 0° to about 9° nose down, airspeed increased to 177 knots, and the airplane descended below the glidepath. The autopilot elevator servo applied nose-up torque, and the airplane stabilized slightly above the glidepath for about 16 seconds. The pitch attitude then increased slightly, causing the airplane to drift above the glidepath as the autopilot applied nose-down torque.
About 2.6 nautical miles from the runway at 2,200 ft msl (923 ft above runway elevation) and 138 knots, the landing gear were lowered. The airplane drifted farther above the glidepath. The elevator servo torque increased, and the electric pitch trim (controlled by the autopilot) increased continuously from 8 to 67 units in the nose-down direction (near full nose-down) as the elevator servo continued applying nose-down torque. The pitch attitude decreased to about 2.5° nose down, but the airplane remained above the glidepath. The course deviation indicator (CDI) showed nearly full-scale "fly down". Engine power was 42% for most of the approach.
About 1.6 miles from the runway at 1,900 ft msl (623 ft above the runway) and 127 knots, as the pitch trim reached 67 units, the autopilot was disengaged. About 15 seconds later, the flaps were extended to 40°, remained for about 5 seconds, then fully retracted. As the flaps retracted, the airplane descended through the glidepath, descent rate increased from about 600 to 1,200 fpm, and pitch attitude slowly increased from about 2° nose down to 2° nose up. Roll attitude varied between 8° left wing down and 3° right wing down. Engine power was reduced to 32% about 4 seconds before data ended. The last recorded data point was at about 0.3 mile from the runway, on extended centerline, at 1,323 ft msl (46 ft above runway), 110 knots, 1,029 fpm descent, wings level, pitch about 2.5° nose up, CDI full-scale "fly up".
About 0.1 mile from the runway, the airplane struck tree tops at approximately runway elevation (about 50 ft tall in a valley) at the edge of a four-lane divided highway perpendicular to the runway. The airplane then descended and impacted terrain and a wooden platform holding the localizer antenna for runway 05, about 500 ft from the approach end of runway 23.
Aircraft and Systems Information
The two-seat, low-wing, composite, retractable tricycle gear airplane was built in 2015. It was equipped with an autopilot and an electric pitch, roll, and yaw trim system. According to a Lancair Owners and Builders Organization training manual, deploying flaps causes the nose to pitch down, requiring up-elevator trim, and that "flight without an operational pitch trim system is difficult."
The Garmin G3X Pilot's Guide includes a section on "Overpowering Autopilot Servos" stating that applying pressure to the pitch controls when the autopilot is engaged can cause the automatic trim to run to an out-of-trim condition. It warns that overpowering the autopilot will cause the trim to run, possibly to the stop, resulting in larger-than-anticipated control forces after disengagement. The guide also notes that the autopilot can disengage automatically due to system failure, invalid sensor data, or inability to compute default modes, but does not indicate disengagement due to excessive control or trim forces. No failures were noted in the recorded data.
Wreckage and Impact
A 175-ft-long debris path extended from the localizer platform along a heading of 215° magnetic to the main wreckage, which came to rest upright on a heading of about 225°. Additional debris was found near the struck trees. The left wingtip and one landing gear door were found in the highway median. Tree branches and limbs were strewn from the tree line across the highway.
Examination revealed all major components present. The left wing was fractured and partially separated about 2 ft from the root; the left flap was completely separated. The right wing was fractured and partially separated at the root, with the right aileron and about 4 ft of outboard wing separated. The vertical stabilizer was fractured in several locations. A 1-ft-long outboard section of the left elevator was separated. The elevator trim tab was deflected trailing edge upward (airplane nose down). The aileron trim tab was faired. The right flap was in the retracted position. All circuit breakers were in except the 3-amp starter relay breaker, which was out.
Rudder controls were intact and continuous. Aileron controls were continuous through several bending overload breaks. Elevator controls were continuous through an overload fracture in the aft push-pull tube rod end. The elevator trim tab was deflected 30°-35° trailing edge up relative to the elevator. The elevator trim tab servo actuator arm was nearly in the full nose-down position; the motor functioned normally when powered. The pitch trim switches on both control sticks functioned normally. The autopilot elevator servo motor rotated freely.
The engine remained attached to the airframe, with the propeller attached to the crankshaft flange. Chordwise scratches were present on all three propeller blades, with leading edge gouges and aft bending on two blades. Top spark plugs exhibited light-colored combustion deposits. The fuel pump discharged fuel when turned by hand. Fuel nozzles were unobstructed. Engine crankshaft rotated by hand produced spark on all six ignition leads, with thumb compression and suction on all cylinders. No anomalies were noted that would have precluded normal operation.
Additional Information
On the evening after the accident, a contractor flew the GPS approach to runway 23 at the request of the airport manager. He noted that the PAPI lighting system appeared consistent with the GPS approach path.
The Hall County Coroner's Office performed an autopsy on the pilot; cause of death was generalized trauma. Toxicology testing identified Alfluzosin and Ibuprofen in urine, neither of which is considered impairing.
A review of the PFD data from the previous four landing approaches showed that they were flown with the autopilot off. Each approach used flaps in two steps (initial 15-20°, then 35-40°) but at slower airspeeds compared to the accident flight. Pitch attitude changes during flap deployment ranged from 1° to 6° nose down. Recorded pitch trim values from all previous landings ranged from -12 (nose up) to +22 (nose down) units. A review of ten previous flights dating back to October 7, 2018, showed limited use of the autopilot for short durations, and no other flights used the autopilot during an approach to landing.