History of Flight
On February 28, 2019, about 1040 central standard time, a Piper PA46-350P airplane, N428CD, was substantially damaged when it was involved in an accident near Shreveport Downtown Airport (DTN), Shreveport, Louisiana. The private pilot and passenger were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.
The pilot and passenger were flying to Vernon, Texas, for a hunting trip. According to air traffic control (ATC) information, the airplane departed runway 32 about 1037. After climbing to 600 ft mean sea level (msl), the pilot was instructed to turn left to a heading of 270° and climb to 12,000 ft msl. Recorded weather indicated overcast clouds at 600 ft above ground level (agl). Radar data showed the airplane entered a climbing left turn that continued beyond the assigned heading of 270°. The controller issued a revised heading of 140°, and the pilot responded "standby."
After climbing to 1,400 ft msl, the airplane's altitude and airspeed began to fluctuate as it continued in a tightening left spiral. About 35 seconds after transmitting "standby," the pilot stated, "we're in trouble up here." The airplane subsequently made a decelerating right turn then rapidly descended. The last ATC data recorded a groundspeed of 31 knots at 575 ft msl.
Onboard data showed the airplane's altitude, vertical velocity, and speed oscillated several times and the turn rate increased during the last minute of the flight. From 10:39:25 to 10:39:58, altitude varied from 1,987 to 822 to 1,980 ft msl and vertical velocity fluctuated from -6,001 to +5,834 ft per minute (fpm). The last data captured at 10:40:07 was 1,217 ft msl and -6,818 fpm.
Personnel Information
A review of ForeFlight and FlightAware data revealed that the pilot typically flew about three flights per month during the 12 months before the accident.
The pilot completed initial turbine transition ground and flight training in February 2016 and accomplished recurrent ground and flight training in May 2018. The flight instructor for the pilot's initial flight training stated that the pilot flew well with the autopilot turned on but that his hand-flying skills during instrument training were weak; the instructor also stressed the importance of getting recurrent training often for hand flying.
Aircraft Information
The airplane underwent a JetProp DLX conversion in 2016 and was equipped with a Pratt & Whitney PT6-35 engine and a composite MTV-16 propeller. Avionics included a Garmin G500 primary flight display (PFD) and multifunction display (MFD), a dual Garmin GTN 750/650 GPS, an Avidyne EX600 MFD, L3 ESI-500 backup instrument system, and a King KFC 225 autopilot.
Based on pilot and passenger weights provided by the coroner, a fuel load of 120 gallons, and baggage weights from the wreckage examination, the airplane's ramp weight was estimated to be 4,906 lbs and the center of gravity was about 145.41 inches. The maximum ramp weight is 4,358 lbs and the allowable center of gravity range was 143.3 to 147.2 inches. The pilot had been informed by Rocket Engineering Corp. of ongoing efforts to increase the maximum ramp weight to 4,518 lbs.
Wreckage and Impact Information
The airplane came to rest inverted about 17 ft below the surface of the Red River. Post-recovery examination revealed the left and right wings were fractured and remained attached to the fuselage, which was deformed with aft buckling. The vertical and horizontal stabilizers were attached to the empennage, and the elevator and trim tab were attached to the vertical stabilizer. The rudder, left aileron, left flap, portions of the right flap, and nose baggage door were separated and not recovered.
Examination of the flight control system found aileron cables remained attached to the control sectors, and cable continuity was established to the cabin controls. Rudder and elevator cable continuity was established through the cabin to their respective control surfaces, and the elevator trim cables showed broom-straw separations aft of the pressure bulkhead. The pitch trim indicator pointed to full nose-down and the pitch trim barrel was in a position correlating to full nose down.
A vacuum-operated attitude indicator (AI) was mounted on the far-right side of the instrument panel. The AI was removed and disassembled; the rotor and housing showed no obvious rotational scoring.
The fuel selector was positioned between left and right tanks, the landing gear selector was down, the flap selector was up, and the standby vacuum pump was on. The throttle, speed, and condition levers remained attached. The throttle lever was set at "INCR," the speed lever fully forward, and the condition lever at a mid-travel position.
The engine remained attached to the firewall with the exhaust section crushed. The propeller, propeller flange, and part of the reduction gearbox were separated and not recovered. An Electronics International MVP-50T engine data monitor (EDM); Appareo Stratus GPS receiver; autopilot; and pitch, roll, and yaw servos were recovered for further examination.
EDM data captured included torque, fuel flow, fuel/oil pressures, and engine rotational speeds. No anomalies were observed during taxi, takeoff, climb, or turning oscillations. Postaccident examination did not reveal any preaccident malfunctions or failures with the airplane or engine that would have precluded normal operation.
Additional Information
The mechanic who performed the airplane's last annual inspection stated that the pilot told him of intermittent issues with the autopilot system, such as not following a selected heading or course. The airplane was scheduled in November 2018 for work on this issue, but the appointment was not kept. In January 2019, the pilot told the mechanic the autopilot issue had not yet been fixed.
About 2 years before the accident, the pilot asked the mechanic to install a "round dial" turn coordinator because the pilot had inadvertently entered an unusual attitude during a previous flight and wanted a turn coordinator available in addition to the attitude information on the "glass panel" avionics. The mechanic, also a pilot, had flown with the accident pilot and thought his instrument flying skills were deficient.
The pilot's girlfriend, who flew with the pilot on several flights during the months before the accident, stated the autopilot would frequently not engage after takeoff. When this occurred, the pilot would focus on getting the autopilot to operate during the departure. On one of these flights, she became concerned when the airplane entered an unusual attitude.
Medical and Pathological Information
According to the Louisiana State University Health Sciences Center autopsy report, the pilot's cause of death was multiple blunt force injuries.
FAA Forensic Sciences Laboratory toxicology testing detected tetrahydrocannabinol's (THC) psychoactive metabolite (11-hydroxy-delta-9-THC) in the pilot's urine but not in his blood. THC's non-psychoactive metabolite, carboxy delta-9 THC (THC-COOH), was detected in the pilot's urine and blood. THC itself was not detected in blood or urine. The metabolite 11-hydroxy-delta-9-THC is as psychoactive as marijuana but is rapidly metabolized to THC-COOH, which can be found in urine days to weeks after last use. Positive test results for THC metabolites in both blood and urine do not reflect recent marijuana use and cannot determine that the user was under the influence at the time of testing.
Toxicology also detected tetrahydrozoline, an over-the-counter eye drop medication commonly marketed as Visine, in the pilot's urine but not in his blood. It is not considered to be impairing.
According to the pilot's girlfriend, the pilot was physically and mentally healthy, routinely played active sports, and had no issues with dizziness or vertigo. She reported he had been using a continuous positive airway pressure machine over the last year to help him sleep soundly and had been sleeping well over the last several months. She thought he was well rested for the flight. Other than his cholesterol medication, the pilot reportedly took a marijuana gummy in the evening to help him sleep.
Tests and Research
The autopilot system was examined at the manufacturer's facility. Testing of the three servos and mounts revealed out-of-tolerance measurements; however, they should not have affected proper function.
Three error codes were logged during the accident flight: manual electric trim (MET) fail, roll monitor fail, and yaw fail. The MET fail code indicated a possible latent failure of the manual electric trim switches detected during flight. According to the maintenance manual, when a MET fail is detected, manual electric trim is disabled, and the autopilot is automatically disengaged. The autopilot remains unavailable until a successful preflight test occurs. All flight director modes remain active.
A roll monitor fail is logged when the aircraft experiences roll rates in excess of +/-14 degrees per second or a roll attitude of +/-45 degrees. The autopilot automatically disconnects when the roll monitor is tripped, and all flight director modes are disengaged.
A yaw fail is logged when a yaw rate in excess of 12 degrees per second exists. When yaw fail is logged, yaw damper mode becomes inactive without affecting other autopilot modes.
Any of the three error codes may or may not have been logged because of a hardware failure not related to the flight computer, and the autopilot did not have to be engaged for an error code to be logged. For example, the maintenance manual recommended checking the control wheel for a physically stuck trim switch following a MET fail error.
If the autopilot had received electrical power via the avionics power switch immediately after engine start, the MET error code, roll monitor fail code, and yaw fail code occurred 29, 41, and 67 seconds after takeoff, respectively. Based on the pilot activating the avionics power switch 30 seconds after engine start, the MET error code likely occurred about 60 seconds after takeoff. The first altitude oscillation recorded on the EDM occurred about 105 seconds after takeoff.