CEN16FA114

The pilot's failure to maintain airplane control during takeoff, which resulted in the airplane exceeding its critical angle of attack and an aerodynamic stall/spin. Contributing to the accident was the pilot's impairment due to his combined use of central nervous system depressant medications and the illicit drug marijuana, which degraded his ability to maintain control of the airplane.

The airline transport pilot and the passenger departed in the experimental amateur-built airplane that he had recently purchased on a cross country flight. After takeoff, the airplane drifted slightly right in a wings-level climbing attitude. A turn to the left with a bank angle of more than 30° began, and the airplane pitched nose-up followed by an immediate nose-down spin to the left. An onboard display unit recorded a left roll in excess of 80° and an indicated airspeed of 79 knots. Given that the airplane's estimated stall speed in level flight was about 49 knots and its estimated stall speed in a 75° bank is about 98 knots, it is likely the airplane entered an aerodynamic stall. An examination of the wreckage did not reveal evidence of any preimpact anomalies that would have prevented normal operation of the airplane. Damage to the propeller blades was consistent with engine power being delivered to the propeller, and witness marks indicated that the canopy was latched. The investigation was unable to determine if the pilot's psychiatric conditions impaired his ability during the accident. There was no evidence that the pilot's cardiovascular disease was impairing. However, toxicology testing detected high levels of the medications buspirone and hydroxyzine and of tetrahydrocannabinol, the active compound in the illicit drug marijuana, in the pilot's blood. All three of these drugs are potentially-impairing, central nervous system (CNS) depressants, and, in combination, each drug may enhance the CNS depressant effects of the other drugs. Therefore, it is likely that the combination of the three drugs impaired the pilot's ability to safely fly the airplane.

According to the airport manager at 4M1, the airplane arrived there about 1600 on Saturday, February 27, 2016. He stated that the pilot did not sound accustomed to aircraft radio phraseology, and the airplane made its approach well below glideslope, almost at the tree tops; he did not see the landing/rollout. The airport manager reported that the pilot was the only person onboard and that the pilot told him that he had just arrived from Florida. The manager fueled the airplane with 12.5 gallons of 100 low lead aviation gasoline. The pilot remarked to the manager how little fuel he had burned since his takeoff from Florida, and he stated he was going to Las Vegas. The pilot purchased a quart of motor oil for the airplane. However, the manager did not see the pilot add the motor oil to the airplane, nor was there a used bottle in the trash receptacle on the aircraft parking ramp after the airplane departed about 1000 the next day (February 28, 2016). The airport manager observed the airplane depart with the pilot and a male passenger onboard. Again, the pilot sounded unfamiliar with radio usage and phraseology. The pilot asked where the airport's tower was located and requested the frequency for Razorback Approach. The airplane departed on runway 25 into a left-quartering headwind of 11 kts gusting to 43 kts. The manager reported that it was "VERY windy" and it appeared that the pilot lifted the airplane off before developing enough ground roll/airspeed for a safe takeoff. The manager further reported that the climb out immediately after liftoff also appeared to be very uncoordinated. The airplane made a wide turn to the northwest, away from the wind, and continued the turn into a southeast heading. He indicated that the airplane's engine sounded normal. The investigation was unable to determine which occupant was manipulating the flight controls during the accident flight. The Tarrant County Medical Examiner determined that the pilot's cause of death was massive blunt force trauma, and the manner was consistent with an accident. The report documented cardiomegaly (an enlarged heart) with moderate to severe coronary artery atherosclerosis but did not identify ischemic heart muscle damage. Tarrant County toxicology testing detected the potentially-impairing sedating antianxiety medication hydroxyzine at 8,298 ng/ml, the antidepressant medication venlafaxine at 20,393 ng/ml, and its metabolite norvenlafaxine at 784 ng/ml in cavity blood. The FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, toxicology testing detected marijuana's potentially-impairing psychoactive compound tetrahydrocannabinol (THC) in lung at 1373 ng/ml, in brain at 22 ng/ml, in liver at 121 ng/ml, and in cavity blood at 56 ng/ml. Tetrahydrocannabinol carboxylic acid (THC-COOH), THC's primary inactive metabolite, was detected in the lung at 102 ng/ml, in brain at 25 ng/ml, in the liver at 1361 ng/ml, in urine at 807 ng/ml, and in cavity blood at 21ng/ml. On his most recent FAA medical application, the pilot denied any medical concerns or the use of medications. Personal medical records from a January 2016 examination (about a month before his FAA medical review) documented a history of multiple psychiatric hospitalizations, recurrent major depression (currently mild), generalized anxiety disorder, and insomnia. His prescribed medications included bupropion (considered potentially impairing) and venlafaxine (generally not considered impairing) for depression and the potentially-impairing medications buspirone, clonazepam, and hydroxyzine for anxiety. The 33-year-old male passenger was not a pilot. However, a flight training handbook was found in his belongings. The Tarrant County Medical Examiner determined the passenger's cause of death was massive blunt force trauma and the manner was consistent with an accident and did not identify any significant natural disease. Toxicology testing in two laboratories detected ethanol ranging from 0.126 - 0.127 g/dl in blood and 0.141 - 0.150 g/dl in vitreous. Ethanol is primarily a social drug that acts as a central nervous system depressant commonly found in beer, wine, and liquor. After ingestion and absorption, ethanol is quickly distributed throughout the body's tissues and fluids fairly uniformly. The distribution pattern parallels the water content and blood supply of each organ. It is also produced after death by microbial activity. In addition to impairing judgment, attention, and response times, ethanol, at doses between 0.06 gm/dL and 0.10 gm/dl blood alcohol concentration, significantly impairs the user's ability to maintain upright posture and balance. At 0752, the recorded weather at the Abilene Regional Airport, near Abilene, Texas, located about 3 miles from 82TS, included wind 340° at 12 kts, visibility 10 statute miles, sky condition clear, temperature 11°C, dew point 2°C, and altimeter 30.10 inches of mercury. The 63-year-old pilot held a Federal Aviation Administration (FAA) airline transport pilot certificate with a multi-engine rating. He held commercial pilot privileges for single-engine land airplanes. The pilot was issued an FAA second-class medical certificate during his most recent medical examination dated February 16, 2016. The medical certificate had a limitation that the pilot must have glasses available for near vision. On the application for this medical certificate, the pilot reported that he had accumulated 8,010 hours of total flight time and 10 hours of flight time in the 6 months before the exam. The airplane came to rest upright about 189 ft and on a magnetic heading of 330° from the departure end of runway 35. The airplane's resting heading was about 360° magnetic. The airplane's propeller and propeller flange separated from the engine crankshaft. The propeller was found embedded in the ground about 1 ft below the surface. When removed, the propeller blades exhibited chordwise abrasions and leading-edge nicks. The engine mounts and engine cowling were deformed rearward and crushed consistent with the nose of the airplane impacting terrain. The leading edge of both wings exhibited aft deformation consistent with a nose-low impact with terrain. The empennage was attached to the fuselage and wrinkle deformation was observed at the juncture of the two. The cockpit canopy was found separated from the fuselage. The canopy's latch was found in the latched position, and the latching assembly was deformed, consistent with impact damage. The canopy handle was missing from its canopy handle block. The center section of the canopy handle block, which holds the canopy handle, exhibited a vertical tear where the canopy handle was housed. The left aileron separated from its wing. The control stick was moved, and the attached right aileron and the elevators moved accordingly. The rod end to the left aileron moved when the control stick was moved. The control cables at the rudder pedals were manipulated by hand, and the rudder moved. Flight control continuity was established. A liquid consistent with 100 low lead aviation fuel was found in the fuel line routed to the engine-driven fuel pump and in the fuel line to the carburetor. The right magneto was found separated from its accessory pad. Both magnetos were removed from the wreckage, and their ignition leads cut near their towers. Both magnetos were rotated by hand, and sparks were observed at all ignition leads. The engine-driven fuel pump sustained impact damage, and its base was separated from its body. The engine-driven fuel pump produced suction when its slotted shaft was manipulated with a flat-bladed screwdriver. A liquid consistent with the smell of aviation gasoline subsequently exited the engine-driven fuel pump fitting. The sparkplugs were removed. One spark plug was oil fouled, and the remaining plugs exhibited a brown color consistent with normal combustion. The carburetor was removed from the intake. The ca