WPR15FA195

The pilot's failure to maintain clearance from terrain during low-level airwork, which resulted in uncontrolled collision with terrain. Contributing to the accident was the pilot's impairment from the combined effects of butalbital and codeine.

The private pilot was performing airwork and was in contact with an air traffic controller. The pilot informed the controller that he would be performing airwork between 2,500 and 10,000 ft mean sea level (msl). The controller explained that he would probably lose radio contact and would not be able to provide flight following below 7,000 ft msl. About 1 hour later, the pilot advised the controller that he would be descending, then would climb to 9,000 ft msl and return to the airport, and the controller acknowledged. Subsequently, the controller made several attempts to contact the pilot, but no further response was received from him. Shortly thereafter, an airplane flying in the area of the accident site reported to air traffic control that a small fire was located in a river bed. Local authorities responded to the fire and confirmed that it was the accident site. A review of Federal Aviation Administration radar data showed the airplane performing multiple turns and rapidly changing altitude and airspeed while performing the airwork. At one point, the airplane descended to less than 100 ft above a mountain ridgeline. The last radar targets showed the airplane heading eastbound about 1,600 ft agl while approaching the area of the accident site. Two witnesses located near the accident site stated that, as the airplane flew overhead, they noted no engine anomalies. Postaccident examination of the wreckage did not reveal any preimpact malfunctions that would have precluded normal operation. Wreckage and impact signatures were consistent with a high-energy high-angle impact with terrain. It is likely that as the pilot continued to perform low level airwork, he did not properly gauge the airplane's distance from terrain and failed to control the airplane in time to avoid impacting terrain. The pilot's high cholesterol and the medications he was using to treat it likely did not cause any acute symptoms. Limited samples were available for toxicology testing; therefore, it could not be determined whether the ethanol detected in the pilot's muscle tissue was due to ingestion or postmortem production nor whether impairment due to ethanol contributed to the accident. The testing also detected butalbital and codeine, both of which are impairing. The butalbital was within the therapeutic level, indicating that he was likely impaired by it. The presence of both codeine and butalbital indicates that the pilot had likely recently used a combination product that contained at least these two medications. Therefore, it is likely that the pilot's mental and/or physical abilities required for the duration of the high workload flight performance was impaired by the combined effects of butalbital and codeine and that this impairment contributed to the accident.

The pilot was ejected from the airplane during the accident sequence. The Ventura County Coroner's Office did not conduct an autopsy on the pilot because of the condition of the body. The pilot had reported high cholesterol and the use of the prescription drugs rosuvastatin and fenofibrate to treat it to the FAA. The FAA's Bioaeronautical Sciences Research Laboratory performed toxicology testing of the pilot's muscle tissue. The testing detected 0.046 gm/dl of ethanol, 2.033 ug/g of butalbital (the therapeutic range is between 1 and 10 ug/ml), and 0.033 ug/g of codeine. Ethanol may be detected due to ingestion, or it may also be produced by postmortem microbial activity in the body. Ethanol significantly impairs pilots' performance even at low levels. FAA regulations prohibit any person from acting or attempting to act as a crewmember of a civil aircraft while having 0.040 gm/dl or more ethanol in the blood. Butalbital and codeine are frequently combined with acetaminophen, aspirin, and/or caffeine in prescription medications to treat pain or headaches. The combination of the two drugs carries the following warning: "Butalbital, Acetaminophen, Caffeine, and Codeine Phosphate Capsules may impair mental and/or physical abilities required for the performance of potentially hazardous tasks such as driving a car or operating machinery. Such tasks should be avoided while taking this combination product. Alcohol and other CNS [central nervous system] depressants may produce an additive CNS depression when taken with this combination product and should be avoided." Examination of the accident site revealed that the airplane was destroyed by high-impact forces and postimpact fire, which was observed along the debris path; the fire burned about 1 acre of land surrounding the accident site. The wreckage, including all major structural airplane components and primary flight controls, was located in a dry creek bed and was contained within a debris path that was about 641 ft long and 355 ft wide. The first identified point of contact (FIPC) was a trough of disturbed ground about 2 ft wide, 20 ft long, and 1 ft deep, consistent with an airplane attitude of 45-degrees nose down and right wing downward about 90-degrees from level flight. The wreckage debris path was oriented along a magnetic heading of about 360° from the FIPC to the main wreckage. A green light emitting diode navigation light was found near the FIPC. At the end of the trough was a crater, about 11 ft in diameter and 5 ft deep. Two separated propeller blades, a landing gear strut with the wheel attached, and distorted pieces of sheet metal were found in and near the crater. The dirt in the crater was discolored and smelled of fuel. A third propeller blade, the wing and fuselage sections, and the engine bull gear assembly were found between the crater and the main wreckage. The main wreckage was located about 180 ft from the FIPC and included the empennage, aft fuselage, firewall, and engine, and the wreckage was twisted and distorted. Wire bundles and cabin instrumentation were found with the main wreckage, and all of it was burned and crushed. The fourth propeller blade was located about 80 ft past the main wreckage. All four propeller blades revealed S-type bending, chordwise scoring, and leading-edge gouging near the tips. The attached parachute and canopy were found in several sections past the main wreckage and in line with the center of the debris field. A single-point refueling port was found 641 ft from the FIPC and was the last piece of wreckage found along the debris path. The aft fuselage and tail section structure were partially intact, and cable control continuity was confirmed to the midsection of the fuselage. The aileron control cables were found with the main wreckage. All primary flight controls were found in the debris field. The engine exhibited thermal discoloration and impact damage. The first stage of the compressor section was visible, and all of the blades exhibited rotational signatures. The third stage was also visible from the damaged housing and exhibited rotational signatures. Follow-up Examination The wreckage was relocated to a secure facility where a layout examination took place. The examination of the wreckage revealed no evidence of any preimpact mechanical malfunctions or failures that would have precluded normal operation. The wing sections exhibited leading edge crush damage. The main spar was found in several sections with bending near the midsection. Each of the ailerons were found in two 3-ft sections. The wing flaps exhibited signatures suggesting that they were in the retracted position during impact. Both elevators and horizontal stabilizers were impact damaged and crushed. The trim actuator shaft had separated midspan, and 45° shear lips were observed on the separation surfaces. The trim actuator shaft was measured from the shaft bolt to the rubber seal and was 3.845 inches long, which equated to about a 0.5° (near neutral) pitch trim position. The rudder and vertical stabilizer sustained impact damage and remained attached via the rudder control cables. The vertical stabilizer and aft fuselage remained secure at all the attachment points. The propeller assembly, which had separated from the engine during the accident sequence, was impact damaged. The cylinder, piston, feathering spring, and hub were found separated into numerous sections. Hub sections were removed from two of the four blade shanks. The blades revealed leading edge gouging and chordwise scoring from the shank areas to the tips. Two of the blades were bent rearward from the midsection to the tip and had a decreased pitch twist from the midsection to the tip. Another blade had a slight rearward bend, and the last blade was bent forward from the midsection to the tip. For further information, refer to the Hartzell Propeller Teardown Report in the public docket for this accident. The engine was found separated in three major sections: the bull gear, second-stage compressor housing and impeller, and the turbine stator outer vane support housing. Other loose engine parts were found in the debris field. The engine exhibited damage signatures consistent with the engine operating during impact. For further information, refer to the Honeywell Aerospace Engine Wreckage Examination Notes in the public docket for this accident. The cabin instruments had separated from the instrument panel and were impact damaged. The rpm gauge face had separated from the instrument housing and was bent; white paint transfer marks were visible near the '100' displayed on the face. The torque gauge face had white paint transfer marks between the '80' and '100' displayed on the face. Data recorded by the Meadows Field Airport, Bakersfield, California, automated weather observation station, located about 41 miles northeast of the accident site, included winds from 180° at 4 knots, visibility clear, temperature 24°C, dew point 3°C, and an altimeter setting of 30.01 inches of mercury. The two-seat, low-wing airplane, serial number (S/N) T31, was manufactured in 1989. It was powered by a Honeywell (Garrett) TPE331-12B-703A engine, S/N P-65617, rated at 1,100 shaft horsepower at a propeller speed of 2,000 rpm. The airplane was equipped with a Hartzell propeller, model HC-D4N-5C. Review of the maintenance records showed that an annual inspection was completed on October 20, 2014. The airplane was produced to meet stringent military requirements and was designed for high-g landing loads; advanced fatigue testing; and spin tests, including inverted spins, at all altitude. On June 22, 2015, about 0930 Pacific daylight time, an experimental, exhibition-category Short Brothers PLC S312 Tucano T MK 1 airplane, N206PZ, impacted terrain about 16 miles south of Maricopa, California. The private pilot was fatally injured, and the airplane was destroyed. The airplane was registered to Tuc