ERA22FA126

Inadequate maintenance, which led to a partial loss of both right and left engine power during takeoff, and the pilot’s subsequent failure to maintain airspeed while maneuvering with one engine at low altitude. Contributing to the accident was the pilot’s failure to detect the partial loss of left engine power during the early part of the takeoff.

The pilot was initiating takeoff following completion of an annual inspection, which included replacing and repairing components of the right engine’s No. 1 cylinder, likely due to detonation that occurred during the flight before the accident flight. During the takeoff on the accident flight, witnesses noted significant smoke trailing the right engine at rotation. The witnesses noted that, as the airplane continued over the runway, the right engine lost power and the right propeller feathered. The landing gear retracted and, at the departure end of the runway, white/blue or white smoke was noted trailing the left engine, followed by a perceived loss of power from that engine. The airplane continued off-airport, encountered an aerodynamic stall, and impacted a tractor-trailer travelling on a nearby highway, resulting in a postimpact fire. Postaccident examination of the airframe revealed no evidence of preimpact failure or malfunction of the flight controls or flaps, and there was no evidence of an in-flight left engine fire. Examination of the engines revealed early signs of detonation on the No. 1 piston of the right engine. In addition, the No. 3 cylinder fuel injector nozzle of the left engine was not installed in the cylinder but remained attached to the fuel injector line throughout the flight. Given these findings, it is likely that both engines sustained a partial loss of engine power during takeoff. The witness reports of seeing smoke trailing the left engine when at the departure end of the runway were likely the result of the No. 3 cylinder fuel injector nozzle that was not installed on its respective cylinder. Based on blade impact angles and performance estimates from the propeller manufacturer, it is likely that the left engine exhibited about a 15% power reduction from full rated power during the takeoff. The reduction of left engine power and corresponding rpm would likely have been evident to the pilot from the moment of full power application until about 60 knots, at which point the airflow over the left propeller would have been sufficient for the propeller to operate at full rated rpm. The witness report of the right engine’s power loss and the feathering of the right propeller was likely the pilot’s response to the start of detonation in the No. 1 cylinder. Causes for detonation include improper ignition timing, high inlet air temperature, engine overheating, oil in the combustion chamber, carbon build-up in the combustion chamber, an issue with the fuel octane, or a lean fuel to air mixture. Although the position of the right mixture control at the start of the takeoff could not be determined from the available evidence, it is unlikely that the pilot would have leaned the fuel to air ratio, especially since it was the first takeoff after repairs due to detonation damage following a flight for which he was the pilot. In addition, operating the engines with the fuel to air ratio leaned during the accident takeoff would have been contrary to the takeoff procedure specified in the Pilot’s Operating Handbook and FAA-approved airplane flight manual. Aside from signs of detonation, the No. 1 cylinder and piston, spark plugs, fuel injector nozzle and line, manifold valve, and engine-driven fuel pump of the right engine were eliminated as having any evidence of preimpact failure or malfunction. Impact and/or heat damage, along with impact-separated components of the ignition system, including both magnetos and ignition harness, baffling, cowling, air induction, and fuel metering systems, as well as there being no remaining fuel due to the postimpact fire, precluded determination of preimpact failure or malfunction for these components. Although the root cause of detonation could not be determined from the available evidence, had maintenance facility personnel thoroughly investigated the fuel metering, ignition, and air induction systems and reviewed data from the engine monitor from the previous flight in which the No. 1 cylinder of the right engine exhibited detonation, it is likely that they could have identified and addressed any mechanical reason for the detonation. While moderate atherosclerosis was detected in one segment of the pilot’s left anterior descending coronary artery, there was no evidence to suggest an acute cardiac event occurred; from medical records, he was in good cardiovascular health. Although a disqualifying stimulant used to treat attention deficit hyperactivity disorder (ADHD) was detected during postaccident toxicological testing, the circumstances of this accident do not suggest inattention or fatigue. Thus, the pilot’s cardiovascular medical condition, the effects of his use of methylphenidate, and his ADHD were likely not factors in this accident.

An autopsy of the pilot was performed by the North Carolina Office of the Chief Medical Examiner. According to the autopsy report, the cause of death was blunt force injuries and the manner of death was accident. Other than moderate atherosclerosis in his left anterior descending coronary artery, no significant natural disease was identified by the medical examiner. Toxicology testing performed by the FAA Forensic Sciences Laboratory detected the central nervous stimulant methylphenidate in the pilot’s urine at 51 nanograms per milliliter (ng/mL); methylphenidate was also detected but not quantified in his cavity blood. The non-impairing pain and fever reducer medication acetaminophen (commonly marketed as Tylenol) was also detected in the pilot’s cavity blood and urine. Toxicology testing performed by the medical examiner did not detect ethanol in the pilot’s pleural cavity blood. Methylphenidate, commonly marketed as Ritalin or Concerta, is indicated for the treatment of attention deficit hyperactivity disorder (ADHD) and for the sleep disorder narcolepsy. Methylphenidate is a controlled substance and has a high potential for abuse; side effects can include psychotic or manic symptoms. Methylphenidate’s therapeutic range is 10 to 60 ng/mL and it has a half-life of 2 to 7 hours. ADHD, formerly called attention deficit disorder (ADD), is a mental health disorder that features inattention, impulsivity, and hyperactivity. It is also associated with impairments in motor inhibition, reaction time, visual-motor coordination, decision-making, and rule-governed behavior. In the inattention type, the person may be disorganized, easily distracted, and have difficulty sustaining focus. Adolescents and young adults with ADHD are 2 to 4 times more likely to have been the driver in a motor vehicle accident than peers without the illness. Results of a recent systematic review indicate that the use of therapeutic levels of stimulants to treat ADHD did not worsen driving performance and generally improved driving performance in ADHD patients. For FAA medical certification, the airman needs to have a neuropsychological evaluation after stopping medications three months before testing. The FAA does not allow the use of methylphenidate for medical certification. After reviewing the medical records, the FAA may deny or grant an unrestricted or special issuance medical certificate. At the time of the pilot’s most recent FAA medical examination, in December 2019, he reported taking no medications and having no medical conditions. Records obtained from the pilot’s primary care doctor for the three years before the accident revealed he first reported ADHD in March 2020, and was prescribed 20 milligrams methylphenidate to be taken in the morning. At the pilot’s request, the dosage was reduced in December 2021 to 10 milligrams to reduce fatigue when the medication wore off. The pilot reported better ability “to stay on track and get things done” while using the medication. The airplane was equipped with two 285-horsepower engines when operated at 2,700 rpm, and each engine was equipped with a two-blade, constant speed, manually feathering, single-acting propeller. The airplane was also equipped with a graphic engine monitor (data from the engine monitor was not available due to extensive heat damage). By design with the installed propellers, at full throttle application and static conditions, the propeller blades would be on the low pitch stop and the rpm would be slightly less than the full rated rpm value. During the takeoff roll, with the propeller low pitch stop position properly set, as the airspeed increased the propeller would remain on the low pitch stop until the propeller/engine rpm reached 2,700, at which time the governor would maintain 2,700 rpm by changing the propeller blade angle. According to the propeller manufacturer, assuming sea level, standard temperature, and the propeller blades on the low pitch stop setting of 14.5°, the propeller would be absorbing about 8% less than full rated rpm at 40 knots true airspeed (KTAS). Using the same sea level and standard temperature conditions but with the propeller blade angle about 1.5° above the low pitch stop setting, or 16°, the propeller would be absorbing full rated power at about 60 KTAS. At about 81 knots calibrated airspeed, which was the published air minimum control airspeed (Vmca), and 16° propeller blade angle, the propeller was absorbing about 243 horsepower, which was about 15% less than full rated power. According to maintenance records and maintenance personnel at EXX, while inbound to their airport in October 2021 for an annual inspection, the No. 1 cylinder of the right engine exhibited “excessively high” cylinder head temperature (CHT) and exhaust gas temperature (EGT) readings. Witnesses at the airport on that date reported seeing the accident pilot land uneventfully with the right propeller feathered and the right engine secured. The pilot later reported on an internet forum that during cruise flight when flying the airplane to the maintenance facility for an annual inspection, he suddenly noted the No. 1 CHT of the right engine was 540°F, which was 80°F above the maximum continuous CHT limit specified in the Pilot’s Operating Handbook and Federal Aviation Administration-approved airplane flight manual. He reported reducing throttle and the mixture control, then pushed them in before noting the EGT increase for 5 cylinders but not for the No. 1 cylinder. He then feathered the right propeller and continued to his destination. During the annual inspection, maintenance personnel identified no compression in the No. 1 cylinder of the right engine. Borescope inspection of the cylinder revealed damage to the cylinder walls and extensive damage to the piston. Repair station personnel attributed the cylinder and piston damage to be detonation caused by pilot-reported excessive leaning of the fuel to air ratio. No troubleshooting was done by the maintenance facility to determine the root cause of the detonation. Further, no engine data from the on-board engine monitor was downloaded for the October 2021 right engine event to identify the reason for the damage. Repairs to the right engine consisted of removing internal contamination; cleaning, flushing, and inspecting components; installing a serviceable cylinder and connecting rod; and installing a piston with untraceable origin. The damaged cylinder, piston, and non-ferrous material found in the oil sump and oil filter were scrapped and not available for the investigation. In addition, new fuel injector nozzles were installed in the right engine in accordance with (IAW) Supplemental Type Certificate (STC) SE09217SC. Following repairs, the engine was test run with the cowling off to check for leaks, then run with the cowling on for 20 to 30 minutes, at times to full power, with no discrepancies noted and with reported normal engine parameters including fuel pressure/fuel flow, manifold pressure, and rpm. Following “extended ground runs,” the right engine oil filter was cut open and the records reflected “only trace amounts of metal found. Will check again after test flight. After engine run, cut open filter to inspect, found no defects at this time. Installed new filter.” The airplane was not test flown following the annual inspection, nor was it required to be. During the annual inspection, there was no discrepancy reported for the right engine baffling. The maintenance facility did not download data from the on-board engine monitor for any post-maintenance engine runs. The airframe and powerplant mechanic with inspection authorization who had performed most of the annual inspection refused to return the airplane to service because he believed the engine should have been removed and sent out for inspection. Another mechanic (who held airframe and powerplant ratings and an inspection authorization) with