BEECH 58

Full Narrative

HISTORY OF FLIGHTOn February 16, 2022, about 1707 eastern standard time, a Beech 58 airplane, N58LF, was destroyed when it was involved in an accident near Lexington, North Carolina. The private pilot was fatally injured, and the driver and passenger of an impacted tractor-trailer sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.
The pilot arrived at Davidson County Airport (EXX), Lexington, North Carolina, that afternoon to pick up his airplane after completion of an annual inspection. Witnesses observed the pilot performing engine runs to varied rpms before departure, then an aborted initial takeoff attempt, followed by a taxi back to the maintenance facility for corrective action due to a reported door latch issue. The pilot then returned to the runway to initiate takeoff.
Three witnesses who were on the airport ramp observed a portion of the takeoff roll, rotation, and initial climb before losing sight of the airplane just before impact. One witness reported seeing smoke trailing the right engine when the airplane rotated. Airport security video captured white smoke trailing the airplane about the time the airplane rotated and continued until the airplane went out of sight of the camera, about halfway down the runway. The second witness, who was also a pilot, reported that the right engine was spewing dense white smoke that the airport video did not accurately depict. The witnesses noted the airplane leveled off or decreased the nose-up pitch attitude, with one reporting hearing engine gyrations that he either associated with one engine losing power or the engines being out of sync. A photograph taken by one of the witnesses when the airplane was about 2,664 ft down the 5,004-ft-long runway depicted the airplane in a climb attitude with the landing gear extended and smoke trailing the right engine. As the airplane continued the landing gear retracted and, about that time, the right engine lost power and the propeller stopped rotating. When the airplane was at the departure end of the runway, either white or white/blue smoke was noted trailing the left engine and the airplane was described as not having power. The airplane was observed banking to the left, stalling, and pitching nose down before disappearing behind terrain.
Another witness, who was located about 1/4 mile north of the accident site, observed the airplane departing, and an “…engine wasn’t turning.” He observed the airplane descend, heard a loud sound, then saw smoke.
The airplane subsequently impacted a tractor-trailer. The driver of the impacted tractor-trailer reported that he was travelling at 65 mph at the time of the collision. After the tractor-trailer turned over and came to rest, the driver and passenger evacuated the vehicle’s cab.
A video recording from a tractor-trailer that was traveling behind the impacted tractor-trailer showed the airplane in a very slight nose-up attitude before impact. Although the impact with the tractor-trailer was not recorded, the video did show the tractor-trailer rolling onto its side and an eruption of flames. AIRCRAFT INFORMATIONThe 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 the maintenance facility researched the engine manufacturer Standard Practice Maintenance Manual Spark Ignited Engines, section 6-5.7, Foreign Object Contamination, and subsequently returned the airplane to service after removing all internal contamination to his satisfaction.
The EXX airport manager reported that there was no record of the pilot purchasing any fuel from them since arriving near the middle of October.
According to a Federal Aviation Administration Safety Team Presentation regarding pre-ignition and detonation, detonation is an explosion of the fuel/air mixture inside the cylinder and occurs near or after top dead center. It causes the fuel/air charge to explode rather than ignite smoothly. Because of the explosion the charge exerts a much higher force on the piston and cylinder, causing a reduction in power. The presentation further indicated that detonation can be caused by improper ignition timing, high inlet air temperature, engine overheating due to bent baffles, or oil or carbon buildup in the combustion chamber. Additionally, a lean fuel to air ratio can cause detonation.
The airplane’s Pilot’s Operating Handbook and FAA-approved airplane flight manual specified that for takeoff the mixture control was to be full rich unless required to be leaned for field elevation. AIRPORT INFORMATIONThe 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 the maintenance facility researched the engine manufacturer Standard Practice Maintenance Manual Spark Ignited Engines, section 6-5.7, Foreign Object Contamination, and subsequently returned the airplane to service after removing all internal contamination to his satisfaction.
The EXX airport manager reported that there was no record of the pilot purchasing any fuel from them since arriving near the middle of October.
According to a Federal Aviation Administration Safety Team Presentation regarding pre-ignition and detonation, detonation is an explosion of the fuel/air mixture inside the cylinder and occurs near or after top dead center. It causes the fuel/air charge to explode rather than ignite smoothly. Because of the explosion the charge exerts a much higher force on the piston and cylinder, causing a reduction in power. The presentation further indicated that detonation can be caused by improper ignition timing, high inlet air temperature, engine overheating due to bent baffles, or oil or carbon buildup in the combustion chamber. Additionally, a lean fuel to air ratio can cause detonation.
The airplane’s Pilot’s Operating Handbook and FAA-approved airplane flight manual specified that for takeoff the mixture control was to be full rich unless required to be leaned for field elevation. WRECKAGE AND IMPACT INFORMATIONExamination of the accident site revealed the airplane impacted on grass immediately adjacent to a three-lane highway. Marks in grass adjacent to the edge of the highway were oriented on a southerly heading and were nearly perpendicular to the highway in that area. The accident site was slightly less than 2,000 ft south-southwest of the departure end of runway 24.
Further examination of the accident site revealed the cockpit and cabin were upright about 394 ft south-southwest from the initial ground impact location. The impacted tractor-trailer was resting on its left side immediately adjacent to the cockpit, cabin, and aft empennage, which was separated. Extensive thermal damage from the postimpact fire was noted to the cockpit and cabin. There was no evidence of in-flight fire in either engine compartment.
Examination of the flight controls revealed no evidence of preimpact failure or malfunction of the primary or secondary controls for roll, pitch, or yaw. The left and right flap actuators were extended 2.25 inches and 2.0 inches, respectively, which equated to flaps retracted. The left and right elevator trim tab actuators were extended 1.3 inches and 1.6 inches, respectfully, which equated to 15° tab trailing edge down, and 27° tab trailing edge down, nose-up position. The rudder trim tab actuator was extended about 4.6 inches which equated to 25° tab trailing edge left, nose right, which was the maximum value. The aileron trim tab actuator was extended 1.4 inches, which equated to 2° tab trailing edge up. The landing gear doors were closed and the landing gear actuator drive rods and the landing gear trunnions were in the retracted position.
The fuel selectors for the left and right engines were positioned to the left and right fuel tanks, respectively. Examination of the airframe fuel supply and vent systems revealed no evidence of preimpact failure or malfunction. However, the fuel supply system on each engine sustained thermal damage that consumed portions of the hoses and aluminum lines. The fuel supply line and hose b-nuts that remained attached to the associated fittings throughout the fuel system were secured. Both fuel boost pumps sustained thermal damage and were not tested.
Examination of the left engine, which separated during the impact sequence, revealed it sustained impact and heat damage. Crankshaft, camshaft, and valvetrain continuity was confirmed. Thumb suction and compression were confirmed for each cylinder during multiple 360° rotations of the crankshaft. No preimpact failure or malfunction was noted to the air induction, exhaust, ignition, or lubricating systems. There was also no evidence of preimpact failure or malfunction of the fuel metering components, including the manifold valve, engine-driven fuel pump, throttle body, and fuel metering valve. The No. 3 fuel injector nozzle was not installed in the cylinder but remained attached to its fuel injector line, and all threads of the separated fuel injector nozzle were sooted. All other nozzles and fuel injector lines remained properly installed. Definitive clean and soot line areas on the threads that engage in the cylinder threads were noted for the remaining nozzles that were properly installed in each cylinder. Metallurgical examination of the crown portions of the outer threads of the No. 3 fuel injector nozzle showed that they were intact and showed no evidence of shearing or thread stripping.
Examination of the right engine, which separated during the impact sequence, revealed crankshaft, camshaft, and valvetrain continuity. Thumb suction and compression were confirmed for each cylinder during multiple 360° rotations of the crankshaft. No preimpact failure or malfunction was noted for the exhaust or lubricating systems. Following removal of the No. 1 cylinder, damage was noted to the aft side of the piston (as installed) near the chamfered edge. Visual examination of the No. 5 cylinder revealed a white residue near the fuel injector nozzle port. The Nos. 1 and 5 cylinder assemblies were examined in detail, and the head portion of the No. 1 piston at the bevel edges showed evidence of minor erosion features, and the skirt portion showed evidence of minor longitudinal scoring marks. The inner top surface of the No. 1 cylinder combustion chamber and the exhaust valve of that cylinder exhibited minor grit blast-like appearance. Fourier transform infrared spectroscopy of the white residue near the No. 5 cylinder fuel injector nozzle port revealed the spectrum was consistent with a carboxyamine or a mixture of materials containing amines and carboxylic acids (common additives to aviation gasoline used for deposit control, antioxidants, and anti-corrosion control often contain these types of materials).
Examination of the ignition system of the right engine revealed both magnetos were impact separated from the engine, and extensive impact damage was noted to the ignition leads. Examination of the No. 1 cylinder spark plugs revealed both exhibited black color and normal wear, and during postaccident testing at 80 psi both plugs produced a strong blue spark with no evidence of preimpact failure or malfunction.
No preimpact failure or malfunction was noted to the right engine exhaust, lubricating system, or manifold valve. Heat damage to the metering valve precluded operational testing without replacement of internal packings or o-rings; testing was not performed. Some non-ferrous particles were noted in the oil pump housing. Disassembly inspection of the engine-driven fuel pump, which was impact-separated from the engine, revealed no evidence of preimpact mechanical failure or malfunction. Operational testing of the pump at the manufacturer’s facility following replacement of impact-damaged components (but without changing the adjustment) revealed the pump discharge pressure was 15.69 psi, or about 47% greater than the maximum specified limit when operated to 2,600 pump rpm.
Examination of the left propeller revealed both blades were bent forward in the thrust direction, consistent with it developing power at the time of impact. Disassembly and examination of the propeller revealed an impact mark in the feather range and two impact marks in the low pitch range of the preload plate of the No. 1 blade. The feather range mark was excluded after concluding it was an impact sequence mark. One impact mark was at blade angle of 29°, while the other impact mark was at blade angle of 16°. Two impact marks were noted in the low pitch range of the preload plate of the No. 2 blade. One impact mark was at blade angle of 29°, while the other impact mark was at blade angle of 14°. The lower values for both blades were in the low pitch range. There was no evidence of preimpact failure or malfunction of the left propeller.
Examination of the left propeller governor, which sustained heat damage, revealed the control arm did move though the return spring was loose, likely due to heat damage. Although operational testing of the left propeller governor was not performed, there was no evidence of preimpact failure or malfunction.
Examination of the right propeller revealed both blades were near the feather position and the internal pitch change mechanism was intact. One blade exhibited chordwise static scoring on the blade face at the tip, while the other blade exhibited slight aft bending, consistent with the propeller not developing power at the time of impact. There was no evidence of preimpact failure or malfunction of the right propeller.
Examination of the right propeller governor revealed it rotated freely. The screen was clean. Some non-ferrous particles flowed from oil in the pump during hand rotation of it. The position of the control head was not documented because of separation of the engine from the airframe. There was no evidence of preimpact failure or malfunction of the right propeller governor. MEDICAL AND PATHOLOGICAL INFORMATIONAn 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.