ERA24FA371

The flight instructor and owner of the airplane had been providing flight instruction to the non-certificated student pilot, who was not yet old enough to obtain a student pilot certificate. Earlier on the day of the accident, the airplane was flown from its home airport to an airport with a grass runway that was about 155 nautical miles away. About 2 hours after the airplane arrived at that airport, a witness observed the airplane as it was departing and recorded a video of its initial takeoff roll from the grass runway. Neither the witness nor the video observed the airplane’s liftoff or the accident. The airplane was later found at the accident site, which was located in a wooded area adjacent to the runway. The airplane was equipped with brake controls only in the left front seat position, where the non-certificated student pilot was seated, so it is likely that the non-certificated student pilot controlled the airplane during at least some portion of the taxi, as it would have been difficult to maneuver the airplane on the ground without differential braking. Because the flight instructor’s logbook indicated that he had been providing instruction to the non-certificated student pilot, it is possible that she also manipulated the flight controls during the accident takeoff. Regardless, the flight instructor was the only certificated pilot aboard the airplane with access to the flight controls, and was responsible for ensuring the airplane remained under positive control. He was also responsible for intervening as necessary to maintain the safe operation of the airplane. Since the airplane was not equipped with brake controls for the front right seat occupant, if an emergency arose during takeoff that required the takeoff to be aborted, the flight instructor would not have the ability to stop the airplane using conventional braking. The only braking option for the flight instructor would be the use of the parking brake. However, there was no evidence that the accident sequence involved an attempted rejected takeoff. Postaccident examination of the accident site and wreckage revealed that the airplane impacted terrain in a left-wing-low, nose-low attitude, consistent with an aerodynamic stall at low altitude. The main landing gear remained extended, and the landing gear control switch was in the extended position, consistent with the accident occurring shortly after takeoff. Examination of the engine revealed that the fuel injector servo throttle stop was missing the plastic material that surrounded the stop pin, which allowed the throttle to move slightly past the normal full throttle stop. The fuel injector servo was tested on a production test bench at an overhaul facility and the servo operated normally. The slight movement of the throttle past the normal full throttle stop likely did not result in a loss of power. Overall, no evidence of any mechanical malfunctions or failures of the engine were found that would have precluded normaloperation. A sound spectrum analysis of the witness video indicated that, at the beginning of the takeoff roll, the propeller was rotating at approximately 2,500 rpm. The airplane was equipped with a constant-speed propeller with a maximum governed speed of 2,700 rpm. The observed propeller speed, approximately 200 rpm below the maximum governed speed, could have been consistent with several possibilities, including the propeller governor setting, reduced engine power, or an improperly positioned propeller control. However, since the video ended early in the takeoff roll, it could not be determined whether the engine’s rpm increased further along the takeoff roll. The airplane’s tachometer was impact damaged; therefore, its accuracy could not be verified. The airplane was equipped with a digital engine monitor that recorded limited engine parameters such as the exhaust gas temperatures (EGT) and cylinder head temperatures (CHT). The last recording revealed that, at the time when recording stopped, the EGTs were at levels consistent with high engine power; though, the engine rpm and manifold pressure could not be precisely calculated. The EGTs were compared to the previous flight that day, and were comparable to those recorded during that flight. Although the available evidence did not allow the engine rpm to be determined throughout the takeoff roll, the engine monitor data provided no evidence of a loss of engine power or other mechanical malfunction that would have precluded normal engine operation. Postaccident examination of the airframe revealed that the alternate air door was in the open position. The alternate air door was intended for use when the air filter or inlet was suspected of being clogged with debris or ice. The airplane’s alternate air door was installed in a location that would bring in unfiltered, warm air from inside the engine cowling, which typically resulted in a slight reduction in engine performance because of the lower density of the warmer air. Because the air filter was not found obstructed during the postaccident examination of the airplane, and icing conditions were not present, it is possible that the flight instructor inadvertently left the alternate air on following an operational check. According to the airplane’s Owner’s Handbook, the alternate air door should be closed for takeoff. Further examination of the airplane’s configuration revealed that the flaps were in the retracted position, which was confirmed by the witness video. The airplane’s Owner’s Handbook recommended a flap setting of 25° for takeoffs from soft fields (like the grass runway the airplane was departing from) to improve takeoff performance. Additionally, the elevator trim was found set for a slightly nose-down attitude, despite the handbook’s recommendation to trim for takeoff so that only very light back pressure on the wheel was required to lift the airplane. Two weight-and-balance calculations were performed. One assumed the airplanedeparted the home airport with full fuel, and the other assumed it departed fueled to an intermediate position. The calculation for full fuel at the home airport revealed that the airplane was within the maximum weight limitations; however, the center of gravity (CG) was forward of the forward-most CG limit. The calculation for the airplane being filled to the intermediate position revealed that it was still within the maximum weight limitations and was just within the forward CG limit. A forward CG can increase the back-elevator pressure and elevator control forces required to control an airplane’s pitch, and can result in a higher stall speed. The airplane’s configuration, including the alternate air in the open position, the flaps retracted rather than being in the 25° setting recommended for takeoffs from a soft surface, and a slight nose-down trim setting, was not consistent with the Owner’s Handbook recommendations for optimizing takeoff performance. Collectively, these configuration discrepancies likely reduced the airplane’s takeoff performance and indicate that the flight instructor had not ensured that the airplane was properly configured before takeoff. Additionally, the airplane’s likely forward-biased CG would have resulted in a higher stall speed, and increased the risk of an aerodynamic stall. Coupled with the reduced takeoff performance as a result of the airplane’s mis-configuration, it is likely that the flight instructor lost control of the airplane during the initial climb after the airplane encountered an aerodynamic stall, resulting in an uncontrolled descent at an altitude too low to recover.

The airplane was equipped with a Lycoming IO-360-B1E engine that produced 180 horsepower at a maximum engine speed of 2,700 rpm. The airplane was equipped with flight controls accessible from both front seats; however, brake controls were installed only at the left front seat position. A review of the airplane’s Owner’s Handbook revealed that flaps were normally retracted for normal takeoffs; however, for short-field takeoffs or takeoffs under difficult conditions, such as a soft surface, takeoff distance could be reduced appreciably by lowering the flaps to 25° (second notch). The Owner’s Handbook also stated that the primary air source (alternate air in the Closed position) should always be used for takeoff. According to the airplane’s maintenance logbooks, the last annual inspection was performed on April 18, 2024, at a tachometer time of 2,134.0. The next entry in the airframe logbook documented the installation of a JPI EDM-700 engine monitor and a Hobbs meter switch. At the time of the last annual inspection, the engine had accumulated 2,134.0 hours total time. According to the engine logbook, the engine had been installed on the airplane on September 16, 1967, and had never been overhauled. The airplane’s maximum gross weight was 2,500 lbs. The aft CG limit was 95 inches regardless of weight. The forward limit was 91.0 inches at 2,500 lbs and 81 inches at 1,925 lbs, with straight line adjustments in between. A fuel consumption calculation was performed to estimate the fuel used for the flight from IJD to B06. The calculation indicated the airplane would have consumed about 10.8 gallons of fuel. Because the airplane’s fuel load when it departed IJD could not be determined, two separate weight-and-balance calculations were performed. Both of these calculations considered the postmortem weights of the airplane’s occupants, the estimated weight of baggage recovered from the airplane after the accident, and the airplane’s basic empty weight of 1,472 as listed in weight and balance documentation found in the wreckage. The first calculation assumed the airplane had been fueled to the maximum capacity (50 gallons). The calculation indicated that, at the time of the accident, the airplane would have weighed 2485.6 lbs with a CG position of 89.87 inches. The CG would have been forward of the calculated forward CG limit of 90.86 inches. The second calculation assumed that the airplane had been filled to the “tabs” (36 gallons). The second calculation indicated that, if the airplane departed IJD with fuel to the “tabs,” it would have weighed 2,401.6 lbs at the time of the accident, with a CG position of 89.69 inches. The CG position would have been just within the calculated forward CG limit of 89.31 inches. According to the FAA’s Pilot’s Handbook of Aeronautical Knowledge, a forward CG location increases the back-elevator pressure and elevator control forces required and results in a higher stall speed due to increased wing loading. On September 8,2024, at 1225 eastern daylight time, a Piper PA-28R-180 airplane, N3757T, was substantially damaged when it was involved in an accident near Vergennes, Vermont. The non-certificated student pilot, flight instructor, and two passengers were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The airplane had departed Windham Airport (IJD), Willimantic, Connecticut, earlier that morning for Basin Harbor Airport (B06), Vergennes, Vermont, about 155 nautical miles away from IJD. ADS-B data revealed that after departing IJD, the airplane flew toward B06. The airplane’s last ADS-B-derived position was recorded at 1016, when the airplane was about 1,000 ft north of the approach end of runway 20 at B06. The ADS-B-reported altitude was 250 ft msl. No ADS-B data were available for the airplane’s departure from B06 on the accident flight. A witness recorded a video of the airplane as it departed B06 on the accident flight. The video’s metadata revealed that the airplane’s takeoff roll began about 1224. The airplane rolled down the runway until it exited the frame and the video ended. A review of the video footage revealed that the flaps were in the retracted position. Additionally, the video captured the sound of the engine operating. The witness did not observe, and the video did not capture, the airplane’s liftoff, initial climb, or the accident. The Vermont Department of Health conducted autopsies on the flight instructor and the uncertificated student pilot. The cause of death for both the flight instructor and the non-certificated student pilot was multiple blunt force injuries, and the manner of death for each was accident. The FAA Forensic Sciences Laboratory performed toxicological testing of postmortem specimens from the flight instructor and the non-certificated student pilot. No tested-for substances were detected in specimens from the non-certificated student pilot. Tamsulosin and Losartan were detected in the flight instructor’s blood and liver. Tamsulosin is an alpha blocker used to treat benign prostatic hyperplasia and is considered acceptable for pilots. Losartan is used to treat high blood pressure and is considered acceptable for pilots by the FAA. According to the flight instructor’s logbook, the occupant in the left front seat had been receiving flight instruction from the flight instructor since April 14, 2024. The left seat occupant did not hold a student pilot certificate and was ineligible to obtain one due to her age; however, her age did not prohibit her from receiving flight instruction. The flight instructor occupied the right front seat. According to FAA records, the flight instructor’s most recent second-class medical certificate was issued on August 12, 2022. A sound spectrum analysis of the witness video was performed to determine the engine rpm at the time of the initial takeoff roll. Between 0 and 2 seconds of elapsed video time, the airplane’s propeller wasapproximately perpendicular to the witness, which negated the Doppler effect. Additionally, because the witness was close to the airplane, the time required for sound to reach the recording device was considered negligible and was not accounted for. A Fast Fourier Transform of the audio over this interval showed a fundamental blade passage frequency (BPF) of 83.5 Hz, corresponding to an engine speed of approximately 2,500 rpm. The continuity and stability of the fundamental BPF and its harmonics throughout the recording were consistent with steady engine operation. The airplane was equipped with a JPI EDM-700 engine monitor, which was recovered for data download. The data were downloaded successfully and showed that the engine monitor was set up to record at a 6-second-per-sample rate. Recorded parameters included cylinder head temperatures (CHT), exhaust gas temperatures (EGT), battery voltage, and shock cooling rate. The last recording was consistent with the accident flight. Early in the recording, the EGTs increased to levels consistent with engine operation. After about 4 minutes and 36 seconds, the EGTs rose to levels consistent with high engine power, ranging from 1,266°F to 1,300°F. The last recorded data point remained with EGTs ranging from 1,297°F and 1,343°F. The data did not show an increase in EGTs before the final data points that would indicate that an engine run-up had been performed. A review of data from the previous flight showed that the first increase in EGTs was brief and consistent with engine operation. A second, sustained increase in EGTs was similar to the EGT levels recorded during the accident flight and ranged from 1,296°F and 1,343°F. The airplane impacted terrain in a wooded area about 375 ft east of the departure end of runway 20 at B06. The first identified impact point was a ground scar that contained a portion of the left wingtip. The airplane came to rest approximately 30 ft from the initial impact point. All major components of the airplane were accounted for within the wreckage area, and there was no evidence of fire. The left wing exhibited impact damage, had separated from the fuselage, and was found inverted and adjacent to the fuselage. The right wing remained attached to the fuselage and displayed impact damage to its leading edge. The fuselage sustained impact damage primarily to the forward cabin area, instrument panel, and engine compartment. The empennage remained attached to the fuselage and was relatively intact. Several branches at the accident site exhibited 45° cuts consistent with propeller strikes. Flight control cable continuity was established for all flight controls except for breaks in the left aileron direct cable and the aileron balance cable. The breaks displayed tensile overload signatures. The stabilator trim mechanism had 0.45 inches of rod extended on the top side of the drum. This position corresponded to a partial nose-down trim setting. The flaps were in the retracted position.The main landing gear was extended, and landing gear control switch was in the extended position. The nose landing gear was impact damaged and found in the retracted position. The tachometer was impact damaged, and the engine rpm needle was captured by a portion of the instrument face. The engine rpm needle indicated approximately 2,300 rpm. The fuel selector valve was in the Left position and in the detent. Low-pressure air was blown through the fuel selector valve, which was unobstructed in both the Left and Right positions. The left main fuel tank was devoid of fuel; however, blue staining was noted around the fuel filler cap and the rivet line around the fuel tank. The left fuel system was breached at the fuel line between the left fuel tank and the fuel selector valve; the damage was consistent with impact. The right fuel tank contained approximately 1.5 gallons of fluid with a color and odor consistent with 100LL aviation fuel. A sample of the fluid from the right fuel tank was free of contaminants and a test using water-finding paste was negative for the presence of water. The right fuel system was breached at the fuel line to the fuel selector valve; the break exhibited signatures consistent with impact damage. The engine remained attached to the airframe by portions of the tubular engine mounts, wires, hoses, and cables. The crankcase remained intact, and there were no signs of a catastrophic engine failure. The crankshaft was rotated by hand, and continuity was established between the crankshaft, camshaft, connecting rods, and associated components. During crankshaft rotation, all four cylinders displayed good thumb compression and suction. All rocker arms and valves operated normally during crankshaft rotation, with the Nos. 2 and 4 rocker arms exhibiting reduced movement, which was consistent with the impact damage to the push rods. The cylinders were inspected using a lighted borescope; all piston faces displayed normal operating and combustion signatures. The cylinder walls displayed varying amounts of surface corrosion and scoring. All intake valve heads displayed normal operating and seating signatures. The No. 1 exhaust valve head displayed a slight greenish tint uniformly around its outer diameter; however, the valve head was intact, was not deformed, and displayed normal seating signatures. The remaining exhaust valves displayed normal operating, combustion, and seating signatures. All overhead components (valve stems, springs, and rocker arms) displayed normal operating and lubrication signatures. Both magnetos remained attached to their respective installation points and exhibited minor impact damage. Due to impact damage to the starter gear and support, magneto timing could not be verified. Both magnetos were removed, and their drive shafts rotated normally. The left magneto impulse coupling remained intact and operated normally during rotation. During impulse coupling operation, the magneto was capable of producing a sparkon all four towers. The right magneto drive was rotated using a drill, and the magneto produced spark on all four towers. The left magneto ignition lead harness displayed significant impact damage, and all four leads were either partially or completely severed; there were no signs of chafing or shorting. The right magneto ignition leads displayed less impact damage; however, several of the leads were partially severed. The right ignition leads were capable of conducting a spark from the magneto to the ignition lead end or to the first section of impact damage. The spark plugs were removed and visually examined and consisted of a mixture of Champion and Tempest plugs. All the spark plugs displayed normal wear and operating signatures when compared with Champion Aviation Service Manual AV6R and Tempest Aviation Spark Plugs Installation and Maintenance Manual 1710A. The fuel pump remained attached to its installation point and was undamaged. Both the inlet and outlet fuel lines remained secured. The fuel pump was disassembled; its internal components displayed normal operating signatures. The fuel pump drive plunger was in place and operated normally during crankshaft rotation. The fuel injector servo remained attached to its installation point and displayed minor impact damage. The throttle and mixture control rod ends remained attached at both the cockpit controls and the fuel injector servo. The throttle and mixture control arms were capable of movement from stop to stop. The throttle stop was missing the plastic material surrounding the stop pin. The alternate air control was found in the Open position in the cockpit. The valve inside the engine cowling was also found in the Open position; however, the airbox was impact damaged. The fuel inlet and outlet fuel lines remained secured, and there were no signs of fuel leaks. The fuel inlet screen was removed and was clear of obstructions. The fuel flow divider remained attached to its installation point and was undamaged. The inlet fuel line and the fuel pressure indication line remained secured, and there were no signs of fuel leaks. The flow divider was removed and disassembled; the internal components displayed normal operating signatures, and there were no signs of obstructions. All four fuel nozzles remained installed in their cylinders and displayed varying amounts of impact damage, with the No. 2 nozzle displaying the most damage. The fuel lines remained secured to the nozzles and flow divider, and there were no signs of fuel leaks. All the fuel nozzles were removed and were unobstructed. The oil suction screen was removed and contained particulates with the consistency of carbon; however, the screen was not obstructed. The oil pressure filter remained attached to the oil filter adapter and exhibited impact damage. The oil filter was removed, and the filter housing was cut open. The filter pleats were visually inspected, and no anomalies were observed. The propeller governor remainedattached to its installation point and exhibited impact damage. The propeller control rod end remained attached to the propeller control arm; however, the control arm had separated from the remainder of the governor in a manner consistent with impact damage. The governor was removed, and the gasket screen was unobstructed. The governor drive was rotated by hand, and the governor pump operated normally. The two-blade constant-speed propeller remained attached to the crankshaft, and both blades were secure in the propeller hub. One propeller blade exhibited minor impact damage including minor aft bending, leading-edge polishing, and a gouge in the leading edge. The opposing propeller blade displayed aft bending and twisting deformation, leading edge polishing, and small gouges near the blade tip. The fuel injector was bench tested and examined at a fuel system overhaul facility. The bench testing demonstrated that the servo was capable of normal operation despite the missing the plastic portion of the throttle stop.