roccoangelella/AeroGraph huggingface dataset:
The pilot stated the engine quit during flight, so he landed the airplane in a river and swam ashore. The airplane was submerged for more than 24-hours before being recovered. After recovery the airframe and engine were examined, but water, impact, and recovery damage inhibited thorough examinations. The fuel system was completely contaminated by water, and it could not be determined if fuel was present at the time of the accident. Examination of the electrical system could not be performed due to water damage. No obvious mechanical anomalies with the airframe or engine were found, and the reason for the reported loss of engine power could not be determined.
Shortly after departure, the pilot detected rapid vibrations from the tail of the helicopter. While returning to the airport, the mounting bolts that secured the tail rotor gearbox to the tail boom failed, which resulted in the separation of the tail rotor. The pilot lost yaw control of the helicopter, but successfully performed an autorotation to the water below. A postaccident examination of the mounting hardware between the tail rotor gearbox input cartridge and the tail boom mating flange found that two of the four bolts were missing; both missing bolts came from the right side of the connection. The left side bolts remained secured in place. The missing bolts’ holes in the input cartridge were deformed and were out of round. All of the 4 bolt holes on the input cartridge displayed imprints from the bolt threads, with the deepest imprints on the right sides of the holes, consistent with movement between the lug holes and the bolt shanks. All tail boom flange bolt holes were examined and found that the threading was present, not stripped, and locking inserts present. About 60 hours before the accident, the tail boom assembly was removed and replaced. As part of this maintenance, the tail rotor input cartridge and gearbox would have been removed from the old tailboom and placed on the new tailboom.  It is likely that, during this procedure, the right-side mounting bolts were not completely secured to the tail boom casting locking inserts and properly torqued, which resulted in the failure of the right side mounting bolts. The helicopter was flown earlier that day without incident or indication of impending failure.
The pilot of the helicopter was conducting a visual flight rules (VFR) cross-country flight from which he failed to return as planned. Radar data depicted the helicopter about 375 ft above ground level and 117 knots with no sudden airspeed or altitude diversions before it impacted an island hillside. The wreckage was located the following day, significantly fragmented and consumed by a postimpact fire. Ground scars and the wreckage distribution were consistent with collision with terrain in a level flight attitude. There was no evidence of mechanical malfunctions or failures that would have precluded normal operation of the helicopter.Review of weather information supported instrument meteorological conditions (IMC) over the area of the accident site and an environment conducive to cloud development below 1,000 ft mean sea level. Satellite data showed that, during the accident timeframe, the northwestern part of the island (where the accident site was located) was affected by cloud cover, although most of the rest of the island was not, or the cloud coverage was not as extensive. The weather information that the pilot may have accessed before the flight could not be determined; however, reports available to him likely depicted higher cloud bases than those present over the accident site at the time of the accident. A first responder reported that low ceilings and visibility were common for the area for that time of year, and typically formed in the early evening hours and persisted overnight into the morning.The circumstances of the accident are consistent with the pilot’s continued VFR flight into a localized area of IMC, which resulted in controlled flight into terrain.
The helicopter operator reported that, during takeoff, the pilot allowed the helicopter to drift aft during a pedal turn, which resulted in the main rotor blades impacting tree branches that outlined the confined area of the landing zone. The pilot completed the remainder of the flight without incident. The helicopter sustained substantial damage to the antitorque gear box. The pilot reported that there were no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation.
The pilot performed two landings on a turf runway and returned for a third approach. The pilot aligned the airplane parallel to the intended runway, about 80 feet to the left of the mowed runway surface. The airplane touched down in dense grass about 3-4 feet tall and travelled about 80 feet before it nosed over and came to rest inverted. The pilot insisted that the brakes had "locked;" however, examination of the airplane revealed that with the brakes fully applied there was little to no braking action and that the airplane rolled with little to no resistance. The accident is consistent with the airplane nosing over due to the landing in tall grass.
The pilot reported that, during landing, the airplane ground looped to the right, the left main landing gear collapsed, and the left wing impacted the ground. The airplane sustained substantial damage to the lower fuselage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.
The pilot reported that, during an agricultural application flight, his attention was focused "on a shed and electrical lines." While maneuvering to the north at a low altitude, the airplane's right wing collided with an unseen galvanized windmill tower. He reported that the tower had blended into the gray sky. He attempted to control the airplane, but it descended and impacted terrain. The airplane sustained substantial damage to both wings and the fuselage. The pilot reported that there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation.
The pilot of the tailwheel-equipped airplane reported that, during takeoff from a soft, grass airstrip, the airplane hit a hole. The airplane then veered right. The pilot attempted to correct to the left, but the airplane hit brush.The airplane sustained substantial damage to the right wing and elevator.The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.
A friend of the pilot located near the lake reported that the pilot had sent him a text message, which said that he was going to do a “fly by” over the lake. The friend stated that, when he saw the airplane, it was about 150 ft above the water and that the pilot did a “wing wag” before the airplane collided with the  power lines strung across the water. The airplane subsequently descended nose down into the water. Postaccident examination of the airplane and engine revealed no evidence of any preaccident mechanical malfunctions or failures that would have precluded normal operation.Toxicological tests detected a level of ethanol in the pilot’s specimens known to cause some impairment. The test results were also consistent with the pilot having recently consumed alcohol before the flight. Therefore, it is likely that the pilot’s impairment from consuming alcohol contributed to the accident.
The pilot reported that, during landing on a remote area, the airplane touched down on the soft tundra, and the airplane nosed over. The pilot added that a better visual assessment of the landing area might have prevented this accident. The airplane sustained substantial damage to both wings. The pilot reported that there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation.
The pilot reported that, during the landing roll, the airplane encountered a "big gust of wind," and the airplane veered left. The airplane exited the runway, impacted a ditch, and nosed over.The airplane sustained substantial damage to the fuselage, vertical stabilizer, and both wings.The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.The airport's automated weather observation station reported that, about 10 minutes after the accident, the wind was from 190° at 10 knots, gusting to 18 knots. The pilot landed the airplane on runway 11. The calculated crosswind component was about 14 knots. The manufacturer's Pilot's Operating Handbook stated, "The maximum allowable crosswind velocity is dependent upon pilot capability as well as aircraft limitations. With average pilot technique, direct crosswinds of 15 knots can be handled with safety."
The pilot reported that during takeoff, as the airplane ascended through about 250 ft above ground level, the engine began to sputter, and he initiated a left turn in an attempt to return to the airport.  Shortly after, the engine lost all power, and the pilot initiated a forced landing to an open area near the departure runway on airport property. During landing, the airplane bounced, became airborne, and traveled across a road before it landed in a parking lot, impacted trees, and came to rest upright.Examination of the engine revealed that the No. 2 cylinder would not produce compression.  Further examination and removal of the cylinder revealed evidence of detonation on the piston and cylinder head.  Due to impact damage sustained to the airplane, throttle, mixture, and propeller control travel limits could not be determined.  Downloaded data from the engine monitoring unit revealed evidence of a low fuel flow rate for takeoff about, or about 8 to 10 gallons per hour below the calculated takeoff fuel burn rate.  Recorded data from the two previous flights before the accident flight indicated that the No. 2 cylinder produced temperatures higher than the manufacturer’s maximum cylinder head temperature limit.  Postaccident testing of the carburetor showed that the carburetor fuel flow rate was slightly higher than the specification and would not have contributed to detonation. It’s likely that the detonation occurred as a result of the reduced fuel flow and lean fuel to air mixture, however, the reason for the reduced fuel flow rate could not be determined.
The noncertificated pilot and passenger had just departed for a local flight. After takeoff, when the airplane was about 100-150 ft above ground level, the pilot felt a loss of engine power and the engine speed decreased to about 3,000 rpm. About 3 seconds later, the engine speed decreased to about 2,300 rpm. The pilot said that he was unable to land on the remaining runway and there were power lines near the departure end of the runway, so he performed a turn back toward the departure runway. According to the pilot, the airplane descended and impacted terrain and sustained substantial damage. Postaccident examination of the airplane revealed no mechanical malfunctions or failures that would have precluded normal operation. According to a carburetor icing chart, the weather conditions were conducive for serious carburetor icing at glide power, about the time of the accident, which would have allowed for carbuerator ice to build up while at reduced power on the ground. The circumstances of the accident are consistent with a loss of engine power due to carburetor icing.
The pilot reported that, during the takeoff roll, the airplane encountered a wind gust, so she added more aileron input to counteract it, but the "gust died down." The airplane then fishtailed, so she attempted to abort the takeoff by reducing power and applying brakes, but the airplane veered right. Despite applying brakes to stop the veer, the left wing settled to the ground, and the airplane came to a stop at the side of the runway. The airplane sustained substantial damage to the left-wing aft spar and engine mounts. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.
While overflying mountainous terrain, the airplane encountered turbulence. The pilot heard a “pop” from the right wing and shortly thereafter, the wing began to shake violently. The pilot was maneuvering the airplane to a forced landing site when the airplane encountered turbulence again and subsequently entered a spin that continued until impact with terrain. The accident site was adjacent to a mountain range where strong thermals likely existed as well as an unstable low-level pressure system. This is likely the cause of the localized turbulence that was encountered by the flight.  Examination of the wing spar revealed in-plane fractures consistent with tensile overstress failure. The fracture sequence started with the fracture of the wing spar, which led to subsequent spar fractures, and eventual buckling and fracture of the connected supporting members and struts. It is likely that the turbulence encounter resulted in excessive loads on the wing and subsequent overstress failure.
The pilot was conducting a maintenance test flight and had been in the air about 15 minutes when airplane began to oscillate up and down. He had difficulty maintaining control, so he made a rapid descent toward the airport. During the rapid descent the oscillation and shaking reduced, but as he decreased the descent rate, the airplane oscillated violently. The airplane landed hard on the grass runway. The airplane sustained substantial damage to the wings, fuselage, and empennage. After the accident, the pilot stated that he thought the tail boom had fractured inflight. A postaccident examination of the airframe revealed that the tubular empennage structure had fractured and was separated. An examination of the fractured section determined that the fractures were due to overstress as a result of the hard landing. A review of the pilot’s calculated weight and balance information revealed that the pilot had incorrectly calculated the weight and balance and that the airplane’s center of gravity (CG) was aft of manufacturer limitations. After the accident, the pilot reported that he was adjusting his CG while airborne, and he placed a bag of bird seed in the passenger seat to assist during the inflight test. The bag was aft of the datum per the manufacturers specifications and would have moved the CG further aft.This likely resulted in an adverse aerodynamic condition and an uncontrollable pitch oscillation.
The pilot and passenger departed on a cross-country flight to their home airport. The passenger reported that, after turning onto final approach for landing, the engine started running rough and the propeller "slowed down." The pilot attempted to restore engine power to no avail. The airplane impacted a 40-ft-tall tree about 550 ft from the runway threshold and about 70 ft north of the extended runway centerline. The pilot did not recall any of the events of the accident flight except the impact with the tree. Examination of the engine revealed no anomalies, and the reason for the loss of engine power could not be determined.
The pilot reported that the airplane landed hard, veered left, and exited the runway. The airplane then impacted terrain and came to rest in a creek. The airplane sustained substantial damage to the left wing. The pilot reported that there were no preimpact mechanical failures or malfunctions with the airplane that would have precluded normal operation.
The pilot was practicing short-field takeoffs from a 3,120-ft soft, turf runway with 800 ft available; the airplane lifted off the ground with about 400 ft of runway remaining. According to the pilot, a light crosswind was present during the takeoff, but the wind may have shifted to a quartering tailwind. During initial climb, the pilot stated he attempted to accelerate briefly in ground effort and subsequently noticed the airplane was climbing poorly and the flight controls "felt sluggish." Unable to clear a line of trees about 300 ft beyond the end of the runway, the pilot pitched down to avoid stalling the airplane and impacted trees. Postaccident examination revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation.Based on the airplane's weight and the ambient conditions, the manufacturer specified that a takeoff distance to clear a 50-ft obstacle was about 920 ft. With a 5 knot tailwind, the takeoff distance to clear a 50 ft obstacle was about 1,100 ft. Further, during the initial climb toward oncoming trees, with little margin for error, the pilot most likely did not adequately accelerate the airplane while in ground effect, as is needed for a soft-field takeoff. Instead, the pilot most likely attempted to climb at a slow speed, which resulted in a settling effect and the inability to clear trees near the departure end of the runway.
The pilots were performing an instructional flight with multiple takeoffs and landings when, during one takeoff, the pilots heard a loud noise, and the right main landing gear (MLG) wheel assembly departed the airplane. The pilots elected to perform an emergency landing at another airport due to its larger runways and emergency personnel and equipment. The airplane landed and came to rest upright on the runway surface. Examination of the airplane after landing revealed that the right main wheel/tire and lower shock absorber assembly departed the upper shock absorber assembly. The separated assembly, which was located near the departure airport, impacted the right horizontal stabilizer after separation, which sustained substantial damage. Metallurgical examination of the assembly revealed that the MLG fractured at the connection between the upper and lower torque knees. Fatigue was identified on a fractured piece of the upper torque knee, and other fractures on the torque knee were consistent with overload. Corrosion assisted in crack initiation, and the crack propagated through fatigue until a critical crack length was reached. It is likely that the fatigue area fractured first and the other connections experienced an increase in loading, which caused them to separate from the MLG assembly.
The pilot was conducting a local flight when the engine started to surge and run rough. He attempted to troubleshoot the problem, but was not able to restore engine power and located a precautionary landing site at an abandoned airstrip. During the landing roll, the airplane drifted right, and the right wing impacted vegetation, which resulted in a ground loop and substantial damage to the airplane.  A postaccident examination of the engine, airframe, and propeller revealed no anomalies that would have precluded normal operation, and the reason for the partial loss of engine power could not be determined.
According to a flight school representative, two solo pilot-rated students were performing pilot-in-command, skills-building training flights. The pilots were taxiing their airplanes to the runway when the pilot in the lead airplane pulled to the right side of the taxiway to allow the pilot in the other airplane to pass. The pilot of the passing airplane was looking at his onboard navigation device as he attempted to pass on the left side of the lead airplane, and his airplane's right wing struck the lead airplane's left wing. Both pilots shut down their airplanes, exited them, and assessed the damage and determined that the damage was minimal, so they departed for the next leg of their training flight. After that flight, flight school maintenance personnel examined the airplanes and found that the lead airplane's left wing aileron and the passing airplane's three right-wing ribs had sustained substantial damage. Both pilots reported that there were no preaccident mechanical malfunctions or failures with the airplanes that would have precluded normal operation.
During a personal flight, the pilot notified air traffic control that he had a rough-running engine, and the pilot declared an emergency. The controller advised the pilot of two diversion airports; the first was located near the airplane’s position at the time, and the second was located about 12 miles south of the airplane’s position. The pilot elected to divert to the second airport. The pilot advised the controller a few minutes later that the airplane would be unable to reach that airport, and the radar track showed a right turn toward the other airport, which was about 8 miles east from the airplane’s position. No further communication from the pilot was received. A witness located near the accident site reported that the airplane maneuvered to avoid power lines and struck light poles before it impacted the ground. A postimpact fire ensued.  Postaccident examination of the wreckage revealed that engine control continuity was established from all the engine controls to their respective engine components. The engine exhibited extensive thermal damage. To prepare the engine for test runs performed by the manufacturer, several components and accessories were replaced due to thermal damage. The engine was successfully run at various power settings. No mechanical anomalies were noted with the recovered parts of the engine and airframe that would have precluded normal operation. As a result, the reason for the partial loss of engine power was not determined.
The pilot of the experimental, amateur-built airplane reported that, while returning to the airport after a local flight, the engine speed "suddenly" decreased from about 5,000 rpm to 2,500 rpm. He trimmed the airplane for its best glide airspeed and began looking for a forced landing site. About 30 seconds later, the engine seized and lost power completely. The airplane touched down short of the pilot's intended landing point and nosed over resulting in substantial damage to the fuselage and empennage. An engine examination revealed that a lower connecting rod bearing had failed, resulting in the total loss of engine power. Maintenance records indicated that an engine overhaul was completed slightly more than 5 years before the accident flight. The engine manufacturer's maintenance schedule specified that an engine overhaul be completed every 5 years or 300 hours, whichever comes first. It is likely that, had the engine been overhauled in accordance with manufacturer guidance, the worn connecting rod bearing would have been detected during the overhaul and resulted in its replacement.
The pilot of the glider reported that, en route to his destination, the glider lost lift, so he diverted to a corn field for landing. During the landing, the glider bounced, and "the canopy popped off of the fuselage" and broke into several pieces. The glider sustained substantial damage to the canopy.The pilot reported that there were no preaccident mechanical failures or malfunctions with the glider that would have precluded normal operation. Although the pilot said he bumped the canopy during the bounced landing, it could not be determined if that or some other mechanism caused the canopy to separate.