roccoangelella/AeroGraph huggingface dataset:
During cruise flight the airplane lost pitch authority after a flutter event partially disabled its elevator and resulted in structural damage to the horizontal and both outboard vertical stabilizers. Although the airplane had limited pitch authority following the event, the pilot was able to successfully land the airplane in a field.The airplane was the subject of an airworthiness directive (AD) concerning play in the pitch trim system, which required inspection of the pitch trim tab for play at 100-hour intervals. The play in the pitch trim system had the potential to cause such a flutter event if not complied with. However, the airplane had just come out of its annual inspection and the pilot also examined the airplane in accordance with the AD just before flight. Additionally, no evidence of such play was observed during a postaccident examination. The pitch trim system had failed, but it appeared to be because of overload damage, likely sustained from the high oscillatory forces induced during the flutter event.Examination of the elevator revealed that the upper lug that connected the elevator pitch control tube to the elevator bellcrank had failed. The weld joints in that area exhibited a lack of fusion and penetration, creating gaps between the filler with the control arm surfaces and the lug. These gaps allowed fatigue cracks to initiate and propagate. Once the cracks had grown large enough, the remaining intact weld material fractured from overstress, leading to the separation of the lug from the control tube.The lug failure resulted in a partial disconnection of the control surface, which likely started the flutter event. This ultimately led to the failure of the pitch trim control arm, which would have exacerbated the flutter.Page 2 of 11 WPR22LA136Corrosion and primer identified at the lug fracture area indicated the surfaces had not been properly prepared before welding. Although the lower lug had not failed, it also exhibited similar evidence of gaps caused by a lack of fusion and penetration.It could not be determined if the lugs were welded at the time of the airplane’s manufacturer, more than 66 years before the accident, or during a subsequent repair.
The 80-hour pilot reported that, while attempting to land in gusty wind conditions, the wind suddenly became “super gusty” as the airplane flew over the runway numbers. The pilot performed a go-around; however, when he added throttle, the engine lost all power and due to the low altitude, he was unable to perform an engine restart. He performed a forced landing near the runway but lost control of the airplane and impacted terrain. The engine was examined, and no anomalies were detected. The left magneto could not be tested due to being waterlogged due to outside storage of the engine before the examination. The National Transportation Safety Board (NTSB) sound spectrum analysis determined that the engine was operating around 1,700 rpm at the time of impact.The airplane’s EDM-900 was downloaded, and the information plotted. The data was not time coded but did show a sharp reduction of horsepower, exhaust gas temperatures, fuel flow, and RPM, that restored briefly before dropping off, likely due to the accident.The video recovered from the accident airplane showed the airplane approaching the runway; after crossing the runway threshold, the airplane floated. There was a slight increase in engine power, and the stall warning horn sounded briefly. The airplane continued to float, and the nose of the airplane pitched up and the stall warning horn was briefly heard again. As the pitch angle continued to increase, the stall warning horn was heard. The engine rpm decreased and popping sounds consistent with a rough running engine were noted. A few seconds later the popping noises ceased, and the engine rpm returned to a higher power setting. The pitch angle continued to increase, and the stall warning was audible. The pilot lost control of the airplane as it entered a stall and impacted terrain.Page 2 of 7 CEN22LA152The sound spectrum analysis indicated that the engine ran rough for about 6 seconds, and then the engine rpm was heard increasing to about 2,100 rpm about 9 seconds before it gradually decreased to 1,700 rpm at impact. The reason for the partial loss of engine power could not be determined.
According to the flight instructor, shortly after takeoff, she heard a “weird” noise coming from the engine and noted a drop in engine rpm. The flight instructor directed the pilot receiving instruction to turn back toward the airport; however, the engine lost all power, and the airplane impacted trees about 1 mile from the departure end of the runway. The airplane sustained substantial damage to the wings, fuselage, and empennage.A postaccident examination of the engine revealed that the engine valvetrain was not timed correctly and that the misalignment resulted in a piston striking a valve. The valve head had separated and fallen into the cylinder, resulting in the total loss of engine power. Examination of the maintenance logbooks revealed that the cylinder head and exhaust camshaft had been replaced the day before the accident flight. Thus, it is likely that the engine’s timing was not set correctly after this maintenance.
The pilot reported that during approach to land on a snow-covered glacier, the airplane was “lower and slower” than his previous approaches to the glacier. He executed a go-around, the wind “shifted”, and the airplane stalled and impacted the terrain. The airplane sustained substantial damage to the fuselage and right wing. The pilot reported no preimpact mechanical failures or malfunctions with the airplane that would have precluded normal operation.
The student pilot reported that he had just departed a grass strip when the wing of the airplane dropped and contacted a power line. The student pilot lost control of the airplane and it collided with terrain. The airplane sustained substantial damage to both wings, the fuselage, and the empennage. No preaccident mechanical failures or malfunctions with the airplane were reported that would have precluded normal operation. Prior to the accident, the student pilot reported that a gust of wind had made the airplane’s wing drop, however a review of weather information found the prevailing wind to be calm.
**This report was modified on April 29, 2024. Please see the docket for the original report.**According to the operator, the lesson syllabus for the instructional helicopter flight included emergency procedures, equipment malfunctions, and vortex ring state (VRS) recognition and recovery. Flight track data, video, and a witness statement indicated that the helicopter was maneuvering at slow speeds about 2,000 ft mean sea level in the minute before the accident and shortly before a 4-ft section of the tailboom separated and the helicopter entered a spiraling descent to the ground. The witness stated that the helicopter appeared to hover when the tail boom separated. The 4-ft section of the tailboom which included the tail rotor came to rest on the roof of a commercial building about 300 ft from the main wreckage. Examination of the helicopter revealed that the main rotor elastomeric teeter stops were severely damaged, and the brackets were bent. The main rotor drive shaft displayed scuff marks where the teeter stops were damaged, consistent with extreme teetering of the main rotor. Main rotor blade contact marks and dents were consistent with the main rotor blades contacting the tailboom in flight, resulting in its separation. Examination of the helicopter and engine did not reveal any preaccident anomalies with the helicopter that would have precluded normal operation. The syllabus for the accident flight included an introduction to VRS and given the flight track information and witness statement, it is possible that the flight instructor was demonstrating, or the pilot receiving instruction was performing, a VRS entry/recovery when the accident occurred. However, since detailed information regarding the helicopter’s flight control and engine parameters was not available, the exact maneuver being conducted at Page 2 of 10 CEN22FA151the time of the tail boom separation could not be determined. The main rotor’s contact with the tailboom is consistent with improper flight control inputs or low rotor RPM. Toxicology testing of the flight instructor revealed the presence of bupropion, an antidepressant medication. Based on the available information, it could not be determined whether effects of the flight instructor’s bupropion use or an associated condition contributed to the accident. Toxicological testing of the pilot receiving instructionrevealed the presence of cetirizine, an antihistamine. It is unlikely that the effects of this medication contributed to the accident.
The flight instructor and student pilot completed several touch-and-go landings and on the final circuit in the traffic pattern, while on the final approach, the student pilot turned the yoke, and felt a sensation like the aileron cable disconnecting. The flight instructor took control of the airplane and noted that he could turn the control yoke 360° without a response from the airplane. Having no aileron control, the airplane veered to the right and descended into trees. A post-impact fire ensued that destroyed the airplane. Examination of the wreckage revealed that there was a break in the aileron control cable system near the right control column. A metallurgical examination of the break in the aileron control cable revealed that the mating fracture surfaces exhibited a flattened area over more than half the cable cross-section, with the remainder of the wires exhibiting features consistent with overstress fractures. The wires in the flattened area exhibited consistent, parallel streaks and witness marks. These marks may indicate wear from rubbing against an adjacent component in this area or they may be consistent with some partial cutting operation. If rubbing of the cable was creating wear, this process would have removed material wire-by-wire, and strand-by-strand over time. The remaining wires would have fractured from tensile overstress when there were no longer enough intact wires to carry the stress. It’s likely the overstress fracture occurred during the final leg of the traffic pattern, which was consistent with reports from the pilot and flight instructor that the flight controls no longer functioned properly during the final landing approach.According to maintenance records, the airplane was inspected, in accordance with the maintenance manual and Part 43 appendix D, 9 times during the 13 months before the accident. According to both inspection checklists, the aileron control cable should have been Page 2 of 8 ERA22LA167inspected and found unairworthy at some point due to its condition. Therefore, it’s likely maintenance personnel overlooked the damaged aileron control cable during the most recent inspections.
The pilot was performing a power-off stall at about 6,500 ft mean sea level during a personal flight. He stated that, as the nose of the airplane dropped, the left canopy latch “let loose.” About 4 to 5 seconds later, the right canopy latch “let go,” and the entire windscreen “popped up like a speed brake.” The airplane’s pitch remained nose down, and the airplane impacted terrain, substantially damaging the left wing and fuselage. Postaccident examination of the wreckage found no preimpact anomalies with the canopy or canopy operating system. Although the pilot reported that the left-side latch came loose before the right-side latch, the examination found that the locking mechanisms engaged and disengaged from both sides of the canopy at the same time when the canopy locking handle was lowered and raised. Examination of the canopy locking system showed that the canopy locking handle required about 1/4 inch of upward movement from the locked and stowed position for the locking mechanisms to reach an over-center position that effectively unlocked the canopy.  The accident circumstances were consistent with the pilot’s loss of control of the airplane during flight after the inadvertent unlocking and opening of the canopy. The reason that the canopy locking handle became unstowed during the accident flight could not be determined based on the available evidence from the investigation.
The flight instructor and student pilot were conducting an instructional flight. The instructor stated that, about 7 minutes after departure and while the airplane was in level flight at 3,500 ft mean sea level, the engine sputtered and the airplane was unable to maintain altitude. The instructor assumed control of the airplane from the student pilot at that time. She performed several troubleshooting steps; however, engine power was not restored. During the descent, the propeller windmilled and, according to the instructor, “the engine would catch” randomly and “operate for a few moments,” but the engine would lose power each time. The instructor also stated that, during a discussion with the student pilot, he indicated that, when he pulled the throttle to idle, the engine “would smooth out somewhat, but would start missing” when the throttle was pushed forward. The instructor executed a forced landing to a field, and the airplane nosed over. The airplane sustained substantial damage to the fuselage, empennage, and both wingsThe atmospheric conditions at the time of the accident were not conducive to the development of carburetor icing. A postaccident examination of the airplane revealed that there was uncontaminated fuel available in the engine and that there was no evidence of mechanical malfunctions or failures that would have precluded normal operation. As a result, the reason for the total loss of engine power could not be determined.
According to the pilot, the airplane sustained a total loss of engine power during the approach to land. Unable to maintain altitude, the pilot initiated a forced landing to rough desert terrain. During the landing roll, the landing gear collapsed and separated, and the airplane slid about 100 ft before coming to rest upright.Examination of the airframe and engine revealed no evidence of preimpact malfunctions or anomalies. Residual fuel was found in fuel lines and fuel components in the airframe and engine. The reason for the loss of engine power was undetermined.
The pilot planned a 1-hour flight to verify airplane performance, systems, and navigation equipment in preparation for a cross-country flight the next day. For most of the accident flight, he operated the airplane with the fuel selector in the main tank position. While transitioning to the destination airport about 500 ft above ground level, the pilot switched the fuel selector to the auxiliary fuel tank. About 2 minutes later, the engine “missed much like if the mags [magnetos] were switched off then immediately back on.” He then turned on the boost pump and switched the fuel selector back to the main fuel tank. Shortly thereafter, the engine lost total power. The pilot’s attempts to restart the engine were unsuccessful. The pilot executed a forced landing to a harvested cornfield. During the landing, the airplane nosed over and sustained substantial damage to the rudder, vertical stabilizer, and both wings. Postaccident examination of the airplane’s wing fuel lines (after the wings were removed) and fuel tanks revealed no anomalies that would have precluded normal operation. The engine was functionally tested at various power settings with an exemplar fuel tank, and no anomalies were noted. Engine operation was only interrupted when the fuel selector valve was placed between the detent selections. Further examination of the airplane wings found that the left fuel tank (main) vent line was completely obstructed with an unspecified material. Given the available evidence, this investigation could not determine if the blocked fuel vent line or an improper fuel selector position caused the loss of engine power.
The pilot of the gyroplane reported that, during the landing roll, he diverted his attention to the dial of the rotor rpm and the gyroplane inadvertently ascended when he did not hold the control stick steady. He attempted to regain control by pushing the control stick forward, but the gyroplane rolled to the right, and the main rotor blade contacted the ground. The gyroplane came to rest on its left side and sustained substantial damage to the stabilizer and rudder. The pilot reported that there were no preaccident mechanical failures or malfunctions with the gyroplane that would have precluded normal operation.
Shortly after takeoff the pilot “felt a force straight down.” The gyroplane impacted the terrain hard, rolled over, and came to rest on its side adjacent to the runway. The gyroplane sustained substantial damage to the fuselage and stabilizers. Reported winds about the time accident included wind gusts and a peak wind of 30 knots. A postaccident examination of the gyroplane revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation.
The flight instructor of the airplane reported that, during an instructional flight with a student flight instructor, he purposely “flared too much and a little too high.” The intent was for the student flight instructor to correct; however, he did not intervene. The flight instructor added full power to abort the landing when the airplane encountered a shift from a headwind to a right quartering tailwind and the airplane drifted to the right. While maneuvering the airplane to stay over the runway, the left aileron struck a runway sign. The airplane sustained substantial damage to the left aileron. The flight instructor reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.
After the landing the pilot stopped the airplane on the taxiway and noted that the airspeed indicator indicated almost 40 knots due to the wind. The pilot taxied the airplane toward the fuel pump with aileron crosswind correction and heard the stall warning horn sound. The wind lifted the right wing, so the pilot pulled the throttle to idle and applied the brakes. The left wing and propeller struck the ground as the wind continued to push the airplane across the ground. The left wing sustained substantial damage. After the pilot egressed, a gust of wing flipped the airplane inverted.
The pilot of the helicopter reported that, while flying in mountainous terrain, he decided to land on top of a ridge for a rest break. The pilot performed a circling reconnaissance of the area before he began his descent to his intended landing spot. During the descent, the pilot felt a wind gust from behind, then the rotor rpm began to decay, and the low rotor rpm light illuminated along with the aural warning horn. The pilot attempted to reestablish power without success as the helicopter continued to descend. To avoid going over the ridge, the pilot intentionally lowered the helicopter to the ground and rolled the helicopter onto its right side. The helicopter sustained substantial damage to the fuselage and tail boom. The pilot reported that there were no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation.
The airplane departed on a visual-flight-rules flight to conduct a routine hurricane/tsunami warning mission. The standard flight route was to fly inland, passing a radar dome before turning west toward the coast. The airplane was then to fly offshore, following the coastline around the island.  Automatic Dependent Surveillance–Broadcast (ADS–B) data showed the airplane never made the turn to the coast and it continued over land and up a ridgeline. The airplane impacted a near-vertical mountain side in a nose-up, wings-level attitude. Witnesses reported hearing the airplane, but they were unable to see it due to the poor visibility near the accident site.Postaccident examination of the airplane revealed leading edge damage to both wings indicative of a controlled flight into terrain. An examination of the available wreckage did not reveal any anomalies that would have prevented normal operation of the flight controls. Although several engine components were not located at the accident site, witnesses reported hearing the engine operating up to the time of impact.Toxicology testing of the pilot’s blood detected the presence of gabapentin, which can produce impairing effect such as sleepiness, dizziness, and/or diminished coordination. However, if the pilot’s judgment was impaired, the copilot could have mitigated his improper decision making. Thus, it is unlikely that gabapentin’s effects on the pilot contributed to the accident.Based on the level attitude of the airplane when it impacted the rising terrain, it is likely the pilot had control of the airplane and flew into terrain that was obscured by the poor visibility.Page 2 of 8 ANC22LA025
The student pilot reported that he completed four uneventful touch-and-go landings. During the fifth and final landing, the airplane touched down onto the runway and bounced. During recovery, a crosswind lifted the left wing. The airplane ground looped, nosed over, and came to rest inverted. The firewall and rudder sustained substantial damage. The pilot reported that there were no mechanical failures or malfunctions with the airplane or engine that would have precluded normal operations.
The pilot reported that, after takeoff when the airplane was about 150 to 200 ft above ground level, the engine lost all power. The pilot made a forced landing in a snow-covered field, during which the airplane nosed over, causing substantial damage to the wings and vertical stabilizer. Postaccident examination of the airplane revealed that the fuel selector was in the left fuel tank position. The left fuel tank contained about 3 gallons of fuel, 1.5 gallons of which was usable. The Cessna Pilot’s Operating Handbook required the fuel selector handle to be in the “both” position for takeoffs and landings. Examination of the engine revealed no evidence of mechanical malfunctions or anomalies that would have precluded normal operation of the engine. Given the fuel selector position, which was not consistent with takeoff procedures, and the limited fuel in the left tank, it is likely that the fuel in the left tank unported or had depleted to a level that resulted in fuel starvation and a subsequent loss of engine power.
The pilot obtained his private pilot certificate about 1 year prior to the accident and had accumulated a total flight experience of approximately 94 hours at the time of the accident. Toward the end of the cross-country flight, the pilot flew a straight-in approach to a valley airport. The airplane made a high-speed approach (about 95 knots true airspeed) with the flaps retracted. Witnesses reported that the airplane touched down and bounced twice on its nose landing gear. When the airplane was toward the end of the runway, engine noise increased, and the airplane began a climbing left turn to clear trees. The airplane subsequently impacted terrain. Postaccident examination of the wreckage revealed no preimpact mechanical malfunctions. The debris path and impact signatures were consistent with an aerodynamic stall. Based on the evidence, the pilot likely made a delayed decision to perform a go-around after touchdown and exceeded the airplane’s critical angle of attack as the airplane began the climbing left turn to avoid trees.