roccoangelella/AeroGraph huggingface dataset:
The solo student pilot reported that, while landing, the airplane "bounced" and then landed "hard." She corrected by pitching the airplane for straight-and-level flight and prepared to flare again. However, the airplane touched down hard on the runway and bounced again. She was able to land the airplane and taxied it to the ramp without further incident.The airplane sustained substantial damage to the fuselage aft of the nosewheel.The student 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 the time of the accident, the wind was from 160° at 7 knots. The student was landing the airplane on runway 32.
The airline transport pilot of the agricultural aerial application flight stated that as the helicopter entered the field to be sprayed, the low rotor rpm annunciation sounded. He attempted to recover rotor rpm, but the rpm continued to decay rapidly. He then used the remaining rotor rpm to cushion a landing onto the field. As the helicopter touched down, it slid about 150-200 ft before the skid dug into soft dirt and the helicopter rolled over. Post-accident examination of the engine by the operator revealed that the no. 6 cylinder had more leakage/lower compression than the previous 100-hour recorded compression checks. Reduced compression on one or more cylinders would have reduced excess power available to maintain a rotor RPM and altitude.
The pilot, who was not instrument rated, was conducting a personal flight in visual meteorological conditions when he flew into an area of instrument meteorological conditions (IMC) with thunderstorm activity. After flying several minutes in IMC, the airplane entered a left turn that became increasingly tighter along with a with a rapid climb that was followed by a rapid descent until the airplane impacted the ground. The airplane was destroyed. Postaccident examination revealed no evidence of a preexisting mechanical malfunction or failure that would have precluded normal operation of the airplane. The spiral flightpath with significant changes in altitude was consistent with the pilot experiencing the effects of spatial disorientation. Weather imagery indicated an outflow boundary ahead of the main cumulonimbus cloud line. The pilot likely encountered gusty and turbulent wind conditions when the airplane flew into the outflow boundary. The adverse weather conditions likely contributed to the pilot’s spatial disorientation. The pilot did not receive a weather briefing before the flight.
After the pilot completed two touch-and-go landings, the airplane was climbing when the engine lost total power. He advanced the throttle full forward, but the engine did not respond. The pilot did not attempt to troubleshoot the loss of power and did not check the fuel selector valve position. The pilot flew the airplane under power lines and executed a forced landing in the marsh during which the airplane sustained substantial damage to the lower fuselage and ailerons. The pilot stated that before takeoff, the left and right main fuel tanks contained 15 and 13 gallons, respectively, and the wing tip fuel tanks contained minimal fuel. A postaccident examination of the airplane revealed that the fuel selector value was positioned to the left tip tank; the tank was not breached during the accident and contained about 10 ounces of fuel. Based on the evidence, it is likely that the pilot did not verify the fuel selector position and had the left tip tank selected, which did not contain enough usable fuel. Thus, the engine experienced a total loss of power due to fuel starvation.
The pilot was in cruise flight in a single-engine airplane when the engine lost power. He selected a road for the forced landing, during which the airplane impacted a power pole and electrical wires. The airplane came to rest inverted and incurred substantial damage to the airplane’s fuselage and wings. Postaccident examination revealed that the engine’s crankshaft had failed due to fatigue.  The accident crankshaft was subject to a mandatory service bulletin (MSB) and subsequent Federal Aviation Administration airworthiness directive (AD) requiring inspection of the crankshaft material for metallurgical anomalies; however, this inspection was not performed on the accident airplane’s crankshaft.A detailed metallurgical examination of the crankshaft revealed that a fatigue crack had progressed through most of the crankshaft web cross section, consistent with relatively low-stress, high cycle fatigue. Because no indications of intergranular fracture or large areas of overstress fracture with the planar dimpled rupture features indicative of thermal damage on the fracture surface were noted, it is unlikely that manufacturing issues resulted in the fatigue cracking even though metallurgical testing revealed that the crankshaft material did not meet specification. Rather, the cracking likely initiated due to stray or excessive wear to the forward journal to web radius. It is further likely that a misalignment during a previous reassembly of the engine that occurred about two years prior when two cylinders were replaced resulted in the failure. Given this information, it is likely that maintenance personnel’s failure to properly align the affected crankshaft during the reassembly resulted in a low-stress high cycle fatigue failure of the crankshaft and the subsequent loss of all engine power. Page 2 of 7 CEN19LA249
The helicopter pilot reported that, during high reconnaissance of a field intended for agricultural application, he saw power lines surrounding the field. He started the application southbound from the northwest section, and after travelling about 300 yards and while about 15 ft above ground level, the helicopter struck a power line, after which the pilot was able to land the helicopter on an adjacent field without further incident. The helicopter sustained substantial damage to the main rotor blade.The pilot reported that there were no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation.
The pilot reported that, after the balloon encountered a thermal en route, he decided to land it in a hayfield surrounded by a wooded area. He added that the balloon was "driven down into the tree branches," and when over the hayfield, it descended and bounced hard to about 10 ft as he deflated the envelope. The balloon landed hard again and then deflated. One passenger sustained serious injuries.The pilot reported that there were no preaccident mechanical failures or malfunctions with the balloon that would have precluded normal operation.
The flight crew was landing the transport-category airplane at a remote, gravel-covered runway. According to the captain, the terrain on the approach to the runway sloped down toward the approach end, which positioned the airplane close to terrain during the final stages of the approach. A video recorded by a bystander showed that while the airplane was on short final approach, it flew low on the glidepath and dragged its landing gear through vegetation near the approach end of the runway. The video showed that, just before the main landing gear wheels reached the runway threshold, the right main landing wheel impacted a dirt and rock berm. The captain said that to keep the airplane from veering to the right, he placed the No. 1 and No. 2 engine propellers in reverse pitch. The flight engineer applied asymmetric reverse thrust to help correct for the right turning tendency, and the airplane tracked straight for about 2,000 ft. The video then showed that the right main landing gear assembly separated, and the airplane continued straight down the runway before veering to the right, exiting the runway, and spinning about 180°, resulting in substantial damage to the fuselage.  On-site examination of the runway revealed several 4-ft piles of rocks and dirt at the runway threshold, which is likely what the right main landing wheel impacted. Given that the airplane landing gear struck vegetation and rocks on the approach to the runway, it is likely that they were below the proper glidepath for the approach.The crew stated there were no preaccident mechanical malfunctions or anomalies that would have precluded normal operation.
The pilot reported that, during the approach, the airplane encountered a downdraft, and the tailwheel landed short of the runway threshold, struck a ditch, and impacted a runway light. The airplane sustained substantial damage to the 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 the wind was a "22+ knot front left quartering crosswind and gusting."
The flight instructor and student pilot had performed several touch-and-go landings; after the final landing, they departed for another airport. Shortly after takeoff, the engine started to vibrate severely and then lost power. The instructor performed a forced landing in a field, which resulted in substantial damage to the airplane's left wing. Postaccident engine examination revealed a failed No. 3 cylinder exhaust valve and extensive erosion on the No. 4 cylinder exhaust valve. The engine had accumulated 2,600 hours since the last overhaul, which was 600 hours beyond the manufacturer's recommended time before overhaul. The flight instructor reported that the leaning technique used while the airplane was on the ground was to lean the mixture during taxi or engine idle. For the engine run-up, they would use a full rich mixture. He added that during flight maneuvers at or below 3,000 ft mean sea level, they would not lean the mixture. However, the exhaust valve erosion is consistent with the engine being operated with an excessively lean fuel mixture over an extended period.
The pilot reported that, while landing, the airplane bounced, and he chose to go around. He stated that he did not recall the airspeed after he applied full power and retracted the flaps to 10° during the initial climb. Subsequently, the airplane aerodynamically stalled and impacted terrain. A witness at the airport reported that the airplane was operating under full power at a high angle of attack.The airplane sustained substantial damage to the fuselage, both wings, and the empennage.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, while landing, the airplane bounced twice on touchdown. During the second bounce, the nose landing gear collapsed, and the airplane then impacted the runway.The airplane sustained substantial damage to the engine mount and firewall.The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.
The student pilot reported that, during landing on a private grass airstrip, the airplane bounced hard, so he added power to stabilize it before continuing the landing. However, the airplane was nearing the end of the airstrip, so he added full power. The instructor stated that he initially assumed the student was performing a go-around, although they had not previously discussed the procedure. As the airplane continued toward the end of the airstrip, the student did not conduct a go-around, so the instructor took control of the airplane and initiated a go-around, but about 15 ft above ground level (agl), the airplane impacted trees beyond the end of the runway, spun, and stopped in the trees about 4 ft agl. The airplane sustained substantial damage to the fuselage and both wings. The instructor reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation and recommended that the student should have had more practice at a conventional airport before practicing at a private airstrip with restricted maneuvering space.
The pilot reported that, during the approach for landing, the airplane was fast and high, but he continued the approach. The airplane subsequently landed on the last third of the runway, and he applied brakes, but the airplane overran the runway and nosed over. The airplane sustained substantial damage to the left-wing lift strut. The pilot reported that there was no preimpact mechanical failures or malfunctions with the airplane that would have precluded normal operation.
During a cross-county flight, the pilot arrived at his planned destination near sunset and was maneuvering to land. While maneuvering, the airplane struck a stand of trees and subsequently impacted terrain. The pilot reported that the airplane’s engine was “running fine” and that there were no preimpact mechanical malfunctions or failures with the airplane that would have precluded normal operation.Postaccident examination of the airframe and engine also revealed no preimpact mechanical anomalies or malfunctions that would have precluded normal operation.
The pilot reported that he left the windows open while completing the Start-up checklist and while taxiing to the runway. During the takeoff roll, he noticed that the passenger window was unsecured. While attempting to secure the window, he momentarily took his eyes off the runway. As he looked back at the runway, the airplane was traveling to the left side of the runway. With insufficient runway to correct direction, the airplane impacted a runway distance marker sign. The airplane sustained substantial damage to the right horizontal stabilizer and elevator. 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, while returning to the airport, the glider descended faster than expected, so he diverted to a field for landing. The glider encountered a wind gust, and the left wing hit the ground. The glider then ground looped to the left. The glider sustained substantial damage to the fuselage, empennage, and right aileron.The pilot reported that there were no preaccident mechanical failures or malfunctions with the glider that would have precluded normal operation.The pilot reported that the wind was from 140°, between about 10 and 20 knots, and gusting. The pilot landed the glider to the south.
The pilot reported that, during landing with a gusting crosswind, the airplane veered right. He applied left rudder, and the airplane veered left and then exited the runway onto gravel. The right main landing gear collapsed, and the right wing impacted the ground. The airplane sustained substantial damage to the right wing. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.
The pilot was conducting a sales demonstration flight with a pilot-rated passenger on board. He reported that, when he started the takeoff run from a lake, three small wakes helped propel the airplane into the air. He stated that the airplane took off on the first attempt, the takeoff was normal, and "there was nothing wrong with the [air]plane at all." He added that, after initiating a 10° right turn to stay over the lake, it felt like the airplane "hit a wall." The airplane then descended rapidly, clipped a tree, and impacted water, which resulted in substantial damage to the fuselage and wings. The pilot-rated passenger said that it took four takeoff attempts to get airborne and that the airplane felt very sluggish and acted as if it did not want to come off the water. Postaccident weight and balance calculations revealed that the airplane was about 57 lbs over its maximum gross weight and outside of the weight and center of gravity limits contained in the pilot's operating handbook. Data retrieved from the airplane's onboard digital-to-analogue converter were consistent with three takeoff attempts, with the airplane becoming airborne on the third attempt. A review of video of the accident flight from witnesses showed the airplane in a nose-high attitude with the flaps extended as it approached trees during the initial climb. As the airplane reached about the midpoint of a stand of trees, the angle of attack appeared to increase and the nose dropped. The right wing then lowered and impacted one of the trees.
The pilot reported that, during a low-level agricultural application pass and shortly after he leveled off the helicopter from a turn, the helicopter struck wires and then impacted terrain. The helicopter sustained substantial damage to the fuselage and the main and tail rotor systems. The operator reported that there were no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation.
The pilot of the Piper reported that, after landing and while taxiing back to his parking spot, he saw a Cessna holding short at the intersection to the same taxiway. He did not see the Cessna move, so he continued to taxi but then felt a "strong impact" as his airplane passed the Cessna. The flight instructor in the Cessna reported that he was taking a passenger on a familiarization flight. After clearing the taxiway from the ramp, he maneuvered the Cessna to the taxiway intersection. He then saw the Piper taxi past him and believed he had adequate clearance, so he continued to maneuver and turned left onto the taxiway. While the instructor simultaneously instructed the passenger while taxiing, the Cessna's left wingtip impacted the Piper's engine and left aileron. The instructor added that he should have waited for the Piper to pass the airplane and should have spent more time briefing the passenger to reduce task saturation. The Piper sustained substantial damage to the left aileron. The Cessna sustained minor damage to the lower engine cowling and propeller. Both pilots reported that there were no preaccident mechanical failures or malfunctions with their airplanes that would have precluded normal operation.
The captain noted that the purpose of the flight was second-in-command pilot training for the first officer and the observer, in turn. He reported that after takeoff, the landing gear retracted normally. The captain executed a practice instrument approach to a missed approach. When they attempted to retract the landing gear after initiating the missed approach, the left main gear in-transit light remained illuminated. The right main and nose landing gears retracted normally. Both hydraulic system low pressure warning lights subsequently illuminated. Efforts to troubleshoot using the emergency checklist and to extend the landing gear manually were not successful. The captain ultimately landed the airplane with the left main landing gear partially extended and subsequently lost directional control, which resulted in a runway excursion and impact with an airport sign. The airplane sustained damage to the outboard left wing, left main landing gear, and left propeller.During a postaccident examination, hydraulic fluid was observed in the left main landing gear wheel well; no hydraulic fluid was observed in the reservoir sight gauge or on the dip stick. Hydraulic pressure was subsequently applied to the airplane, and no leaks were observed in the landing gear system. Thus, the source of the hydraulic fluid leak could not be determined. In addition, the reason that the landing gear failed to fully extend during the emergency extension procedure could not be determined because no preaccident anomalies were observed.
The pilot reported that, while being towed, the glider began to climb, and the canopy opened. The pilot released the glider from the tow airplane, and he reached up and closed the canopy. He decreased the glider's airspeed and made a 180° right turn to final. On final, the glider was high, and he deployed the airbrakes, but the canopy opened again. The pilot closed the canopy and held it shut with his left hand while trying to control the glider with his right hand, but the altitude decreased "very quickly." The glider's wingtip struck a shipping container just short of the runway. The glider sustained substantial damage to the left wing and the empennage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the glider that would have precluded normal operation.
The pilot reported that, about 5 minutes after takeoff, at an altitude about 500 ft above ground level, the engine lost partial power. The pilot performed a forced landing to a field, during which the airplane sustained substantial damage. Examination of the engine revealed that the compressor front support (No. 1) bearing had failed, resulting in compressor rotor misalignment. The rotor misalignment resulted in severe impeller-to-shroud rub, including wear-through in several locations, flow disruption, and the engine power loss. The reason for the bearing failure could not be determined based on the available information.
The pilot reported that he departed with 19 gallons of fuel onboard, and about 3 hours and 41 minutes into the cross-country flight, the engine “quit.” The pilot performed a forced landing in a soybean field, during which the airplane nosed over and came to rest inverted. The airplane sustained substantial damage to the rudder, empennage, and canopy bulkhead.Examination revealed no evidence of fuel in the fuel tank, which was intact. No mechanical anomalies were found with the engine. Based on the available information, it is likely that the total loss of engine power was the result of fuel exhaustion.
The No. 1 (left) engine low pressure compressor (LPC) stage 1 integrally bladed rotor (IBR) separation was caused by a high cycle fatigue (HCF) crack that originated at the runout of an airfoil leading edge root radius. Acoustic tests, instrumented flight tests, and multiple analytical methods were completed and identified a mechanically coupled LPC stage 3 and stage 1 IBR mode excitation driven by an acoustic coincidence with the 2.5 bleed valve duct cavity. At high engine speeds in specific flight conditions, unsteady or turbulent airflow generated by the LPC IBR blade tips created an acoustic tone as it passed over the 2.5 bleed valve duct cavity, located immediately aft of the LPC (Figure 1). The acoustic tone excited a LPC stage 3 IBR blade 1st bending mode that was mechanically transferred through the LPC module to the LPC stage 1 IBR where a stiffwise bending mode was excited. The resultant stresses on the LPC stage 1 IBR blades exceeded material limits and subsequently led to crack formation and eventual progression to overload failure. Page 2 of 9 ENG19IA029Figure 1- Engine LPC Diagram Identifying the stage 3 IBR / 2.5 Bleed Valve Acoustic InteractionFactors that contributed to the LPC acoustic coincidence within the engine operating range were installation of electronic engine control (EEC) Software V2.11.7.2 and low engine operating hours. EEC Software V2.11.7.2 modified the LPC inlet guide vane (IGV) schedule to improve engine surge/stall margin in high power flight phases such as top of climb, by rotating the vanes in the closed direction. The revised vane schedule inadvertently created conditions that were favorable for LPC IBR 3 and IBR 1 flutter onset.  New engines have tighter clearances between the LPC IBR blade tips and the outer air seals. The tighter clearances created unsteady loading at the blade tip region and resulted in stronger acoustic coupling and flutter response. Flight test data confirmed that acoustic coincidence and flutter response within the engine operating range was significantly reduced following an engine rub in period.The Powerplant Group Chairman’s Factual Report available in the investigation docket includes additional information on the LPC acoustic coincidence and the testing and analytical methods used to identify the failure mode.