Flight

The pilot, sole on board, departed Příbram Airport in the early afternoon on a private flight to Moravská Třebová. About 15 minutes into the flight, while cruising in good weather conditions, he encountered engine problems and elected to divert to Benešov Airfield. Shortly later, some cooling liquid leaked from the engine into the cabin and on the windshield, reducing the pilot's vision. He elected to make an emergency landing in a cornfield when, upon touchdown, the aircraft crashed and came to rest upside down with its right wing torn off. There was no fire. The pilot was injured and the aircraft was damaged beyond repair.

Before the personal instrument flight rules flight began, the pilot obtained a preflight weather briefing that indicated that instrument meteorological conditions, convective activity, and moderate-to-severe icing conditions would be occurring along the route of flight. According to track data, while the pilot was navigating to avoid weather, the pilot was using the autopilot for maneuvering. After the pilot reported to air traffic control that the airplane would be turning direct to its destination, the performance analysis of track data showed that the airplane began a slight left turn with a bank angle of about 10°, which was consistent with the intended route of flight. However, the turn then reversed, and the airplane began banking to the right, reaching about 120° right wing down during the next 70 seconds and showing a slow oscillation in pitch attitude. Satellite imagery showed that the airplane was likely in instrument meteorological conditions when it began a rapid descent, and the airplane’s descent rate was about 7,000 feet per minute. Postaccident examination of the airplane and right engine (the left engine was not recovered) revealed no evidence of any preimpact mechanical malfunctions or failures that would have precluded normal operation. The dynamics of the airplane’s movements after the right turn began indicated that the airplane likely was not being actively controlled when it diverted from the intended flightpath. The circumstances of this accident were thus consistent with the pilot’s lack of timely recognition that the autopilot was disengaged. The available evidence for this accident precluded a determination of where the pilot’s attention was directed while navigating direct to the destination. However, the turbulence would have increased the pilot’s workload, and the restricted visibility conditions would have prevented the pilot’s use of outside cues to detect deviations in the airplane’s attitude. Also, the initial roll rates might not have been sufficient to provide reliable cues to the pilot of the developing bank, and the convective conditions would likely have made it difficult for the pilot to detect and recover from the fully developed unusual attitude.

The student pilot, who was not qualified to operate the airplane, reportedly flew from California to Pennsylvania on a commercial flight the morning of the accident to pick up and fly the accident airplane, which he purchased, to California. The student pilot departed Pennsylvania at 0719 and made several en route stops before arriving at the departure airport at 1949. A witness stated that the airplane’s right engine quit during taxi at the last en route stop and the pilot said he "cut it a little close on fuel." Another witness said that the pilot was “really tired” and planned to fly over the mountains for his return flight. The student pilot was not in communications with air traffic control while en route from the departure airport and did not receive an instrument flight rules clearance to operate the flight in class A airspace as required by Federal Aviation Regulations. The airplane was not equipped with automatic dependent surveillance-broadcast as required for flight in class A airspace. Radar track data indicate the airplane last departed from Fort Collins, Colorado, and maneuvered while climbing to 16,000 ft. The airplane proceeded west/southwest for a little over 40 miles before climbing to about 22,000 ft. The airplane then made several large heading changes and altitude changes between 20,000 ft and 23,000 ft before entering a tight looping turn to the left and losing altitude rapidly before track data was lost. All components of the airplane were distributed along the wreckage path in a manner consistent with a low-angle, high-speed impact with terrain. The airplane was destroyed. A green cylindrical tank consistent in color with an oxygen tank was separated from the airframe and was found along the wreckage path. Portions of pneumatic lines were attached to the tank and exhibited impact damage and separations from impact. Due to accident-related damage, the amount of the tank’s contents prior to the accident are unknown, and the functionality, if any, of the oxygen system is unknown. The reason for the airplane’s impact with terrain could not be determined based on available evidence.

The aircraft crashed in unknown circumstances in a wooded area located near La Libertad and was totally destroyed by impact forces and a post crash fire. Both pilots were killed. Guatemalan Authorities reported the aircraft was engaged in a contraband mission and a load of 762 kilos of cocaine was found.

The pilot was conducting a Part 135 on-demand cargo flight in instrument meteorological conditions. After executing a second missed approach, he informed air traffic control (ATC) of his intentions to divert to an airport located about 36 miles to the southeast. About 7 minutes after executing the second missed approach, the pilot began making unintelligible radio communications that ATC characterized as very garbled and difficult to understand, “almost hypoxic.” ATC then instructed the pilot to utilize oxygen. About 19 minutes after the second missed approach, ATC informed the pilot that the airplane had descended 1,600 ft, not following assigned course vectors or instructions and asked if everything was alright, to which no response was received. After attempting to relay communications through other airplanes in the area, an unintelligible response was received from the accident airplane. ATC then made numerous transmissions to the accident pilot urging him to utilize oxygen and open a window. No further communications were received from the accident airplane. A witness reported that he saw the airplane descend out of a low overcast cloud layer at a high rate of descent. The airplane then abruptly transitioned into a steep climb before re-entering the clouds. A few seconds later, he heard the airplane impact terrain and responded to the accident site. The sudden change in communications from the pilot indicates a possible impairment. When combined with the ATC data, the witness account, and the lack of any mechanical irregularities or malfunctions with the airplane, it is likely the pilot experienced difficulty controlling the airplane due to impairment. While the pilot was at an increased risk for an acute cardiovascular event, the extremely limited available medical evidence leaves no way to quantify that risk and no evidence regarding whether such an event occurred. As a result, whether the pilot was incapacitated by an acute medical event cannot be determined from the available medical information.

The twin engine aircraft was engaged in an illegal flight carrying two pilots and a probable load of cocaine bags. En route, the aircraft crashed in unknown circumstances in a prairie located in a mountainous area near Iriona. The aircraft disintegrated on impact and both occupants were killed.

The pilot departed on an instrument flight rules cross-country flight with three passengers. While enroute at a cruise altitude about 6,000 ft mean sea level (msl), the pilot discussed routing and weather avoidance with the controller. The controller advised the pilot there was a gap in the line of weather showing light precipitation, and that the pilot could pass through it and then proceed on course. The controller assigned the pilot a heading, which the pilot initially acknowledged, but shortly thereafter, he advised the controller that the airplane was pointed directly at a convective cell. The controller explained that the heading would keep the pilot out of the heavy precipitation and that he would then turn the airplane through an area of light precipitation. The pilot responded, saying that the area seemed to be closing in fast, the controller acknowledged and advised the pilot if he did not want to accept that routing, he could be rerouted. The pilot elected to turn toward a gap that he saw and felt he could fly straight through it. The controller acknowledged and advised the pilot that course would take him through moderate precipitation starting in about one mile extending for about four miles; the pilot acknowledged. Radar information indicated that the airplane entered an area of heavy to very heavy precipitation, likely a rain shower updraft, while in instrument meteorological conditions, then entered a right, descending spiral and broke up in flight. Examination of the wreckage revealed no evidence of a preaccident malfunction or failure that would have prevented normal operation. The airplane was equipped with the capability to display weather radar "mosaic" imagery created from Next Generation Radar (NEXRAD) data and it is likely that the pilot was using this information to navigate around precipitation when the airplane encountered a rain shower updraft with likely severe turbulence. Due to latencies inherent in processes used to detect and deliver the NEXRAD data from the ground site, as well as the frequency of the mosaic-creation process used by the service provider, NEXRAD data can age significantly by the time the mosaic image is created. The pilot elected to navigate the hazardous weather along his route of flight based on the data displayed to him instead of the routing suggested by the controller, which resulted in the penetration of a rain shower updraft, a loss of airplane control, and a subsequent inflight breakup.

The pilot and two passengers departed on an instrument flight rules cross-country flight in night instrument meteorological conditions (IMC). The pilot was instructed by air traffic control to climb to 12,000 ft, and then cleared to climb to FL230. The pilot reported to the controller that the airplane encountered freezing drizzle and light rime icing during the climb from 6,500 ft to 8,000 ft mean sea level (msl). As the airplane climbed through 11,600 ft msl, the pilot reported that they had an issue with faulty deicing equipment and needed to return to the airport. The controller instructed the pilot to descend and cleared the airplane back to the airport. When asked by the controller if there was an emergency, the pilot stated that they “blew a breaker,” and were unable to reset it. As the controller descended the airplane toward the airport, the pilot reported that they were having issues with faulty instruments. At this time, the airplane was at an altitude of about 4,700 ft. The controller instructed the pilot to maintain 5,000 ft, and the pilot responded that he was “pulling up.” There was no further communication with the pilot. Review of the airplane’s radar track showed the airplane’s departure from the airport and the subsequent turn and southeast track toward its destination. The track appeared as a straight line before a descending, right turn was observed. The turn radius decreased before the flight track ended. The airplane impacted terrain in a right-wing-low attitude. The wreckage was scattered and highly fragmented along a path that continued for about 570 ft. Examination of the wreckage noted various pieces of the flight control surfaces and cables in the wreckage path. Control continuity could not be established due the fragmentation of the wreckage; however, no preimpact anomalies were found. Examination of the left and right engines found rotational signatures and did not identify any pre-impact anomalies. A review of maintenance records noted two discrepancies with the propeller deice and surface deice circuit breakers, which were addressed by maintenance personnel. Impact damage and fragmentation prevented determination of which circuit breaker(s) the pilot was having issues with or an examination of any deicing systems on the airplane. The radio transmissions and transponder returns reflected in the radar data indicate that the airplane’s electrical system was operational before the accident. It is likely that the pilot’s communications with the controller and attempted troubleshooting of the circuit breakers introduced distractions from his primary task of monitoring the flight instruments while in IMC. Such interruptions would make him vulnerable to misleading vestibular cues that could adversely affect his ability to effectively interpret the instruments and maintain control of the airplane. The pilot’s report of “faulty instruments” during a decreasing radius turn and his initial distraction with the circuit breakers and radio communications is consistent with the effects of spatial disorientation.

While on an instructional flight in icing and instrument meteorological conditions (IMC), the pilots indicated that they were having instrumentation difficulties to air traffic control. They initially reported a problem with the autopilot, then a navigational issue, which they later indicated were resolved, and finally they reported it was a problem with the left side attitude indicator. After air traffic control cleared them to their destination, the airplane entered a descending left turn, which continued into a 360° descending turn. An inflight breakup resulted, with the wreckage being scattered over 7,000 ft of wooded terrain. Examination of the engines revealed there were no anomalies that would have precluded normal operation prior to the accident. Control cable continuity was established from the flight controls in the cockpit to all flight control surfaces through multiple overload failures. The pitot-static system was examined, and no blockages were noted. Since there was rotational scoring noted on the vertical gyro and the directional gyro, it’s likely they were operating at the time of the accident. Furthermore, the left side attitude indicator examination revealed that there were no anomalies with the instrument. Examination of the deice valves for the deicing boots revealed that the left wing deice valve did not operate. Corrosion was visible in all three valves and it could not be determined if the corrosion was a result of postimpact environmental exposure. Furthermore, since the cockpit switch positions were compromised in the accident, it could not be determined if the pilots were operating the deicing system at the time of the accident. However, most of the pilot reports (PIREPs) in the area indicated light icing and the airplane performed a 6,000 ft per minute climb just before the loss of control. Given this information, it is unlikely the icing conditions made the airplane uncontrollable. A review of the pilots’ flight experience revealed that the pilot in the left seat did not hold a type rating for the accident airplane model but was scheduled to attend flight training to obtain such a type rating. The pilot in the right seat, who also held a flight instructor certificate, did hold a type rating for the airplane. Given that the remarks section of the filed flight plan described the flight as a “training flight” and the left-seat pilot’s plan to obtain a type rating for the accident airplane model, it is likely the pilot in the left seat was the flying pilot for the majority of the flight. Although the right-seat pilot's autopsy noted coronary artery disease, the condition was poorly described. The circumstances of the accident are not consistent with sudden physical impairment or incapacitation; therefore, it is unlikely it contributed to the event. Toxicology testing identified diphenhydramine, which can cause significant sedation, in the right-seat pilot’s blood. However, the level present at the time of the accident was too low to quantify. Therefore, it is unlikely effects from diphenhydramine contributed to the accident. Prior to entering the descending right turn, air traffic control noted that the airplane was not following assigned headings and altitudes and the pilots’ reported having autopilot problems. Subsequently, the pilots’ reported they were using the right attitude indicator as they had difficulties with the left-side indicator. Information was insufficient to evaluate whether the reported difficulties were the result of a malfunction of the autopilot or the pilots’ management of the autopilot system. However, the reported difficulties likely increased the pilots’ workload, may have diverted their attention while operating in IMC and icing conditions, resulting in task saturation, and may have increased their susceptibility to spatial disorientation. It is also possible that the onset of spatial disorientation was the beginning of the pilots’ difficulties maintaining the airplane’s flight track and what they perceived to be an instrumentation problem. Regardless, since the left seat pilot was not rated to fly the airplane, the right seat pilot’s workload would have increased by having to diagnose the issue, assess the situation, and maintain positive airplane control. The airplane’s track data are consistent with the known effects of spatial disorientation, leading to an inflight loss of control and subsequent inflight breakup.

On 27 January 2020, at approximately 1309 hours local time (L), an E-11A, tail number (T/N) 11-9358, was destroyed after touching down in a field in Ghanzi Province, Afghanistan (AFG) following a catastrophic left engine failure. The mishap crew (MC) were deployed and assigned to the 430th Expeditionary Electronic Combat Squadron (EECS), Kandahar Airfield (KAF), AFG. The MC consisted of mishap pilot 1 (MP1) and mishap pilot 2 (MP2). The mission was both a Mission Qualification Training – 3 (MQT-3) sortie for MP2 and a combat sortie for the MC, flown in support of Operation FREEDOM’S SENTINEL. MP1 and MP2 were fatally injured as a result of the accident, and the Mishap Aircraft (MA) was destroyed. At 1105L, the MA departed KAF. The mission proceeded uneventfully until the left engine catastrophically failed one hour and 45 minutes into the flight (1250:52L). Specifically, a fan blade broke free causing the left engine to shutdown. The MC improperly assessed that the operable right engine had failed and initiated shutdown of the right engine leading to a dual engine out emergency. Subsequently, the MC attempted to fly the MA back to KAF, approximately 230 nautical miles (NM) away. Unfortunately, the MC were unable to get either engine airstarted to provide any usable thrust. This resulted in the MA unable to glide the distance remaining to KAF. With few options remaining, the MC maneuvered the MA towards Forward Operating Base (FOB) Sharana, but did not have the altitude and airspeed to glide the remaining distance. The MC unsuccessfully attempted landing in a field approximately 21 NM short of FOB Sharana.