CEN22FA081

The limitations of the see-and-avoid concept as a method for self-separation of aircraft, which resulted in an inflight collision. Contributing to the accident was the absence of collision avoidance technology on both aircraft.

A Cessna 208B airplane collided with a powered paraglider during cruise flight at 5,000 feet mean sea level (msl) in Class E airspace. Based on video evidence, the powered paraglider operator impacted the Cessna’s right wing leading edge, outboard of the lift strut attachment point. The outboard 10 ft of the Cessna’s right wing separated during the collision. The Cessna impacted terrain at high vertical speed in a steep nose-down and inverted attitude. The powered paraglider operator was found separated from his seat style harness. The paraglider wing, harness, and emergency parachute were located about 3.9 miles south of the Cessna’s main wreckage site. Based on video evidence and automatic dependent surveillance-broadcast (ADS-B) data, the Cessna and the powered paraglider converged with a 90° collision angle and a closing speed of about 164 knots. About 8 seconds before the collision, the powered paraglider operator suddenly turned his head to the right and about 6 seconds before the collision, the powered paraglider maneuvered in a manner consistent with an attempt to avoid a collision with the converging Cessna. Research indicates that about 12.5 seconds can be expected to elapse between the time that a pilot sees a conflicting aircraft and the time an avoidance maneuver begins. Additionally, research suggests that general aviation pilots may only spend 30-50% of their time scanning outside the cockpit. About 8 seconds before the collision (when the powered paraglider operator’s head suddenly turned to the right), the Cessna would have appeared in the powered paraglider operator’s peripheral view, where research has demonstrated visual acuity is very poor. Additionally, there would have been little apparent motion because the Cessna and the powered paraglider were on a collision course. Under optimal viewing conditions, the powered paraglider may have been recognizable to the Cessna pilot about 17.5 seconds before the collision. However, despite the powered paraglider’s position near the center of his field of view, the Cessna pilot did not attempt to maneuver his airplane to avoid a collision. Further review of the video evidence revealed that the powered paraglider was superimposed on a horizon containing terrain features creating a complex background. Research suggests that the powered paraglider in a complex background may have been recognizable about 7.4 seconds before the collision. However, the limited visual contrast of the powered paraglider and its occupant against the background may have further reduced visual detection to 2-3 seconds before the collision. Thus, after considering all the known variables, it is likely that the Cessna pilot did not see the powered paraglider with sufficient time to avoid the collision. The Cessna was equipped with a transponder and an ADS-B OUT transmitter, which made the airplane visible to the air traffic control system. The operation of the powered paraglider in Class E airspace did not require two-way radio communication with air traffic control, the use of a transponder, or an ADS-B OUT transmitter and therefore was not visible to air traffic control. Neither the Cessna nor the powered paraglider were equipped with ADS-B IN technology, cockpit display of traffic information, or a traffic alerting system. Postmortem toxicological testing detected the prescription antipsychotic medication quetiapine, which is not approved by the Federal Aviation Administration (FAA), in the Cessna pilot’s muscle specimen but the test results did not provide sufficient basis for determining whether he was drowsy or otherwise impaired at the time of the collision (especially in the absence of any supporting details to suggest quetiapine use). Testing also detected ethanol at a low level (0.022 g/dL) in the Cessna pilot’s muscle specimen, but ethanol was not detected (less than 0.01 g/dL) in another muscle specimen. Based on the available results, some, or all of the small amount of detected ethanol may have been from postmortem production, and it is unlikely that ethanol effects contributed to the accident. The Cessna pilot likely did not have sufficient time to see and avoid the powered paraglider (regardless of whether he was impaired by the quetiapine) and, thus, it is unlikely the effects of quetiapine or an associated medical condition contributed to the accident.

Based on the video footage recovered from the powered paraglider, visual meteorological conditions prevailed with no clouds or visibility restrictions. At the time of the accident, the sun’s position relative to the accident site was to the southeast (137° true) and was about 22.3° above the horizon. Cessna Pilot The Cessna pilot’s last aviation medical examination was completed on June 14, 2021. At that time, he reported no medication use. He reported a history of anxiety due to legal issues and family stress, and a 2008 court-martial with dishonorable discharge from the Air Force. He had used the antidepressant/sleep aid medication trazodone for a short time in 2008 and was issued a FAA Letter of Eligibility for medical certification for his anxiety and legal issues in 2011. No significant issues were identified at the Cessna pilot’s last aviation medical examination, and he was issued a first-class medical certificate without limitation. An autopsy of the Cessna pilot was performed by Fort Bend County Medical Examiner Office. The autopsy report was reviewed by a National Transportation Safety Board (NTSB) Medical Officer. According to the autopsy report, the cause of death was multiple blunt force trauma, and the manner of death was accident. The ability of the autopsy examination to evaluate for natural disease was extremely limited by the extent of traumatic injury. The FAA Forensic Sciences laboratory performed toxicological testing of postmortem specimens from the Cessna pilot. The prescription antipsychotic medication quetiapine was detected in muscle tissue. Ethanol was detected in one muscle specimen at 0.022 g/dL but was not detected in another muscle specimen. No blood was available for FAA testing. Quetiapine, sometimes marketed as Seroquel, is a prescription antipsychotic medication. In the United States, quetiapine is approved by the Food and Drug Administration (FDA) for treating schizophrenia. Quetiapine is also FDA-approved for treating acute episodes of mania and depression in bipolar disorder, and as part of chronic multi-drug treatment of bipolar disorder. Additionally, quetiapine is approved as part of multi-drug treatment of major depressive disorder. Quetiapine is regularly prescribed for off-label (non-FDA-approved) uses, including in low doses for treatment of insomnia without underlying psychiatric illness. Some other possible off-label uses include chronic single-drug treatment of bipolar disorder, as well as treatment of post-traumatic stress disorder and anxiety. Quetiapine commonly causes drowsiness, especially in the initial days after starting a treatment regimen. This is a result of the drug’s sedating antihistamine effects, to which users may develop tolerance over time. Quetiapine also has multiple other potential adverse side effects. The drug typically carries a warning that it has the potential to impair judgment, thinking, and motor skills, and that users should be cautioned about performing activities requiring mental alertness, such as operating a motor vehicle or hazardous machinery, until they are reasonably certain that the drug does not affect them adversely. The FAA considers quetiapine to be a “do not issue/do not fly” medication. According to the FAA medical case review for this accident, quetiapine is unacceptable for FAA medical certification because of the underlying conditions it is used to treat. In addition to being used medicinally, quetiapine has emerged as a potential drug of misuse and abuse. Commonly, abuse of quetiapine involves its use in combination with recreational substances such as cocaine, marijuana, alcohol, benzodiazepines, or opioids. Users may seek to enhance those substances’ desired effects or to self medicate for undesired symptoms caused by substance use or withdrawal. Some people may abuse quetiapine seeking effects of hypnosis or euphoria, although the drug’s ability to produce a pleasurable “high” in the absence of other recreational drugs is not clear. People also sometimes misuse or abuse quetiapine seeking relief from anxiety or insomnia. A review of the Cessna pilot’s primary care medical records from a period of 3 years before the crash date did not document any use of quetiapine, the presence of any psychiatric disorder, or any history of substance abuse. Ethanol is a type of alcohol. It is the intoxicating alcohol in beer, wine, and liquor, and, if consumed, can impair judgment, psychomotor performance, cognition, and vigilance. FAA regulation imposes strict limits on flying after consuming ethanol, including prohibiting pilots from flying with a blood ethanol level of 0.04 g/dL or greater. However, consumption is not the only possible source of ethanol in postmortem specimens. Ethanol can be produced by microbes in a person’s body after death. Postmortem ethanol production is made more likely by extensive traumatic injury and can cause an affected toxicological specimen to test positive for ethanol while another specimen from the same person tests negative. Powered Paraglider Operator An autopsy of the powered paraglider operator was performed by Fort Bend County Medical Examiner Office. The autopsy report was reviewed by a NTSB Medical Officer. According to the autopsy report, the powered paraglider operator’s cause of death was blunt force injuries, and his manner of death was accident. The autopsy did not identify any significant natural disease. The FAA Forensic Sciences laboratory performed toxicological testing of postmortem specimens from the powered paraglider operator, which did not detect any ethanol or tested-for drugs. On December 21, 2021, about 0926 central standard time, a Cessna 208B airplane, N1116N, collided with a powered paraglider while inflight near Fulshear, Texas. The pilot of the Cessna and the non-certificated powered paraglider operator were fatally injured. The Cessna was destroyed and the powered paraglider sustained substantial damage. The Cessna was operated as a Title 14 Code of Federal Regulations (CFR) Part 135 cargo flight, and the powered paraglider was operated as a Title 14 CFR Part 103 personal flight. According to air traffic control data, about 0910, the Cessna departed George Bush Intercontinental Airport (IAH), Houston, Texas, and flew southwest toward Victoria Regional Airport (VCT), Victoria, Texas. At 0917:53, the Cessna pilot was cleared to climb and maintain 5,000 ft mean sea level (msl). At 0924:08, the Cessna pilot asked the air traffic controller, “… confirm you wanted me at five thousand opposite direction traffic.” The controller replied that he wanted the Cessna to remain at 5,000 ft msl, but to expect a higher altitude soon. According to ADS-B track data, between 0925:31 and 0925:34, the Cessna departed level flight at 5,000 ft msl and entered a rapidly increasing descent. At 0925:34, the final recorded ADS-B track data was at 4,725 ft msl and about 0.5 mile northeast of the Cessna’s main wreckage site. As of the final recorded ADS-B track point, the Cessna was descending about 8,960 feet per minute. The powered paraglider was not equipped with a transponder or an ADS-B OUT transmitter and, as such, the powered paraglider’s position was not displayed on the air traffic controller’s display. Postaccident review of available radar data revealed sporadic primary returns near where the Cessna departed level flight and ADS-B data was lost. However, these primary returns were not displayed on the controller’s display and did not have a reported altitude. The powered paraglider operator was using a video camera that captured the final 7 minutes 13 seconds of the flight. The recovered camera footage included a field of view that captured almost the entirety of the paraglider operator, the paraglider rigging, and the paraglider wing. The recovered audio track did not align with the video footage and was subsequently determined not r