CEN21LA088

The noncertificated pilot and flight instructor departed on an instructional flight in the experimental airplane. The airplane was later located about 1/3 mile south of the departure airport. There were no witnesses to the accident. The airplane sustained substantial damage to the wings and fuselage. A postaccident examination of the airplane revealed that engine exhibited detonation and scoring of its cylinders, which would have resulted in a loss of engine power. Incorrect timing, poor fuel quality, and lubrication breakdown could have contributed, however, based on the available evidence, the reason for the detonation could not be determined. The impact damage of the airplane and lack of ground scarring was characteristic of a low-speed nose-down impact with terrain, which would have resulted from an aerodynamic stall. The airplane make and model is categorized as rapidly losing energy (airspeed/altitude) when there is a loss or reduction of engine power. The airplane was equipped with a snow mobile engine. The required airplane flight testing was not performed following the installation of the engine and, as a result, may have induced negative handling qualities during low-speed flight, such as those near the stall flight regime. Although the flight instructor’s autopsy showed signs of heart disease it’s unlikely this impaired his ability to respond to the engine failure. Additionally, the noncertificated pilot’s autopsy showed cardiovascular disease that increased his risk of experiencing a sudden impairing or incapacitating medical event. Toxicology testing detected Duloxetine; a medication commonly used to treat depression. Metaxalone, cetirizine, and Chlorthalidone were also detected and combined had the potential to cause impairment. However, because the flight instructor was the only qualified pilot abord the airplane, held the responsibility for ensuring the safe operation of the flight, and for responding to the engine emergency, the noncertificated pilot would have not had the skill or experience to play more than a very limited role. Thus, it is unlikely that the effects of his medical conditions or medications contributed to the accident.

The amount of fuel in the airplane at takeoff is unknown. On December 15, 2009, the Operating Limitations for Light Sport Aircraft for the airplane were issued by the Federal Aviation Administration (FAA) for the airplane showing it was equipped with a Rotax 582 engine, serial number 5503744, engine. At the time of the accident, the engine that was installed had the following data plate information: Rotax 670, serial number 4088286. An engine logbook entry dated November 18, 2014, stated that the installed engine was “custom built by Rotax Rick.” The Rotax 670 engine was designed and manufactured by Rotax as a snowmobile engine. The installation of the Rotax Rick 670 engine was a major change to the airplane and there was no record in the FAA airworthiness file and the aircraft logs stating that the airplane was flight tested in accordance with Part 91.319, which required a flight test after a major change was made to the airplane. The airplane was not equipped with nor was it required to have a stall warning system or an angle-of-attack indicator. Advisory Circular (AC) 90-109A, Transition to Unfamiliar Aircraft, states that experimental airplane flight operations represent a small percentage of flight hours but a significant percentage of general aviation accidents. The AC states that consideration should be made to add stall warning devices and that an airplane’s response to control inputs usually degrades at slower speeds, requiring larger deflections to achieve the desired response. The AC categorizes the Rans S-12 as a low-inertia and/or high-drag airplane. Appendix 4 of the AC defines low-inertia and/or high-drag airplanes as those airplanes that rapidly lose energy (airspeed/altitude) when there is a loss or reduction of engine power. According to the flight instructor’s life partner, the flight instructor flew the accident airplane by himself about 1-2 weeks prior to the accident. After the flight instructor flew the accident airplane, he tried to talk the pilot into buying an “actual” airplane because he felt the airplane was dangerous especially for someone new to flying and even more so if conditions were not perfect. There were no air traffic control communications/services provided to the airplane. On December 15, 2020, about 2300 central standard time, a Rans S-12XL, N449JP, was involved in an accident near Port Isabel, Texas. The noncertificated pilot, who was the airplane owner, and a flight instructor were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. A student pilot who had flown with the flight instructor in another airplane prior to the accident flight stated that he and the instructor landed at Port Isabel-Cameron County Airport (PIL), Port Isabel, Texas. They then taxied to a hangar on the east side of the fixed base operator at PIL. The student pilot dropped the flight instructor off, and the flight instructor walked over to the hangar and met two men,one of whom was the accident noncertificated pilot. The student pilot said he saw them move the accident airplane out of the hangar. The student pilot last saw the flight instructor about 1540. An alert notice was issued due to the airplane being overdue. The airplane was located about ½ mile south runway 35 at PIL. There were no witnesses that reported seeing the accident. An autopsy of the instructor pilot cited the cause of death as blunt force trauma due to an aircraft crash and the manner of death was an accident. Toxicology testing of the samples from the instructor pilot were negative for drugs and alcohol. An autopsy of the noncertificated pilot cited the cause of death as blunt force trauma due to an aircraft crash and the manner of death was an accident. Toxicology testing of the samples from the noncertificated pilot detected Duloxetine, Metaxalone, cetirizine, and Chlorthalidone in blood and urine. The flight instructor’s only logbook entry for flight in the accident airplane was dated December 9, 2020, for a flight that was 1.0 hour in duration. The last flight in the logbook was dated December 14, 2020, for a flight in a Cessna 172. The airplane was resting in a nose-down attitude and damage was consistent with a low-speed impact with terrain. The airplane sustained substantial damage to the wings and fuselage. There was no ground scarring that preceded the location of the wreckage. All airplane components were at the accident site. The flight controls and control surfaces were intact and connected. Examination of the engine revealed that the magneto side engine cylinder was disintegrated consistent with detonation, and the walls of both cylinders were scored. The reason for the detonation occurring could not be determined. The amount of fuel aboard the airplane at the time of the accident is unknown due to fuel spillage resulting from the airplane resting attitude. There was fuel present in the engine’s carburetor bowls at the accident site.