CEN24FA305

The intent of the flight was to reposition the airplane to another airport. Multiple witnesses reported that the airplane taxied from its hangar to the departure end of the turf runway which was wet from recent rains. During the taxi, intermittent engine backfires were heard. The airplane taxied into position and began its takeoff roll. Witnesses heard the engine backfire again and saw the airplane come to a complete stop about 300 ft down the runway. After a few minutes, the engine rpm increased again, and the airplane started another takeoff roll. One witness observed the airplane pitch up abruptly at a high angle and climb to about 200 ft, enter an aerodynamic stall, and impact terrain. Postaccident examination of the accident site revealed that the airplane’s takeoff roll tire tracks were observed veering to the left about 50 ft off the runway. The tracks went through tall, uncut grass that was bordering the runway, and the ground under the tall grass was boggy and water saturated. Separated small pieces of the horizontal stabilizer were found in the tall grass, and a portion of the right elevator was embedded in the top of a barbed wire fence that bordered the boggy area. The airplane impacted the terrain in a left wing down, nose low attitude about 200 ft from the fence. Postaccident examination of the airframe and engine revealed no mechanical anomalies that would have precluded normal operation. The pilot’s most recent medical certification had been issued via Special Issuance due to medical history including coronary artery disease with a stent. The pilot’s autopsy identified a coronary artery stent, moderate coronary and cerebral artery plaque, and severe aortic plaque. The pilot’s medical condition increased his risk of cardiovascular-related impairment. Although such impairment cannot be excluded by autopsy evidence alone, no specific evidence of such impairment was identified.

The FAA publication H-8083-25A, Pilot's Handbook of Aeronautical Knowledge, stated that an aerodynamic stall results from a rapid decrease in lift caused by the separation of airflow from the wing's surface brought on by exceeding the critical angle of attack (AOA). AOA is defined as the acute angle between the chord line of the airfoil and the direction of the relative wind. An aerodynamic stall can occur when the airplane flies too slowly, or when higher wing loads are imposed due to maneuvers such as pull-ups or banked flight. According to the FAA Airplane Flying Handbook (FAA-H-8083-3A): At the same gross weight, airplane configuration, and power setting, a given airplane will consistently stall at the same indicated airspeed if no acceleration is involved. The airplane will, however, stall at a higher indicated airspeed when excessive maneuvering loads are imposed by steep turns, pull-ups, or other abrupt changes in its flightpath. Stalls entered from such flight situations are called 'accelerated maneuver stalls,' a term, which has no reference to the airspeeds involved. Stalls which result from abrupt maneuvers tend to be more rapid, or severe, than the unaccelerated stalls, and because they occur at higher-than-normal airspeeds, and/or may occur at lower than anticipated pitch attitudes, they may be unexpected by an inexperienced pilot. Failure to take immediate steps toward recovery when an accelerated stall occurs may result in a complete loss of flight control, notably, power-on spins. On August 6, 2024, about 1820 central daylight time, a Cessna 172F airplane, N7905U, sustained substantial damage when it was involved in an accident near Brazoria, Texas. The pilot sustained fatal injuries. The airplane was operated as a Title 14 Code of Federal Regulations part 91 personal flight. The intent of the flight was to move the airplane from Eagle Airpark (2TE0), Brazoria, Texas, to Texas Gulf Coast Regional Airport (LBX), Lake Jackson, Texas. Several witnesses observed the airplane taxi from its hangar to the departure end of the turf runway 11 which was wet from recent rains. A witness, who was an airframe and powerplant mechanic, reported that the engine sounded as if it was intermittently backfiring during the taxi. The airplane taxied into position and began its takeoff roll. The witness heard the engine backfire again and saw the airplane come to a complete stop about 300 ft down the runway. He then heard the engine rpm increase and the airplane started another takeoff roll. The airplane then went out of his line of sight. Another witness, who was located on the opposite side of the runway as the previous witness, observed the airplane taxi from its hangar to the runway. She stated that the airplane started its takeoff roll and stopped on the runway. The airplane stopped for a few minutes, then the airplane started a takeoff roll again. She then observed the airplane pitch up abruptly at a high angle and climb to about 200 ft. Shestated that the left wing of the airplane stalled, and the airplane spiraled down to the left until ground impact. Several other witnesses near the accident site reported similar observations of the accident sequence. The 82-year-old male pilot’s last aviation medical examination was August 3, 2022. At that time, he reported medical history including high blood pressure and past coronary artery stenting. He reported using the medications amlodipine/benazepril, atorvastatin, and clopidogrel. His application was deferred due to his history of coronary stenting. He provided additional information to the FAA and was granted an Authorization for Special Issuance of third-class medical certification in December 2023. He was issued a third-class medical certificate limited by a requirement to use corrective lenses to meet vision standards at all distances, and not valid after August 31, 2024. The County of Galveston Medical Examiner’s Office, La Marque, Texas, conducted an autopsy of the pilot. According to the autopsy report, the cause of death was blunt force trauma, and the Medical Examiner recommended the manner of death be classified as accident. The autopsy identified coronary artery disease with a left anterior descending coronary artery stent and diffuse plaque causing an average of 50% narrowing of the coronary arteries. Severe, complex, friable aortic plaque also was present, as was moderate plaque of the cerebral arteries. The FAA Forensic Sciences Laboratory performed toxicological testing of postmortem specimens from the pilot. The testing detected dextromethorphan, dextrorphen, famotidine, amlodipine, benazepril, benazeprilat and atorvastatin in the pilot’s blood and urine. Clopidogrel was detected in urine and was not detected in blood. Dextromethorphan is a cough suppressant medication that is available without a prescription in a variety of cold and allergy products. Dextromethorphan is not typically impairing at levels associated with appropriate medicinal use. FAA guidance indicates that pilots who use dextromethorphan should observe a waiting period for the drug to be cleared from circulation before flying. Dextrorphan is a metabolite of dextromethorphan. Famotidine is a stomach acid suppression medication that is available without a prescription. Amlodipine and benazepril are two prescription medications available alone or as a combination product for treatment of high blood pressure. Benazeprilat is a metabolite of benazepril. Atorvastatin is a prescription medication commonly used to help control cholesterol and reduce cardiovascular risk. Clopidogrel is a prescription antiplatelet medication that can be used to reduce cardiovascular risk in certain medical conditions, including coronary artery stenting. Clopidogrel, atorvastatin, amlodipine, benazepril, and famotidine are not typically impairing. Postaccident examination of the accident site showed that the airplane impacted the ground in a left wing down, nose low attitude.Tire tracks from the airplane during the takeoff roll were observed veering to the left about 50 ft off the runway. The tracks went through tall, uncut grass that was bordering the runway. The ground under the tall grass was boggy and water saturated. Metal pieces of a carport frame (various lengths and 2-inch by 2-inch square) structure were found lying flat amidst the grass, about 50 ft left of the edge of the runway. The airport manager reported that the metal pieces were remnants from a recent hurricane. Evidence at the accident site showed that the left main landing gear wheel and bottom side of the airplane’s horizontal stabilizer contacted the metal pieces as the airplane passed through the grass. Small pieces of the horizontal stabilizer and white paint chips (consistent with the airplane’s paint) were found amidst the grass. The contact with the metal pieces was consistent with the airplane rotating for takeoff after it veered off the runway surface, as it passed through the tall, uncut grass in the boggy area. The boggy area was bordered by a 4 ft high barbed wire fence. The outboard 4 ft of the airplane’s right elevator was found embedded in the top wire of the fence. The main wreckage of the airplane was about 200 ft from the fence, and the direction of impact was about 090°. The fuel tanks were found breached, and an unknown amount of fuel had leaked out of the tanks after the accident. Disassembly of the engine and engine accessories did not reveal any pre-impact anomalies. Engine drive continuity was established, and fuel was found in the fuel lines and the carburetor bowl. The fuel was visually examined and found free of contaminants and water. About 3 gallons of fuel were drained from the right fuel tank. The fuel was free of contaminants and water. The cockpit fuel selector lever and the airframe fuel valve were found in the right tank position. The fuel valve was found functional. The carburetor heat control was in the OFF position. Examinations of the airframe, flight controls, and fuel system did not reveal any pre-impact anomalies, and flight control continuity was confirmed. The flap actuator position corresponded with a flap extension setting of 20°.