WPR19FA262

The pilot’s failure to maintain adequate airspeed and exceedance of the aircraft's critical angle of attack while turning during climb out, which resulted in an aerodynamic stall.

The flight instructor and his passenger departed for a work flight that tested radar in an airplane that was near its maximum weight limit. Videos of the accident flight showed that the airplane took off from the runway, climbed out, appeared to level off for a few seconds, then entered a right bank turn. After about 90° of turn, the airplane banked sharply to the right and entered a steep nose-down descent. The airplane impacted a building about 3/4 mile east of the airport. Postaccident examination of the airframe and engine revealed no preimpact anomalies that would have precluded normal operation. A video of the accident flight and impact markings at the accident site were consistent with the airplane entering an aerodynamic stall then steeply descending to the ground. It is likely that the pilot failed to maintain airspeed during the turn, which resulted in an exceedance of the aircraft's critical angle of attack and an aerodynamic stall. Toxicology testing of the pilot’s specimens detected low concentrations of ethanol and diphenhydramine that generally would not be considered impairing.

The airplane owner’s manual listed the stall speeds at the maximum gross weight of 2,350 pounds and no flaps as 64 miles per hour (mph) at no bank angle, 66 mph at 20° of bank, 73 mph at 40° of bank, and 91 mph at 60° of bank. The airplane owner’s manual also listed the maximum rate of climb for the gross weight of 2,350 pounds as about 638 ft per minute (above standard day temperature correction included). A current weight and balance form could not be located and the amount of fuel on the airplane could not be determined, so an accurate weight and balance could not be determined. However, calculating the accident aircraft’s weight with empty and full fuel loads, the weights of the occupants, and the weight of the electronic equipment would put the airplane about 30 to 234 pounds below its maximum weight limit depending on its fuel load. Examination of the accident site revealed that the airplane impacted the roof of a building about 3/4 mile east of the airport at an elevation of about 108 ft. The right wing was dangling off the roof and remained connected through the control cables. All major components of the airplane were contained within the main wreckage site, and most of the wreckage debris, consisting of small fragments, was scattered about 30 ft from the main wreckage. On the roof top, the left wing had partially separated and remained attached to the spar carry through structure. The fuselage came to rest pointed downward on a heading of about 086° magnetic. The left wing sustained substantial leading-edge damage on the entire span, and the leading edge was bent upwards. The left flap and aileron were attached at all their respective attachment points. The left tank fuel cap was observed secured. The left main landing gear strut, wheel, and a portion of the wheel fairing had separated and were located on the ground near the main wreckage. The forward portion of the fairing was embedded in the roof. The right wing sustained substantial leading-edge damage on the inboard third of the wing. The right flap and aileron were attached at all their respective attachment points. The fuel cap was observed secured. Fuel was observed leaking out of the outboard end of the wing during recovery. The right main wheel and fairing had separated and was located on the roof. The empennage remained attached to the fuselage and was relatively intact. The vertical stabilizer and rudder were attached to their respective attachment points. The left and right horizontal stabilators were attached and relatively intact. The instrument control panel and cabin area were substantially damaged. The engine came to rest partially attached to the front of the fuselage near the ground. The engine appeared to be attached at its engine mounts. The carburetor and gascolator were still attached. The controls to the carburetor were intact. The rocker cover panels were attached, but the front right cover exhibited impact damage. All engine accessories appeared to be present. No oil was observed leaking at the wreckage site. The intake appeared to be free of obstructions. The exhaust tubing was attached and appeared to be intact. All the fuel lines were attached. The two-bladed propeller was attached to the crankshaft. Both blades exhibited chordwise scratching and trailing edge twisting. The spinner and propeller hub were still attached to the crankshaft flange. The propeller spinner was crushed and exhibited impact markings. Postaccident airframe and engine examination established flight control continuity from the ailerons to the wing root, aileron continuity from the cabin to the cockpit controls, and rudder and elevator continuity to the flight controls. The flaps were confirmed to be near the zero-flap position by the flap actuator. The vertical speed indicator showed a descent of about 1,800 ft per minute. The fuel selector handle was in the “both” position. The fuel selector case was removed, and the valve was determined to be selected to both tanks using compressed air and no obstructions were observed. The fuel strainer gasket screen and bowl were clear of contaminants. Postaccident examination of the engine revealed that the engine sustained impact damage on the exhaust system, alternator, and right forward rocker cover. One engine mount was observed fractured and the crankcase was intact. All intake and exhaust rocker arms, shafts, and valve springs behind the rocker covers were intact with no anomalies observed. The crankshaft was able to be rotated by hand and rotational continuity was established throughout the engine and valve train in all cylinders. All cylinders displayed appropriate compression and suction in the proper firing order. Timing was confirmed to be appropriate. Both magnetos were removed and during manual rotation, spark was observed on all the ignition leads. The top spark plugs were removed, and the spark plugs electrodes exhibited normal wear signatures. A borescope inspection of the cylinders revealed evidence of normal operational conditions Postaccident examination of the airframe and engine revealed no preimpact mechanical anomalies or malfunctions that would have prevented normal operation. On September 19, 2019, about 1202 Pacific daylight time, a Cessna 177 airplane, N2323Y, was destroyed when it was involved in an accident near Torrance, California. The commercial pilot was fatally injured, and the passenger was seriously injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 other work use flight. The passenger did not recall the events leading up to the accident. A review of videos taken from personal electronic devices revealed that the airplane took off from the runway and climbed out. After several seconds, the airplane appeared to level off for a few seconds then entered a right banked turn. After about 90° into the turn, the airplane banked sharply to the right and entered a steep nose down descent. Several witnesses located near the departure end of the runway reported that the airplane went into a right banked turn and, shortly thereafter, it nose-dived towards the ground. One witness reported that the airplane attained an altitude of between 350-400 above ground level and was not climbing before it banked right and then stalled. The airplane impacted a building about 3/4 mile east of the Zamperini Field Airport (TOA) Torrance, California. The Goleta Star company had been developing and test flying their radar technology in several different platforms since about 2006. In 2017, it began renting the accident airplane from the previous owner that was located at TOA. The accident flight was the first flight of the accident airplane after the company had acquired it, hired a local mechanic to maintain it, rented it out, and provided the previous owner with a pilot. The County of Los Angeles Department of Medical Examiner-Coroner, Los Angeles, California, performed an autopsy on the pilot and determined that the cause of death was attributed to multiple blunt force traumatic injuries. Toxicology testing by the Federal Aviation Administration’s (FAA's) Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, detected 0.015 gm/dL ethanol in the pilot’s heart blood, 0.055 gm/dL ethanol in his vitreous fluid, and 0.097 gm/dL ethanol in his urine. Methanol was detected in his urine but not in his heart blood or vitreous fluid. The FAA laboratory also detected the sedating antihistamine diphenhydramine in the pilot’s blood and urine. Ethanol is a social drug commonly consumed by drinking beer, wine, or liquor. Ethanol acts as a central nervous system depressant; it impairs judgment, psychomotor functioning, and vigilance. Effects of ethanol on aviators are generally well understood; it significantly impairs pilot performance, even at very low levels. While the acute effects of ethanol can vary depending o