ERA22FA050

The pilot was performing a personal flight. The airplane departed the traffic pattern, flew 2 miles north, and then turned and flew west for 1 mile. During the final 2 minutes of the flight, the airplane’s ground speed slowed from 102 to 49 mph. After the ground speed decreased to about 55 mph, the airplane abruptly turned left and rapidly descended. The final data return was recorded when the airplane was about 100 ft above ground level and 80 ft from the accident site. A home surveillance video that captured the final moments of the accident flight showed that the airplane was in a steep descending left bank before impacting the ground. Another home surveillance video captured the sound of the engine until impact. Postaccident examination of the airplane revealed no evidence of preimpact mechanical malfunctions that would have precluded normal operation. The propeller signatures, cut tree roots, audio recording, and engine data were all consistent with the engine producing power at the time of impact. The weight and balance of the airplane and flap configuration (either extended flaps of 15° or 33°) could not be determined. Nevertheless, according to the airplane owner’s manual, the airplane’s stall speed likely ranged from 62 to 68 mph. The exact weight and balance of the airplane and flap configuration between extended flaps of 15° or 33° could not be determined. Thus, the available evidence for this accident (the automatic dependent surveillance-broadcast (ADS-B) data, GPS data, and surveillance videos) showed that the pilot likely allowed the airplane’s airspeed to decay below the aerodynamic stall speed for any configuration, which caused the airplane’s critical angle of attack to be exceeded. As a result, the airplane entered an aerodynamic stall and spin from which the pilot was unable to recover.

According to the pilot’s logbook, the airplane accumulated at least 66.3 hours of flight time since its last annual inspection. The amount of fuel on the airplane before the accident could not be determined from the available evidence for this investigation. The airplane owner’s manual indicated that the aerodynamic stall speeds at gross weight varied according to bank angle and flap setting, as shown in figure 3. Figure 3. Stall speeds shown in airplane owner’s manual. On November 8, 2021, about 1257 eastern standard time, a Mooney M20F, N3284F, was substantially damaged when it was involved in an accident near Earl L. Small Jr. Field/Stockmar Airport (20GA), Villa Rica, Georgia. The airline transport pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to a friend of the pilot, the purpose of the flight was to “warm up the oil” because he and the pilot planned to change the engine oil and check the cylinder compression in preparation for an upcoming annual inspection. According to automatic dependent surveillance-broadcast (ADS-B) data provided by the Federal Aviation Administration, the airplane departed 20GA at 1253:49. About 1 minute later, the airplane departed the airport traffic pattern area and flew about 2 miles north on a 360° heading. A review of the data downloaded from the airplane’s JPI 700 engine data monitor revealed that the exhaust gas temperatures and the cylinder head temperatures were climbing within the normal operating range. At 1255:20, the temperatures began to decrease gradually for 40 seconds and then began climbing again until the end of the data at 1256:12. At 1256:25, the airplane flew west on a 273° heading for about 1 mile, entered a spiraling left descent, and impacted a wooded area about 3.3 miles from the airport. The last ADS-B return, at 1257:23, showed that the airplane was about 100 ft above ground level and 80 ft from the accident site. Figures 1 and 2 show the airplane’s flightpath and ground speeds, respectively. During the final 10 seconds of the flight, the airplane’s ground speed decreased from 71 to 51 mph, increased back to 71 mph, decreased to 49 mph, and increased to 96 mph. GPS data from the airplane’s Garmin 396 GPSMap device were similar to ADS-B data. Figure 1. Accident airplane’s flightpath and altitude. Figure 2. Accident airplane’s ground speeds (in mph) during final 40 seconds of ADS-B data. The pilot’s friend did not hear any distress calls on the airport common traffic advisory frequency about the time of the accident. According to home surveillance videos that captured the final moments of the accident flight, the airplane was in steep left bank before impacting the ground, and engine noise could be heard until the sound of impact. According to his wife, the pilot had flown the accident airplane since he was 16 years old. The airplane came to rest in a heavily wooded area at an elevation of 1,020 ft. Theairplane was upright and in a level attitude on a 240° heading. All major components of the airplane were located near the main wreckage. Multiple trees near the main wreckage exhibited no impact damage. There was no smell of fuel at the accident site. The fuselage remained intact and was impact crushed. Flight control continuity was established from all flight control surfaces to their respective flight controls in the cockpit. The empennage remained attached to the fuselage and was twisted to the left. The horizontal stabilizers and elevators exhibited a small amount of wrinkling damage. The rudder and vertical stabilizer remained attached to the empennage. The vertical stabilizer was wrinkled. The wings remained attached to the fuselage, and both fuel tanks were breached. Both flaps were extended. The engine remained attached to the airframe. Crankshaft and valvetrain continuity were confirmed when the crankshaft was rotated through 360° of motion. Thumb compression and suction were obtained on all cylinders. Fuel was found in the fuel lines, fuel servo, fuel pump, and fuel manifold. The fuel injectors were removed, and none of them were obstructed. The spark plugs were removed, and all exhibited severe wear and were light gray in color compared with the Champion Check-A-Plug Chart. The magnetos were removed and provided sparks on all towers. The oil filter was removed and disassembled, and no debris was noted in the filter. The propeller remained attached to the engine. Both propeller blades remained attached to the hub. One propeller blade exhibited bending at the tip. The other propeller blade was curled, its tip was torn off, and the blade exhibited chordwise scratching. In addition, a root in the ground near that propeller blade was cut at a 45° angle.