In-Flight Breakup During High-Speed Descent in Reduced Visibility (N444AM)

Flight Progression and Weather Conditions The aircraft departed an airport and headed toward a VORTAC located approximately 30 nautical miles to the west. Initial radar contact was recorded at 1159, with the Mode C transponder indicating an altitude of 3,500 feet mean sea level (msl). As the aircraft approached the VORTAC, its altitude increased to 4,900 feet msl. It continued climbing past the filed VFR flight plan altitude of 8,500 feet msl, reaching 12,900 feet msl. The final six minutes of radar data showed the aircraft at various altitudes, beginning at 11,000 feet msl and climbing to a maximum of 12,700 feet msl. During the last three minutes, the aircraft executed numerous left and right climbing and descending turns before reversing course. The next-to-last radar return at 1221:24 indicated an altitude of 11,900 feet msl. Nineteen seconds later, the final radar return reported an altitude of 7,700 feet msl, with a computed vertical speed of 13,263 feet per minute between the two returns. The weather environment included multiple cloud layers at 9,000, 12,000, and 16,000 feet, along with reduced visibility aloft due to smoke and haze from wildfires affecting large portions of Southern California. ## Wreckage Distribution and Structural Findings The wreckage was scattered over a 0.2-nautical-mile distance, with the main wreckage located approximately 0.5 miles northwest of the last radar return. The northern end of the debris path contained pieces of the left elevator, followed by sections of the right stabilizer and elevator, and additional sections from both horizontal empennage surfaces. Fragments of the vertical stabilizer, rudder, and both ailerons were also found along the path. The southern 100 feet of the debris path included the fuselage, both sets of wings, engines, and propellers. The aircraft impacted the ground inverted, with the wings separating just outboard of the nacelles at the initial point of impact. Examination of the wreckage indicated that all structural failures were the result of overload.