History of Flight
On May 31, 2020, at approximately 1546 central daylight time, a Piper PA-28-235 airplane, N8991W, was destroyed in an accident near Carlinville, Illinois. The pilot and three passengers sustained fatal injuries. The flight was operated as a personal flight under Title 14 Code of Federal Regulations Part 91.
Data from automatic dependent surveillance–broadcast (ADS-B) and an Appareo Stratus recording unit indicated that the flight departed around 1518 and proceeded northeast, climbing to about 5,500 ft mean sea level. Around 1543, the airplane entered a left bank of about 15°, which continued until the airplane headed southwest. The bank angle then increased to about 50° before the airplane turned back northeast. Approximately 25 seconds later, the airplane rolled out of the left turn and immediately entered a right turn with a bank angle of 60°. During this right turn, the airplane reached an altitude of 5,685 ft and slowed to about 85 kts. It then began to descend, and airspeed increased. At 1545:54, the right bank steepened to about 110°.
By 1546:07, the altitude had decreased to 2,850 ft, the descent rate exceeded 18,700 ft per minute, and airspeed surpassed 200 kts. During this period, the pitch angle changed from +10° (nose up) to -52° (nose down), eventually reaching -63° nose down before data ended around 1546:10. At that moment, the airplane was between 2,000 ft and 2,500 ft msl (1,400 ft to 1,900 ft above ground level). The maximum computed load factor during the recorded data was 4.72 G, occurring about 1546:06. The airplane was in a steep spiral dive, traveling approximately 35 kts above the never-exceed airspeed (VNE) of 171 kts, and was oriented away from the accident site, which was about 0.15 nm north-northeast of the final data point. No data were available to determine the flight path from the final data point to the accident site.
A witness reported seeing the airplane moving up and down in a series of dips, with five or six such cycles. She then observed the airplane enter a nose dive and spiral downward. Initially heading south, the airplane appeared intact as it dove, but it broke apart as it neared the ground.
Aircraft Information
The airplane was a normal category Piper PA-28-235. The applicable limit load factor was 3.8 G, with an ultimate load factor of 5.7 G. A weight and balance calculation based on estimated occupant, baggage, and fuel loadings suggested that the airplane was within the gross weight and center-of-gravity limitations specified by the manufacturer.
Wreckage and Impact Information
The wreckage was located in an open field adjacent to a storage building and a pond. A portion of the left wing had penetrated the storage building roof and came to rest inside. The debris path was about 400 ft long. The main wreckage comprised the fuselage, engine, and propeller; the fuselage was fragmented and the cabin compromised. The engine sustained impact damage and the engine mount was fragmented, though the propeller remained attached. Both wings, the vertical stabilizer, and the stabilator had separated from the fuselage. All flight control surfaces were found within the debris field, consistent with a low-altitude in-flight breakup.
Postaccident examination revealed that both wings had separated at the root, with wing spars exhibiting upward bending near the fracture surfaces, indicative of positive load factors at separation. The fracture surfaces had a dull, grainy appearance typical of overstress. The ailerons, including counterweights, were separated from the wings and located within the debris path. Control cable and rod separations were also consistent with overstress.
The stabilator separated except for the center spar section, which remained attached to the aft fuselage hinge points. The balance weight and mast were intact, and the stabilator control cables remained attached to the mast and were continuous to the cockpit. The vertical stabilizer separated except for its aft spar, which remained attached to the fuselage; the rudder remained attached at each hinge point, with control cables continuous to the cockpit. No preimpact anomalies were identified in the flight control system.