Piper PA28 N8991W accident near Carlinville, Illinois

Probable cause

The pilot’s attempted recovery from a steep descent which inadvertently exceeded the ultimate load factor of the airframe and resulted in a low-level inflight breakup.

NTSB analysis

Position data depicted the airplane in cruise flight on a northeast course toward the destination airport at 5,500 ft mean sea level (msl). Shortly before the accident, the airplane entered a left turn with a gradually steepening bank angle. After completing a 360º turn and returning to a northeast course, the airplane immediately transitioned into a right turn that continued until the airplane again returned to a northeast course. Airplane bank angles reached 50° and 60° in the left and right turns, respectively. As the right turn continued, the airplane entered a descent and the airspeed increased. The bank angle ultimately reached about 110° (right wing down), the pitch attitude reached 63° nose down, and the airspeed increased to over 200 kts during the descent. The maximum computed load factor based on the available data was 4.72 G. The position data ended when the airplane was between 2,000 ft and 2,500 ft msl (1,400 ft and 1,900 ft above ground level). At the end of the data, the airplane was in a steep, spiral dive and about 35 kts above the never-exceed airspeed (VNE). The airplane was established on a southwesterly course away from the accident site at that time.

The wreckage debris path was oriented on a northeasterly course and was about 400 ft long. The wreckage distribution was consistent with a low-altitude inflight break up. In addition, the presence of all airframe structural components and flight control surfaces within the debris path was consistent with the airplane being structurally intact as it approached the accident site. A postaccident examination revealed that the wing structure failed as a result of overstress. No preimpact anomalies with respect to the flight control system were identified. As a result, the steep descent was likely an intentional action by the pilot but for reasons that could not be determined.

The investigation did not have any data from which to determine the flightpath from the final data point to the accident site. However, because the final segment of the flightpath was toward the southwest and the debris path was oriented to the northeast, it is clear that the pilot attempted to pull out of the dive and, in doing so, reversed course. That maneuver, which was initiated from a steep, spiral dive and above VNE, resulted in the pilot inadvertently exceeding the ultimate load factor for the airframe. The excessive load factor caused the separation of the wings and stabilator, and a loss of control of the airplane.

Text from the NTSB. Open the NTSB docket for CEN20LA201 for the full record.