What happened
During the landing phase at a remote airfield featuring a gravel-covered runway, the flight crew was performing an approach on a terrain that sloped downward toward the runway threshold. This topography resulted in the aircraft flying at a low altitude relative to the glidepath. During the short final approach, the aircraft's landing gear made contact with vegetation located near the start of the runway. Just before the main landing gear reached the threshold, the right main wheel struck a berm composed of dirt and rocks.
In an attempt to maintain directional control and prevent the aircraft from veering toward the right, the captain transitioned the No. 1 and No. 2 engine propellers into reverse pitch. The flight engineer utilized asymmetric reverse thrust to counteract the rightward pull, allowing the aircraft to maintain a straight track for approximately 2,000 feet. However, the right main landing gear assembly subsequently detached from the aircraft. Following this separation, the aircraft continued down the runway before veering right and exiting the paved surface, where it underwent a 180-degree spin. The incident resulted in substantial damage to the fuselage.
Findings
An investigation of the runway environment identified several piles of rocks and dirt, measuring approximately 4 feet in height, positioned at the runway threshold. The impact of the right main landing gear with these obstacles is considered the primary factor in the gear separation. Because the landing gear had previously interacted with vegetation during the approach, it is concluded that the aircraft was operating below the required glidepath during the final stages of the landing.