Accident Sequence
The flight crew was conducting a landing on a remote, gravel-covered runway. According to the captain, the terrain on the approach sloped downward toward the runway threshold, placing the airplane close to the ground during the final stages of the approach. A bystander's video recording captured the airplane on short final approach, indicating it was flying low on the glidepath and dragging its landing gear through vegetation near the approach end of the runway. Just before the main landing gear wheels reached the runway threshold, the right main landing wheel struck a dirt and rock berm.
Crew Actions
To prevent the airplane from veering to the right after the impact, the captain placed the propellers of both engines into reverse pitch. The flight engineer applied asymmetric reverse thrust to help correct the right turning tendency. The airplane then tracked straight for approximately 2,000 feet before the right main landing gear assembly separated. The airplane continued straight down the runway, then veered to the right, exited the runway, and spun approximately 180 degrees, resulting in substantial damage to the fuselage.
Examination and Findings
On-site examination of the runway revealed several piles of rocks and dirt at the runway threshold, which investigators determined were likely what the right main landing wheel impacted. The fact that the landing gear struck vegetation and rocks on approach suggests the airplane was below the proper glidepath. The crew stated that there were no preaccident mechanical malfunctions or anomalies that would have precluded normal operation.
Probable Cause
The National Transportation Safety Board determined the probable cause of this accident was the pilot's failure to maintain an adequate glidepath during the approach, which resulted in the airplane impacting rocks and dirt at the runway threshold, a separation of the right main landing gear, and a loss of directional control.