What happened
In 1994, an aircraft that had been stored for an extended period in Khartoum, Sudan, was prepared for flight operations. The aircraft had been acquired previously for the purpose of transporting equipment from Afghanistan to Sudan. During its period of inactivity, the plane's condition had deteriorated, with the engine intakes and exhaust systems filled with sand, the batteries depleted, and the tires deflated.
During the preparation process, the tires were reinflated and the hydraulic systems were charged using hydraulic fluid instead of the required nitrogen. Upon starting the engines, the crew conducted a test flight consisting of three touch-and-go maneuvers. Following the completion of these maneuvers, the aircraft attempted to land, but the main braking system failed to function. The secondary or alternate braking system also failed to engage.
After the crew shut down the engines and cut the fuel supply, the aircraft was unable to decelerate sufficiently. The plane continued to travel down the runway at a speed of approximately 60 knots before exiting the paved surface and colliding with a sandpile. The impact resulted in substantial damage to the light aircraft, and the airframe was subsequently abandoned at the Khartoum site.
Findings
- The aircraft's hydraulic system was improperly serviced with hydraulic fluid alone, omitting the necessary nitrogen charge.
- The failure of both the primary and alternate braking systems prevented the aircraft from stopping within the runway limits.