What happened
On a scheduled flight from Shanghai-Hongqiao Airport to Tokyo, a DC-8 departed at 13:57 local time with 113 passengers and 11 crew members on board. Approximately nine minutes into the flight, the crew detected an unusual noise originating from the lower middle section of the airframe. This was accompanied by several critical system failures, including low hydraulic levels, low pressure in the hydraulic reservoir air, a total loss of hydraulic system pressure, and abnormal indications regarding flap positions. Additionally, the aircraft experienced a complete loss of air brake pressure.
Due to these malfunctions, the flight crew decided to abort the mission and return to Shanghai for an emergency landing. During the approach to runway 36, the aircraft touched down with excessive speed. The plane subsequently overran the runway and came to a stop in a drainage ditch. While all 124 occupants successfully evacuated the aircraft, 23 individuals sustained injuries during the incident.
Findings
Investigations determined that an explosion occurred within the air brake bottle. This event caused significant damage to 13 tubes within the hydraulic system as well as 2 tubes belonging to the emergency air brake system. The destruction of these components led to the failure of the flaps to extend properly and resulted in the loss of both normal and emergency wheel braking capabilities. Consequently, the aircraft's roll-out distance after touchdown exceeded the available runway and stopway length, making it impossible for the pilot to halt the plane within the safety limits of the runway.