What happened
On October 22, 2003, a Nippon Cargo Airlines Boeing 747-200F, registration JA8191, was performing a scheduled cargo flight from New Tokyo International Airport (Narita) to Anchorage, USA. During the takeoff roll on runway 34L, the aircraft's rotation was initiated at a speed significantly lower than required for its actual takeoff weight. This premature rotation caused the lower part of the aft fuselage to strike the runway surface, resulting in moderate damage to the aircraft.
Despite the contact, the aircraft successfully became airborne. During the initial climb, the crew experienced a stick shaker activation while performing a standard departure turn, which led to the discovery of incorrect takeoff speed data. Due to the uncertainty regarding the structural integrity of the tail following the strike, the crew decided to return to Narita. The aircraft dumped fuel as requested and landed safely at approximately 22:49. There were no injuries among the four persons on board.
The investigation
Investigators from the Aircraft and Railway Accidents Investigation Commission (ARAIC) examined the Digital Flight Data Recorder (DFDR), air traffic control recordings, and interviewed the flight crew. The investigation focused on the discrepancy between the planned takeoff speeds and the actual speeds used during the rotation. The team also reviewed the takeoff data card prepared by the flight engineer and analyzed the aircraft's flight path and pitch attitude during the takeoff roll.
Findings
- The primary cause of the accident was that the rotation was initiated at a speed lower than appropriate for the aircraft's takeoff weight.
- The flight engineer prepared the takeoff data card using values from the chart corresponding to the aircraft's zero fuel weight rather than its actual takeoff weight.
- The flight engineer failed to reconfirm the values, and the error went undetected during the cockpit cross-checks.
- The captain, the trainee pilot, and the first officer all accepted the erroneous speed values on the data card without doubt.
- At the time of the accident, the procedure for preparing takeoff data cards at the airline was handled solely by the flight engineer, without a requirement for other crew members to participate in the preparation or verification process.