What happened
On the early morning of 25 June 2007, a Cathay Pacific Airways Boeing 747-267B, registration B-HIH, was preparing for a cargo flight from Stockholm/Arlanda airport to Dubai. The flight crew had arrived at the airport as passengers following delays to their previous flight.
During the departure preparations, the aircraft was positioned at a cargo ramp for pushback. After the engines were started and the pushback procedure was completed, the aircraft was prepared to taxi under its own power. However, approximately 45 seconds after the ground technician indicated that the tow vehicle should be disconnected and removed, the aircraft began to taxi.
At the time of the movement, the tow vehicle had been disconnected from the nose wheel and was repositioning to allow the driver to move to the forward driving position. The vehicle had not yet moved far enough to be visible to the pilots. As the aircraft moved, the left inner engine struck the upper corner of the tow vehicle. The impact tore the engine cowling and caused significant damage to the engine systems, resulting in a jet fuel leak. The aircraft taxied a short distance before the damaged engine ceased operation.
The investigation
The Swedish Accident Investigation Authority (SHK) examined the sequence of events, the cockpit voice recorder, and the flight data. The investigation focused on the communication between the ground crew and the flight deck, the adequacy of the aircraft's checklists, and the physical positioning of the ground vehicle. Investigators also looked into the physiological state of the crew, noting that the pilots had been awake for approximately 18 to 20 hours at the time of the incident.
Findings
- The aircraft's checklist lacked a specific requirement for the pilots to receive a clear visual signal (such as a "thumbs up") from the ground technician before commencing taxi.
- The tow vehicle was not positioned within the pilots' field of vision when the aircraft began its movement.
- Inadequate checklists regarding the verification of an all-clear signal from ground personnel was a primary cause.
- The concentration of the flight crew was likely impaired by fatigue, as they had been awake for nearly 20 hours.
- Operational delays and incorrect runway information earlier in the night had contributed to a high-pressure environment.