What happened
In the early hours of 4 August 2007, two Boeing 777-200ER aircraft, registered as 9V-SVH and 9V-SVO, were involved in a wingtip collision at Singapore Changi Airport. The incident occurred while 9V-SVO was undergoing a standard pushback from Bay F37 and 9V-SVH was taxiing along Taxiway C1.
As the crew of 9V-SVH approached the pushback in progress, they observed 9V-SVO positioned closely to their path. The crew contacted Ground Control to clarify their clearance. The controller instructed the crew to proceed past the stationary aircraft if they deemed there was sufficient separation. Relying on a visual assessment, the pilot-in-on-command decided to continue the taxi. However, at approximately 01:03 hrs, the left wingtip of 9V-SVH struck the right wingtip of 9V-SVO, resulting in structural damage to the fiberglass panels, slats, and ailerons of both aircraft. There were no injuries to the passengers or crew.
The investigation
The investigation focused on the decision-making processes of the flight crews, the accuracy of the clearance assessment, and the instructions provided by Air Traffic Control. Investigators examined the specific method used by the pilot of 9V-SVH to judge distance, which involved using a screw on the cockpit window pillar as a visual reference point.
Furthermore, the investigation looked into the ground controller's role, noting that while the controller was aware that pushbacks from Bay F37 could interfere with taxiway traffic, they had provided a conditional clearance rather than a definitive instruction to hold. The investigation also reviewed the actions of the air tug ground crew, who were attempting to assess the clearance themselves when the impact occurred.