The accumulation of multiple human errors can occur. To prevent accidents, it is essential to establish systems that ensure safety.

We speak of the Jan. 2, 2024, collision between a Japan Airlines (JAL) passenger jet and a Japan Coast Guard aircraft at Tokyo's Haneda Airport. The Japan Transport Safety Board (JTSB) has released an interim report on its investigation into the incident.

The report revealed that the coast guard aircraft mistakenly believed it had received clearance to enter the runway. This error went unnoticed by the air traffic controller and the JAL aircraft, which was in the process of landing. These three factors combined to result in the collision.

The captain of the coast guard plane explained to the JTSB that the air traffic controller had instructed him to "enter the runway and wait." However, the actual instruction had been to proceed only to the stopping position before the runway.

Analysis of the cockpit voice recorder showed that the captain and co-pilot only partially repeated and confirmed the instructions they received. Instead, they were focused on preparing for takeoff.

At the time, the coast guard aircraft was transporting relief supplies for victims of the Jan. 1 Noto Peninsula earthquake, which had struck the previous day. The aircraft's departure had been delayed due to mechanical issues, and the captain, concerned about the crew's return schedule, was in a hurry to take off.

There was still an opportunity to avoid the collision at the last moment. Fifteen seconds before the impact, another air traffic controller, who was handling a different task, noticed the coast guard aircraft on the runway. However, the warning message was not effectively communicated, and no action was taken.

The air traffic control system also had flaws. An alert indicating unauthorized runway entry appeared on the monitor at the control desk, but the air traffic controller failed to notice it. The alert system was reportedly disregarded because it had not been decided how to respond when it activated, and it sometimes triggered even in noncritical situations.

Following the accident, safety measures were introduced. The alert system was updated to include audible warnings, and the number of air traffic controllers was increased.

Although the JTSB continues its investigation to prepare a final report, which is expected to take time, immediate safety measures must be implemented. These measures should address both hardware and software systems.

There is also a growing need to develop new systems that utilize digital technology to allow relevant parties to share risk information.

With the increasing number of inbound foreign visitors, Haneda Airport has expanded its flight slots, making it one of the busiest globally. Further growth in air travel demand is anticipated.

The findings from this investigation must serve as lessons to advance efforts to prevent similar incidents in the future.