What happened
On April 22, 2022, a Japan Coast Guard Eurocopter EC225LP, registration JA687A, was on final approach to the helipad at Kansai International Airport. The aircraft had received landing clearance from the Tower air traffic controller. Simultaneously, an airport inspection vehicle was conducting a scheduled runway inspection.
During the approach, the Ground air traffic controller, believing that the Tower had approved the vehicle's entry into the helipad area, cleared the vehicle to proceed. This clearance was based on a series of ambiguous communications between the Tower and Ground controllers regarding the vehicle's inspection route. While the Tower controller had authorized the helicopter to land, they had not intended to grant permission for the vehicle to enter the helipad.
As the Eurocopter EC225LP turned toward the landing site, the flight crew visually identified the vehicle entering the taxiway connected to the helipad. The co-pilot alerted the Tower to the vehicle's presence. Consequently, the Tower instructed the helicopter to execute a go-around to avoid a collision. The vehicle, attempting to evacuate the area, entered the helipad briefly before exiting.
The investigation
The JTSB investigation focused on the coordination between the Tower and Ground control positions. Investigators examined cockpit and cockpit voice recorders from JA687A, the vehicle's drive recorder, and air traffic control communication and radar records. The investigation scrutinized the nature of the verbal exchanges between the controllers and the lack of explicit approval protocols for vehicle movements into the helipad area.
Findings
- The primary cause was that the inspection vehicle entered the helipad while the Eurocopter EC225LP was cleared to land.
- The Ground controller issued the vehicle clearance because the coordination between the Tower and Ground was not made in an explicit manner, leading the Ground controller to believe the Tower had approved the vehicle's entry.
- The ambiguity in communication was exacerbated by the fact that the helipad is used less frequently than runways, resulting in less frequent use of specialized safety reminders or coordination protocols for that specific area.
- A lack of effective Team Resource Management (TRM) prevented the controllers from identifying the discrepancy in their respective perceptions of the vehicle's authorized route.