Summary of Incident
On May 22, 2023, at 09:03 Japan Standard Time, a helicopter operated by Aero Asahi Corporation landed at T Helipad at Chubu Centrair International Airport, which was different from the runway assigned by air traffic control. The aircraft, an Aerospatiale AS355F2 with registration JA6718, had taken off from Yao Airport at 08:30 for personnel transport.
Flight History
Approximately 10 nautical miles west of the airport, the helicopter requested landing instructions from the tower. The controller instructed the helicopter to report over West Point, a visual reporting point. Despite not having reached it, the captain reported over West Point. The controller, perceiving the pilot as unfamiliar, decided to clear the helicopter to land on the runway, which is more easily recognizable than the helipad. At 08:58, when the helicopter passed West Point, the controller instructed a position report at 1 nautical mile west. At 09:01, the controller issued a landing clearance: "RUNWAY 36, CLEARED TO LAND, NEARBY A8 ON THE ACTIVE." The captain read back: "ROGER. CLEARED TO LAND RUNWAY38, A7. CONFIRM A7?" The controller replied "NEARBY A8," and the captain acknowledged. The helicopter crossed the runway near Taxiway A7 and headed toward T Helipad. The controller, after looking down at equipment, looked up and saw the helicopter approaching T Helipad. The ground controller advised that the helicopter had crossed the runway. At 09:03:14, the controller called: "YOU MISSED RUNWAY, AND YOU ARE LANDING AT T HELIPAD." The helicopter landed at T Helipad at 09:03:27.
Captain's Response
The captain and flight operation assistant had no prior experience flying to the airport. They had interviewed other pilots and were told that aircraft are always cleared to land at T Helipad. They did not expect a runway clearance. When the controller specified a touchdown point near Taxiway A8, the captain was unable to understand promptly but did not confirm. He interpreted it as supplementary information indicating the helipad's location. The flight operation assistant thought the controller specified a runway crossing point. Both missed the phrase "ON THE ACTIVE." The captain questioned Taxiway A7 versus A8, but despite the controller's correction, continued assuming clearance to T Helipad.
ATC Phraseology
According to Japanese ATC standards, landing clearance on a runway requires the runway number first, while clearance to a helipad mentions the helipad name first. This difference is also described in the Aeronautical Information Manual Japan.
Probable Causes
The probable cause of this serious incident was that when the helicopter was cleared to land on Runway 36 by the Tower, the captain most likely mistakenly believed that it was cleared to land at T Helipad and it landed at the helipad.