What happened
On July 9, 2018, an Aerospatiale AS332L helicopter, registration JA9690, operated by Aero Asahi Corporation, landed on a runway at Toyama Airport that was currently occupied by a runway inspection vehicle. The flight had departed from a temporary airfield in Fukui Prefecture with four people on board.
During a shift rotation at the control tower, the Tower Controller was performing equipment checks on an emergency radio. During this period, a request was received from a Mitsubishi Pajero inspection vehicle to enter the runway. The controller granted clearance to the vehicle. However, while attempting to revert the radio frequencies to their original settings, the controller failed to use the required "Runway Closed" reminder on the wind indicator.
At approximately 14:05 JST, the pilot of the Aerospatiale AS332L received landing clearance for Runway 02. The pilot, believing the runway was clear because no other aircraft were communicating on the tower frequency, proceeded with the landing. The helicopter landed on the runway, passing near the inspection vehicle, which was positioned on the north side of the strip. The pilot did not notice the vehicle during the approach or after touchdown.
The investigation
The Japan Transport Safety Board (JTSB) examined air traffic control communication records, airport surveillance video, and statements from the pilot, the tower controller, the coordinator position controller, and the vehicle operators. The investigation focused on the sequence of communications during the controller shift change and the failure to utilize the mandatory runway closure indicators. The investigation also reviewed the pilot's visual scanning procedures and the coordination between the tower and the coordinator position.
Findings
- The Tower Controller forgot the presence of the inspection vehicle on the runway after being distracted by simultaneous radio communications and the need to adjust emergency radio frequencies.
- The controller failed to appropriately scan the full length of the runway before issuing landing clearance and neglected to use the prescribed "Runway Closed" reminder.
- The pilot's visual scan was limited to the threshold and touchdown area, failing to detect the vehicle on the runway.
- A lack of effective coordination occurred between the tower controller and the coordinator position controller, as the latter did not intervene despite noticing discrepancies in the flight progress logs.
Safety action
Following the incident, the Civil Aviation Bureau (CAB) instructed all Japanese aerodrome control towers to reinforce the use of runway reminders and provide specialized training. Toyama Airport implemented several changes, including relocating the emergency radio to allow operation from the seated position, rescheduling equipment checks to avoid overlap with runway inspections, and improving the clarity of air traffic logbooks.