What happened
On December 12, 2022, at approximately 11:31 JST, a Cessna 172P, registration JA4121, was performing a landing approach at Saga Airport for flight training. During the final stages of the approach, a vehicle tasked with bird sweeping entered the active runway, necessitating an immediate go-around by the aircraft.
At the time of the incident, weather conditions were clear with good visibility and a northeast wind of 10 knots. The aircraft had just completed its base turn when the Air Traffic Service Flight Information Officer identified the runway incursion and instructed the pilot to abort the landing. The closest proximity between the approaching aircraft and the vehicle was approximately 2,36 and m.
The investigation
The investigation examined radio communication logs, airport surveillance footage, and statements from the personnel involved. Investigators reviewed the use of two different radio frequencies: Frequency A, used by the aircraft and the Air Traffic Service, and Frequency B, used by the bird sweep staff to communicate with the airport office.
Surveillance cameras confirmed that the vehicle stopped briefly at the apron and again before the runway before proceeding onto the active surface. The investigation also scrutinized the training records of the bird sweep staff, noting that while the staff member had completed initial safety training, they had not been included in the mandatory biannual recurrent training due to an administrative error.
Findings
- The bird sweep staff member requested permission to enter the runway but was explicitly instructed by the Air Traffic Service Flight Information Officer to hold position because an aircraft was approaching.
- The driver performed an incorrect read-back, stating they were cleared to enter, and proceeded onto the runway.
- The driver was likely attempting to complete the task quickly due to a high volume of birds in the area and a desire to finish the sweep before the next scheduled flight.
- A contributing factor was the radio volume settings; the volume on the Air Traffic Service radio was set to a lower level (10 instead of the standard 18), which may have hindered the driver's ability to clearly hear the instruction to stay off the runway.
- The vehicle entered the runway without obtaining proper authorization.
- The bird sweep staff had not received required recurrent safety training because they were omitted from the airport's training distribution list.
Safety action
Following the incident, the airport office implemented several measures, including requiring bird sweeps to be conducted by two people and providing updated flight schedules for small aircraft to all relevant personnel. Additionally, the airport has introduced new training for bird sweep staff regarding Air Band Radio terminology and implemented a checklist for inspecting radio equipment before operations.