A Batik Air Boeing 737-800 passed within 1,000ft of terrain on an approach to Canberra in which it passed below the safe altitude.
The incident occurred on 14 June 2024 as the aircraft (PK-LDK) operated the airline’s inaugural flight on the Denpasar-Canberra route, arriving in the city’s airspace before airport controllers started work, according to a preliminary report by the Australian Transport Safety Bureau.
At 05:51 local time, the crew requested air traffic control clearance for an ILS approach to runway 35, but Melbourne air traffic control responded that the Canberra tower was closed, and common traffic advisory frequency (CTAF) procedures applied.
As the aircraft was above the desired flightpath, the crew decided to hold at waypoint MOMBI and reduce altitude.
Owing to crew inputs, the aircraft descended to 4,700ft, while the minimum holding altitude was 5,600ft. The Melbourne Centre controller failed to observe to see that the aircraft was operating below the minimum holding altitude.
Meanwhile, the Canberra Tower controller was getting ready to commence service and observed that the aircraft was below minimum holding altitude. The controller made “multiple unsuccessful attempts to contact the crew” on the Canberra CTAF frequency.
“As the Canberra Tower controller did not have a direct means of communication with the Melbourne Centre controller, the Tower controller contacted a Melbourne Approach controller to relay their concerns to the Melbourne Centre controller,” says the ATSB.
As the aircraft continued its turn to MOMBI, it crossed over the easter slopes of Mount Campbell just 924ft above ground level, before joining the ILS approach.
“At about the same time, the Canberra Approach controller also identified that the aircraft was operating below the minimum altitude,” says the ATSB.
“The controller contacted the crew to provide a safety alert and asked the crew if they were ‘visual’. The crew responded advising that they were ‘visual with the runway’ and continued the approach.”
The aircraft landed at 06:02 without further incident.
The ATSB continues to investigate the incident, which it rates as “serious.”
It reports that a number of safety actions have already been taken. Canberra Airport has revised crew briefing materials to provide more detailed information about its air traffic control hours, CTAF procedures, holding requirements, and safe altitude requirements.
Batik Air has adjusted its schedule so that the Denpasar-Canberra flight now arrives during Canberra Tower and Approach operating hours.
