The Australian Transport Safety Bureau (ATSB) has concluded that the pilots involved in a rare mid-air collision near Mangalore Victoria in February 2020 took no action to avoid the crash even though they had been alerted by ATC.
Beech D95 Travel Air VH-AEM was on an IFR training flight from Tyabb to Mangalore when it collided with Piper Seminole VH-JQF 4 nm south of Mangalore Airport. VH-JQF was on an IFR flight to Essendon via waypoint LACEY.
Each aircraft contained a student and an instructor, none of whom survived the collision.
The ATSB report released today concluded that even though Melbourne Centre had issued traffic information to both aircraft after receiving Short-term Collision Alerts (STCA) on the radar, there was no evidence that either aircraft made any changes to their track to avoid each other.
“The ATSB identified that, following receipt of verbal traffic information provided to both aircraft by air traffic control, the pilots did not successfully manoeuvre or establish direct radio communications to maintain separation, probably due to the collision risk not being recognised,” said ATSB Chief Commissioner Angus Mitchell.
“The investigation also determined that while it is probable the aircraft were in instrument meteorological conditions at the time of the collision, due to extensive cloud in the area, the known limitations of the ‘see-and-avoid’ principle meant that the pilots were unlikely to have seen each other in sufficient time to prevent the collision even in clear weather."
The crew of AEM flew to Mangalore at 6000 feet and were told by Melbourne Centre that there was no IFR traffic for their descent. VH-JQF was yet to appear on the ATC radar. Three minutes later, they were told that JQF would soon depart for a track to the south.
Two minutes later JQF sent a departure report that they were passing 2700 on climb to 7000 and tracking to LACEY. This required the crew to make a left-hand turn to intercept the direct track from Mangalore to LACEY within 5 nm of the airport. ATC informed JQF that AEM was inbound passing 5000 for "not above 4000", which the crew of the Seminole acknowledged.
An STCA was triggered soon after, but the controller assessed that JQF would pass behind AEM. The ATSB determined, however, that this was based on the current track of JQF and did not allow for the left turn required to intercept the LACEY track within 5 nm.
Another STCA showed that JQF would pass behind AEM and that the two aircraft would have a vertical separation of 500 feet. A third STCA occured seconds before the accident, but the controller took no action as traffic had been passed to both aircraft, which were in non-controlled airspace, where separation responsibility lies with the pilots in command.
"As such, if made aware of traffic, either via advice from air traffic control, a received broadcast, or any other means, it is vitally important for pilots that the traffic is hazard assessed and, if necessary, a plan is established to assure separation," Mitchell said.
The ATSB has concluded that the airspace surrounding Mangalore was not unsafe, but under current procedures there was nothing to prevent the accident happening again.
"In that context, while the available evidence in this investigation does not support a conclusion that the present self-separation system is unsafe, there is an opportunity to potentially reduce safety risk further," the investigation report states.
"The ATSB therefore supports systemic enhancements to the overall air traffic system that have been assessed by regulatory and air traffic specialists, in keeping with their obligations as providing a net overall safety increase.
"Key examples of such enhancements include increased use of controlled airspace and ADS-B aircraft surveillance data (both by air traffic services and in-cockpit) [and] improved monitoring of air traffic movements (both quantity and complexity) to assist the identification of increasing risk areas."
Airservices Australia indicated last year an intention to create a Surveillance Flight Information Service (SFIS) around Mangalore similar to the one now in operation at Ballina, but the implementation was delayed pending a CASA review of the Mangalore airspace.
The SFIS amalgamates Flight Information Services (FIS) in the surrounding Class G and Surveillance Information Service (SIS) to achieve what Airservices says will be an increase in safety.
Industry analysts say that an SFIS would not have prevented the February 2020 accident because SFIS is only traffic information and is not controlled airspace, the only airspace classification that allows for ATC to provide separation vectors.
The full report is on the ATSB website.