Separation reduced between two aircraft above Jandakot Airport, south of Perth, after one of the pilots did not identify an amended instruction from air traffic control, and their incomplete readback was not corrected by the controller, an ATSB final report explains.
On 12 June 2025, a student pilot was returning to Jandakot at the conclusion of a solo navigation flight in a twin-engine Piper PA-44 Seminole. At the same time, a single-engine Cessna 172 was approaching the airport from the training area.
Air traffic control (ATC) directed the pilot of the faster Seminole to overtake the Cessna as they approached the circuit. However, when the Seminole did not pass the Cessna prior to joining the circuit, ATC amended the instruction, telling the Seminole to 'follow the Cessna'.
"The Seminole pilot did not identify this final part of the amended instruction, likely due to receiving an unexpected cockpit traffic alert at the time the approach clearance was issued," ATSB Director of Transport Safety Stuart Macleod said.
"Consequently, the Seminole passed the Cessna as per the original clearance, reducing separation between the two aircraft."
Although a key element of the revised approach clearance, the pilot's readback of ATC's instructions was incomplete.
"This was not corrected by the controller as the Manual of Air Traffic Services did not explicitly require sequencing instructions to be read back," Mr Macleod said.
"This was a missed opportunity to resolve the situation and, more generally, provided no assurance that this safety-critical aspect had been correctly understood."
Airservices Australia has subsequently conducted a review, and says it will investigate a change to the Manual of Air Traffic Services, and the respective Aeronautical Information Publication reference, to include the instruction 'follow' in the list of items requiring readback.
"This incident highlights the importance of ensuring that pilots and air traffic control all have an accurate situational understanding, especially when plans change," Mr Macleod summarised.
"Sequencing of aircraft is a safety critical component of assuring separation and needs to be unambiguous for all.
"Pilots should seek confirmation from controllers if they are unsure of what is required of them, and ATC should confirm that pilots have a correct understanding of sequencing requirements, if there is any doubt."
You can find here the final report: Separation occurrence involving Piper PA-44, VH-KZJ, and Cessna 172, VH-ZER, near Jandakot Airport, Western Australia, on 12 June 2025
