What happened
On June 9, 2021, two aircraft were performing instructional training flights in the circuit patterns for runway 28L at EPBC. The first aircraft, an Aero AT3-R1/00 with registration SP-RWG, was performing a circuit, followed by a Cessna 152, registration SP-KOG, which was maintaining separation behind the lead aircraft. During the maneuvers, a third aircraft was also entering the circuit from the VFR Foxtrot point.
The instructor in the SP-RWG misidentified radio communications, incorrectly believing the Cessna 152 was the aircraft entering the circuit behind them. During the second turn, the SP-RWG performed the maneuver approximately 20 seconds late and on the outside of the published circuit, drifting about 1 km away from the standard track. Meanwhile, the Cessna 152 was flying a shorter path on the inside of the circuit. As both aircraft approached the third turn, the separation between them significantly decreased.
Upon reaching the downwind position, the crew of the SP-RWG observed the Cessna 152 to their right, slightly behind and lower by approximately 100-150 feet. The instructor in the SP-RWG requested that the Cessna 152 crew establish separation. However, the instructor in the Cessna 152 believed their aircraft was in front. The two instructors exchanged conflicting views over the radio but did not reach an agreement. Eventually, the Cessna 152 overtook the SP-RWG during the third turn, and separation was subsequently re-established without further incident.
The investigation
The PKBWL examined flight track logs and radio communications. The analysis revealed that the SP-RWG had flown the first and second turns outside the published circuit path, with the second turn being the most significant deviation. Conversely, the Cessna 152 was flying a typical circuit but was shortening the turns. The investigation also noted that the flight controller did not intervene despite the identifiable risk of a near-midair collision.
Findings
- Improper analysis of the traffic situation within the circuit patterns.
- The crew of the SP-RWG executed the second turn outside the published flight path.
- Both crews experienced a loss of situational awareness, leading to a mutual, incorrect belief that they held priority in the circuit.
- The flight controller failed to react to the potentially hazardous situation.
Safety action
- The incident was discussed at a conference involving the airport manager and both training organizations.
- The airport manager implemented a traffic limit, restricting the circuit to a maximum of six aircraft, with an average circuit time of 9-10 minutes, to improve separation maintenance.