What happened
On November 26, 2021, at 16:20 UTC, a Boeing 738 operated by Flybondi Líneas Aéreas, registered as LV-HKN, was performing a descent within the SIS FIR. The aircraft was operating flight FO5120 from Aeroparque Jorge Newbery (SABE) to Posadas International Airport (SARP). During the descent phase, the aircraft's Traffic Collision Avoidance System (TCAS) issued a Traffic Advisory (TA) signal.
The alert was triggered by the presence of another commercial aircraft, a Boeing 763 with registration N538LA, operated by LATAM Cargo. This second aircraft, flying flight 1504 from Guarulhos (SBGR) to Santiago (SCEL), was maintaining a cruise altitude between flight levels 320 and 330 near the BOKIL position. The encounter occurred while the Flybondi aircraft was transitioning through these altitudes.
The investigation
The investigation focused on the interaction between the two aircraft within the Misiones airspace. The JST examined the flight paths and the activation of the TCAS alert. The analysis confirmed that the alert was a result of a convergent flight path between the descending commercial flight and the cruising cargo flight. No damage to either aircraft was reported, and there were no injuries or fatalities associated with this event.