Commercial Fixed Wing
Flight Crew Air Transport Pilot (ATP)
Flight Crew Total 6980; Flight Crew Type 212
Communication Breakdown
ATC Issue All Types; Conflict Airborne Conflict; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Flight Crew Took Evasive Action
Procedure; Airspace Structure; Human Factors
[We were] south of POVLA intersection; in radio and radar contact with Amazonica control; Noticed traffic ahead approximately 40 miles climbing to or thru our altitude of FL380. The aircraft leveled at our altitude of FL380. Queries to Amazonica control went unanswered. I initiated a turn to the right and the monitoring pilot broadcast our intentions on the VHF assigned frequency. The other aircraft had realized the situation and queried Amazonica control with no response and also initiated a turn off course. We passed well clear of the each other and rejoined the airway.No TCAS Traffic Alert or Resolution Advisory were received. Further radio transmissions between Amazonica and the other aircraft seemed to indicate that they had accepted a clearance meant for another flight [with similar call sign]. Flight continued uneventfully to our destination.
[Report narrative contained no additional information.]
Air crew initiated their own evasive action to avoid other aircraft at same altitude while at cruise in foreign airspace. ATC did not assist.