Commercial Fixed Wing
Flight Crew Air Transport Pilot (ATP)
Communication Breakdown; Confusion
ATC Issue All Types; Conflict Airborne Conflict; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued New Clearance; Flight Crew Took Evasive Action
Human Factors; ATC Equipment / Nav Facility / Buildings
During cruise flight at FL370 we checked in with Amazonica Center with call sign and Flight Level. We were given a Climb clearance to FL380 by a female controller. Radio conditions were 5/5. I read back '[Call Sign] Departing FL370; Climbing FL380; [Call Sign]'. The climb was accomplished and we leveled off at FL380. Almost immediately; both the Captain and I recognized TCAS traffic Co-Altitude at approximately 40NM and 12 O'clock . The CA initiated an evasive turn to the right while I simultaneously contacted Amazonica ATC for clarification. Upon contact with Amazonica the Radio conditions had deteriorated to 2/2 with the normal Amazonica Echo; after a short delay we were able to understand another climb clearance to FL400; I advised unable; due to weight. Shortly thereafter a male controller issued a descent to FL370 clearance. He also advised us to use [registration N-number] for future comm with his sector. The traffic was [another air carrier]; they also initiated an evasive right turn. At no time did we get a Resolution Advisory/Traffic Advisory from TCAS. After the incident; while back on course; we observed [two Company aircraft] also on our same sector frequency; while not able to read them we were able to read ATC in communication with them.The radio conditions have been an ongoing problem in many [Amazonica] sectors with many controlling agencies. Evidently they simulcast on a number of frequencies and there is a terrible echo that we have had to work around for many; many years. Normally it is an inconvenience that we work around; but obviously in this case; safety was the overriding concern. I would like to see an FAA test flight program established with host countries to identify and eliminate the problem. Also; if the US carriers could coordinate with each other and foreign carriers to eliminate call sign similarities to the maximum extent possible it would be helpful when unsatisfactory radio conditions arise.
B777 First Officer reported communication difficulties with Amazonica Center led to a traffic conflict at FL380.