B737-700
Situational Awareness; Communication Breakdown
ATC Issue All Types; Conflict Airborne Conflict
Flight Crew Took Evasive Action
Human Factors; Procedure
While approaching VESKA at our assigned altitude of FL380; we noticed another aircraft at our altitude when he was about 80 NM from us. We started watching him and realized he was probably also headed directly for VESKA. As he got closer; it appeared that we would only have about 2 NM separation if nothing was done. The Center prior to being handed off to Port-Au-Prince; did not respond to our inquiry about the other aircraft. When it became apparent that we were on our own; we turned early before VESKA and initiated a climb. We had the other aircraft in sight by this time and could see that he was not changing course or altitude. While in the climb; we got an RA to climb at 1;000 FPM. We complied with the RA and increased our rate of climb. We leveled off about FL388 and then returned to FL380. Our separation at the closest point was about 500 FT and 4 NM. No other aircraft were in the immediate area according to our TCAS. Identification; we were unable to get Center to respond to our inquiries about the other aircraft at our altitude approaching VESKA. Center gave us a hand-off to Port-Au-Prince and I told him about the RA. It turns out he gave us the wrong frequency and we had to find the correct Port-Au-Prince frequency on our own. I told Center and Port-Au-Prince about the RA. Nobody seemed all that concerned. Port-Au-Prince came back a minute later and wanted to verify that I'd said we had an RA. Also; there was no sign whatsoever that the other aircraft saw us or heard us. Response; after the event we sent an ACARS message to Dispatch informing them of the RA. They responded that they were making the required report. On initial contact with Center; he said 'RADAR contact.' Later on; he asked our estimate for VESKA. Although he never said 'RADAR service terminated' I suspected he didn't have RADAR contact with us anymore. In the future I will ask the controller if I suspect he's lost RADAR contact. We were monitoring guard but got too busy when we got close to VESKA to try to contact the other aircraft. In the future I will make an early attempt to use guard to get ATC's and the other aircraft's attention.
Air Carrier with foreign Center experienced a conflict event; observing traffic for up to 80 miles but unable to contact ATC facility; the reporter noting 'guard' frequency should have be used in this instance.