Narrative:

While flying on airway ur 979 with our lights on and one mile right of course northwest of naslo (N1147.0 W01309.0); roberts control had instructed us to call dakar over komab. Over the broadcast in the blind frequency we heard a garbled transmission but understood the aircraft was at FL320. We called twice and requested location of aircraft at Fl320 with no response. We then saw a target on TCAS moving left to right at FL320. It seemed to stop when it crossed our airway appearing to be coming down the airway toward us. After about five to ten seconds I said lets change course to be sure to go behind it. The roberts controller came on and told the other aircraft to descend immediately to FL310 in which he responded 'it's too late' as we passed behind him with a TA. Both roberts and the other pilot sounded very shaken. Shortly after the event I asked roberts control twice for the identity of the other aircraft and received no response. We called the other aircraft on 126.9 with no response. About ten minutes later another air carrier called us back with the identity of the other aircraft. Our dispatcher said the flight was on ub 728. This flight entered roberts' airspace at a correct altitude for his course of 192. If there were high altitude hot spots I would call this one; ur 979 between naslo and badia.

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Original NASA ASRS Text

Title: An air carrier Captain reported a conflict at FL320 while flying in Roberts Control airspace on UR 979 where it intersects with UR 728.

Narrative: While flying on Airway UR 979 with our lights on and one mile right of course northwest of NASLO (N1147.0 W01309.0); Roberts Control had instructed us to call Dakar over KOMAB. Over the broadcast in the blind frequency we heard a garbled transmission but understood the aircraft was at FL320. We called twice and requested location of aircraft at Fl320 with no response. We then saw a target on TCAS moving left to right at FL320. It seemed to stop when it crossed our airway appearing to be coming down the airway toward us. After about five to ten seconds I said lets change course to be sure to go behind it. The Roberts Controller came on and told the other aircraft to descend immediately to FL310 in which he responded 'It's too late' as we passed behind him with a TA. Both Roberts and the other pilot sounded very shaken. Shortly after the event I asked Roberts Control twice for the identity of the other aircraft and received no response. We called the other aircraft on 126.9 with no response. About ten minutes later another air carrier called us back with the identity of the other aircraft. Our Dispatcher said the flight was on UB 728. This flight entered Roberts' airspace at a correct altitude for his course of 192. If there were high altitude hot spots I would call this one; UR 979 between NASLO and BADIA.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.