Originally Posted by marciovp
Approaching Brasilia the pilots said to ATC here we are, at 370. ATC said OK, "have a good trip". Nobody said anything about changing altitude.
The radar screen in Brasilia showed for seven minutes after the Legacy passed Brasilia that the transponder was OK showing 370 but the software from Brasilia was showing 360. Software in Brasilia entered the original written flight plan not requiring that ATC talked and confirmed 360 with the pilots. The icon was showing 370:360. A discrepancy.
Then transponder OFF. There was clear indication in the radar screen in Brasilia that the transponder was off. A military primary radar entered the picture and sent information 360. The written original flight plan also was there. So 360Z360 (Z means unreliable). Also transponder OFF. For about one hour. No communication between ATC and pilots even the radio was working. The pilots also did not see the Transponder OFF sign, in small letter, in yellow in their screen.
Then the lack of communication, one trying to call the other more that a dozen times. When ATC was able to say something to the pilots it was nothing about altitude, and there was no concern. It was to tell them the frequency of Manaus.
That is interesting, because if U.S. controllers had the same equipment and same circumstances, our procedures would have detected the conflict and this "wouldn't" have happened. Which confirms all blame here is on Brazil's ATC, either the controller or their system. Modern ATC is set up to still work even with one aircraft's transponder failure, plus radio failure, plus confusion with assigned altitude, plus no TCAS... Brazil needs to catch up!