but starting at 4:02 p.m., northwest of brasilia, there's a problem. "the legacy's" radar data is no longer being received by air traffic control. >> at some point during the flight, the transponder, which provides altitude information to the controller, inadvertently disappeared. >> a transponder is critical, not only to relay key information to air traffic control and nearby planes but also in order to enable tcas, the traffic alert and collision avoidance system, which warns pilots when another plane is too close. >> traffic, traffic. >> and advises preventive action. >> climb, climb. >> in addition to the missing transponder signal, which is preventing the "legacy" from sending its data, there's another problem, well-documented radio dead zones over the amazon. beginning at 4:26 p.m., air traffic control and the "legacy" pilots make several attempts to verbally communicate, all unsuccessful. under normal circumstances, they would acknowledge each other's calls. >> brazilian air traffic control system in its overall shoddy performance had misprogram

before becoming the president or the still present elect we flew to brasilia in santiago in the verysame day. and this has a lot of meaning for us. it's clear that brazil is our largest partner to its clear that we cannot think about ourselves without thinking about brazil. but it's also clear that we believe, deeply believe, in the bios beyond the perspective of ourselves and of the region. this notion of having a view of atlantic versus pacific is just plain wrong. if i were not here, i would say plain stupid but i cannot say that. [laughter] it's just wrong. so our view is, and this was discussed between president macri and the other present at the time but it's not something you. people can say now, well, you're starting something new. no. this was discussed then and we agree that there's a combination of outlines the pacific they can become a vicious circle. after that we were invited to become -- and we decide to accept that privilege. so we are no observers of the pacific alliance. we think that in the end, south america, latin america has to really strengthen its integration.