B777-200
Flight Crew Air Transport Pilot (ATP)
Communication Breakdown
ATC Issue All Types
Human Factors
The frequency 128.2 was in use over Bolivian airspace on airway UL417 at the time indicated. No alternate frequency was available. The transmissions from LaPaz control were so garbled and unreadable as to render the frequency useless between LOKOX and RBC. We would not have been able to receive any instructions from the controller in the event of an emergency; nor would we have been able to confirm if the Controller properly received any emergency calls from us.[Someone needs to] ensure Bolivia performs proper checks on their equipment and repairs transmitters or antennae as required. In lieu of that; I advise we avoid overfly of Bolivia until they can demonstrate their communications are reliable.
A B777 First Officer advised pilot/controller communications within a sector of Bolivian airspace were unreadable and suggested flight in that area be avoided until reliable communications could be verified.