A319
Air Traffic Control Fully Certified
Communication Breakdown; Confusion
Deviation / Discrepancy - Procedural Other / Unknown; Inflight Event / Encounter Weather / Turbulence
General None Reported / Taken
Human Factors; Weather
Air Carrier X checked in on frequency; asking for deviations and direct TADPO (the crossing fix into Cuban airspace). I told him unable direct TADPO but to deviate right then direct MTH when able; I was giving the aircraft MTH because of the Special Interest Flight requirements to return them to their route as soon as possible. Air Carrier X told me that he had weather and needed TADPO; I then told him to deviate right for the weather and go to MTH and that there was no known precipitation south of MTH. The pilot rogered that clearance. Air Carrier X continued to fly and not deviate and flew directly through the weather that he had been cleared to deviate around. The flight then reported a loss of 500 FT and 'Heavy' turbulence. We then asked if it was Moderate; Severe; or Extreme. The pilot responded with Extreme. Pilot was asked if there was any damage to the airplane or injury to passengers. Pilot replied with a negative. I am not 100% certain if I called the weather to the pilot; but assumed that since he was saying he needed to deviate that he was going around it. The plane encountered the weather just as I was being removed from the sector to allow for training of another Controller. I think the briefing was a distraction. I think there may have been some communication/language issues with the Air Carrier X pilot and may have not understood I was giving him deviations and just needed him to return to course sooner than he requested. I also think I could have done a better job calling the weather to the pilot especially when I didn't see the turn. I also will make sure that all things are taken care of prior to giving a position relief briefing.
ZMA Controller described an 'Extreme' turbulence encounter experienced by a foreign air carrier after being authorized to deviate; the Controller listing language barriers and lack of weather information as contributory.