RPT BY DISPATCHER STATES THAT UNKNOWN ACR TYPE ACFT SUFFERED LOSS OF PRESSURIZATION OVER HAZARDOUS TERRAIN IN NORTHERN MEXICO. DURING EMER DSCNT; ACFT LOST CONTACT WITH ARTCC AND WITH DISPATCH. JUST PRIOR TO INITIATING A SEARCH FOR THE ACFT; THE RPTR WAS NOTIFIED IT WAS ON FINAL TO A DOMESTIC ARPT TO WHICH IT HAD DEVIATED.

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FLT WAS APPROX 100 NM SW OF MMCU IN MEXICO WHEN WE EXPERIENCED A RAPID LOSS OF CABIN PRESSURE. FLT DSNDED FROM FL350 AND RECOVERED PRESSURE AT APPROX FL180. CREW CLBED BACK TO FL310 AND ONCE AGAIN EXPERIENCED PRESSURE LOSS AT THIS POINT. THE CAPT DECIDED TO DIVERT TO ELP AND ADVISED THAT HE TRIED TO CONTACT DISPATCH; BUT WAS UNABLE. THE ACFT DID NOT HAVE HF RADIO; SO NO VOICE PATCH WAS AVAILABLE. ACARS WAS NOT IN RANGE AS MESSAGES DID NOT XMIT. THE CAPT SAID HE ASKED MONTEREY ATC TO CONTACT DISPATCH AND GAVE THEM MY DESK NUMBER. MMTY CTR DID NOT CALL DISPATCH. THEY CALLED MAZATLAN CTR TO CANCEL FLT ABC'S FLT PLAN. MMZT CTR CALLED SJD OPS WHO THEN CALLED DISPATCH. BY THEN; THE STORY WAS THAT FLT ABC HAD AN EMER DEPRESSURIZATION AND MMTY HAD LOST COM WITH THEM AFTER PASSING THEM TO ZAB. I STARTED A SEARCH FOR FLT ABC. ACARS MESSAGES WERE NOT ANSWERED. MMTY CTR SAID THAT THEY NO LONGER HAD CONTACT WITH THEM. ABZ CTR SAID THEY DID NOT HAVE THEM AS YET. THEY SAID THEY SHOWED HIM ON THE TSD HDG S THROUGH MEXICO. AT THAT POINT; ELP OPS CALLED AND SAID HE WAS ON THE INBOUND WITH NO EMER. I THEN SPOKE TO ELP TWR WHO CONFIRMED HIS INBOUND. HE WAS NOT DECLARING AN EMER. HE RELAYED PRESSURE LOSS AND GETTING LOW ON FUEL. THE FLT LANDED WITHOUT INCIDENT. THE CAPT EXPLAINED BOTH PRESSURE LOSSES AS A MYSTERY; BUT ALSO EXPRESSED THAT HE WAS UNABLE TO CONTACT DISPATCH. THIS DEFINITELY QUALIFIES AS A LOSS OF COMPANY COMS. BASED ON THE INFO PROVIDED TO ME BY ATC; I HAD A FLT IN MEXICO AIRSPACE IN TERRAIN WHO HAD EXPERIENCED AN EMER DEPRESSURIZATION WHOM I WAS UNABLE TO CONTACT AND WHOM BOTH CTLING SECTORS SAID THEY DID NOT HAVE CONTACT WITH. I WAS ABOUT TO DECLARE A MISSING ACFT WHEN ELP OPS CALLED. THE TIME SPAN FROM INITIAL NOTIFICATION BY SJD OPS TO DISPATCH FROM THE TIME CONFIRMED ACFT APCH TO ELP WAS ABOUT 20 MINS. THIS IS THE TIME FRAME I CONSIDER THE FLT MISSING. ACTUAL LOSS OF COMPANY COMS TIME FRAME COULD BE CONSIDERABLY LONGER.