Narrative:

Merida center called unknown traffic at unknown altitude. We spotted him at 2 O'clock position slightly lower and rapidly converging. The air force spc airborne warning and control system aircraft spotted us about the same time and made an evasive left turn to pass behind and just below us. I don't know whether the airborne warning and control system was aware of us much before he made his turn. We were well within mexican airspace and they were not aware of his altitude or anything other than position. This event should not have happened and was certainly exciting to any passenger who witnessed it. I believe that the airborne warning and control system was not where he should have been and had he not have taken a left turn I would have had to pull up and turn sharply, probably to the right to keep him in sight. Supplemental information from acn 238832: while in cruise, merida center reported fast moving traffic at 3 O'clock heading southeast with no squawk. Made visual contact with an military spc aircraft heading southeast at a slightly lower altitude (estimate he was at FL300). Aircraft deviated very late by turning left, to pass just behind at what we estimated to be less than 1 mi. The late deviation by the spc suggests that they did not know that we were in the area. Merida center had no radio contact, nor were they aware that the spc was in their airspace. The supervisor on duty said that he was going to file a report to houston center, as this was not the first time that aircraft had flown through merida airspace without a flight plan, and without communicating with ATC. I do not know if military aircraft are allowed to fly around without a flight plan or without communicating with ATC, but if so it seems like an accident waiting to happen.

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Original NASA ASRS Text

Title: FLC OF LGT ACR ACFT CRUISING AT HIGH ALT OBSERVE A MIL SPC ACFT TAKE EVASIVE ACTION TO AVOID THEM AFTER CTR RPTED 'UNKNOWN TFC.'

Narrative: MERIDA CTR CALLED UNKNOWN TFC AT UNKNOWN ALT. WE SPOTTED HIM AT 2 O'CLOCK POS SLIGHTLY LOWER AND RAPIDLY CONVERGING. THE AIR FORCE SPC AIRBORNE WARNING AND CTL SYS ACFT SPOTTED US ABOUT THE SAME TIME AND MADE AN EVASIVE L TURN TO PASS BEHIND AND JUST BELOW US. I DON'T KNOW WHETHER THE AIRBORNE WARNING AND CTL SYS WAS AWARE OF US MUCH BEFORE HE MADE HIS TURN. WE WERE WELL WITHIN MEXICAN AIRSPACE AND THEY WERE NOT AWARE OF HIS ALT OR ANYTHING OTHER THAN POS. THIS EVENT SHOULD NOT HAVE HAPPENED AND WAS CERTAINLY EXCITING TO ANY PAX WHO WITNESSED IT. I BELIEVE THAT THE AIRBORNE WARNING AND CTL SYS WAS NOT WHERE HE SHOULD HAVE BEEN AND HAD HE NOT HAVE TAKEN A L TURN I WOULD HAVE HAD TO PULL UP AND TURN SHARPLY, PROBABLY TO THE R TO KEEP HIM IN SIGHT. SUPPLEMENTAL INFO FROM ACN 238832: WHILE IN CRUISE, MERIDA CTR RPTED FAST MOVING TFC AT 3 O'CLOCK HDG SE WITH NO SQUAWK. MADE VISUAL CONTACT WITH AN MIL SPC ACFT HDG SE AT A SLIGHTLY LOWER ALT (ESTIMATE HE WAS AT FL300). ACFT DEVIATED VERY LATE BY TURNING L, TO PASS JUST BEHIND AT WHAT WE ESTIMATED TO BE LESS THAN 1 MI. THE LATE DEV BY THE SPC SUGGESTS THAT THEY DID NOT KNOW THAT WE WERE IN THE AREA. MERIDA CTR HAD NO RADIO CONTACT, NOR WERE THEY AWARE THAT THE SPC WAS IN THEIR AIRSPACE. THE SUPVR ON DUTY SAID THAT HE WAS GOING TO FILE A RPT TO HOUSTON CTR, AS THIS WAS NOT THE FIRST TIME THAT ACFT HAD FLOWN THROUGH MERIDA AIRSPACE WITHOUT A FLT PLAN, AND WITHOUT COMMUNICATING WITH ATC. I DO NOT KNOW IF MIL ACFT ARE ALLOWED TO FLY AROUND WITHOUT A FLT PLAN OR WITHOUT COMMUNICATING WITH ATC, BUT IF SO IT SEEMS LIKE AN ACCIDENT WAITING TO HAPPEN.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.