Narrative:

Mayaguez is an uncontrolled airport. There was an light transport Y on the ramp picking up a 'med-evacuate/evacuation' patient. I reported leaving the ramp and taxiing to runway 9. The wind was 140/6. We performed all the necessary checklists. Upon our arrival to the holding area of runway 9 I reported to mayaguez traffic our intentions of taxiing onto runway 9 for takeoff. When the takeoff roll was started prpa called. I thought that, maybe, there was something unsecured or hanging out so I rejected the takeoff. Prpa advised the nature of the call by saying that there was another aircraft on the runway. I immediately taxied right of centerline and toward the taxiway. I advised that I was taxiing out of the runway. When I reported clear, the light transport Y advised that he was 'rolling.' I talked to prpa and he advised that we had broadcasted at the same time. I don't know if he knew that I had started taxiing but I definitely did not know that he had taxied at the same time I did. When I lined up with runway 9 centerline, I could not see any other traffic opposite us -- the runway has a slope and he could not see me either. I think that this is a very serious hazard and apparently it was not the fault of either flight crew. What can be done to prevent another situation like this one? (I do find it hard to believe that the light transport Y transmitted 3 times at the same time we transmitted. Nevertheless, things like this do happen, even with a control tower in operation.) prpa transmitted on the FAA assigned frequency off 122.8 which is the same frequency for all the uncontrolled airports in the whole island of puerto rico. This practice causes confusion among the pilots flying in and out of these airports, especially maz and bqn, due to their close location. I transmitted my intentions 3 times.

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Original NASA ASRS Text

Title: COMMUTER LTT TKOF ABORT BECAUSE OF OPPOSITE DIRECTION TKOF SAME RWY.

Narrative: MAYAGUEZ IS AN UNCTLED ARPT. THERE WAS AN LTT Y ON THE RAMP PICKING UP A 'MED-EVAC' PATIENT. I RPTED LEAVING THE RAMP AND TAXIING TO RWY 9. THE WIND WAS 140/6. WE PERFORMED ALL THE NECESSARY CHKLISTS. UPON OUR ARR TO THE HOLDING AREA OF RWY 9 I RPTED TO MAYAGUEZ TFC OUR INTENTIONS OF TAXIING ONTO RWY 9 FOR TKOF. WHEN THE TKOF ROLL WAS STARTED PRPA CALLED. I THOUGHT THAT, MAYBE, THERE WAS SOMETHING UNSECURED OR HANGING OUT SO I REJECTED THE TKOF. PRPA ADVISED THE NATURE OF THE CALL BY SAYING THAT THERE WAS ANOTHER ACFT ON THE RWY. I IMMEDIATELY TAXIED R OF CENTERLINE AND TOWARD THE TAXIWAY. I ADVISED THAT I WAS TAXIING OUT OF THE RWY. WHEN I RPTED CLR, THE LTT Y ADVISED THAT HE WAS 'ROLLING.' I TALKED TO PRPA AND HE ADVISED THAT WE HAD BROADCASTED AT THE SAME TIME. I DON'T KNOW IF HE KNEW THAT I HAD STARTED TAXIING BUT I DEFINITELY DID NOT KNOW THAT HE HAD TAXIED AT THE SAME TIME I DID. WHEN I LINED UP WITH RWY 9 CENTERLINE, I COULD NOT SEE ANY OTHER TFC OPPOSITE US -- THE RWY HAS A SLOPE AND HE COULD NOT SEE ME EITHER. I THINK THAT THIS IS A VERY SERIOUS HAZARD AND APPARENTLY IT WAS NOT THE FAULT OF EITHER FLC. WHAT CAN BE DONE TO PREVENT ANOTHER SITUATION LIKE THIS ONE? (I DO FIND IT HARD TO BELIEVE THAT THE LTT Y XMITTED 3 TIMES AT THE SAME TIME WE XMITTED. NEVERTHELESS, THINGS LIKE THIS DO HAPPEN, EVEN WITH A CTL TWR IN OP.) PRPA XMITTED ON THE FAA ASSIGNED FREQ OFF 122.8 WHICH IS THE SAME FREQ FOR ALL THE UNCTLED ARPTS IN THE WHOLE ISLAND OF PUERTO RICO. THIS PRACTICE CAUSES CONFUSION AMONG THE PLTS FLYING IN AND OUT OF THESE ARPTS, ESPECIALLY MAZ AND BQN, DUE TO THEIR CLOSE LOCATION. I XMITTED MY INTENTIONS 3 TIMES.

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.