Narrative:

Sbound on ug 426 near tokut intersection from panama to quito. Panama center had cleared us to FL330. Near tokut panama switched us to bogota control. We made a position report and reported passing FL310 for FL330 which bogota acknowledged. Shortly thereafter bogota called back and instructed us to maintain FL310. We acknowledged this new clearance and started a descent from FL317. At this time we noticed traffic on the TCASII display at minus 7 (700 ft below us) heading directly toward us. The target display changed from white to yellow. We realized we were descending toward the target aircraft. The target aircraft's altitude showed minus 4 at 5 mi in front of us when we were at FL314. We began an aggressive climb. Just after beginning the climb the TCASII RA commanded 'descend' followed almost immediately by changing to a 'climb' command. We continued our aggressive climb to FL330 which was our original assigned altitude from panama center. Bogota control again told us to go to FL310. We advised bogota we had climbed to FL330 due to a TCASII TA and that, that was our assigned altitude from panama center. Now in total contradiction to her previous instructions the bogota controller said we were supposed to cross tokut at FL330, and she was going to check with panama (we received no such restr from panama, just climb to FL330). The controller said nothing further about the incident. There was obviously some miscom somewhere. The bogota controller's english was poor and perhaps she was confusing her english numbers. The TCASII helped to prevent what might have been a disaster, in spite of its initially incorrect command. Callback conversation with reporter revealed the following information: reporter stated that the instructions from ATC were understandable. Language barrier was in the form that the ATC controller didn't know enough english words to ask or command everything that needed to be said. Flight crew had been cleared to FL330, but as they climbed out of FL310 the ATC controller requested them to descend back to FL310. ATC stated they had the instruction to cross tokut at FL330, but flight crew never received that instruction. ATC controller checked with pervious ARTCC to confirm that was the instruction given, however, no ARTCC verified that instruction was given. Either it was missed or never issued, flight crew believes it was never issued. Flight crew was watching oncoming traffic for quite some time, this same traffic was at the altitude flight crew was cleared to. It was confusing to this reporter. Nevertheless, when TCASII sounded the flight crew followed all RA commands to gain separation.

Google
 

Original NASA ASRS Text

Title: TCASII RA SAVES THE DAY DURING A CONFLICT IN SOUTH AMERICA AIRSPACE. B727.

Narrative: SBOUND ON UG 426 NEAR TOKUT INTXN FROM PANAMA TO QUITO. PANAMA CTR HAD CLRED US TO FL330. NEAR TOKUT PANAMA SWITCHED US TO BOGOTA CTL. WE MADE A POS RPT AND RPTED PASSING FL310 FOR FL330 WHICH BOGOTA ACKNOWLEDGED. SHORTLY THEREAFTER BOGOTA CALLED BACK AND INSTRUCTED US TO MAINTAIN FL310. WE ACKNOWLEDGED THIS NEW CLRNC AND STARTED A DSCNT FROM FL317. AT THIS TIME WE NOTICED TFC ON THE TCASII DISPLAY AT MINUS 7 (700 FT BELOW US) HEADING DIRECTLY TOWARD US. THE TARGET DISPLAY CHANGED FROM WHITE TO YELLOW. WE REALIZED WE WERE DSNDING TOWARD THE TARGET ACFT. THE TARGET ACFT'S ALT SHOWED MINUS 4 AT 5 MI IN FRONT OF US WHEN WE WERE AT FL314. WE BEGAN AN AGGRESSIVE CLB. JUST AFTER BEGINNING THE CLB THE TCASII RA COMMANDED 'DSND' FOLLOWED ALMOST IMMEDIATELY BY CHANGING TO A 'CLB' COMMAND. WE CONTINUED OUR AGGRESSIVE CLB TO FL330 WHICH WAS OUR ORIGINAL ASSIGNED ALT FROM PANAMA CTR. BOGOTA CTL AGAIN TOLD US TO GO TO FL310. WE ADVISED BOGOTA WE HAD CLBED TO FL330 DUE TO A TCASII TA AND THAT, THAT WAS OUR ASSIGNED ALT FROM PANAMA CTR. NOW IN TOTAL CONTRADICTION TO HER PREVIOUS INSTRUCTIONS THE BOGOTA CTLR SAID WE WERE SUPPOSED TO CROSS TOKUT AT FL330, AND SHE WAS GOING TO CHK WITH PANAMA (WE RECEIVED NO SUCH RESTR FROM PANAMA, JUST CLB TO FL330). THE CTLR SAID NOTHING FURTHER ABOUT THE INCIDENT. THERE WAS OBVIOUSLY SOME MISCOM SOMEWHERE. THE BOGOTA CTLR'S ENGLISH WAS POOR AND PERHAPS SHE WAS CONFUSING HER ENGLISH NUMBERS. THE TCASII HELPED TO PREVENT WHAT MIGHT HAVE BEEN A DISASTER, IN SPITE OF ITS INITIALLY INCORRECT COMMAND. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT THE INSTRUCTIONS FROM ATC WERE UNDERSTANDABLE. LANGUAGE BARRIER WAS IN THE FORM THAT THE ATC CTLR DIDN'T KNOW ENOUGH ENGLISH WORDS TO ASK OR COMMAND EVERYTHING THAT NEEDED TO BE SAID. FLC HAD BEEN CLRED TO FL330, BUT AS THEY CLBED OUT OF FL310 THE ATC CTLR REQUESTED THEM TO DSND BACK TO FL310. ATC STATED THEY HAD THE INSTRUCTION TO CROSS TOKUT AT FL330, BUT FLC NEVER RECEIVED THAT INSTRUCTION. ATC CTLR CHKED WITH PERVIOUS ARTCC TO CONFIRM THAT WAS THE INSTRUCTION GIVEN, HOWEVER, NO ARTCC VERIFIED THAT INSTRUCTION WAS GIVEN. EITHER IT WAS MISSED OR NEVER ISSUED, FLC BELIEVES IT WAS NEVER ISSUED. FLC WAS WATCHING ONCOMING TFC FOR QUITE SOME TIME, THIS SAME TFC WAS AT THE ALT FLC WAS CLRED TO. IT WAS CONFUSING TO THIS RPTR. NEVERTHELESS, WHEN TCASII SOUNDED THE FLC FOLLOWED ALL RA COMMANDS TO GAIN SEPARATION.

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.