Narrative:

Mexico city approach (119.7) cleared us direct to mex VOR. Previously we had been cleared by center direct smo. Approach then cleared us direct smo and gave us descent clearance to 11000 ft. Approach then cleared us for the SMO2 arrival and the VOR-DME 5L approach. Backgnd information: we were approaching smo from the northeast quadrant 4-5 NM in trail of a widebody transport. Approximately 7 NM northeast smo approach tells us 'you are off the approach, turn right heading 190 degrees.' we read back and questioned the right turn, as 190 degrees was to our left and we knew high terrain was to the right but since we had been assigned several large speed reductions to maintain our interval on the widebody transport it seemed the controller was turning us the long way around for spacing. (3 speed reductions 30 KTS each.) approach then cleared us to 10000 ft. We read back the descent clearance and again questioned the right turn. After another 25-30 degrees of heading change we again questioned the controller about the direction of turn. Again he replied 'affirmative, right turn heading 190 degrees.' because neither the captain nor I felt comfortable with the situation we did not leave 11000 ft. After a few more degrees of heading change the approach controller told us 'maintain VFR at all times (we were IMC) that we were entering an area where the terrain exceeds 15000 ft and that we should turn left heading 140 degrees immediately.' a left 50 degree bank turn was initiated towards 140 degrees and a 4000+ FPM rate of climb (at 160 KTS and go around power) was made towards 16000 ft. At about 13500 ft we broke out on top and could see in the bright moonlight we were clear of terrain. Approach then vectored us to intercept the final and we landed without further incident. How we got in the situation is a big question in my mind -- did the controller confuse right and left? Hindsight says rather than question the direction of turn, we should have questioned the high terrain, or just flat refused the right turn. Terrain above 13000 exists 3 NM due west of smo. An accident is an unbroken chain of events. In this case a link or 2 were broken before the chain was complete. If you're not happy with a clearance be explicit -- we assumed 'you are off the approach' meant we were being vectored off the approach, and then we questioned the direction of turn rather than our real concern, the terrain. Perhaps to a united states controller the equation right turn, mountains would've been clear -- but to a foreign controller, across both cultural and language barriers, an entirely different meaning was presented. Mountains were our concern, not right or left and we should have said so.

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Original NASA ASRS Text

Title: ACR LGT DISPUTED A CLRNC DURING VECTOR FOR APCH TO MEX. MMEX THEN ADVISED THE ACFT TO MAINTAIN VMC DUE TO TERRAIN.

Narrative: MEXICO CITY APCH (119.7) CLRED US DIRECT TO MEX VOR. PREVIOUSLY WE HAD BEEN CLRED BY CENTER DIRECT SMO. APCH THEN CLRED US DIRECT SMO AND GAVE US DSCNT CLRNC TO 11000 FT. APCH THEN CLRED US FOR THE SMO2 ARR AND THE VOR-DME 5L APCH. BACKGND INFO: WE WERE APCHING SMO FROM THE NE QUADRANT 4-5 NM IN TRAIL OF A WDB. APPROX 7 NM NE SMO APCH TELLS US 'YOU ARE OFF THE APCH, TURN R HDG 190 DEGS.' WE READ BACK AND QUESTIONED THE R TURN, AS 190 DEGS WAS TO OUR L AND WE KNEW HIGH TERRAIN WAS TO THE R BUT SINCE WE HAD BEEN ASSIGNED SEVERAL LARGE SPD REDUCTIONS TO MAINTAIN OUR INTERVAL ON THE WDB IT SEEMED THE CTLR WAS TURNING US THE LONG WAY AROUND FOR SPACING. (3 SPD REDUCTIONS 30 KTS EACH.) APCH THEN CLRED US TO 10000 FT. WE READ BACK THE DSCNT CLRNC AND AGAIN QUESTIONED THE R TURN. AFTER ANOTHER 25-30 DEGS OF HDG CHANGE WE AGAIN QUESTIONED THE CTLR ABOUT THE DIRECTION OF TURN. AGAIN HE REPLIED 'AFFIRMATIVE, R TURN HDG 190 DEGS.' BECAUSE NEITHER THE CAPT NOR I FELT COMFORTABLE WITH THE SITUATION WE DID NOT LEAVE 11000 FT. AFTER A FEW MORE DEGS OF HDG CHANGE THE APCH CTLR TOLD US 'MAINTAIN VFR AT ALL TIMES (WE WERE IMC) THAT WE WERE ENTERING AN AREA WHERE THE TERRAIN EXCEEDS 15000 FT AND THAT WE SHOULD TURN L HDG 140 DEGS IMMEDIATELY.' A L 50 DEG BANK TURN WAS INITIATED TOWARDS 140 DEGS AND A 4000+ FPM RATE OF CLB (AT 160 KTS AND GAR PWR) WAS MADE TOWARDS 16000 FT. AT ABOUT 13500 FT WE BROKE OUT ON TOP AND COULD SEE IN THE BRIGHT MOONLIGHT WE WERE CLR OF TERRAIN. APCH THEN VECTORED US TO INTERCEPT THE FINAL AND WE LANDED WITHOUT FURTHER INCIDENT. HOW WE GOT IN THE SITUATION IS A BIG QUESTION IN MY MIND -- DID THE CTLR CONFUSE R AND L? HINDSIGHT SAYS RATHER THAN QUESTION THE DIRECTION OF TURN, WE SHOULD HAVE QUESTIONED THE HIGH TERRAIN, OR JUST FLAT REFUSED THE R TURN. TERRAIN ABOVE 13000 EXISTS 3 NM DUE W OF SMO. AN ACCIDENT IS AN UNBROKEN CHAIN OF EVENTS. IN THIS CASE A LINK OR 2 WERE BROKEN BEFORE THE CHAIN WAS COMPLETE. IF YOU'RE NOT HAPPY WITH A CLRNC BE EXPLICIT -- WE ASSUMED 'YOU ARE OFF THE APCH' MEANT WE WERE BEING VECTORED OFF THE APCH, AND THEN WE QUESTIONED THE DIRECTION OF TURN RATHER THAN OUR REAL CONCERN, THE TERRAIN. PERHAPS TO A UNITED STATES CTLR THE EQUATION R TURN, MOUNTAINS WOULD'VE BEEN CLR -- BUT TO A FOREIGN CTLR, ACROSS BOTH CULTURAL AND LANGUAGE BARRIERS, AN ENTIRELY DIFFERENT MEANING WAS PRESENTED. MOUNTAINS WERE OUR CONCERN, NOT R OR L AND WE SHOULD HAVE SAID SO.

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.