Narrative:

I was on flight from svmi acting as PNF. We received clearance of the marrs alpha departure as filed climb to FL360 for runway 10. The captain and I briefed the airport specific page and the departure with special emphasis on the 4000 ft restr on climb out; even with the clearance of FL360. After departure; we contacted departure control who was very busy and speaking in spanish. We finally got a word in and we were instructed to 'climb 240 direct avelo due to traffic.' I made sure with the captain that we both heard the same thing and then read the clearance of climb to FL240 and proceed direct to avelo. Departure did not correct and continued talking in spanish to everyone else. As we were climbing to FL240 we were passing 5000 ft and I noticed an aircraft at 2 O'clock position and then noticed on our TCAS he was descending and close to our altitude. The captain increased the climb and we got a TCAS TA but no RA. Departure questioned what we were doing. We told him that we were doing what was assigned to us. We continued climb and rest of flight without any other problems. We talked about what might have happened in the communication problem. We believe the miscom came when he said 'climb 240;' which we believe he meant 'climb to 40' as in FL40; but the transition altitude is 12000 ft in svmi so we heard climb two four zero; and read back climb to FL240. If he had used the correct phraseology of climb to 4000 ft we would have understood. Supplemental information from acn 699036: the miscom occurred with the clearance 'climb to four zero;' which we heard and read back as 'climb two four zero.'

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Original NASA ASRS Text

Title: B737-800 FLT CREW HAS AN ALT EXCURSION DURING CLB FROM SVMI.

Narrative: I WAS ON FLT FROM SVMI ACTING AS PNF. WE RECEIVED CLRNC OF THE MARRS ALPHA DEP AS FILED CLB TO FL360 FOR RWY 10. THE CAPT AND I BRIEFED THE ARPT SPECIFIC PAGE AND THE DEP WITH SPECIAL EMPHASIS ON THE 4000 FT RESTR ON CLBOUT; EVEN WITH THE CLRNC OF FL360. AFTER DEP; WE CONTACTED DEP CTL WHO WAS VERY BUSY AND SPEAKING IN SPANISH. WE FINALLY GOT A WORD IN AND WE WERE INSTRUCTED TO 'CLB 240 DIRECT AVELO DUE TO TFC.' I MADE SURE WITH THE CAPT THAT WE BOTH HEARD THE SAME THING AND THEN READ THE CLRNC OF CLB TO FL240 AND PROCEED DIRECT TO AVELO. DEP DID NOT CORRECT AND CONTINUED TALKING IN SPANISH TO EVERYONE ELSE. AS WE WERE CLBING TO FL240 WE WERE PASSING 5000 FT AND I NOTICED AN ACFT AT 2 O'CLOCK POS AND THEN NOTICED ON OUR TCAS HE WAS DSNDING AND CLOSE TO OUR ALT. THE CAPT INCREASED THE CLB AND WE GOT A TCAS TA BUT NO RA. DEP QUESTIONED WHAT WE WERE DOING. WE TOLD HIM THAT WE WERE DOING WHAT WAS ASSIGNED TO US. WE CONTINUED CLB AND REST OF FLT WITHOUT ANY OTHER PROBS. WE TALKED ABOUT WHAT MIGHT HAVE HAPPENED IN THE COM PROB. WE BELIEVE THE MISCOM CAME WHEN HE SAID 'CLB 240;' WHICH WE BELIEVE HE MEANT 'CLB TO 40' AS IN FL40; BUT THE TRANSITION ALT IS 12000 FT IN SVMI SO WE HEARD CLB TWO FOUR ZERO; AND READ BACK CLB TO FL240. IF HE HAD USED THE CORRECT PHRASEOLOGY OF CLB TO 4000 FT WE WOULD HAVE UNDERSTOOD. SUPPLEMENTAL INFO FROM ACN 699036: THE MISCOM OCCURRED WITH THE CLRNC 'CLB TO FOUR ZERO;' WHICH WE HEARD AND READ BACK AS 'CLB TWO FOUR ZERO.'

Data retrieved from NASA's ASRS site as of January 2009 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.