Narrative:

Upon receiving our ATC clearance, there was a fair amount of confusion on how we were cleared, due to the language transition from the mexican controller and the flight crew. We, therefore, had the clearance reread 3 times to verify what ATC wanted us to do on our departure. Our understanding for our clearance was 'depart runway 33 at mmto, intercept the 314 degree radial to 8 NM then left turn back to the toluca VOR, cross at or above 14000 ft, cleared to FL250, then continue on the conto 1 departure to mexico city transition fpr.' however, as we were passing 16400 ft at 8 NM on the 314 degree radial, the departure controller (toluca) asked us to verify our altitude. When we did, he informed us that we should be at 14000 ft until the toluca VOR to prevent conflicts with arriving and departing aircraft to mexico city. I told him that the clearance we had received on the ground was to climb unrestr to FL200 and to cross the toluca VOR at or above 14000 ft. At no time was there any conflict with other aircraft. To correct this situation, the clearance received on the ground should read 'climb to cross the tlc VOR at 14000 ft and then climb unrestr to FL200.' supplemental information from acn 504390: this could have been avoided if mmto tower controller had used standard phraseology, or if mmto had ACARS capability. Company should also issue a 'fly safe' NOTAM to alert crews to nonstandard climb clrncs.

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Original NASA ASRS Text

Title: AN A300 CARGO CREW CLBS ABOVE THE ALT THAT DEP CTLR THOUGHT THEY HAD BEEN CLRED TO BY TWR CTLR AT MMTO, FO.

Narrative: UPON RECEIVING OUR ATC CLRNC, THERE WAS A FAIR AMOUNT OF CONFUSION ON HOW WE WERE CLRED, DUE TO THE LANGUAGE TRANSITION FROM THE MEXICAN CTLR AND THE FLC. WE, THEREFORE, HAD THE CLRNC REREAD 3 TIMES TO VERIFY WHAT ATC WANTED US TO DO ON OUR DEP. OUR UNDERSTANDING FOR OUR CLRNC WAS 'DEPART RWY 33 AT MMTO, INTERCEPT THE 314 DEG RADIAL TO 8 NM THEN L TURN BACK TO THE TOLUCA VOR, CROSS AT OR ABOVE 14000 FT, CLRED TO FL250, THEN CONTINUE ON THE CONTO 1 DEP TO MEXICO CITY TRANSITION FPR.' HOWEVER, AS WE WERE PASSING 16400 FT AT 8 NM ON THE 314 DEG RADIAL, THE DEP CTLR (TOLUCA) ASKED US TO VERIFY OUR ALT. WHEN WE DID, HE INFORMED US THAT WE SHOULD BE AT 14000 FT UNTIL THE TOLUCA VOR TO PREVENT CONFLICTS WITH ARRIVING AND DEPARTING ACFT TO MEXICO CITY. I TOLD HIM THAT THE CLRNC WE HAD RECEIVED ON THE GND WAS TO CLB UNRESTR TO FL200 AND TO CROSS THE TOLUCA VOR AT OR ABOVE 14000 FT. AT NO TIME WAS THERE ANY CONFLICT WITH OTHER ACFT. TO CORRECT THIS SIT, THE CLRNC RECEIVED ON THE GND SHOULD READ 'CLB TO CROSS THE TLC VOR AT 14000 FT AND THEN CLB UNRESTR TO FL200.' SUPPLEMENTAL INFO FROM ACN 504390: THIS COULD HAVE BEEN AVOIDED IF MMTO TWR CTLR HAD USED STANDARD PHRASEOLOGY, OR IF MMTO HAD ACARS CAPABILITY. COMPANY SHOULD ALSO ISSUE A 'FLY SAFE' NOTAM TO ALERT CREWS TO NONSTANDARD CLB CLRNCS.

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.