Narrative:

In mexico city I requested our clearance from clearance delivery. Clearance delivery initially read us our clearance out of order - skipping past the SID and starting with a fix; and then giving us the SID within additional fixes; and then 'as filed.' both the captain and I followed along as the clearance was read to us by referencing our copies of the printed-out flight plan. I had checked off the course on the printed flight plan as the clearance was read. Both the captain and I commented verbally that the clearance was given out of the normal sequence. As I was about to read back the clearance; someone else contacted clearance delivery (in spanish) and I had to delay my read back until that conversation (in spanish) was complete; at which time clearance delivery said [to us]; 'please read back your clearance; I was unable to get it.' I read back the clearance as follows; referencing the written flight plan I had in front of me with my checked -off navigation points: [air carrier X] is cleared to [destination] via toluca 6A; tlc; UJ12 ('uniform juliet 12'); gdl; UJ3 ('uniform juliet 3'); LMM ('lima mike mike'); then as filed...' clearance delivery responded; 'read back correct.' later in cruise near the gdl VOR; an air traffic center controller queried us as to the route we were given; saying he believed we should have been on J42 rather than UJ12 (J42 is south of UJ12). The captain told the center controller that UJ12 was the route we had read back to clearance delivery and was told 'read back correct.' the center controller responded 'okay' and appeared to take it in stride.I'm not sure what happened - either we missed the change in the clearance when initially read to us; and then clearance delivery missed our erroneous read back; or; clearance delivery failed to give us the revised clearance. The language barrier (heavily accented) compounded by the clearance being read to us out of sequence were contributing factors if the first scenario is the case.

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Original NASA ASRS Text

Title: Flight crew reported a possible track deviation after departing MMMX. One reporter cited language difficulties and lack of standard clearance protocols as contributing.

Narrative: In Mexico City I requested our clearance from Clearance Delivery. Clearance Delivery initially read us our clearance out of order - skipping past the SID and starting with a fix; and then giving us the SID within additional fixes; and then 'as filed.' Both the Captain and I followed along as the clearance was read to us by referencing our copies of the printed-out flight plan. I had checked off the course on the printed flight plan as the clearance was read. Both the Captain and I commented verbally that the clearance was given out of the normal sequence. As I was about to read back the clearance; someone else contacted Clearance Delivery (in Spanish) and I had to delay my read back until that conversation (in Spanish) was complete; at which time Clearance Delivery said [to us]; 'please read back your clearance; I was unable to get it.' I read back the clearance as follows; referencing the written flight plan I had in front of me with my checked -off navigation points: [Air Carrier X] is cleared to [destination] via Toluca 6A; TLC; UJ12 ('uniform Juliet 12'); GDL; UJ3 ('uniform juliet 3'); LMM ('lima mike mike'); then as filed...' Clearance Delivery responded; 'read back correct.' Later in cruise near the GDL VOR; an Air Traffic Center Controller queried us as to the route we were given; saying he believed we should have been on J42 rather than UJ12 (J42 is south of UJ12). The Captain told the Center Controller that UJ12 was the route we had read back to Clearance Delivery and was told 'read back correct.' The Center Controller responded 'okay' and appeared to take it in stride.I'm not sure what happened - either we missed the change in the clearance when initially read to us; and then Clearance Delivery missed our erroneous read back; or; Clearance Delivery failed to give us the revised clearance. The language barrier (heavily accented) compounded by the clearance being read to us out of sequence were contributing factors if the first scenario is the case.

Data retrieved from NASA's ASRS site 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.