Narrative:

This situation developed during the initial climb out. During climbout we were issued a climb clearance by local ATC; which both the captain and I were unsure of. We both believe we were issued a climb to 'five seven; four hundred meters.' we both knew this was an improper altitude assignment; so we queried the controller again to clarify the assignment with ATC. We both heard the readback as 'climb to 5;700 meters' which we read back verbatim; then climbed to 5;700 meters. A few minutes later the same controller issued a nearly 90 degree right turn; and told to 'maintain level.' again we read back the new clearance and executed the approximately 90 degree right turn. A few more minutes elapsed were then instructed to turn left to a heading of 360. After a few moments; we were re-cleared direct to a NDB; then; on course. The controller then asked what our altitude was; and of course we responded '5;700 meters assigned' and heard a garbled transmission regarding 5;400 meters. Startled; we attempted to verify our assigned altitude of 5;700 meters; but before we got a response; a new controller took over and issued a new climb clearance to a higher flight level. At no time was there a separation error as verified by onboard TCAS. Both the captain and myself agree that a combination of very poor ATC transmission quality coupled with the language problem could have placed us in a situation an altitude deviation could have occurred; in spite of many attempts to clarify our climb instructions with chinese ATC. If in doubt; ask for a readback of an ambiguous clearance; no matter how many times it takes; until both crew members are sure they understand the ATC clearance they have been issued. Also; it is vital that proper ICAO phraseology be used when operating in countries where the local language or dialect can impose a challenge to the most seasoned crews.

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Original NASA ASRS Text

Title: A G550 crew operating in foreign airspace did not clearly understand their altitude assignment even after repeatedly requesting clarification.

Narrative: This situation developed during the initial climb out. During climbout we were issued a climb clearance by local ATC; which both the Captain and I were unsure of. We both believe we were issued a climb to 'five seven; four hundred meters.' We both knew this was an improper altitude assignment; so we queried the Controller again to clarify the assignment with ATC. We both heard the readback as 'climb to 5;700 meters' which we read back verbatim; then climbed to 5;700 meters. A few minutes later the same Controller issued a nearly 90 degree right turn; and told to 'maintain level.' Again we read back the new clearance and executed the approximately 90 degree right turn. A few more minutes elapsed were then instructed to turn left to a heading of 360. After a few moments; we were re-cleared direct to a NDB; then; on course. The Controller then asked what our altitude was; and of course we responded '5;700 meters assigned' and heard a garbled transmission regarding 5;400 meters. Startled; we attempted to verify our assigned altitude of 5;700 meters; but before we got a response; a new Controller took over and issued a new climb clearance to a higher flight level. At no time was there a separation error as verified by onboard TCAS. Both the Captain and myself agree that a combination of very poor ATC transmission quality coupled with the language problem could have placed us in a situation an altitude deviation could have occurred; in spite of many attempts to clarify our climb instructions with Chinese ATC. If in doubt; ask for a readback of an ambiguous clearance; no matter how many times it takes; until both crew members are sure they understand the ATC clearance they have been issued. Also; it is vital that proper ICAO phraseology be used when operating in countries where the local language or dialect can impose a challenge to the most seasoned crews.

Data retrieved from NASA's ASRS site as of April 2012 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.