Narrative:

Inbound to beijing on A596, maintaining 12000 meters, assigned altitude. I was PNF, handling radio communications. Had been on duty 17 hours in a 19 hour duty day (augmented crew) due to delayed departure. Body clock time was XA45. Fatigue was a factor. Shenyang control issued us a descent clearance to 9800 meters approximately 160 NM northeast of bedog intersection. We read back clearance and began descent after checking meters/ft conversion chart (9800 meters = 32200 ft). During descent, we saw TCASII traffic at 12 O'clock, 1100 ft below, opposite direction. TCASII issued an RA 'don't descend' and we complied. After TCASII issued 'clear of conflict' we continued descent towards 9800 meters. (We had had visual contact with traffic.) shenyang control then asked why we were below 10800 meters. We responded that we were descending to our assigned altitude of 9800 meters. Shenyang then said we were not clrd to 9800 meters and to maintain 10800 meters. There was not enough free air on the frequency or controller fluency in english for us to resolve the misunderstanding. Understanding radio communications on international flts is always a challenge. China is difficult not only because of the strong accents and lack of english fluency on the part of the controllers, but because of the heavy radio traffic and frequent multiple xmissions. Also, fatigue and circadian problems are always present. It is possible to take every precaution (slow, deliberate readbacks, and only standard terminology, as well as double-checking all clrncs among crew members) and still get it wrong. Or perhaps, shenyang control actually did say 9800 meters by mistake and later denied it. Be careful! Another good report for TCASII!

Related reports:

Google
 

Original NASA ASRS Text

Title: NMAC. ALTDEV DUE TO MISCOM BTWN FOREIGN CTLR AND FLC. LANGUAGE BARRIER. RESULTANT ALTDEV CAUSED TCASII RA WHICH THE FLC FOLLOWED. CTLR INTERVENED TO CLARIFY ALT ASSIGNMENT. FATIGUE A FACTOR. 17TH HR OF A 19 HR DUTY DAY.

Narrative: INBOUND TO BEIJING ON A596, MAINTAINING 12000 METERS, ASSIGNED ALT. I WAS PNF, HANDLING RADIO COMS. HAD BEEN ON DUTY 17 HRS IN A 19 HR DUTY DAY (AUGMENTED CREW) DUE TO DELAYED DEP. BODY CLOCK TIME WAS XA45. FATIGUE WAS A FACTOR. SHENYANG CTL ISSUED US A DSCNT CLRNC TO 9800 METERS APPROX 160 NM NE OF BEDOG INTXN. WE READ BACK CLRNC AND BEGAN DSCNT AFTER CHKING METERS/FT CONVERSION CHART (9800 METERS = 32200 FT). DURING DSCNT, WE SAW TCASII TFC AT 12 O'CLOCK, 1100 FT BELOW, OPPOSITE DIRECTION. TCASII ISSUED AN RA 'DON'T DSND' AND WE COMPLIED. AFTER TCASII ISSUED 'CLR OF CONFLICT' WE CONTINUED DSCNT TOWARDS 9800 METERS. (WE HAD HAD VISUAL CONTACT WITH TFC.) SHENYANG CTL THEN ASKED WHY WE WERE BELOW 10800 METERS. WE RESPONDED THAT WE WERE DSNDING TO OUR ASSIGNED ALT OF 9800 METERS. SHENYANG THEN SAID WE WERE NOT CLRD TO 9800 METERS AND TO MAINTAIN 10800 METERS. THERE WAS NOT ENOUGH FREE AIR ON THE FREQ OR CTLR FLUENCY IN ENGLISH FOR US TO RESOLVE THE MISUNDERSTANDING. UNDERSTANDING RADIO COMS ON INTL FLTS IS ALWAYS A CHALLENGE. CHINA IS DIFFICULT NOT ONLY BECAUSE OF THE STRONG ACCENTS AND LACK OF ENGLISH FLUENCY ON THE PART OF THE CTLRS, BUT BECAUSE OF THE HVY RADIO TFC AND FREQUENT MULTIPLE XMISSIONS. ALSO, FATIGUE AND CIRCADIAN PROBS ARE ALWAYS PRESENT. IT IS POSSIBLE TO TAKE EVERY PRECAUTION (SLOW, DELIBERATE READBACKS, AND ONLY STANDARD TERMINOLOGY, AS WELL AS DOUBLE-CHKING ALL CLRNCS AMONG CREW MEMBERS) AND STILL GET IT WRONG. OR PERHAPS, SHENYANG CTL ACTUALLY DID SAY 9800 METERS BY MISTAKE AND LATER DENIED IT. BE CAREFUL! ANOTHER GOOD RPT FOR TCASII!

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.