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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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Flight crew of B747-400 unable to clarify reason for not accepting a climb clearance with speed restr due to language barrier.
| Attributes | |
| ACN | 365823 |
| Time | |
| Date | 199704 |
| Day | Sat |
| Local Time Of Day | 0001 To 0600 |
| Place | |
| Locale Reference | atc facility : rjt |
| State Reference | FO |
| Altitude | msl bound lower : 33000 msl bound upper : 35000 |
| Environment | |
| Flight Conditions | IMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | artcc : rjtg |
| Operator | common carrier : air carrier |
| Make Model Name | B747-400 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other Other |
| Flight Phase | cruise other |
| Route In Use | enroute : other oceanic enroute : pacific |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : instrument pilot : atp pilot : commercial pilot : flight engineer |
| Experience | flight time last 90 days : 250 flight time total : 21500 flight time type : 2400 |
| ASRS Report | 365823 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : commercial |
| Events | |
| Anomaly | other anomaly other |
| Independent Detector | other controllera other flight crewa |
| Resolutory Action | none taken : unable |
| Consequence | Other |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | other |
Narrative:
While en route seoul, korea, to sfo and in japanese airspace, we received a mach number restr for mach .84 at FL330. Since our plan called for mach .86 and mach .84 would result in higher fuel burn and time en route, we requested FL350 at mach .86, but tokyo control responded unable due traffic. When tokyo control handed us off to tokyo radio, we again requested FL350 at mach .86, but were again denied. Later we received a clearance from tokyo radio to climb to FL350 and maintain mach .84. We declined the clearance explaining we did not want FL350 unless we could maintain mach .86 and we would maintain mach .84 at FL330. Tokyo radio responded with, roger, maintain mach .84. At our next position report, tokyo radio questioned our altitude FL330 and asked if we received a clearance to FL350. Our response was to explain once again our requirement for higher mach .86 at FL350, and mach .84 only at FL330, as we previously explained. After some delay, tokyo radio relayed the clearance to maintain mach .84 at FL330. Apparently our original rejection of this clearance was misunderstood by the japanese radio operator and then miscommunicated our intentions to tokyo control. Assuming we would climb to FL350 as requested and maintain mach .84 we felt we used care in communicating with the japanese radio operator, but it is evident we should have broken the rejection into 3 parts -- ie, 1) unable mach .84 at FL350. 2) maintaining mach .84 at FL330. 3) request mach .86 cruise. This might have more clearly defined our intentions and better expressed our cruise concerns. We need better use of oceanic airspace to avoid cruise restraint conflicts between aircraft operating normally at higher and lower speeds. This would be possible if we were allowed use of our fans navigation system. Furthermore, use of data link/direct line communications in foreign airspace reduces concerns for misinterp due to language constraints. Both would be possible but for governmental restraint in the use of these aids.
Original NASA ASRS Text
Title: FLC OF B747-400 UNABLE TO CLARIFY REASON FOR NOT ACCEPTING A CLB CLRNC WITH SPD RESTR DUE TO LANGUAGE BARRIER.
Narrative: WHILE ENRTE SEOUL, KOREA, TO SFO AND IN JAPANESE AIRSPACE, WE RECEIVED A MACH NUMBER RESTR FOR MACH .84 AT FL330. SINCE OUR PLAN CALLED FOR MACH .86 AND MACH .84 WOULD RESULT IN HIGHER FUEL BURN AND TIME ENRTE, WE REQUESTED FL350 AT MACH .86, BUT TOKYO CTL RESPONDED UNABLE DUE TFC. WHEN TOKYO CTL HANDED US OFF TO TOKYO RADIO, WE AGAIN REQUESTED FL350 AT MACH .86, BUT WERE AGAIN DENIED. LATER WE RECEIVED A CLRNC FROM TOKYO RADIO TO CLB TO FL350 AND MAINTAIN MACH .84. WE DECLINED THE CLRNC EXPLAINING WE DID NOT WANT FL350 UNLESS WE COULD MAINTAIN MACH .86 AND WE WOULD MAINTAIN MACH .84 AT FL330. TOKYO RADIO RESPONDED WITH, ROGER, MAINTAIN MACH .84. AT OUR NEXT POS RPT, TOKYO RADIO QUESTIONED OUR ALT FL330 AND ASKED IF WE RECEIVED A CLRNC TO FL350. OUR RESPONSE WAS TO EXPLAIN ONCE AGAIN OUR REQUIREMENT FOR HIGHER MACH .86 AT FL350, AND MACH .84 ONLY AT FL330, AS WE PREVIOUSLY EXPLAINED. AFTER SOME DELAY, TOKYO RADIO RELAYED THE CLRNC TO MAINTAIN MACH .84 AT FL330. APPARENTLY OUR ORIGINAL REJECTION OF THIS CLRNC WAS MISUNDERSTOOD BY THE JAPANESE RADIO OPERATOR AND THEN MISCOMMUNICATED OUR INTENTIONS TO TOKYO CTL. ASSUMING WE WOULD CLB TO FL350 AS REQUESTED AND MAINTAIN MACH .84 WE FELT WE USED CARE IN COMMUNICATING WITH THE JAPANESE RADIO OPERATOR, BUT IT IS EVIDENT WE SHOULD HAVE BROKEN THE REJECTION INTO 3 PARTS -- IE, 1) UNABLE MACH .84 AT FL350. 2) MAINTAINING MACH .84 AT FL330. 3) REQUEST MACH .86 CRUISE. THIS MIGHT HAVE MORE CLRLY DEFINED OUR INTENTIONS AND BETTER EXPRESSED OUR CRUISE CONCERNS. WE NEED BETTER USE OF OCEANIC AIRSPACE TO AVOID CRUISE RESTRAINT CONFLICTS BTWN ACFT OPERATING NORMALLY AT HIGHER AND LOWER SPDS. THIS WOULD BE POSSIBLE IF WE WERE ALLOWED USE OF OUR FANS NAV SYS. FURTHERMORE, USE OF DATA LINK/DIRECT LINE COMS IN FOREIGN AIRSPACE REDUCES CONCERNS FOR MISINTERP DUE TO LANGUAGE CONSTRAINTS. BOTH WOULD BE POSSIBLE BUT FOR GOVERNMENTAL RESTRAINT IN THE USE OF THESE AIDS.
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.