Narrative:

En route to sfo, just prior to oak fir, the radar was painting WX at 12 O'clock position (approximately 80 mi). We asked for a deviation 'right of course up to 20 mi for WX,' from tokyo radio. After some delay, tokyo responded with 'unable deviation.' we informed tokyo that we must deviate around WX. They responded by saying unable deviation and to stand by. After another delay, tokyo radio called us back and stated 'unable deviation.' we insisted that we must have a deviation for WX. They again insisted on no WX deviation. At no time did they suggest an alternative plan of action, ie, climb or descent with deviation. So, in accordance with air carrier flight operations manual we accomplished the following (deviation required without clearance): 1) turned on all exterior lights. 2) immediately informed tokyo radio of our intentions to deviate. 3) broadcast our position and intentions on 121.5 MHZ. 4) started deviation laterally to the right. 5) a deviation of at least 10 mi was planned so we climbed 500 ft (eastbound, right deviation). 6) no conflicting traffic was observed visually or on TCASII. 7) at approximately 10 mi, it was determined that we could return to course. We returned to course and descended back to assigned altitude. We advised tokyo that we were back on course. I suspect tokyo was coordinating with oakland, causing delay in reply. Conclusion: due to the large volume of traffic over this route and the requirements to avoid dangerous WX for safety reasons, I think shorter response times to WX deviation requests are necessary. Also, ATC should, if possible, suggest a course of action.

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Original NASA ASRS Text

Title: B747-400 FLC ASKS TOKYO RADIO FOR A 20 NM DEV AROUND TSTMS AHEAD OF ACFT. TOKYO CTR, RJTG, DENIES REQUEST, '...UNABLE.' AFTER SEVERAL REQUESTS, CAPT ELECTS TO USE HIS COMMAND AUTH AND DECLARES AN EMER WITH AIRLINE APPROVED PROCS USED IN HIS DIVERSION. RPTR COMPLAINS OF NO ALTERNATIVES BEING OFFERED BY ATC.

Narrative: ENRTE TO SFO, JUST PRIOR TO OAK FIR, THE RADAR WAS PAINTING WX AT 12 O'CLOCK POS (APPROX 80 MI). WE ASKED FOR A DEV 'R OF COURSE UP TO 20 MI FOR WX,' FROM TOKYO RADIO. AFTER SOME DELAY, TOKYO RESPONDED WITH 'UNABLE DEV.' WE INFORMED TOKYO THAT WE MUST DEVIATE AROUND WX. THEY RESPONDED BY SAYING UNABLE DEV AND TO STAND BY. AFTER ANOTHER DELAY, TOKYO RADIO CALLED US BACK AND STATED 'UNABLE DEV.' WE INSISTED THAT WE MUST HAVE A DEV FOR WX. THEY AGAIN INSISTED ON NO WX DEV. AT NO TIME DID THEY SUGGEST AN ALTERNATIVE PLAN OF ACTION, IE, CLB OR DSCNT WITH DEV. SO, IN ACCORDANCE WITH ACR FLT OPS MANUAL WE ACCOMPLISHED THE FOLLOWING (DEV REQUIRED WITHOUT CLRNC): 1) TURNED ON ALL EXTERIOR LIGHTS. 2) IMMEDIATELY INFORMED TOKYO RADIO OF OUR INTENTIONS TO DEVIATE. 3) BROADCAST OUR POS AND INTENTIONS ON 121.5 MHZ. 4) STARTED DEV LATERALLY TO THE R. 5) A DEV OF AT LEAST 10 MI WAS PLANNED SO WE CLBED 500 FT (EBOUND, R DEV). 6) NO CONFLICTING TFC WAS OBSERVED VISUALLY OR ON TCASII. 7) AT APPROX 10 MI, IT WAS DETERMINED THAT WE COULD RETURN TO COURSE. WE RETURNED TO COURSE AND DSNDED BACK TO ASSIGNED ALT. WE ADVISED TOKYO THAT WE WERE BACK ON COURSE. I SUSPECT TOKYO WAS COORDINATING WITH OAKLAND, CAUSING DELAY IN REPLY. CONCLUSION: DUE TO THE LARGE VOLUME OF TFC OVER THIS RTE AND THE REQUIREMENTS TO AVOID DANGEROUS WX FOR SAFETY REASONS, I THINK SHORTER RESPONSE TIMES TO WX DEV REQUESTS ARE NECESSARY. ALSO, ATC SHOULD, IF POSSIBLE, SUGGEST A COURSE OF ACTION.

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.