Narrative:

We crossed longitude 180 at FL370 at 38 hours hnl standard time. It was dark with no moon. The radar showed some WX activity ahead and it appeared it would be best to deviate to left of course. We called on HF and received permission to deviate 30 mi to the left of course. As we continued, more and more WX cells kept popping up and compelled us to deviate further to the left. Captain called again and received permission to deviate 60 mi left of course coupled with the instruction to be back on course by 165W and to be at FL370 by 170W. We were in a block of 350 to to 370 at the time so we immediately climbed to FL370. Then it appeared an area well to the right side opened up. As we proceeded further we were forced to turn more and more right. We were forced to turn to the right so much that we ended up paralleling 170 west for awhile actually backing away from crossing 170W. Hnl radio frequency was extremely congested and static was furious. It was impossible to communication with hnl as soon as and as often as we desired. We were given clearance to continued deviation so long as we were back on course by the time we crossed 165W. My radar was clearly deficient. A foggy clutter area develops gradually a few hours after takeoff and dissipates before landing. I have seen this problem written up, the reply is 'unable to duplicate.' the situation made it most efficient to have captain rely more on his scope and also looking out of his windshield. That way he could give me verbal directions while I backed up the autoplt. He clearly would have been overloaded if he had tried to ascertain the best course while flying the airplane at the same time. It was also necessary to utilize second officer by having him continually adjust the engine thrust to maintain airspeed within reasonable parameters. I kept it on autoplt control, feeling it could do a better job than I. All 3 of us were extremely busy during the entire time we were passing through that very large area of storm activity. While flight planning at osaka, we did not receive a satellite photo of the flight planned route. The only information we had on that storm area was a small area around 180 with cells occasionally reaching FL350. It appeared to be easily avoided. The actual storm area was much larger in area and intensity than forecast. Had we known how large and energetic it really was, I'm sure captain would have required a different routing. It always appeared that there were a few cells ahead that we could get around. But new ones continually appeared as we proceeded. I suppose this was a classic textbook case of the cells being strong enough to block any view of the cells behind them. Given the nature of the situation, there was no way to give any kind of realistic estimate of when we would cross 170W. If we had decided to provide a new estimate as to when we would cross 170W, it would have been based on nothing of substance, only wild conjecture. It was obvious the original estimate was no good and a new estimate would probably have been accepted as being realistic and controller decisions would be based upon it. I think it far better for the controller to make his decisions upon the knowledge that our original estimate was not good and that we couldn't yet give a new one. While the loss of time sep between flts (down to 13 mins) is regrettable, I do not see how it could have been avoided, given the deficiencies in WX forecasting, WX radar and HF communications that we experienced.

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Original NASA ASRS Text

Title: ACR WDB FAILED TO UPDATE POSITION ESTIMATE WHEN DEVIATING AROUND TSTM ACTIVITY ON EXTENDED OVER WATER OPERATION. RESULT WAS LESS THAN STANDARD SEPARATION WITH OTHER FLT ON SAME OCEANIC TRACK.

Narrative: WE CROSSED LONGITUDE 180 AT FL370 AT 38 HRS HNL STANDARD TIME. IT WAS DARK WITH NO MOON. THE RADAR SHOWED SOME WX ACTIVITY AHEAD AND IT APPEARED IT WOULD BE BEST TO DEVIATE TO LEFT OF COURSE. WE CALLED ON HF AND RECEIVED PERMISSION TO DEVIATE 30 MI TO THE LEFT OF COURSE. AS WE CONTINUED, MORE AND MORE WX CELLS KEPT POPPING UP AND COMPELLED US TO DEVIATE FURTHER TO THE LEFT. CAPT CALLED AGAIN AND RECEIVED PERMISSION TO DEVIATE 60 MI LEFT OF COURSE COUPLED WITH THE INSTRUCTION TO BE BACK ON COURSE BY 165W AND TO BE AT FL370 BY 170W. WE WERE IN A BLOCK OF 350 TO TO 370 AT THE TIME SO WE IMMEDIATELY CLBED TO FL370. THEN IT APPEARED AN AREA WELL TO THE RIGHT SIDE OPENED UP. AS WE PROCEEDED FURTHER WE WERE FORCED TO TURN MORE AND MORE RIGHT. WE WERE FORCED TO TURN TO THE RIGHT SO MUCH THAT WE ENDED UP PARALLELING 170 W FOR AWHILE ACTUALLY BACKING AWAY FROM XING 170W. HNL RADIO FREQ WAS EXTREMELY CONGESTED AND STATIC WAS FURIOUS. IT WAS IMPOSSIBLE TO COM WITH HNL AS SOON AS AND AS OFTEN AS WE DESIRED. WE WERE GIVEN CLRNC TO CONTINUED DEVIATION SO LONG AS WE WERE BACK ON COURSE BY THE TIME WE CROSSED 165W. MY RADAR WAS CLEARLY DEFICIENT. A FOGGY CLUTTER AREA DEVELOPS GRADUALLY A FEW HRS AFTER TKOF AND DISSIPATES BEFORE LNDG. I HAVE SEEN THIS PROB WRITTEN UP, THE REPLY IS 'UNABLE TO DUPLICATE.' THE SITUATION MADE IT MOST EFFICIENT TO HAVE CAPT RELY MORE ON HIS SCOPE AND ALSO LOOKING OUT OF HIS WINDSHIELD. THAT WAY HE COULD GIVE ME VERBAL DIRECTIONS WHILE I BACKED UP THE AUTOPLT. HE CLEARLY WOULD HAVE BEEN OVERLOADED IF HE HAD TRIED TO ASCERTAIN THE BEST COURSE WHILE FLYING THE AIRPLANE AT THE SAME TIME. IT WAS ALSO NECESSARY TO UTILIZE S/O BY HAVING HIM CONTINUALLY ADJUST THE ENG THRUST TO MAINTAIN AIRSPD WITHIN REASONABLE PARAMETERS. I KEPT IT ON AUTOPLT CONTROL, FEELING IT COULD DO A BETTER JOB THAN I. ALL 3 OF US WERE EXTREMELY BUSY DURING THE ENTIRE TIME WE WERE PASSING THROUGH THAT VERY LARGE AREA OF STORM ACTIVITY. WHILE FLT PLANNING AT OSAKA, WE DID NOT RECEIVE A SATELLITE PHOTO OF THE FLT PLANNED ROUTE. THE ONLY INFO WE HAD ON THAT STORM AREA WAS A SMALL AREA AROUND 180 WITH CELLS OCCASIONALLY REACHING FL350. IT APPEARED TO BE EASILY AVOIDED. THE ACTUAL STORM AREA WAS MUCH LARGER IN AREA AND INTENSITY THAN FORECAST. HAD WE KNOWN HOW LARGE AND ENERGETIC IT REALLY WAS, I'M SURE CAPT WOULD HAVE REQUIRED A DIFFERENT ROUTING. IT ALWAYS APPEARED THAT THERE WERE A FEW CELLS AHEAD THAT WE COULD GET AROUND. BUT NEW ONES CONTINUALLY APPEARED AS WE PROCEEDED. I SUPPOSE THIS WAS A CLASSIC TEXTBOOK CASE OF THE CELLS BEING STRONG ENOUGH TO BLOCK ANY VIEW OF THE CELLS BEHIND THEM. GIVEN THE NATURE OF THE SITUATION, THERE WAS NO WAY TO GIVE ANY KIND OF REALISTIC ESTIMATE OF WHEN WE WOULD CROSS 170W. IF WE HAD DECIDED TO PROVIDE A NEW ESTIMATE AS TO WHEN WE WOULD CROSS 170W, IT WOULD HAVE BEEN BASED ON NOTHING OF SUBSTANCE, ONLY WILD CONJECTURE. IT WAS OBVIOUS THE ORIGINAL ESTIMATE WAS NO GOOD AND A NEW ESTIMATE WOULD PROBABLY HAVE BEEN ACCEPTED AS BEING REALISTIC AND CTLR DECISIONS WOULD BE BASED UPON IT. I THINK IT FAR BETTER FOR THE CTLR TO MAKE HIS DECISIONS UPON THE KNOWLEDGE THAT OUR ORIGINAL ESTIMATE WAS NOT GOOD AND THAT WE COULDN'T YET GIVE A NEW ONE. WHILE THE LOSS OF TIME SEP BTWN FLTS (DOWN TO 13 MINS) IS REGRETTABLE, I DO NOT SEE HOW IT COULD HAVE BEEN AVOIDED, GIVEN THE DEFICIENCIES IN WX FORECASTING, WX RADAR AND HF COMS THAT WE EXPERIENCED.

Data retrieved from NASA's ASRS site as of August 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.