B747 flight crew over the pacific on a trans-oceanic flight reported deviating from cleared track to...

Attributes
ACN	1379519
Time
Date	201608
Local Time Of Day	0001-0600
Place
Locale Reference	RJJJ.ARTCC
State Reference	FO
Aircraft 1
Make Model Name	B747 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Route In Use	Oceanic
Flight Plan	IFR
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 240 Flight Crew Total 22934
Person 2
Function	Pilot Flying First Officer
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 150 Flight Crew Total 5367 Flight Crew Type 190
Events
Anomaly	ATC Issue All Types Deviation - Procedural Clearance Deviation - Track / Heading All Types Inflight Event / Encounter Weather / Turbulence

Narrative:

Pilot flying (PF) observed weather ahead with anvil cloud tops and advocated an early lateral offset. Weather radar painted yellow and red on our track with visible lightning. Controller pilot data link communication (cpdlc) was logged into rjjj so I requested L15 for weather. After a few minutes with no response; I contacted tokyo radio by voice on 5628HZ. They acknowledged our voice request to deviate; however; we did not receive a timely response from fukuoka oceanic. Absent a clearance to offset; I requested via cpdlc clearance to climb to FL320 and immediately backed that up with a voice request. [Several minutes later]; the PF began to offset left of course enough to clear the anvil. I turned on all exterior lights and broadcast our intentions on 123.45MHZ. TCAS indicated a line of traffic ahead in our projected deviation path. [A few minutes later] we received cpdlc 'unable due to traffic.' this response was ambiguous because we had two active requests at the time; offset and altitude. Three minutes later I sent another cpdlc request L40 for weather. Eventually; passing abeam the anvil and in trail of other traffic also deviating we reached 42NM offset from our cleared track. [Several minutes later]; cpdlc clearance received to climb and maintain FL300 and deviate up to L40; report level and report back on course. I sent cpdlc report back on route; and [later] I sent cpdlc report level FL300. TCAS targets did not escalate to TA at any time. Turbulence became light to occasional moderate.

Original NASA ASRS Text

Title: B747 flight crew over the Pacific on a trans-oceanic flight reported deviating from cleared track to avoid thunderstorms when they had difficulty getting a clearance from Oceanic Control.

Narrative: Pilot Flying (PF) observed weather ahead with anvil cloud tops and advocated an early lateral offset. Weather radar painted yellow and red on our track with visible lightning. Controller Pilot Data Link Communication (CPDLC) was logged into RJJJ so I requested L15 for WEATHER. After a few minutes with no response; I contacted Tokyo Radio by voice on 5628HZ. They acknowledged our voice request to deviate; however; we did not receive a timely response from Fukuoka Oceanic. Absent a clearance to offset; I requested via CPDLC clearance to climb to FL320 and immediately backed that up with a voice request. [Several minutes later]; the PF began to offset left of course enough to clear the anvil. I turned on all exterior lights and broadcast our intentions on 123.45MHZ. TCAS indicated a line of traffic ahead in our projected deviation path. [A few minutes later] we received CPDLC 'UNABLE DUE TO TRAFFIC.' This response was ambiguous because we had two active requests at the time; offset and altitude. Three minutes later I sent another CPDLC request L40 for WEATHER. Eventually; passing abeam the anvil and in trail of other traffic also deviating we reached 42NM offset from our cleared track. [Several minutes later]; CPDLC clearance received to climb and maintain FL300 and deviate up to L40; report level and report back on course. I sent CPDLC Report BACK ON ROUTE; and [later] I sent CPDLC Report LEVEL FL300. TCAS targets did not escalate to TA at any time. Turbulence became light to occasional moderate.

Data retrieved from NASA's ASRS site 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.

B747 flight crew over the pacific on a trans-oceanic flight reported deviating from cleared track to avoid thunderstorms when they had difficulty getting a clearance from oceanic control.