B747 crew had encounter with severe clear air turbulence.

Attributes
ACN	459931
Time
Date	200001
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : rjaa.airport
State Reference	FO
Altitude	msl bound lower : 37000 msl bound upper : 37500
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B747-400
Operating Under FAR Part	Part 121
Navigation In Use	other other
Flight Phase	cruise : level
Route In Use	enroute : pacific
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 250 flight time total : 22000 flight time type : 1300
ASRS Report	459931
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter : weather inflight encounter : turbulence non adherence : clearance other spatial deviation
Independent Detector	other flight crewa other flight crewb other flight crewb other other : 5 other other : 4
Resolutory Action	flight crew : declared emergency
Consequence	other Other
Supplementary
Problem Areas	Weather
Primary Problem	Weather

Narrative:

En route nrt-hnl in cpolc control with tokyo control and autoplt engaged, encountered brief severe clear air turbulence at FL370. Seatbelt sign on and announcements to remain seated had been made. 5 flight attendants and 3 passenger suffered minor injuries. Captain initiated climb to FL375 and offset 5 mi to right (south) without clearance in an attempt to avoid further encounter. Returned to FL370 after several mins. Reported altitude and turbulence to tokyo control via data link. Changed altitude without clearance because of time needed to communicate via cpolc and/or HF radio and severity of turbulence.

Original NASA ASRS Text

Title: B747 CREW HAD ENCOUNTER WITH SEVERE CLR AIR TURB.

Narrative: ENRTE NRT-HNL IN CPOLC CTL WITH TOKYO CTL AND AUTOPLT ENGAGED, ENCOUNTERED BRIEF SEVERE CLR AIR TURB AT FL370. SEATBELT SIGN ON AND ANNOUNCEMENTS TO REMAIN SEATED HAD BEEN MADE. 5 FLT ATTENDANTS AND 3 PAX SUFFERED MINOR INJURIES. CAPT INITIATED CLB TO FL375 AND OFFSET 5 MI TO R (S) WITHOUT CLRNC IN AN ATTEMPT TO AVOID FURTHER ENCOUNTER. RETURNED TO FL370 AFTER SEVERAL MINS. RPTED ALT AND TURB TO TOKYO CTL VIA DATA LINK. CHANGED ALT WITHOUT CLRNC BECAUSE OF TIME NEEDED TO COMMUNICATE VIA CPOLC AND/OR HF RADIO AND SEVERITY OF TURB.

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.