B747 WX avoidance altitude deviation arrival narita using captain emergency authority/authorized.

Attributes
ACN	447924
Time
Date	199908
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : rjtg.airport
State Reference	FO
Altitude	msl bound lower : 36500 msl bound upper : 37000
Environment
Flight Conditions	VMC
Weather Elements	Thunderstorm
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : rjtg.artcc
Operator	common carrier : air carrier
Make Model Name	B747 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	other other
Flight Phase	cruise other
Route In Use	enroute : pacific
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	447924
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 non adherence : clearance non adherence : far other spatial deviation
Independent Detector	aircraft equipment : altitude alert other flight crewa other flight crewb
Resolutory Action	flight crew : returned to original clearance flight crew : returned to assigned altitude flight crew : exited adverse environment
Supplementary
Problem Areas	Weather Flight Crew Human Performance Environmental Factor
Primary Problem	Weather

Narrative:

Got clearance around WX from tokyo radio, 50 NM to north, needed 75-80 mi to get around WX. Transmitted location on 121.5, 128.95. Turned lights on and descended 500 ft. Stayed in visual conditions, then returned back on course.

Original NASA ASRS Text

Title: B747 WX AVOIDANCE ALTDEV ARR NARITA USING CAPT EMER AUTH.

Narrative: GOT CLRNC AROUND WX FROM TOKYO RADIO, 50 NM TO N, NEEDED 75-80 MI TO GET AROUND WX. XMITTED LOCATION ON 121.5, 128.95. TURNED LIGHTS ON AND DSNDED 500 FT. STAYED IN VISUAL CONDITIONS, THEN RETURNED BACK ON COURSE.

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.