Heading track deviation in overwater operation after emergency declared.

Attributes
ACN	285369
Time
Date	199410
Day	Wed
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : gum
State Reference	GU
Altitude	msl bound lower : 39000 msl bound upper : 41000
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zoa tower : bur
Operator	common carrier : air carrier
Make Model Name	B747 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	cruise other other
Route In Use	enroute : other oceanic enroute : pacific
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time total : 20000
ASRS Report	285369
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	inflight encounter : weather non adherence : clearance other anomaly other other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	controller : issued new clearance flight crew : exited adverse environment
Consequence	Other
Supplementary
Primary Problem	Weather
Air Traffic Incident	Pilot Deviation

Narrative:

I observed heavy precipitation on radar. At 100 NM with 1/2 down antenna tilt, a strong return was received. We asked hnl arinc for deviation up to 30 NM left. At 20 NM to go to the WX our request was denied due to lack of time separation on a trailing aircraft. I informed arinc that I was exercising emergency authority/authorized and deviating, and that we would accept FL410. Arinc came back with a clearance to FL410 and deviation approved. By that time we were past the WX and returning to course after a 10 NM deviation. We informed arinc of this and stated that we would be 1 min late at 180E (our next fix). We requested to maintain FL390. This was approved. I did not feel that I could subject my aircraft and passenger to the WX depicted on my scope. I felt that any loss of separation would be minimal and easily rectified. I applaud ATC for stating the reason for denial of my request. This allowed me to make a more informed decision.

Original NASA ASRS Text

Title: HDG TRACK DEV IN OVERWATER OP AFTER EMER DECLARED.

Narrative: I OBSERVED HVY PRECIPITATION ON RADAR. AT 100 NM WITH 1/2 DOWN ANTENNA TILT, A STRONG RETURN WAS RECEIVED. WE ASKED HNL ARINC FOR DEV UP TO 30 NM L. AT 20 NM TO GO TO THE WX OUR REQUEST WAS DENIED DUE TO LACK OF TIME SEPARATION ON A TRAILING ACFT. I INFORMED ARINC THAT I WAS EXERCISING EMER AUTH AND DEVIATING, AND THAT WE WOULD ACCEPT FL410. ARINC CAME BACK WITH A CLRNC TO FL410 AND DEV APPROVED. BY THAT TIME WE WERE PAST THE WX AND RETURNING TO COURSE AFTER A 10 NM DEV. WE INFORMED ARINC OF THIS AND STATED THAT WE WOULD BE 1 MIN LATE AT 180E (OUR NEXT FIX). WE REQUESTED TO MAINTAIN FL390. THIS WAS APPROVED. I DID NOT FEEL THAT I COULD SUBJECT MY ACFT AND PAX TO THE WX DEPICTED ON MY SCOPE. I FELT THAT ANY LOSS OF SEPARATION WOULD BE MINIMAL AND EASILY RECTIFIED. I APPLAUD ATC FOR STATING THE REASON FOR DENIAL OF MY REQUEST. THIS ALLOWED ME TO MAKE A MORE INFORMED DECISION.

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.