A B767 crew had difficulty understanding their clearance as given by reykjavik control.

Attributes
ACN	535466
Time
Date	200201
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : bicc.airport
State Reference	FO
Altitude	msl single value : 32000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : eisn.artcc artcc : bird.artcc
Operator	common carrier : air carrier
Make Model Name	B767 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 70 flight time total : 11000 flight time type : 1700
ASRS Report	535466
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	non adherence : clearance other anomaly other other spatial deviation
Independent Detector	other flight crewa other flight crewb other other : 3
Resolutory Action	controller : issued new clearance
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	ATC Human Performance Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We had received part of our oceanic clearance from shannon control and were handed off reykjavik control. We had a great deal of difficulty understanding their instructions. We misunderstood the clearance and did not follow the new one until reinstructed by reykjavik control. The concern is for a gross navigation error. I'm not sure how to avoid this since we just couldn't understand our clearance. Data link clerances really help eliminate confusion when it's used.

Original NASA ASRS Text

Title: A B767 CREW HAD DIFFICULTY UNDERSTANDING THEIR CLRNC AS GIVEN BY REYKJAVIK CTL.

Narrative: WE HAD RECEIVED PART OF OUR OCEANIC CLRNC FROM SHANNON CTL AND WERE HANDED OFF REYKJAVIK CTL. WE HAD A GREAT DEAL OF DIFFICULTY UNDERSTANDING THEIR INSTRUCTIONS. WE MISUNDERSTOOD THE CLRNC AND DID NOT FOLLOW THE NEW ONE UNTIL REINSTRUCTED BY REYKJAVIK CTL. THE CONCERN IS FOR A GROSS NAV ERROR. I'M NOT SURE HOW TO AVOID THIS SINCE WE JUST COULDN'T UNDERSTAND OUR CLRNC. DATA LINK CLERANCES REALLY HELP ELIMINATE CONFUSION WHEN IT'S USED.

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.