Air carrier widebody transport deviated from clearance route on extended overwater operation. Amende...

Attributes
ACN	82926
Time
Date	198803
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : sea
State Reference	WA
Altitude	msl bound lower : 37000 msl bound upper : 37000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zoa
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 4 Turbojet Eng
Navigation In Use	Other
Flight Phase	cruise other
Route In Use	enroute : direct enroute : other oceanic enroute : pacific
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : atp pilot : instrument
Experience	flight time last 90 days : 240 flight time total : 22100 flight time type : 6500
ASRS Report	82926
Person 2
Function	other personnel other
Events
Anomaly	other spatial deviation
Independent Detector	other controllera
Resolutory Action	none taken : detected after the fact other
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	other

Narrative:

Subject: ATC communication error with commercial radio causing an oceanic navigation error. Flight cleared per original ICAO routing on bottom of flight plan. At mid ocean clearance was changed to '47N/140W direct 48N/130W direct dolff intersection direct tatoosh direct sea.' just after 150 west clearance was further changed to 'present position direct dolff intersection direct tofino direct tatoosh direct sea.' fix map shows the initial route, second route and third route. I deduce that the third clearance was meant to be only 'dolff intersection direct tofino direct tatoosh direct sea.' all clrncs were accepted and read back per company procedures, as was reprogramming and checking of the instruments. Aircraft flew as cleared. Arinc (ATC) questioned our 140W position (48 degrees north/140W), which was where the direct routing took us. This was apparently where their misunderstanding came to light. Aircraft proceeded as cleared. Parenthetically vancouver center noted we were 10 mi north of dolff intersection terminal offset readouts on instruments were 20, 3, 3. Apparently #1 pulled 2 and 3 north in 'triple mix.' after arrival I called FAA oak oac and spoke with supervisor. He stated that company aircraft was out of the picture, the problem was a communication breakdown between ATC and commercial radio. Fix? Find and fix the spot where communication broke down between the center and commercial radio.

Original NASA ASRS Text

Title: ACR WDB DEVIATED FROM CLRNC ROUTE ON EXTENDED OVERWATER OPERATION. AMENDED CLRNC ROUTE WAS FOLLOWED AS RECEIVED, BUT APPARENTLY MESSAGE WAS GARBLED BETWEEN CTLR AND COMMERCIAL RADIO.

Narrative: SUBJECT: ATC COM ERROR WITH COMMERCIAL RADIO CAUSING AN OCEANIC NAVIGATION ERROR. FLT CLRED PER ORIGINAL ICAO ROUTING ON BOTTOM OF FLT PLAN. AT MID OCEAN CLRNC WAS CHANGED TO '47N/140W DIRECT 48N/130W DIRECT DOLFF INTXN DIRECT TATOOSH DIRECT SEA.' JUST AFTER 150 W CLRNC WAS FURTHER CHANGED TO 'PRESENT POS DIRECT DOLFF INTXN DIRECT TOFINO DIRECT TATOOSH DIRECT SEA.' FIX MAP SHOWS THE INITIAL ROUTE, SECOND ROUTE AND THIRD ROUTE. I DEDUCE THAT THE THIRD CLRNC WAS MEANT TO BE ONLY 'DOLFF INTXN DIRECT TOFINO DIRECT TATOOSH DIRECT SEA.' ALL CLRNCS WERE ACCEPTED AND READ BACK PER COMPANY PROCS, AS WAS REPROGRAMMING AND CHKING OF THE INSTRUMENTS. ACFT FLEW AS CLRED. ARINC (ATC) QUESTIONED OUR 140W POS (48 DEGS N/140W), WHICH WAS WHERE THE DIRECT ROUTING TOOK US. THIS WAS APPARENTLY WHERE THEIR MISUNDERSTANDING CAME TO LIGHT. ACFT PROCEEDED AS CLRED. PARENTHETICALLY VANCOUVER CENTER NOTED WE WERE 10 MI N OF DOLFF INTXN TERMINAL OFFSET READOUTS ON INSTRUMENTS WERE 20, 3, 3. APPARENTLY #1 PULLED 2 AND 3 N IN 'TRIPLE MIX.' AFTER ARR I CALLED FAA OAK OAC AND SPOKE WITH SUPVR. HE STATED THAT COMPANY ACFT WAS OUT OF THE PICTURE, THE PROB WAS A COM BREAKDOWN BTWN ATC AND COMMERCIAL RADIO. FIX? FIND AND FIX THE SPOT WHERE COM BROKE DOWN BTWN THE CENTER AND COMMERCIAL RADIO.

Data retrieved from NASA's ASRS site as of August 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.

Air carrier widebody transport deviated from clearance route on extended overwater operation. Amended clearance route was followed as received, but apparently message was garbled between controller and commercial radio.