Widebody transport on oceanic flight misses amended clearance on ACARS. Heading deviation.

Attributes
ACN	242150
Time
Date	199305
Day	Thu
Local Time Of Day	0001 To 0600
Place
Locale Reference	atc facility : zqm
State Reference	FO
Altitude	msl bound lower : 35000 msl bound upper : 35000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zid
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	cruise other
Route In Use	enroute : other oceanic enroute : atlantic enroute airway : czqm
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 12500 flight time type : 3200
ASRS Report	242150
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 150 flight time total : 5000 flight time type : 270
ASRS Report	242130
Events
Anomaly	other anomaly other
Independent Detector	other controllera
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	other

Narrative:

I just returned from my rest period and we were approaching the fix 'steam.' the oceanic clearance had been received and accepted over the data link (ACARS). The clearance was just as we were filed. A little later, moncton asked that we read back the clearance. I believe the clearance was read back as 'oystr', 54N 50W, etc., and was accepted, as this was our filed flight plan. But, gander had sent another message over the data link, which had a change in the routing. The new was 'oystr,' 55N 50W, etc. We became aware of this new routing when we made our position report over 'oystr.' moncton said, I thought gander had cleared you to 55N 50W. He said that he would check with gander.' while he was talking to gander, we located the message with the amended routing to 55N 50W and proceeded immediately to 55N 50W and informed moncton that we were direct to 55N 50W. Moncton said something like, 'that's great or good.' we then called gander radio with our position over 'oystr,' ETA for 55N 50W and asked for a verification of this routing. They took about 2-3 mins and called us back with the entire clearance, 'oystr,' 55N 50W, etc. -- The rest of the clearance was as we had originally filed. This new clearance had not been accepted over the ACARS, as it was set aside. This new clearance had the same number as our first clearance with the addition of a 'B' at the end of the number. We had received another previous clearance message with the same number as our clearance, but with an 'a' at the end of the number. This one had no changes. Receiving a clearance and then receiving an amended clearance with the same number can lead to problems. If center wants to amend the clearance using data link, then I suggest a completely new number. That will get our attention a lot better. A voice amended clearance would, in my opinion, be even better. More communication between the flight crew. There were some distrs during this period of time due to a flight attendant who was injured just prior to our clearance problems.

Original NASA ASRS Text

Title: WDB ON OCEANIC FLT MISSES AMENDED CLRNC ON ACARS. HDG DEV.

Narrative: I JUST RETURNED FROM MY REST PERIOD AND WE WERE APCHING THE FIX 'STEAM.' THE OCEANIC CLRNC HAD BEEN RECEIVED AND ACCEPTED OVER THE DATA LINK (ACARS). THE CLRNC WAS JUST AS WE WERE FILED. A LITTLE LATER, MONCTON ASKED THAT WE READ BACK THE CLRNC. I BELIEVE THE CLRNC WAS READ BACK AS 'OYSTR', 54N 50W, ETC., AND WAS ACCEPTED, AS THIS WAS OUR FILED FLT PLAN. BUT, GANDER HAD SENT ANOTHER MESSAGE OVER THE DATA LINK, WHICH HAD A CHANGE IN THE ROUTING. THE NEW WAS 'OYSTR,' 55N 50W, ETC. WE BECAME AWARE OF THIS NEW ROUTING WHEN WE MADE OUR POS RPT OVER 'OYSTR.' MONCTON SAID, I THOUGHT GANDER HAD CLRED YOU TO 55N 50W. HE SAID THAT HE WOULD CHK WITH GANDER.' WHILE HE WAS TALKING TO GANDER, WE LOCATED THE MESSAGE WITH THE AMENDED RTING TO 55N 50W AND PROCEEDED IMMEDIATELY TO 55N 50W AND INFORMED MONCTON THAT WE WERE DIRECT TO 55N 50W. MONCTON SAID SOMETHING LIKE, 'THAT'S GREAT OR GOOD.' WE THEN CALLED GANDER RADIO WITH OUR POS OVER 'OYSTR,' ETA FOR 55N 50W AND ASKED FOR A VERIFICATION OF THIS RTING. THEY TOOK ABOUT 2-3 MINS AND CALLED US BACK WITH THE ENTIRE CLRNC, 'OYSTR,' 55N 50W, ETC. -- THE REST OF THE CLRNC WAS AS WE HAD ORIGINALLY FILED. THIS NEW CLRNC HAD NOT BEEN ACCEPTED OVER THE ACARS, AS IT WAS SET ASIDE. THIS NEW CLRNC HAD THE SAME NUMBER AS OUR FIRST CLRNC WITH THE ADDITION OF A 'B' AT THE END OF THE NUMBER. WE HAD RECEIVED ANOTHER PREVIOUS CLRNC MESSAGE WITH THE SAME NUMBER AS OUR CLRNC, BUT WITH AN 'A' AT THE END OF THE NUMBER. THIS ONE HAD NO CHANGES. RECEIVING A CLRNC AND THEN RECEIVING AN AMENDED CLRNC WITH THE SAME NUMBER CAN LEAD TO PROBS. IF CTR WANTS TO AMEND THE CLRNC USING DATA LINK, THEN I SUGGEST A COMPLETELY NEW NUMBER. THAT WILL GET OUR ATTN A LOT BETTER. A VOICE AMENDED CLRNC WOULD, IN MY OPINION, BE EVEN BETTER. MORE COM BTWN THE FLC. THERE WERE SOME DISTRS DURING THIS PERIOD OF TIME DUE TO A FLT ATTENDANT WHO WAS INJURED JUST PRIOR TO OUR CLRNC PROBS.

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.