Narrative:

This reporter was captain on a part 121 air carrier B747-400. We were flying on an oceanic track under control of oakland oceanic (kzak) when we requested a climb to FL370 with kzak via fans data link. Kzak responded with unable FL370 due to company traffic, included with this response was an unrequested clearance to climb to FL360. This message was printed and read by both PF and PNF as per company SOP and accepted. Neither pilot perceived the climb to FL360, we both fixated on the unable FL370 due to company traffic part of the message. We did not make the climb to FL360. After the next position report, ATC asked us to confirm our altitude, we responded to level at FL350. At this time ATC pointed out the fact we had been cleared to FL360. We then asked ATC to confirm that we were cleared to FL360, which they did. We then climbed to FL360. There were no known conflicts during this time. After reporting level, we reviewed the printed ATC messages and ATC log. We had clearly been given FL360 and accepted the clearance. Both the PF and PNF had missed the climb instruction and had acknowledged what they perceived had been ATC telling us that FL370 was unavailable. Possible reasons for missing the climb portion of this communication are: fixating on the expected portion of the message, crew fatigue, and most importantly the expectation that ATC would send a message that would say FL360 is available, do you want it? This has been the most common response to this type of situation. This reporter recommends that you read and re-read all fans clrncs, agree what it truly says then accept it. With this new form of communication, ATC should be careful to word and structure their clrncs as close as possible to a clearance given verbally.

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Original NASA ASRS Text

Title: THE 2 MANNED CREW OF A B747-400 AT FL350 RECEIVES AND ACCEPTS AN UNSOLICITED CLB TO FL360 AFTER REQUESTING FL370, BUT FAILS TO CLB IN ACCORD WITH THE NEW CLRNC FROM ZAK, AK.

Narrative: THIS RPTR WAS CAPT ON A PART 121 ACR B747-400. WE WERE FLYING ON AN OCEANIC TRACK UNDER CTL OF OAKLAND OCEANIC (KZAK) WHEN WE REQUESTED A CLB TO FL370 WITH KZAK VIA FANS DATA LINK. KZAK RESPONDED WITH UNABLE FL370 DUE TO COMPANY TFC, INCLUDED WITH THIS RESPONSE WAS AN UNREQUESTED CLRNC TO CLB TO FL360. THIS MESSAGE WAS PRINTED AND READ BY BOTH PF AND PNF AS PER COMPANY SOP AND ACCEPTED. NEITHER PLT PERCEIVED THE CLB TO FL360, WE BOTH FIXATED ON THE UNABLE FL370 DUE TO COMPANY TFC PART OF THE MESSAGE. WE DID NOT MAKE THE CLB TO FL360. AFTER THE NEXT POS RPT, ATC ASKED US TO CONFIRM OUR ALT, WE RESPONDED TO LEVEL AT FL350. AT THIS TIME ATC POINTED OUT THE FACT WE HAD BEEN CLRED TO FL360. WE THEN ASKED ATC TO CONFIRM THAT WE WERE CLRED TO FL360, WHICH THEY DID. WE THEN CLBED TO FL360. THERE WERE NO KNOWN CONFLICTS DURING THIS TIME. AFTER RPTING LEVEL, WE REVIEWED THE PRINTED ATC MESSAGES AND ATC LOG. WE HAD CLRLY BEEN GIVEN FL360 AND ACCEPTED THE CLRNC. BOTH THE PF AND PNF HAD MISSED THE CLB INSTRUCTION AND HAD ACKNOWLEDGED WHAT THEY PERCEIVED HAD BEEN ATC TELLING US THAT FL370 WAS UNAVAILABLE. POSSIBLE REASONS FOR MISSING THE CLB PORTION OF THIS COM ARE: FIXATING ON THE EXPECTED PORTION OF THE MESSAGE, CREW FATIGUE, AND MOST IMPORTANTLY THE EXPECTATION THAT ATC WOULD SEND A MESSAGE THAT WOULD SAY FL360 IS AVAILABLE, DO YOU WANT IT? THIS HAS BEEN THE MOST COMMON RESPONSE TO THIS TYPE OF SIT. THIS RPTR RECOMMENDS THAT YOU READ AND RE-READ ALL FANS CLRNCS, AGREE WHAT IT TRULY SAYS THEN ACCEPT IT. WITH THIS NEW FORM OF COM, ATC SHOULD BE CAREFUL TO WORD AND STRUCTURE THEIR CLRNCS AS CLOSE AS POSSIBLE TO A CLRNC GIVEN VERBALLY.

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.