ALTDEV OVER THE ATLANTIC.

Narrative

WE WERE GIVEN 33000 FT FOR THE XING BY SHANWICK CLRNC. WE WERE LEVEL AT FL310 WHEN CHKING IN WITH LONDON CTL. I ASKED FOR FL330 AS THAT WAS OUR ALT FOR THE XING. THE CTLR RESPONDED THAT HE WOULD CHK. SEVERAL MINS LATER CTLR CALLED US BACK AND CLRED US TO CLB TO FL350. I CALLED HIM BACK SAYING WE WANTED FL330 AND; IF WE COULD NOT HAVE THAT; WE WOULD RATHER STAY AT FL310. AS I WAS TALKING TO THE CTLR THE FO RESET THE MODE CTL PANEL TO FL350 AND BEGAN A VERT SPD CLB TO FL350. AFTER MY SECOND REQUEST FOR FL330; THE FO UNDERSTOOD THE CTLR TO SAY MAINTAIN FL330 NOW. FO THEN RESEET THE MCP TO FL330. I RESPONDED TO THE CTLR TO MAINTAIN FL310. I DID NOT SEE THE FO CHANGE THE MODE CTL PANEL OR INITIATE THE VERT SPD CLB. APPROX 1 MIN LATER; LONDON CTL CALLED AND SAID WE WERE NOT GIVEN AUTHORIZATION TO CLB; DSND BACK TO FL310. WE WERE AT FL322 AND PROMPTLY DSNDED. STRICT ADHERENCE TO OUR ALT WINDOW SETTING PROCS WOULD HAVE AVOIDED THIS. SUPPLEMENTAL INFO FROM ACN 302787: THE CAPT SAID HE HAD GIVEN US INITIAL CLB TO FL350 AND; WHEN HE CALLED BACK; HE HEARD HIM SAY MAINTAIN FL310 WHEN I HEARD MAINTAIN FL330 NOW. THE CAPT SAID HE HAD NOT NOTICED I HAD STARTED THE CLB AS HE WAS BUSY TALKING WITH THE CTLR OVER OUR FL330 ALT CLRNC REQUEST. I HAD RESET THE MODE CTL PANEL AS HE WAS DISCUSSING OUR ALT OF FL330 SO I COULD CLB TO OUR INITIAL CLRED ALT OF FL350. I HAD THOUGHT THE CAPT SAW IT.