WW24 EXPERIENCES ALTDEV WHEN THE ALT CAPTURE FUNCTION OF THE AUTOPLT IS DISENGAGED.

Narrative

WE WERE IN THE CLB PHASE OF THE FLT AND THE ACFT WAS BEING FLOWN BY THE AUTOPLT. ZDC CLRED US TO CLB TO FL320. IN THE COCKPIT; FL320 WAS SET IN THE ALT SELECT WINDOW. ALT SELECT (CAPTURE) WAS SELECTED ON THE FLT DIRECTOR. UPON REACHING FL320; THE AUTOPLT DID NOT CAPTURE AND HOLD THE ALT SELECTED. WE (CREW) NOTICED AND STARTED CORRECTIVE ACTION AT FL324. BY THE TIME CLB WAS STOPPED AND A DSCNT WAS STARTED THE ACFT HAD REACHED ABOUT FL325. WE (CREW) DSNDED THE ACFT BACK TO FL320. AROUND FL323 IN THE DSCNT THE CTLR ASKED US OUR ALT. WE REPLIED WE WERE LEVELING AT FL320. UPON REACHING FL320 THE CTLR AGAIN ASKED US OUR ALT. WE (CREW) REPLIED LEVEL AT FL320. SHORTLY AFTERWARDS THE CTLR CLRED US TO OUR CRUISE ALT OF FL360. THIS ACFT HAS RECENTLY GONE THROUGH AN EXTERIOR AND INTERIOR REFURBISHMENT; DEC/05. IN THE COCKPIT THE PLT SEATS WERE COMPLETELY OVERHAULED WITH NEW FOAM INSIDE AND LEATHER AND SHEEPSKIN EXTERIOR. THE FLT DIRECTOR CTL MODULE IS ON THE L SIDE OF THE CTR PEDESTAL. THE PLT EAT OVERHANGS THAT SIDE OF THE PEDESTAL DIRECTLY OVER THE CTL MODULE. I BELIEVE THAT IN MOVING ABOUT IN THE SEAT THE OVERHANG PORTION OF THE SEAT CUSHION DESELECTED THE ALT SELECT MODE. AT THIS TIME WE ARE CHANGING THE PLT SEATS DESIGN AND REPOSITIONING THE FLT DIRECTOR CTL MODULE IN THE CTR PEDESTAL.