Airbus has commenced mating of the cockpit section of its first A350 to the twinjet's forward fuselage at its Saint Nazaire plant in France.
The mating process will "continue over the coming weeks", the airframer said, before the entire forward section is flown to the final assembly line in Toulouse.
Aerolia has produced the cockpit and nose section components while the fuselage section was manufactured in Germany by Premium Aerotec.
"This will be the first major section of the A350 to enter the final assembly line," said Airbus.
It will form part of the static test airframe but will be "closely" followed by the initial flying prototype, one of five flight-test A350s to be manufactured.
Airbus had been intending to begin final assembly of the static aircraft by the end of this year, but has slipped the schedule into the first half of 2012. The maiden flight will take place in the first half of 2013, with A350 delivery set for 2014.