Boeing says plans to produce up to five 787 widebodies each month by year-end are on track with the loading of the first airframe on to a temporary surge line in the manufacturer’s Everett, Wash, facility.

The surge line, the third 787 assembly facility, was announced in 2009 when Boeing revealed plans to locate the second production line in Charleston, South Carolina.

Located in building 40-24, the former 767 manufacturing site sandwiched between the 777 and 747-8 lines, the site was completed on schedule in June but initially used for completion of finished airframes requiring change incorporation.

“However, we have now activated the surge line by loading the first airplane to be built on the line,” says a Boeing spokesman. “We are making steady progress toward increasing the production rate from the current 3.5 airplanes per month to five airplanes per month by the end of the year and 10 per month by the end of 2013.”

Boeing says the first new aircraft to be assembled on the surge line is line number 80, a Rolls-Royce Trent 1000-powered version destined for LAN Airlines of Chile. The South American carrier is due to take delivery of its first Everett-made 787 Aug. 31, although Boeing declines to comment on the expected completion date of the first aircraft made on the surge line. It does, however, add that the initial rate will be slower than the first production line in building 40-26. “We are taking some extra time on this airplane to ensure our tooling and parts deliveries are operating per plan,” says the spokesman.

Unlike the Charleston or 40-26 lines which move nose-to-tail, the 40-24 line appears to be a hybrid of the old and new Boeing assembly systems. The first two positions replicate the original 787 line in 40-26, while the later two retain the conventional slant position arrangement of earlier production lines. For now Boeing is sticking to its plan of using the surge line until Charleston hits the three per month rate in late 2013, though having invested considerable funds in the new facility it has the option of using the site as part of its longer term goal to go beyond 10 per month.

This production rate is scheduled to be achieved at the end of 2013, when Everett will be producing seven aircraft per month and Charleston another three.

Commenting earlier this year Pat Shanahan, senior VP and general manager of Airplane Programs at Boeing Commercial Airplanes described the additional capacity as “risk protection” in the run-up to the start of 787-9 assembly.

“When we go to the 787-9 we’re rate protected if we want to run the -9s down one line and -8s on the other,” he says.