Boeing has greatly expanded a little-publicized plan to establish a modification line in San Antonio for 787s produced before the flight test phase is complete.

The precise number of airframes remains in flux, but at least the first 20 787s assembled in Everett will fly to Boeing’s maintenance hub for military aircraft in San Antonio.

Boeing’s plan taps an experienced pool of about 400 freelance aerospace technicians in San Antonio to rapidly modify production aircraft to the post-flight test certification standard, as well as refurbish the six flight test airframes before delivery to customers.

The exact number of airframes shipped to San Antonio will depend on the 787’s final schedule for the flight test phase and how rapidly workers in Everett can assemble new airframes during the at least seven-month flight test phase now scheduled to begin in June.

San Antonio’s role in the 787 production system first emerged in July. That’s when Boeing quietly announced that 11 airframes, including six flight test aircraft, would be modified and refurbished at the maintenance hub for US Air Force airlifters and tankers, such as the KC-135, KC-10 and C-17.

But two programme delays that have pushed back both the 787’s original first flight and first delivery dates by at least nine months. The delays also have prompted Boeing to revisit the plan for San Antonio’s emerging role.

On 15 January, Keith Graf, an aerospace economic development official for Texas’s state government, told a public forum in San Antonio that Boeing has doubled the number of airframes to at least 20, and that the number may continue to rise.

Texas state and local officials hope the modification line will eventually lead to a larger, long-term role in the programme, perhaps as a permanent maintenance hub in the US for 787 airframes.

Boeing Integrated Defense Systems division will manage the contract workers hired for the 787 modification line.

A San Antonio-based Boeing spokeswoman confirms the site’s existing facilities will be leveraged by the 787 programme to perform “change incorporation and refurbishment” tasks on the 787. The precise nature of the role and the statement of work are still being defined, she adds. The start date for the modification line also remains in flux.

The San Antonio facility may be uniquely equipped to help ease the workload for the Everett assembly line during the critical period of the 787’s transition from flight test to full-rate production.

In recent years, the Boeing’s defence division in San Antonio remodeled their facilities on Everett’s lean production techniques, incorporating a pulsed-line for extensive modification work on the KC-135 fleet. The facility can also draw from the San Antonio region’s deep labour stock of aerospace maintenance and modification workers.