Boeing may assemble the re-engined 737 Max in the same facility as it builds the 737 NG family of aircraft in Renton, Washington.
Beverly Wyse, 737 programme vice-president and general manager, said a potential third line for the Max would be placed in Renton with the two existing lines by relocating engine, empennage and line work staging areas positioned between Line 1 and a mezzanine that runs the length of the building.
Commercial production at Renton is split between two lines in the 4-481 building. Line 1, the wider of the two lines, would likely play host to Line 3 for the 737 Max.
With a third line capable of 21 aircraft per month, Wyse said that, over time, 737 production rates could climb to 60 aircraft per month, including the 737 Max.
The relocated functions would be moved elsewhere in building or nearby. Eventually, 737 Max production would overtake the two 737 NG lines as building accelerates, though concurrent production of each family could eventually take place on each line.
The Max line, like the other two, would have a potential capacity of 21 aircraft per month, and would start as a dedicated final assembly line for the re-engined aircraft, due for first delivery in the fourth quarter of 2017.
Following the selection of Renton for 737 Max final assembly, many speculated Boeing would either build a third line in the so-called "saw-tooth" building (named for its jagged roofline) where the P-8A Poseidon, a heavily modified 737-800 for military use, is assembled.
A third 737 line would have probably have shared commercial production with the P-8A, or Boeing may have shifted the P-8 final assembly to Boeing Field in Seattle.
It will be one to two years before Boeing makes a final decision on exactly where at the Renton plant the 737 Max will be assembled. Both Wyse and a union official said building the 737 Max alongside the 737 NG seems most likely.
Wyse's comments came during an informal press conference following a celebration at the Renton factory of the 737 production advancing from 31.5 to 35 aircraft per month, a record for the programme.
737 production rates will rise to 38 per month in 2013 and 42 per month in 2014.