Boeing says it has achieved a production rate of 35 airplanes per month at its Renton, Wash., factory as it continues to climb toward building 42 airplanes a month by early 2014. Each new rate is a company record.

Boeing says it and its suppliers are adhering to high manufacturing quality despite the pressures of building up production rates. The first new aircraft at the higher rate, a 737-800 for AWAS Aviation Services, left the line with only eight jobs to be completed outside of the normal production sequence, says VP Beverly Wyse, general manager of 737 production.

Out-of-sequence work is not unusual if parts do not arrive on time during assembly. The parts in question are not essential for flight safety but are needed for the aircraft to be fully serviceable for customers. If too many are delayed, the delivery process bogs down, creating major delivery headaches for Boeing and its airline customers—an issue the company is facing in its 787 program.

Many suppliers serve multiple prime contractors, including rival Airbus, which is building up its own rates in response to strong demand throughout commercial aviation. So the ability of Boeing’s supply chain to respond to the 737 buildup has been a major focus at Renton.

“We only experienced three parts shortages during production,” Wyse says.

Boeing says its Renton employees will now work on stabilizing the 35/month rate in anticipation of the next bump-up, to 38/month in the second quarter of 2013.

In the meantime, Wyse and her production team must plan for the introduction of the 737 MAX into the Renton factory flow. MAX is the more fuel-efficient re-engined 737 Next Generation series that Boeing is offering airlines as an alternative to the NG series. It is expected to enter service in 2017.