Boeing's 17,000 unionised engineers, scientists and technicians have ratified new four-year contracts, averting a strike that chief executive Kelly Ortberg warned would have halted 777-9 certification work and slowed 737 Max production.

The Society of Professional Engineering Employees in Aerospace (SPEEA) announced the ratification vote on 1 October, five days before the existing contract's 6 October expiration. The new deal takes effect on 7 October.

"We are marching forward to test, design and certify airplanes," says SPEEA representative Bryan Corliss.

Had members rejected the offer, they could have walked out starting 7 October — a scenario Boeing could ill afford as it works through certification of the 777-9 and ramps narrowbody output.

SPEEA organises Boeing's technical workforce in two units: a "professional" division of roughly 13,000 engineers and scientists, and a "technical" group of about 4,000 analysts, designers and technicians.

Both groups voted down Boeing's initial contract offer in August. The ratification vote on the company's second offer closed over the past week, and the margin reflected that lingering divide. The professional division approved the deal with 67% support; the technical unit passed it by only 54%.

"We secured many victories that some people thought were completely out of reach when this negotiation cycle started," SPEEA's negotiation team says. "All of these gains would not have been possible without your individual actions and our collective strength."

The four-year contracts deliver an immediate 10% wage increase on 2 October, followed by a further 4% in March 2027 and 6% annually in 2028, 2029 and 2030 — a cumulative 36% over the term, according to the union.

"We're pleased with the outcome of the vote. We look forward to working with our team to support our company's continued recovery and meeting our customer commitments now and into the future," says Ben Nimmergut, Boeing vice-president and functional chief engineer for production engineering.

The cost of avoiding a stoppage is substantial. Compounding wage growth across a 17,000-person engineering workforce adds a significant fixed-cost layer to Boeing's overhead at a time when the company is still working to restore production rates and clear a backlog that depends on certification milestones, not just assembly-line throughput.

The stakes were clear well before the vote. In September, Ortberg warned publicly that a SPEEA strike would be widely disruptive, forcing Boeing to stop 777-9 certification work and slow 737 Max production. Unlike the machinists' strike that shut down 737 assembly in late 2024, a walkout by SPEEA's members would have struck directly at the design and certification staff that federal regulators require to approve new aircraft variants.

With the ratification, Boeing removes a labour risk that sat squarely across its two most consequential programmes. The 777-9 — the largest variant of the 777X family — remains uncertified and years behind its original schedule, while 737 Max output continues its cautious climb under Federal Aviation Administration scrutiny following the 2024 quality and safety crisis.

The agreement locks in labour peace on the engineering side until 2030, and Boeing will now aim to convert that certainty into certification progress and delivery performance.