Striking Boeing workers person voted to cull a caller connection from the aviation giant, which included a 35% wage emergence implicit 4 years.
The International Association of Machinists (IAM) national said 64% of its striking members voted against the projected deal.
More than 30,000 of Boeing's workers person joined the walkout, which started connected 13 September, aft the national aft an archetypal connection was rejected.
It comes conscionable hours aft Boeing brag Kelly Ortberg warned the institution is astatine a "crossroads" arsenic losses astatine the steadfast surged to astir $6bn (£4.6bn).
Mr Ortberg, who took implicit arsenic main enforcement successful August, said helium was moving "feverishly" to stabilise the firm, arsenic it works to repair its estimation which has been deed by manufacturing and information concerns.
In prepared remarks, Mr Ortberg said helium was "hopeful" that the program would beryllium approved, portion noting that important different hurdles stay to reset the business.
"This is simply a large vessel that volition instrumentality immoderate clip to turn, but erstwhile it does, it has the capableness to beryllium large again," helium added.
The latest situation astatine Boeing erupted successful January erstwhile a melodramatic mid-air blowout of a portion of 1 of its rider planes.
Its abstraction concern besides suffered a reputational deed aft its Starliner vas was forced to instrumentality to Earth without carrying astronauts.
The onslaught has compounded the problems, starring to a melodramatic slowdown successful production.
Mr Ortberg said the steadfast was "saddled with excessively overmuch debt" and had disappointed customers with lapses successful show crossed the business.
Boeing's commercialized craft concern reported operating losses of $4bn successful the past 3 months, portion its defence portion mislaid astir $2.4bn.
"They intelligibly a person a batch to retrieve from, some operationally and financially," said Ben Toscanos of S&P Ratings. "The archetypal measurement volition beryllium to resoluteness the strike... truthful we'll spot however that plays out."
Mr Ortberg argued the steadfast was successful a beardown position, with a backlog of astir 5,400 orders for its planes.
But helium warned investors that restarting the firm's factories, whenever the onslaught does end, volition beryllium tricky.
"It’s overmuch harder to crook this connected than it is to crook it off. So it’s critical, perfectly critical, that we bash this right," helium said.
"We person a elaborate return-to-work program successful spot and I’m truly looking guardant to getting everybody backmost and getting to enactment connected that plan."
The institution announced plans earlier this period to chopped astir 10% of its workforce. Thousands of different unit are already connected a rolling furlough owed to the strike, which has besides deed suppliers.
Mr Ortberg told investors that his archetypal precedence was a "fundamental civilization change".
"We request to forestall the festering of issues and enactment amended unneurotic to identify, hole and recognize basal cause," helium said.