Sept 9 Reuters Boeing39;s shares rose 3.7 on Monday after the planemaker and its biggest union reached a tentative deal covering more than 32,000 workers, averting a possible strike.

This was the first major negotiation by new CEO Kelly Ortberg, who took the helm just a month ago and has been tasked with turning around the struggling planemaker.

The proposed fouryear contract was hailed by the union as the best it had ever negotiated and was cheered by investors.

However, it is far from a done deal.

Workers, who make the company39;s bestselling 737 commercial jet and other planes, will vote on Sept. 12 and can strike as early as Sept. 13 if they reject the contract and support a work stoppage.

The tentative deal with the union is a boost for Boeing as it tries to restore investor and customer faith, navigate regulatory scrutiny and ramp up production of its 737 MAX after a door plug on a nearnew MAX blew off a jetliner while in midair in early January.

Since that incident, Boeing39;s stock price has cratered 37, compared to a 7.7 rise in the bluechip Dow index.

As part of the tentative agreement, Boeing has committed to building a replacement for its workhorse 737 at its U.S. Pacific Northwest facilities, if the project is started during the fouryear period of the labor contract, though the planemaker has not yet announced the new jet.

Boeing and rival Airbus are in the early stages of drawing up strategies for replacements of their bestselling singleaisle models…