Boeing's shares rose 5% before the bell on Monday after the planemaker and its biggest union reached a tentative deal covering more than 32,000 workers, averting a possible strike. The proposed four-year contract was hailed by the union as the best it had ever negotiated.

Boeing and its largest union said Sunday they reached agreement on a new contract that, if ratified, will avoid a strike that threatened to shut down aircraft production by the

The proposed deal is contingent on union members ratifying before midnight Thursday Pacific time, when the strike would otherwise commence.

The agreement, reached just days before the machinists’ contract was set to expire Sept. 12, could help Boeing avoid a costly strike.

Boeing and its largest union reached agreement on a new contract that, if ratified, will avoid a strike that threatened to shut down aircraft production.

The proposed four-year 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

Boeing said 33,000 workers represented by the International Association of Machinists and Aerospace Workers would get pay raises of 25% over the four-year contract, with average wages rising 33% due to seniority step increases. That is less than the 40% the union had demanded during negotiations.

Boeing’s most sizeable Texas footprint is in San Antonio, where it’s the area’s largest aerospace employer. Other key locations are in Plano, Irving and Dallas.

After an overwhelmingly negative reaction to a tentative deal with Boeing, union leader Jon Holden said he expects rank-and-file members to reject the contract.