Society of Professional Engineering Employees in Aerospace is expected to overwhelmingly reject a new contract offer by Boeing Co., Seattle, said Stanley Sorscher, a member of the unions executive board and the negotiating committee. The companys contract offer would move all the SPEEA workers into its cash balance pension plan as of Jan. 1 without giving them the choice of staying in the traditional pension plan. Although negotiations between Boeing and the SPEEA broke down earlier this week for unrelated reasons, Boeings offer for inclusion under the company cash balance plan also fell short of expectations, Mr. Sorscher said. The union members had hoped to choose between the old and the new plans, but the company said that was "impossible, he said. The SPEEA contract expires Dec. 1.