No. 84-7356. Argued and Submitted February 11, 1985. Decided May 13, 1985. David A. Rosenfeld, Van Bourg, Weinberg, Roger Rosenfeld, San Francisco, Cal., for petitioner. Kathleen Murray, Elliott Moore, N.L.R.B., Washington, D.C., for respondent. James A. Carter, San Francisco, Cal., for intervenor. On Petition to Review an Order of the National Labor Relations Board. Before KENNEDY, ALARCON and NELSON, Circuit Judges. NELSON, Circuit Judge: International Association of Machinists and Aerospace Workers