We consider the feasibility to find approximate non-preemptive schedules by metric approach for NP-complete problem of scheduling on two parallel identical machines with precedence delays for jobs or jobs of lengths 1 and 2 with makespan minimization. The execution of the job can be started only after the completion of any of its predecessors. We researched the application of methods looking for optimal solution for P2 | prec, pj = 1 | Cmax. We have tested Coffman's and Sethi's algorithms.