This paper describes a frequency domain numerical method for predicting noise radiation from ducted fans, including acoustic treatment and nonuniform background flow effects. The method solves the Euler equations linearized about a mean flow in the frequency domain. A pseudo-time derivative term is added to the frequency domain equations so that a time marching technique can be employed to drive the acoustic field to steady state explicitly. This approach makes distributed parallel computing more viable for equations of this type and allows use of well known convergence acceleration techniques, such as multigrid, to obtain the solutions efficiently. Simulations of the JT15D and a generic engine are shown at various operating conditions with comparison to results from time domain studies and available experimental data.