Numerical simulations of the compressible, 3-D non reacting flow in the engine inlet section of a concept hypersonic air-breathing vehicle are presented. These simulations have been carried out using FLUENT. For all the results reported, the mesh has been refined to achieve area-averaged wall y+ about 105. Mass flow rate through the intake and stagnation pressure recovery are used to compare the performance at various angles of attack. The calculations are able to predict the mode of air-intake operation (critical and subcritical) for different angles of attack. Flow distortion at the intake for various angles of attack is also calculated and discussed. The numerical results are validated by simulating the flow through a 2-D mixed compression hypersonic intake model and comparing with the experimental data. © 2006, DESIDOC.