Compressor and turbine blades of aircraft engines are liable to failure from a number of causes. Their subsequent containment within the immediate confines of the engine has long posed problems for the designer aiming for minimum weight designs. To assist the understanding of the dynamics of the containment problem, a series of small scale model tests have been conducted. The particular tests reported, deal with the failure mechanism at the point of impact. A theoretical analysis in support of the results obtained is developed. Fairly good agreement is obtained between tests and theory and the read-across to full scale containment tests indicates that the containment problem is capable of scaling if linear velocities are kept constant. A discontinuity in the behavior of materials with respect to their just contained energy capacity has been identified. While several contributory factors can be suggested, a fully satisfactory explanation is not found.