This study has provided a survey of hail physical characteristics and hail size distribution properties. It also attempts to present the hail threat based to some extent upon correlation between global meteorological models and limited existing data. The extreme values provide worst case estimates for hail density and relative frequency as a function of size. The probability tables can be used as an estimate of the worst case probabilities of intercepting hail of different sizes for use in designing aircraft structures. The tables also indicate that multiple hits from smaller hailstones are potentially a problem that aircraft designers need to consider.
A review has been produced of the use of composites in aircraft production, the existing test standards that are relevant for hail threat, the mechanical characteristics of ice and the damage caused to test composite structures. This has been carried out for a range of relevant hail sizes and impact velocities.
This report is intended to provide input for the development of a harmonised hail threat and simulation definition.