RISK ASSESSMENT OF ACCIDENT ASSOCIATED WITH AIRCRAFT TRANSPORTATION

The new 1996 IAEA regulation for the transportation of radioactive material states a 90 mls drop test on unyielding surface for packages transported by air. This figure originates from a statistical analysis on civil aircraft accident during the period 1975 to 1985. A review on the 1983-1989 period demonstrates comparable velocity with a less stringent definition of accident. The statistical analyses are combined with the hardness of the fly-over ground and the impact angle to generate probabilities curves giving the occurrence of a mechanical stress overtaking the drop test velocity. The following steps were carried out: • Statistical analysis of the accident database from the ICAO (International Civil Aviation Organisation) to appreciate the accident characteristics with special attention to the impact velocitiy and angle • Modelling of the impact speed in each phase of flight (Take off, Climbing, Cruise, Approach and Landing), in order to evaluate the probability of occurrence of a given crash impact for different flight configurations • Qualitative analysis of recorder failures available in France As the statistical analysis is based on the available impact speed, a bias can be introduced if major crashes are neglected. In this respect, the qualitative analysis should give some elements to characterize the relationship between the non-availability of the information recorded on the black box and the severity of the accident.