Since the mythical dawn of man's attempt to emulate birds and fly, and some believe this started with Icarus, man has been frustrated by his apparent inability to predict or prevent occasional disaster arising from failure of his mechanical aids to flight. From ancient Icarus with his ultimate and disastrous thermal structural failure, to the present and future aircraft the same problem although now in a more sophisticated and complex form, confronts the aircraft designer and engineer of today.

This paper is not intended to be a comprehensive treatise on Aircraft Accident Investigation as a whole because this is a subject of many facets and problems, but rather is it intended to draw attention in basic and elementary form to some types of mechanical failures or inadequate design criteria which have caused accidents to aircraft in the past, the methods used in their diagnosis and, what is perhaps more important, some lessons that have been learnt from them.