This series investigates the reasons behind plane crashes and how they could have been prevented. Each episode shows a re-enactment of a particular accident and the subsequent investigation. Eye-witnesses, victims and relatives are interviewed about the effects these catastrophes have had on them and their loved ones. In Canada, where the series originated, the show is called \'Mayday\'. In the US it is \'Air Emergency\'. Everywhere else it is called \'Air Crash Investigation\'.