WS MoreOrLess: How safe is flying?

The Germanwings A320 tragedy, in which 150 people died, is the latest in a series of fatal crashes over the past year. Are more planes crashing, or does it just seem that way? Plus: is the number of penalties Chelsea Football Club have been awarded in the Premier League this season "abnormally low" as they have claimed? This programme was first broadcast on the BBC World Service.