Sorry if my original post was unclear. I was referring to the almost vertical
steps at the rear door of the ATR72. By coincidence I had dinner this evening
with a friend who showed me a photo of a Dash 8 at my local airport.
They now have a quite long kind of a 'bridge' which they use instead of
the Aircrafts own steps. I suppose that having this thing they will also use
it for the ATR. Obviously I did not mean to imply that the Aircraft or its doors
was unsafe, I only wondered how the safety of the steps was determined.
Thanks to those who responded. John