Reference the incident today when a Ryanair plane depressurised and
had to make an emergency landing at Lemoge, can any of the experts on
this group say why planes depressurise spontaneously at 30,000 feet?

Presumably if a door flies open, or a window blows out, this could
happen but what is the most common cause?

In message <3cn8b45a3dpcin5bri026dr6jvs9g1tbqh@4ax.com>
Alasdair bobaxter.coo.uk> wrote:

Don't know if there are enough such incidents to refer to a common cause, but
some form of mechanical failure is the most likely, or possibly a bird
strike. There doesn't seem to have been an explosive decompression from the
reports I've seen on the news pages which would suggest a relatively slow
leak through a small puncture.