Nasty Ice!

In article , "Manuel"
wrote:

GRAZ, Austria (AP) - It was an inelegant intruder on a sunny
afternoon: a chunk of ice from a jetliner toilet that broke free and
slammed into an Austrian family's garden.


I thought that airplane toilets didn't flush outboard in-flight... so I
googled for it and found this:
http://www.faa.gov/fsdo/ord/blueice.htm

So how is this possible? Several news agencies quoted it, but it just
doesn't make sense to me.

Anyone?

-Manuel



Sometimes the dump valves (which are used for servicing them) leak.