Re: Aircraft Toilets

From:         John Murphy <>
Organization: Rogue Publications Limited
Date:         12 May 95 03:22:52 
References:   1
View raw article
  or MIME structure

In article <airliners.1995.509@ohare.Chicago.COM>
  "Neil Harding" writes:

> My girlfriend does not believe me when I tell her that certain older,
> currently flying airliners deposit their sanitary waste out of the back
> of the aircraft during flight. Which leads to the phenomenon known as
> 'blue ice'.
> Please could someone inform me of types of aircraft which do this, as
> this matter is currently forming a bet for a dinner!

I'm sure this will produce lots of replies from experts but I ofer my four
penneth.  If aircraft toilets were allowed to discharge the waste from
toilets while cruising they would emerge are large blacks which would
fall to earth and cause consierable damage, if not injury, on the ground.
  As a result all aircraft toilets to my knowledge contain their waste
to tansk which are discreetly emptied on landing by little trucks with
septic tanks on the back upon landing.
  As the outside temperature of the average airliner during cruise is well
below freezing level a problem does emerge, that the septic sustems of airliners
leak and that the fluids which leak from them freeze on the outside of the
aircraft and eventually accumulate enough mass to form clumps which have
been known to fall off in flight and alight in people's gardens.
  The blue in blue ice is disinfectant which is used to prevent
fermentation in effluent tanks.
  A friend of mine who is an aircraft engineer has told me that
aircraft toilets cause more line maintenance problems than any other
aircraft system, including galley and undercarriages.
  They do however have a strange fsscination and I, for one, would
welcome a detailed discussion in this group about the workings of
various aircraft toilets.  Which is the best etc?
  I am told that if travelling in Concorde is is adviable not to
occupy the toilets during transition from supersonic to subsonic flight
as the internal bulkheads cool at a different rate from the external
and that dor several minutes the toilet doors are jammed shut.
  Am I being perculularly English in being ineterested in this subject,
it is well-known that the English like jokes about farting and so on,
or is it something which constantly perplexes the professional
aviation world?

John Murphy
Rogue Publications Limited,
Telephone +1371 876340