Re: Halon

["William Wade" <billwade@Concentric.net>]

  Martin and Simon- I can't recall the reference, but I recently read the
opposite. There was also an Aviation Consumer test article around '91- '92
comparing effectivness of powder, CO2, and Halon that you might want to look
up.
 The gist of the recent article was that if you have a high enough
concentration of CO2 to extinguish a fire, you will be snuffed as well. CO2
displaces the O2 in the area of the fire until combustion can no longer be
supported. I don't know how Halon works chemically (perhaps someone knows
and could explain?). It apparently migrates to the site of combustion (it's
commonly termed "heat seeking"). I would expect you could use it sparingly
in the cockpit as needed without flooding the whole area. With dry chemical
you would have a cloud of dust that would coat everything in the cockpit
including your eyes and lungs. Of the alternatives I think Halon is the
least objectionable. My impression is that long term exposure may be
unpleasant but is not likely to be fatal.
  Don't forget that byproducts from burning plastics and upholstery will do
you in as well, sometimes by a delayed reaction. By all means vent once the
fire is out.
  The FAA might have replaced all of their units due to the fact that Halon
is currently illegal for use in anything BUT aircraft. It is the only system
being considered by the airlines- their concern seems to be whether
replacement Halon will be available in future. (Search Avweb for "halon").
  Who needs ozone when we've got SPF 40?  ; )  -Bill

prototype Super Chipmunk N18EF
Velocity Classic RG N6098S in the works