Re: Inert Gas in Fuel Tanks

From:         "P. Wezeman" <>
Organization: The University of Iowa
Date:         Thu, 7 Nov 1996 05:44:20 GMT
References:   1
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On Mon, 28 Oct 1996, in a posting by Scott Odle, the sci.aeronautics
moderator wrote:

> Moderator's note:  
> Unlike the laity, who frequently say that "you can't put a price on a
> human life", you can do exactly that.  When I was in college in the
> late '60s, the price the California Department of Transport (now
> Caltrans) put on one life was $100,000 per year.  That is, if an
> improvement was projected to save one life per year, the Department
> would only proceed with the improvement if the cost was less than
> $100,000 per year.  For improvements that didn't require continuing
> maintainence, I believe the criterion was one life in five years.
> Since airliners aren't falling out of the sky with great regularity
> because the ullage isn't filled with inert gas, I'd say that it's not
> likely to happen.  Maybe someone would like to ask the FAA, NTSB, and
> major airlines what their criterion (price per life) is?  Also ask the
> airlines how much money they're saving on those plastic bottles, of
> course.  MFS]

   I read several years ago that, for purposes of public policy in the
United States, the value of a human life was set at about two million
dollars; that is, the government would spend up to that amount to save
one life. This is a calculation based on what economists call revealed
choice.  According to this principle the value that our society places
on a life can be judged by the risks that we take voluntarily when we
drive cars, operate farm machinery, work as police officers, etc. in
pursuit of our goals. Most industrialized countries have come up with
some such value: some higher, some lower. Of course, this applies only
to random lives and not to such things as rescuing trapped miners
after a cave-in where we are working to save specific people.

   I have the strong impression that our spending on airliner safety
is anomalously high, but if anyone has any numbers that would support
of contradict this I would like to see them. The whole point of
putting a monetary value on a human life is not to express our
philosophy of capitalism (Rule of acquisition number 157: Put a price
on everything.) but to allow tradeoffs of our finite resources so that
we are saving the greatest possible number of lives within our means.
If it would cost ten million to save a life by improving airline
safety but it would cost one million to save a life by installing
traffic signals at dangerous road intersections, then we would save
ten times as many people for the same cost by installing the signals.

   Others have noted a disproportionate concern with air safety
compared with other dangers. Some say that since so many die at once
in a crash that it has a strong impact on the national consciousness.
Thomas Wolfe suggested in his book "The Right Stuff" that pilots as a
group do not care to believe that they are subject to random danger
not under their control, and so have taken to tracing every mishap
back to its cause by some human error in judgement, procedure,
training, design, or workmanship and in so doing have systematically
eliminated these causes. Others say that airline passengers find
danger in a plane to be less acceptable than danger in a car that they
control. Busses and trains do have similar safety to airliners, which
would support this theory.

   Perhaps the fact that progress in airliner design tends to come in
generations as new technology accumulates (The Constellation and the
DC-7 were built about the same time, then the 707 and DC-8, then
widebodies) means that we have between times a surplus of aviation
talent who are best employed in improving safety.

   If the crash of flight 800 is determined to be a fuel tank
explosion it would not surprise me if, as well as eliminating the
source of ignition, they look at inert gas filling, active fire
suppression systems, or other protections against unknown sources of
ignition in the future. This would be similar to what was done after
the Comet disasters, where the square corner that was the starting
point of the crack in the Comet's fuselage was changed and the
fuselage was also redesigned so that a fatigue crack could no longer
become self-propagating.

[Moderator's note:  I'd expect them to settle on open-cell foam in the
tanks if they can get it approved.  Not much maintainence, no routine
servicing, cheap, and light.  Besides, it wouldn't be another item on
the MEL.  MFS]

                        Peter Wezeman, anti-social Darwinist

                             "Carpe Cyprinidae"

[Moderator's query:  Seize the minnows?  MFS]