See this link to an article that includes the Strong
company's view that there need be no specific limit
to the life of a properly maintained and stored Strong
canopy:

http://www.strongparachutes.com/Pages/Articles.html




At 17:18 13 January 2006, Eric Greenwell wrote:
wrote:
In the USA, there isn't really any life span of canopies
set for by
the FAA. However, some manufacturers are limiting
their life span of
canopies, or harness/containers systems. For example,
National limits
their life span to 15 years, Paraphernalia Softie
is doing the same,
but Strong Enterprises rigs are good to use as long
as they pass the
canopy/canopy fabric tests.

Do the manufacturers give a reason for this, such as
discovering
parachutes that are no longer safe after 15 years,
or industry tests
that shows fabric deteriorates in a manner that can't
be found by
inspection? Or is this simply a convenient way to limit
their liability?
Without knowing more, I see no reason to buy anything
but a Strong
parachute. Why buy a parachute that's worthless (or
maybe unsafe) after
15 years?

From what you say below, there are many stress factors
on a parachute,
and the implication is the industry (or at least some
of it) doesn't
know to test for potential problems. What puzzles me
is these packing an
usage stresses don't seem very demanding for synthetic
fabrics. Sport
parachutes get much more handling and use (jumping
a parachute seems
like far more stress than using it as a cushion!),
so it's hard to
understand why our chutes should degrade significantly
in 15 years.

On the other hand, Performance Designs
wants to see reserve canopies in their factory after
40 repack cycles.
If the canopy passes the tests they will return it
back to you and you
are good to go. Having said that, me as a rigger,
I am not repacking
parachutes that are older than 15 years. And in general,
if I remember
correctly, the PIA (Parachute Industry Association)
also agrees that 15
years is the 'life span' of a canopy but I am not
quite positive on
that. I'll check with them and let you know. The problem
with
parachutes is not the age alone. There is some other
factors playing
important role in the fabric degradation. The main
factor is the repack
cycle. According to the FAA, if your canopy is made
of synthetic fibers
the repack cycle is 120 days and 60 days in a case
on natural fibers
but that is history. The main degradation of fabric
comes from handling
and repacking the canopy. When the rig is due for
a repack the canopy
is pulled out of container or deployment bag in a
case of sport
parachute. Then the rigger inspects the whole system,
let the canopy
dry up and if everything is a OK it goes back into
the container or
deployment bag. This insertion into the deployment
bag or container is
the biggest stress for the fabric. And then you fly
in it. You sit on
it. It works in some cases as a cushion. And after
your are done
flying, you leave it in the direct sunlight, high
temperatures and then
when you put your glider away in the trailer the poor
rig is being
cooked. In some cases people will take them home....well,
at list they
were attempting that, because the rig rides in a trunk
of your car in
heat and cold. There is a push from the industry with
the FAA to change
the repack cycle to 180 days. That will help with
multiple issues. I
jumped a main sport parachute that sit in a deployment
bag for over 2
years. It worked just fine. Still, I believe that
a good parachute is
worth spending the money and it is worth of having
and flying with it.



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Eric Greenwell
Washington State
USA