Lifespan of a parachute canopy?

Eric Greenwell wrote:
Marc Ramsey wrote:
I think you'll find that just about all emergency parachutes use
rubber bands, my Mini-Softie certainly has them...


Hmmm...curious! I'll put National back on the list long enough borrow
one of the club member's to try one in the glider, but their 20 service
life is still the lowest. Maybe it's type of rubber bands; for example,
ones out of silicone could take an enormous temperature range.

If my rigger is any indication, whatever "special" type of rubber bands
the chute may have been manufactured with, within a few years they'll
all be replaced by the generic rubber bands the rigger keeps on the
shelf. He's always warned me not to leave any parachute in the trunk of
a car or any other area that is going to exceed 120F, if I don't want to
end up with a gummy mess of rubber bands preventing my chute from
opening properly...

Marc

To All:

I replace the rubber stows holding your lines in place every time I am
repacking a chute. They only cost a few cents. Keep in mind that in the
past there wasn't any standards in place to which the parachute systems
were designed and build. Nowadays we have TSO. So, your older canopies
are not TSO'd...but when you get your rig back from your rigger ask him
this: "would you put this rig on your back and go make a jump in it?"
If he is not hesitant you are probably a OK but if you hear "well, I
don't know.." well, that parachute is probably not as airworthy as it
might sounds. Another aspect of using emergency parachutes is the speed
of deployment...in many cases the speed will be in excess of 200 kts.
It is hard to determine some outcomes, but myself I rather have a good
rig on my back. Some canopies are designed to be deployed at 130 kts.
and some at 150 kts. If you have sufficient altitude to slow your
freefall down to about 120 you are fine. But how about those low level
openings? Do you think that your chances of survival are the same
regardless of the age of the canopies or do you think that new(er)
canopy will give you a better chance?

Jacek Kobiesa
Washington State

Jacek why all the fear mongering? Not many riggers are going to
enthusiastic about jumping a round reserve, simply because it's round
and there much more comfortable ways to go parachuting these days.
All of these old rigs that are reasonably airworthy are as likely to
work as when they were built.
Yes newer is better, if you have the knowledge or are willing to gain
the knowledge to use a ramair pilot rig. Otherwise there is likely no
significant difference between a round reserve built yesterday and one
built twenty or thirty years ago.

The question of parachute life has been debated on this newsgroup more
than once. I see that we're no closer to resolution. At least one
respected U.S. manufacturer says there is no finite life if cared for
properly. Many U.S. riggers won't pack anything over 20 years old. One
rigger in this thread sets a 15-year life and says "why take a chance
with your life?" And the rest of us are left to wonder who's right.

I'm in the same situation as Eric. My parachute is 24 years old. My
biggest problem now is finding a rigger who will pack it and in whom I
have confidence that he will thoroughly evaluate it. A few years ago I
took advantage of the opportunity to watch an experienced rigger
inspect (with pull test) and pack my chute at one of the national
soaring contests. I was reassured by his care and expertise and also by
his appreciate comment that my canopy was in great shape.

My chute might be unusual--it was stored twice, for 5 years and 3 years
respectively, in a bag, indoors, unused. It's never been stored in the
cockpit except overnight in a contest (and the glider always goes in
the trailer each night). I cover it against the sun on the launch grid.
I average only 20 to 30 flights a year. And I'll admit that even when I
have flown regularly, I haven't always had it repacked every 120 days
so if that's the primary source of wear, it's benefitted from that,
too.

The 20-year life to which so many riggers refer seems to be based at
least in part on liability concerns. Some of the guys I've talked to
admit that a chute may be in great shape after 20 years but they don't
want to repack it lest some other unrelated problem result in an injury
or death and the lawyers come looking for deep pockets, suing everyone.
National Parachute, who made the canopy, happily repacked it until it
was 20 years old. In fact, they offered to pack it the last time just a
few days before the anniversary so I could use it for one more season.
Does anyone really believe that something catastrophic occurs when the
calendar turns over one more day?

On the other hand, it seems just as obvious that carelessness and abuse
can render a chute unserviceable long before 20 years. So it's
important to have an expert doing the inspection and repacking each
time. I just wish our legal system didn't force honest, capable riggers
to abdicate responsibility for older chutes because they're afraid of
being wrongly punished.

I do take issue with the criticism that pilots flying expensive
composite gliders risk their lives because they're too cheap to buy a
chute every 15 or 20 years. That's flawed and presumptuous logic.
First, parachutes aren't cheap. Anyone who assumes that the owner of,
say, an ASW-24 must be rich and so can afford to plunk down $1,000
to $1,500 for a new chute without gulping is guilty of the same dubious
reasoning that thieves sometimes use to justify their misdeeds (i.e.,
"he's rich; he can afford it").

Second, I don't believe I'm risking my life unreasonably. The chances
of my being involved in an accident where I must use the parachute are
very small. Even then, the chances that my chute won't open promptly
and perform properly simply because it's more than 20 years old are
also very small. The combination of these two risks is likely far
smaller than the risks I incur coming into Manhattan every day to work,
or flying gliders, or skiing, or doing any number of other things in my
life. The easiest way to reduce risk for me would be to curl up in a
corner wearing a crash helmet and never venture outside again. But
that's not the answer, either.

I'm as safety conscious as anyone else and more so than
many--particularly when it comes to my flying equipment--as anyone
who's snored through one of my safety lectures at a contest will
attest. What I'm looking for is a knowledgeable, balanced view. Strong
Parachute's approach (see link in earlier posting) is the kind of
information and advice I appreciate.

Chip Bearden
ASW 24 "JB"

..
"Eric Greenwell" wrote in message
...

And I just discovered my Strong has them, too, so it's apparently not an
issue, at least the way I store and use my parachute. If it was, I think I
riggers packing it over it's 26 year life would've mentioned a problem if
they'd seen one.


I assume, then, that you have never actually seen this 'chute that you have
been wearing for how many years?

Shouldn't you at least pop it once before you get it re-packed to see for
yourself and get familier with what you own, what it takes to "pull the
ripcord", what the risers look like, what you would likely tug on to steer
it, etc.???

Worried about rubberbands? See for yourself what shape they are in after
being stored.

Or is it just the engineer in me that makes me do things like that?

--
Geoff
the sea hawk at wow way d0t com
remove spaces and make the obvious substitutions to reply by mail
Spell checking is left as an excercise for the reader

Capt. Geoffrey Thorpe wrote:
.
"Eric Greenwell" wrote in message
...

And I just discovered my Strong has them, too, so it's apparently not an
issue, at least the way I store and use my parachute. If it was, I think I
riggers packing it over it's 26 year life would've mentioned a problem if
they'd seen one.



I assume, then, that you have never actually seen this 'chute that you have
been wearing for how many years?

Shouldn't you at least pop it once before you get it re-packed to see for
yourself and get familier with what you own, what it takes to "pull the
ripcord", what the risers look like, what you would likely tug on to steer
it, etc.???

All good ideas, and I did pull the ripcord on it once years ago. It was
so easy, that I haven't bothered to do it again. I do re-read the manual
once a year (or similar article), so I think I'll be able to tell the
steering rings from whatever other stuff is within reach. I also sit in
the cockpit now and then, visualizing exiting the glider, operating the
jettison levers and seat belt release, looking for the ripcord, tugging
it, and so on.

Actually seeing the parachute innards probably wouldn't do me any good,
since I don't have any training in evaluating their condition.


Worried about rubberbands? See for yourself what shape they are in after
being stored.

I've just come from talking with the rigger that's done my parachute for
several years. He says he replaces them routinely on the parachutes he
repacks if they don't look like the new ones, but not necessarily every
time.

I did test the rubber bands that come wrapped around our newspaper.
Fifteen minutes at 275 deg F didn't seem to affect them at all, so it's
more than temperature that causes them to degrade (I'm guessing they
just get old). They didn't become brittle at 0 deg F, either, so I've
stopped worrying about them.

He also said my canopy was in excellent condition, that the harness was
very good, but if I wanted to get a new parachute, he'd could help with
that, too.

--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA