USA-Parachute Repack Change?

[Ray Lovinggood]

On the SSA webpage, http://www.ssa.org/society/ListNewsArticleDtl.
asp?id=432
there is an article about extending the repack requirement
from 120 days to 180 days.

(If the url is split onto two lines, make sure you
paste it all in your brower.)

This was posted on Friday, 14 JAN 05

Ray Lovinggood
Carrboro, North Carolina, USA

[[email protected]]

Yes. This push for 180 days repack cycle is in place for past 4 or 5
years. The Parachute Industry Association, the USPA are all pushing for
that. In Europe the repack cycle right now is 180 days and there are no
problems. If we can get more organizations like the SSA and AOPA to
support that, maybe the FAA will change its bureaucratic approach and
make the changes to the FARs. The fact of the matter is that I have not
seen a modern parachute with a mold or fungus issue even though I
repacked quite a few rigs. It just doesn't happen. But on the other
hand tandem jumps were made in the U.S. for over 20 years before the
FAA accepted the findings and change the rules. Go figure.

[Mark James Boyd]

I think the 180 day requirement would actually
result in the sale of MORE parachutes, and an increase in their use.
USPA among others seems to have figured this out too.
The vast improvements in materials and techniques for
manufacture have really made the 120 day requirement silly.

In article . com>,
> wrote:
>Yes. This push for 180 days repack cycle is in place for past 4 or 5
>years. The Parachute Industry Association, the USPA are all pushing for
>that. In Europe the repack cycle right now is 180 days and there are no
>problems. If we can get more organizations like the SSA and AOPA to
>support that, maybe the FAA will change its bureaucratic approach and
>make the changes to the FARs. The fact of the matter is that I have not
>seen a modern parachute with a mold or fungus issue even though I
>repacked quite a few rigs. It just doesn't happen. But on the other
>hand tandem jumps were made in the U.S. for over 20 years before the
>FAA accepted the findings and change the rules. Go figure.
>


--

------------+
Mark J. Boyd

[Bill Zaleski]

On 19 Jan 2005 13:08:21 -0800, (Mark James Boyd)
wrote:

>"The vast improvements in materials and techniques for
>manufacture have really made the 120 day requirement silly."

I am a FAA Master Parachute Rigger. I am not aware of any "vast
improvments" since the change of repack cycle from 60 to 120 days many
years ago. If you know of any specifics, please advise. You are
misinformed.

[[email protected]]

180 days would still be at least 185 days too long. The only argument
for sticking with 120 or 180 days is the work that the riggers would
lose.

I just had my skydiving reserve repacked two months ago. That cost me
$75, and it doesn't look like I'm going to get to use it before it's
due again. It's a scam and I'm sick of it.

ted/2NO

[[email protected]]

obviously that should read "185 days too short". Lack of air time ...

[Eric Greenwell]

wrote:
> 180 days would still be at least 185 days too long. The only argument
> for sticking with 120 or 180 days is the work that the riggers would
> lose.

That is what my rigger says, too, and blames it on the associations.

> I just had my skydiving reserve repacked two months ago. That cost me
> $75, and it doesn't look like I'm going to get to use it before it's
> due again. It's a scam and I'm sick of it.

180 days will let many (most?) fly the season with a legal parachute.
Others will pleased that the number of days they fly with an illegal
parachute is now reduced by 90.

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

Eric Greenwell
Washington State
USA

[Mark James Boyd]

Yes, Bill, I still believe that parachutes made from
man made fibers are a vast improvement
in materials and techniques for parachute manufacture.

I believe they are superior to the natural fibers like silk and
cotton which I believe are more susceptible to mildew, mold, and rot.

We went over this last year when I recommended to folks on
this group that they avoid parachutes made of natural fibers.
And I remember your objections to this.

But I agree with USPA and PIA that the parachute repack
cycle should be extended.

Perhaps you don't believe that the use of man made fibers
is a vast improvement. Or perhaps you think extending
the minimum repack cycle for these parachutes is not warranted.
If so, please provide coutering references and specifics
to the information contained in:

www.pia.com/piapubs/pia180_2.pdf

In article >,
Bill Zaleski > wrote:
>On 19 Jan 2005 13:08:21 -0800, (Mark James Boyd)
>wrote:
>
>>"The vast improvements in materials and techniques for
>>manufacture have really made the 120 day requirement silly."
>
>I am a FAA Master Parachute Rigger. I am not aware of any "vast
>improvments" since the change of repack cycle from 60 to 120 days many
>years ago. If you know of any specifics, please advise. You are
>misinformed.
>


--

------------+
Mark J. Boyd

[Mark James Boyd]

Ted,

Yes, you might be right. The whole idea of having a parachute
in the glider may just be a bad idea anyway. Sure there are
a minute number of saves using a parachute, but where are the
statistics about how many people were killed
when the extra weight of the chute against their back
crushed their lungs during a high-G impact?

I'd like to see some crash test dummies in a car with
chutes on, and have them slam into walls at high speed.
One wonders how much the extra pounds on the back
multiplied by the Gs of impact
may help the shoulder harnesses and seatbelt
cut into the ribcage and lungs.

Yeah, the riggers and parachutists don't talk about that
part too much. Or how the extra pounds marginally raised the
stall speed just enough to cause a fatal stall/spin instead of
a close call or less-than-fatal injury.

Kind of like going to a donut shop and asking for recommendations
for dinner. Riggers and sport parachutists have a pretty
strong opinion about how important parachutes are...

In article om>,
> wrote:
>180 days would still be at least 185 days too long. The only argument
>for sticking with 120 or 180 days is the work that the riggers would
>lose.
>
>I just had my skydiving reserve repacked two months ago. That cost me
>$75, and it doesn't look like I'm going to get to use it before it's
>due again. It's a scam and I'm sick of it.
>
>ted/2NO
>


--

------------+
Mark J. Boyd

[Mark James Boyd]

Well, some of the sealed BRS systems have a 6 year
repack cycle, IIRC. At 20-30 pounds, maybe the
extra weight isn't such a good idea (Brian Carpenter
recommends against them for ultralights for just this reason).
But it IS an option for some aircraft...

In article . com>,
> wrote:
>obviously that should read "185 days too short". Lack of air time ...
>


--

------------+
Mark J. Boyd

[Bill Zaleski]

There have been no "vast improvements" since the repack cycle was
increased from the previous 60 day requirement to the present 120
days. If you think the move from man made materials to synthetics is
relevant, consider that natural fibers have not been used for
parachutes in over 50 years. Apples and oranges. "Hit the silk" is
only a joke now.



On 19 Jan 2005 17:13:48 -0800, (Mark James Boyd)
wrote:

>Yes, Bill, I still believe that parachutes made from
>man made fibers are a vast improvement
>in materials and techniques for parachute manufacture.
>
>I believe they are superior to the natural fibers like silk and
>cotton which I believe are more susceptible to mildew, mold, and rot.
>
>We went over this last year when I recommended to folks on
>this group that they avoid parachutes made of natural fibers.
>And I remember your objections to this.
>
>But I agree with USPA and PIA that the parachute repack
>cycle should be extended.
>
>Perhaps you don't believe that the use of man made fibers
>is a vast improvement. Or perhaps you think extending
>the minimum repack cycle for these parachutes is not warranted.
>If so, please provide coutering references and specifics
>to the information contained in:
>
>www.pia.com/piapubs/pia180_2.pdf
>
>In article >,
>Bill Zaleski > wrote:
>>On 19 Jan 2005 13:08:21 -0800, (Mark James Boyd)
>>wrote:
>>
>>>"The vast improvements in materials and techniques for
>>>manufacture have really made the 120 day requirement silly."
>>
>>I am a FAA Master Parachute Rigger. I am not aware of any "vast
>>improvments" since the change of repack cycle from 60 to 120 days many
>>years ago. If you know of any specifics, please advise. You are
>>misinformed.
>>

[Ted Wagner]

Not just that, Mark. A repack is like a surgical procedure, carrying with it
the risk of something going wrong, like leaving the closing loop locked with
a cheater pin or a tool left under the stitches. How many of us undergo
voluntary surgical procudures because some nameless doc says we have to.
Much rather have the procedure done on an irregular basis by a doc I know
and can trust and can even watch.

"Mark James Boyd" > wrote in message
news:41ef0ac1$1@darkstar...
> Ted,
>
> Yes, you might be right. The whole idea of having a parachute
> in the glider may just be a bad idea anyway. Sure there are
> a minute number of saves using a parachute, but where are the
> statistics about how many people were killed
> when the extra weight of the chute against their back
> crushed their lungs during a high-G impact?
>
> I'd like to see some crash test dummies in a car with
> chutes on, and have them slam into walls at high speed.
> One wonders how much the extra pounds on the back
> multiplied by the Gs of impact
> may help the shoulder harnesses and seatbelt
> cut into the ribcage and lungs.
>
> Yeah, the riggers and parachutists don't talk about that
> part too much. Or how the extra pounds marginally raised the
> stall speed just enough to cause a fatal stall/spin instead of
> a close call or less-than-fatal injury.
>
> Kind of like going to a donut shop and asking for recommendations
> for dinner. Riggers and sport parachutists have a pretty
> strong opinion about how important parachutes are...
>
> In article om>,
> > wrote:
>>180 days would still be at least 185 days too long. The only argument
>>for sticking with 120 or 180 days is the work that the riggers would
>>lose.
>>
>>I just had my skydiving reserve repacked two months ago. That cost me
>>$75, and it doesn't look like I'm going to get to use it before it's
>>due again. It's a scam and I'm sick of it.
>>
>>ted/2NO
>>
>
>
> --
>
> ------------+
> Mark J. Boyd

[Mark James Boyd]

Well, Ted,

I see your point, but in my experience riggers are VERY professional.
One or two incidents like this at the local skydiving
club (where the jumpers know their equipment just as well
as the rigger, in many cases) and that guy is moving on.

I don't think the excessively short repack cycles are
anyones INTENTIONAL desire to make a problem. I don't think rigger
attitudes about how incredibly critical the parachute is
can be considered out of place. Both of these things just lack
perspective. And the FAA goes to the "professional" organization
to get opinions. They just don't understand that
PIA and USPA aren't the sum total of wisdom in the entire
world about parachutes. The users of the emergency chutes
have wisdom too. This isn't intentionally overlooked, it's
just much harder to get feedback from a less concentrated
group.



For example, I'm likely to choose an emergency chute that is
5% less likely to open safely but allows me to sit comfortably
on it for 5 hours instead of only 2. In fact, I'd
pay 20% more for this feature.

Riggers would say this is crazy talk. The parachute opening
is the most important thing! Well, that's true, but
only if you try to open it. That's the part they don't
understand. And they don't understand that the extra fatigue
caused by a wicked uncomfortable chute can cause an accident.

Is there such a chute? Probably not. But you get my point...

article <1106289159.505cc1fc175211f038a97c7bee2c4ae4@terane ws>,
Ted Wagner > wrote:
>Not just that, Mark. A repack is like a surgical procedure, carrying with it
>the risk of something going wrong, like leaving the closing loop locked with
>a cheater pin or a tool left under the stitches. How many of us undergo
>voluntary surgical procudures because some nameless doc says we have to.
>Much rather have the procedure done on an irregular basis by a doc I know
>and can trust and can even watch.
>
>"Mark James Boyd" > wrote in message
>news:41ef0ac1$1@darkstar...
>> Ted,
>>
>> Yes, you might be right. The whole idea of having a parachute
>> in the glider may just be a bad idea anyway. Sure there are
>> a minute number of saves using a parachute, but where are the
>> statistics about how many people were killed
>> when the extra weight of the chute against their back
>> crushed their lungs during a high-G impact?
>>
>> I'd like to see some crash test dummies in a car with
>> chutes on, and have them slam into walls at high speed.
>> One wonders how much the extra pounds on the back
>> multiplied by the Gs of impact
>> may help the shoulder harnesses and seatbelt
>> cut into the ribcage and lungs.
>>
>> Yeah, the riggers and parachutists don't talk about that
>> part too much. Or how the extra pounds marginally raised the
>> stall speed just enough to cause a fatal stall/spin instead of
>> a close call or less-than-fatal injury.
>>
>> Kind of like going to a donut shop and asking for recommendations
>> for dinner. Riggers and sport parachutists have a pretty
>> strong opinion about how important parachutes are...
>>
>> In article om>,
>> > wrote:
>>>180 days would still be at least 185 days too long. The only argument
>>>for sticking with 120 or 180 days is the work that the riggers would
>>>lose.
>>>
>>>I just had my skydiving reserve repacked two months ago. That cost me
>>>$75, and it doesn't look like I'm going to get to use it before it's
>>>due again. It's a scam and I'm sick of it.
>>>
>>>ted/2NO
>>>
>>
>>
>> --
>>
>> ------------+
>> Mark J. Boyd
>
>


--

------------+
Mark J. Boyd

[Mark James Boyd]

A study recently came out about obesity and
fatalities in car crashes. It has made
some national news.

http://apha.confex.com/apha/132am/techprogram/paper_86775.htm

Apparently, people with a higher Body Mass Index (obesity)
have a higher fatality rate than those with a lower BMI.

The research does not rule out the possibility
of co-morbidity (the fatal rate is just caused because
obese people are just more susceptible to death in general).

But it does suggest that part or all of the morbitity may be
attributable to the extra weight during the crash impact,
and the additional momentum the extra weight creates and
strains the body during high velocity crashes.

For example, a person who weighs 200 pounds at a certain
height would have a higher body mass index if they
weighed 220 pounds. No mention is made of whether
wearing an additional 20 pounds on ones back during a crash
would be equivalent to an increased BMI.

The BMI index is calculated by dividing weight in Kg
by the square of the height in meters.

Studies are inconclusive about possible causes of
the obesity-morbidy data. Further research, including
use of crash test dummies of different
BMIs, is planned to follow up this research.

Does having an extra 20 pounds behind you during an
impact of more than 20 Gs cause enough additional
stress to measurably increase the chance of
death in an accident? Or is the link of BMI to
morbidity in this paper based on correlation
to other factors of obesity (high blood pressure,
difficulty during lifesaving procedures, etc.)?
The researchers haven't yet been able to
get enough data to isolate causality, so
we don't know yet.

But the obese crash test dummies should give some
better ideas in future tests. We'll see...
--

------------+
Mark J. Boyd

[Stewart Kissel]

Does having an extra 20 pounds behind you during an
impact of more than 20 Gs cause enough additional
stress to measurably increase the chance of
death in an accident?

As opposed to that 20 pounds of silk over your head
allowing you to float down?

[Eric Greenwell]

Mark James Boyd wrote:

> Does having an extra 20 pounds behind you during an
> impact of more than 20 Gs cause enough additional
> stress to measurably increase the chance of
> death in an accident?

An interesting question. I didn't read the study, but ...

I suspect car crashes don't relate well to glider crashes, because the
structural strength is so different. The structure of the car allows 30G
and more without serious invasion into the driver's compartment, but
gliders probably can't even do 10 G.

"Obese" generally implies overweight of 20%+, and the parachutes I'm
familiar with are 15 pounds or less, so for even a lightweight like
yourself, that's less than 10%.

The pilots I know that survived crashes were mostly injured from the
waist down. Trunk injuries were inconsequential by comparison.

And finally, major trunk injuries in fatal accidents are generally
attributed to "submarining" under the seat belts, though problem is
better controlled in the newer gliders.

I'm sure the weight of the parachute is a liability in a crash, but the
evidence from crashes seems indicate it's a small factor. On the other
hand, I know several people that would be dead except for their parachute.


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

Eric Greenwell
Washington State
USA

[f.blair]

Since I needed mine in 1988 when my Open Cirrus broke into two pieces, I
think having it that day was a very good idea.
I don't consider that a 'minute save'.

Fred

"Mark James Boyd" > wrote in message
news:41ef0ac1$1@darkstar...
> Ted,
>
> Yes, you might be right. The whole idea of having a parachute
> in the glider may just be a bad idea anyway. Sure there are
> a minute number of saves using a parachute, but where are the
> statistics about how many people were killed

[Mark James Boyd]

In article >,
Stewart Kissel > wrote:
>Does having an extra 20 pounds behind you during an
>impact of more than 20 Gs cause enough additional
>stress to measurably increase the chance of
>death in an accident?
>
>As opposed to that 20 pounds of silk over your head
>allowing you to float down?

EXACTLY! If you are more likely to
be in a impact where the extra 20
pounds is the difference between life and death,
than to be in a situation where parachuting is
the only option, then wearing a chute is
something to consider.

So how many chute saves have there been compared
to fatal accidents where the pilot almost
survived? If a 20 pound chute adds 4% to impact morbidity,
and lifesaving use of the chute only happens one time
for every 50 impact crashes, then there are things to
consider.

I'm not talking about situations where wearing or not
wearing seems pretty clear. Competitions, aerobatics, test
flights, formation flight may be
pretty hard to argue. And pattern tows, winch launches
in unsoarable weather seem the same way.

But what about ridge soaring alone on a
day away from MTRs, nobody else around, in a
well established sturdy glider?

I wonder, because I have a parachute, and I tend to
fly in an isolated area, with no MTRs and no
company. And I read Kempton Izuno's stuff about
wearing a chute on a wave day and wondering
about being dragged at 40 knots along the ground
if he bailed.

Sure, if you gotta have it to save your life,
then you got to have it. But for every chute
save, how many impact fatalities have there been?
How many of these had a chute as a contributing
factor because they increase effective BMI?

I don't know the answer. But one part of it comes
from the ratio of bailouts to fatal impacts.
I'd really like to see stats on that...
--

------------+
Mark J. Boyd

[John Galloway]

.. like being better not to wear seat belts in a car
- or have an air bag - because they have been known
to cause injury?

John Galloway

At 23:30 21 January 2005, Mark James Boyd wrote:
>In article ,
>Stewart Kissel wrote:
>>Does having an extra 20 pounds behind you during an
>>impact of more than 20 Gs cause enough additional
>>stress to measurably increase the chance of
>>death in an accident?
>>
>>As opposed to that 20 pounds of silk over your head
>>allowing you to float down?
>
>EXACTLY! If you are more likely to
>be in a impact where the extra 20
>pounds is the difference between life and death,
>than to be in a situation where parachuting is
>the only option, then wearing a chute is
>something to consider.
>
>So how many chute saves have there been compared
>to fatal accidents where the pilot almost
>survived? If a 20 pound chute adds 4% to impact morbidity,
>and lifesaving use of the chute only happens one time
>for every 50 impact crashes, then there are things
>to
>consider.
>
>I'm not talking about situations where wearing or not
>wearing seems pretty clear. Competitions, aerobatics,
>test
>flights, formation flight may be
>pretty hard to argue. And pattern tows, winch launches
>in unsoarable weather seem the same way.
>
>But what about ridge soaring alone on a
>day away from MTRs, nobody else around, in a
>well established sturdy glider?
>
>I wonder, because I have a parachute, and I tend to
>fly in an isolated area, with no MTRs and no
>company. And I read Kempton Izuno's stuff about
>wearing a chute on a wave day and wondering
>about being dragged at 40 knots along the ground
>if he bailed.
>
>Sure, if you gotta have it to save your life,
>then you got to have it. But for every chute
>save, how many impact fatalities have there been?
>How many of these had a chute as a contributing
>factor because they increase effective BMI?
>
>I don't know the answer. But one part of it comes
>from the ratio of bailouts to fatal impacts.
>I'd really like to see stats on that...
>--
>
>------------+
>Mark J. Boyd
>

[Mark James Boyd]

I don't see the parallel here. Pilot parachutes were never
intended to reduce injury during a glider impact with terrain.
Parachute presence during such an impact certainly
doesn't DECREASE injury. Rather we are discussing whether
the increase in impact injuries is so small, or
negligible, as to be overcome by the benefit of wearing
parachutes for situations where they are a benefit.

In article >,
John Galloway > wrote:
>. like being better not to wear seat belts in a car
>- or have an air bag - because they have been known
>to cause injury?
>
>John Galloway
>
>At 23:30 21 January 2005, Mark James Boyd wrote:
>>In article ,
>>Stewart Kissel wrote:
>>>Does having an extra 20 pounds behind you during an
>>>impact of more than 20 Gs cause enough additional
>>>stress to measurably increase the chance of
>>>death in an accident?
>>>
>>>As opposed to that 20 pounds of silk over your head
>>>allowing you to float down?
>>
>>EXACTLY! If you are more likely to
>>be in a impact where the extra 20
>>pounds is the difference between life and death,
>>than to be in a situation where parachuting is
>>the only option, then wearing a chute is
>>something to consider.
>>
>>So how many chute saves have there been compared
>>to fatal accidents where the pilot almost
>>survived? If a 20 pound chute adds 4% to impact morbidity,
>>and lifesaving use of the chute only happens one time
>>for every 50 impact crashes, then there are things
>>to
>>consider.
>>
>>I'm not talking about situations where wearing or not
>>wearing seems pretty clear. Competitions, aerobatics,
>>test
>>flights, formation flight may be
>>pretty hard to argue. And pattern tows, winch launches
>>in unsoarable weather seem the same way.
>>
>>But what about ridge soaring alone on a
>>day away from MTRs, nobody else around, in a
>>well established sturdy glider?
>>
>>I wonder, because I have a parachute, and I tend to
>>fly in an isolated area, with no MTRs and no
>>company. And I read Kempton Izuno's stuff about
>>wearing a chute on a wave day and wondering
>>about being dragged at 40 knots along the ground
>>if he bailed.
>>
>>Sure, if you gotta have it to save your life,
>>then you got to have it. But for every chute
>>save, how many impact fatalities have there been?
>>How many of these had a chute as a contributing
>>factor because they increase effective BMI?
>>
>>I don't know the answer. But one part of it comes
>>from the ratio of bailouts to fatal impacts.
>>I'd really like to see stats on that...
>>--
>>
>>------------+
>>Mark J. Boyd
>>
>
>


--

------------+
Mark J. Boyd

[John Galloway]

Mark,

>'Rather we are discussing whether
>the increase in impact injuries is so small, or
>negligible, as to be overcome by the benefit of wearing
>
>parachutes for situations where they are a benefit'

When you said that it was precisely the parallel.
The number of motor accidents of a type where the
seat belt or airbag causes more injury than they prevent
is dwarfed by the number in which they save injury
- and I would be totally amazed if the same were not
true for parachutes in gliders.

Apart from anything else far more glider impacts are
closer to the line of the pilot's back than at right
angles to it. That's why the cockpit crash tests
are done in roughly that direction and why submarining
is a major issue.

I think this is your parallel to my recent String Theory:-)

John



At 08:00 22 January 2005, Mark James Boyd wrote:
>I don't see the parallel here. Pilot parachutes were
>never
>intended to reduce injury during a glider impact with
>terrain.
>Parachute presence during such an impact certainly
>doesn't DECREASE injury. Rather we are discussing
>whether
>the increase in impact injuries is so small, or
>negligible, as to be overcome by the benefit of wearing
>
>parachutes for situations where they are a benefit.
>
>
>In article ,
>John Galloway wrote:
>>. like being better not to wear seat belts in a car
>>- or have an air bag - because they have been known
>>to cause injury?
>>
>>John Galloway
>>
>>At 23:30 21 January 2005, Mark James Boyd wrote:
>>>In article ,
>>>Stewart Kissel wrote:
>>>>Does having an extra 20 pounds behind you during an
>>>>impact of more than 20 Gs cause enough additional
>>>>stress to measurably increase the chance of
>>>>death in an accident?
>>>>
>>>>As opposed to that 20 pounds of silk over your head
>>>>allowing you to float down?
>>>
>>>EXACTLY! If you are more likely to
>>>be in a impact where the extra 20
>>>pounds is the difference between life and death,
>>>than to be in a situation where parachuting is
>>>the only option, then wearing a chute is
>>>something to consider.
>>>
>>>So how many chute saves have there been compared
>>>to fatal accidents where the pilot almost
>>>survived? If a 20 pound chute adds 4% to impact morbidity,
>>>and lifesaving use of the chute only happens one time
>>>for every 50 impact crashes, then there are things
>>>to
>>>consider.
>>>
>>>I'm not talking about situations where wearing or not
>>>wearing seems pretty clear. Competitions, aerobatics,
>>>test
>>>flights, formation flight may be
>>>pretty hard to argue. And pattern tows, winch launches
>>>in unsoarable weather seem the same way.
>>>
>>>But what about ridge soaring alone on a
>>>day away from MTRs, nobody else around, in a
>>>well established sturdy glider?
>>>
>>>I wonder, because I have a parachute, and I tend to
>>>fly in an isolated area, with no MTRs and no
>>>company. And I read Kempton Izuno's stuff about
>>>wearing a chute on a wave day and wondering
>>>about being dragged at 40 knots along the ground
>>>if he bailed.
>>>
>>>Sure, if you gotta have it to save your life,
>>>then you got to have it. But for every chute
>>>save, how many impact fatalities have there been?
>>>How many of these had a chute as a contributing
>>>factor because they increase effective BMI?
>>>
>>>I don't know the answer. But one part of it comes
>>>from the ratio of bailouts to fatal impacts.
>>>I'd really like to see stats on that...
>>>--
>>>
>>>------------+
>>>Mark J. Boyd
>>>
>>
>>
>
>
>--
>
>------------+
>Mark J. Boyd
>

[Bert Willing]

That's one of the most stupid argument against parachutes I ever heared...

--
Bert Willing

ASW20 "TW"


"Mark James Boyd" > a écrit dans le message de news:
41f186bd$1@darkstar...
> In article >,
> Stewart Kissel > wrote:
>>Does having an extra 20 pounds behind you during an
>>impact of more than 20 Gs cause enough additional
>>stress to measurably increase the chance of
>>death in an accident?
>>
>>As opposed to that 20 pounds of silk over your head
>>allowing you to float down?
>
> EXACTLY! If you are more likely to
> be in a impact where the extra 20
> pounds is the difference between life and death,
> than to be in a situation where parachuting is
> the only option, then wearing a chute is
> something to consider.
>
> So how many chute saves have there been compared
> to fatal accidents where the pilot almost
> survived? If a 20 pound chute adds 4% to impact morbidity,
> and lifesaving use of the chute only happens one time
> for every 50 impact crashes, then there are things to
> consider.
>
> I'm not talking about situations where wearing or not
> wearing seems pretty clear. Competitions, aerobatics, test
> flights, formation flight may be
> pretty hard to argue. And pattern tows, winch launches
> in unsoarable weather seem the same way.
>
> But what about ridge soaring alone on a
> day away from MTRs, nobody else around, in a
> well established sturdy glider?
>
> I wonder, because I have a parachute, and I tend to
> fly in an isolated area, with no MTRs and no
> company. And I read Kempton Izuno's stuff about
> wearing a chute on a wave day and wondering
> about being dragged at 40 knots along the ground
> if he bailed.
>
> Sure, if you gotta have it to save your life,
> then you got to have it. But for every chute
> save, how many impact fatalities have there been?
> How many of these had a chute as a contributing
> factor because they increase effective BMI?
>
> I don't know the answer. But one part of it comes
> from the ratio of bailouts to fatal impacts.
> I'd really like to see stats on that...
> --
>
> ------------+
> Mark J. Boyd

[John Galloway]

Just for the interest of those who are not aware of
the work of English pilot, Dr Tony Segal, on glider
pilot fatalities and injuries - there is a series of
6 very detailed articles written by him on the basis
of his research in the Gliding Magazine archive starting
here:

http://www.glidermagazine.com/FeatureArticle.asp?id=68

This series is well worth revisiting. Statistically,
spinal injuries from downward impacts are the main
concern for we (aging) glider pilots.

He is still the man to ask and is presenting a lecture
on the subject in a couple of weeks at Boscombe Down:

http://www.raes.org.uk/raes/divisionsandbranches/branch.asp?sessid
=&branch=12

John Galloway

[Mark James Boyd]

So from the broader perspective of whether a "safety" device
contributes to safety ultimately or reduces it, yes, I
see there is a parallel. I was thinking you were drawing
a parallel in another way, which you weren't.

From reviewing the articles, and what you and Eric said, I
think the combined ideas are that:

1) The spinal compression axis is far more of a factor than
the forward momentum.

2) Parachute weight doesn't increase compression
noticably along the spinal axis (parachute weight doesn't
contribute to submarining significantly).

3) During the impact along that axis, the paracute weight
forces are borne almost entirely by the seat frame under it
rather than by the pilot.

So based on this, the extra weight of a parachute has
perhaps some effect, but this effect is negligible
in sailplane terrain impact accidents.

The key difference here is how the weight causes effects
differently in a car vs. a sailplane. The semi-reclined
sailplane seat position is significantly different than
in most automobiles.

Does this sum up what you all seem to have said?
Is there anything else I missed?

In article >,
John Galloway > wrote:
>Mark,
>
>>'Rather we are discussing whether
>>the increase in impact injuries is so small, or
>>negligible, as to be overcome by the benefit of wearing
>>
>>parachutes for situations where they are a benefit'
>
>When you said that it was precisely the parallel.
>The number of motor accidents of a type where the
>seat belt or airbag causes more injury than they prevent
>is dwarfed by the number in which they save injury
>- and I would be totally amazed if the same were not
>true for parachutes in gliders.
>
>Apart from anything else far more glider impacts are
>closer to the line of the pilot's back than at right
>angles to it. That's why the cockpit crash tests
>are done in roughly that direction and why submarining
>is a major issue.
>
>I think this is your parallel to my recent String Theory:-)
>
>John
>
>
>
>At 08:00 22 January 2005, Mark James Boyd wrote:
>>I don't see the parallel here. Pilot parachutes were
>>never
>>intended to reduce injury during a glider impact with
>>terrain.
>>Parachute presence during such an impact certainly
>>doesn't DECREASE injury. Rather we are discussing
>>whether
>>the increase in impact injuries is so small, or
>>negligible, as to be overcome by the benefit of wearing
>>
>>parachutes for situations where they are a benefit.
>>
>>
>>In article ,
>>John Galloway wrote:
>>>. like being better not to wear seat belts in a car
>>>- or have an air bag - because they have been known
>>>to cause injury?
>>>
>>>John Galloway
>>>
>>>At 23:30 21 January 2005, Mark James Boyd wrote:
>>>>In article ,
>>>>Stewart Kissel wrote:
>>>>>Does having an extra 20 pounds behind you during an
>>>>>impact of more than 20 Gs cause enough additional
>>>>>stress to measurably increase the chance of
>>>>>death in an accident?
>>>>>
>>>>>As opposed to that 20 pounds of silk over your head
>>>>>allowing you to float down?
>>>>
>>>>EXACTLY! If you are more likely to
>>>>be in a impact where the extra 20
>>>>pounds is the difference between life and death,
>>>>than to be in a situation where parachuting is
>>>>the only option, then wearing a chute is
>>>>something to consider.
>>>>
>>>>So how many chute saves have there been compared
>>>>to fatal accidents where the pilot almost
>>>>survived? If a 20 pound chute adds 4% to impact morbidity,
>>>>and lifesaving use of the chute only happens one time
>>>>for every 50 impact crashes, then there are things
>>>>to
>>>>consider.
>>>>
>>>>I'm not talking about situations where wearing or not
>>>>wearing seems pretty clear. Competitions, aerobatics,
>>>>test
>>>>flights, formation flight may be
>>>>pretty hard to argue. And pattern tows, winch launches
>>>>in unsoarable weather seem the same way.
>>>>
>>>>But what about ridge soaring alone on a
>>>>day away from MTRs, nobody else around, in a
>>>>well established sturdy glider?
>>>>
>>>>I wonder, because I have a parachute, and I tend to
>>>>fly in an isolated area, with no MTRs and no
>>>>company. And I read Kempton Izuno's stuff about
>>>>wearing a chute on a wave day and wondering
>>>>about being dragged at 40 knots along the ground
>>>>if he bailed.
>>>>
>>>>Sure, if you gotta have it to save your life,
>>>>then you got to have it. But for every chute
>>>>save, how many impact fatalities have there been?
>>>>How many of these had a chute as a contributing
>>>>factor because they increase effective BMI?
>>>>
>>>>I don't know the answer. But one part of it comes
>>>>from the ratio of bailouts to fatal impacts.
>>>>I'd really like to see stats on that...
>>>>--
>>>>
>>>>------------+
>>>>Mark J. Boyd
>>>>
>>>
>>>
>>
>>
>>--
>>
>>------------+
>>Mark J. Boyd
>>
>
>


--

------------+
Mark J. Boyd

[Eric Greenwell]

Mark James Boyd wrote:
> So from the broader perspective of whether a "safety" device
> contributes to safety ultimately or reduces it, yes, I
> see there is a parallel. I was thinking you were drawing
> a parallel in another way, which you weren't.
>
> From reviewing the articles, and what you and Eric said, I
> think the combined ideas are that:
>
> 1) The spinal compression axis is far more of a factor than
> the forward momentum.
>
> 2) Parachute weight doesn't increase compression
> noticably along the spinal axis (parachute weight doesn't
> contribute to submarining significantly).
>
> 3) During the impact along that axis, the paracute weight
> forces are borne almost entirely by the seat frame under it
> rather than by the pilot.
>
> So based on this, the extra weight of a parachute has
> perhaps some effect, but this effect is negligible
> in sailplane terrain impact accidents.
>
> The key difference here is how the weight causes effects
> differently in a car vs. a sailplane. The semi-reclined
> sailplane seat position is significantly different than
> in most automobiles.
>
> Does this sum up what you all seem to have said?
> Is there anything else I missed?

It does for me.


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

Eric Greenwell
Washington State
USA

[John Galloway]

Mark,

Sorry for the slow reply. Yes - that seems to be a
fair summary.

John

At 05:00 23 January 2005, Mark James Boyd wrote:
>So from the broader perspective of whether a 'safety'
>device
>contributes to safety ultimately or reduces it, yes,
>I
>see there is a parallel. I was thinking you were drawing
>a parallel in another way, which you weren't.
>
>From reviewing the articles, and what you and Eric
>said, I
>think the combined ideas are that:
>
>1) The spinal compression axis is far more of a factor
>than
>the forward momentum.
>
>2) Parachute weight doesn't increase compression
>noticably along the spinal axis (parachute weight doesn't
>
>contribute to submarining significantly).
>
>3) During the impact along that axis, the paracute
>weight
>forces are borne almost entirely by the seat frame
>under it
>rather than by the pilot.
>
>So based on this, the extra weight of a parachute has
>perhaps some effect, but this effect is negligible
>in sailplane terrain impact accidents.
>
>The key difference here is how the weight causes effects
>differently in a car vs. a sailplane. The semi-reclined
>sailplane seat position is significantly different
>than
>in most automobiles.
>
>Does this sum up what you all seem to have said?
>Is there anything else I missed?
>
>In article ,
>John Galloway wrote:
>>Mark,
>>
>>>'Rather we are discussing whether
>>>the increase in impact injuries is so small, or
>>>negligible, as to be overcome by the benefit of wearing
>>>
>>>parachutes for situations where they are a benefit'
>>
>>When you said that it was precisely the parallel.
>>The number of motor accidents of a type where the
>>seat belt or airbag causes more injury than they prevent
>>is dwarfed by the number in which they save injury
>>- and I would be totally amazed if the same were not
>>true for parachutes in gliders.
>>
>>Apart from anything else far more glider impacts are
>>closer to the line of the pilot's back than at right
>>angles to it. That's why the cockpit crash tests
>>are done in roughly that direction and why submarining
>>is a major issue.
>>
>>I think this is your parallel to my recent String Theory:-)
>>
>>John
>>
>>
>>
>>At 08:00 22 January 2005, Mark James Boyd wrote:
>>>I don't see the parallel here. Pilot parachutes were
>>>never
>>>intended to reduce injury during a glider impact with
>>>terrain.
>>>Parachute presence during such an impact certainly
>>>doesn't DECREASE injury. Rather we are discussing
>>>whether
>>>the increase in impact injuries is so small, or
>>>negligible, as to be overcome by the benefit of wearing
>>>
>>>parachutes for situations where they are a benefit.
>>>
>>>
>>>In article ,
>>>John Galloway wrote:
>>>>. like being better not to wear seat belts in a car
>>>>- or have an air bag - because they have been known
>>>>to cause injury?
>>>>
>>>>John Galloway
>>>>
>>>>At 23:30 21 January 2005, Mark James Boyd wrote:
>>>>>In article ,
>>>>>Stewart Kissel wrote:
>>>>>>Does having an extra 20 pounds behind you during
>>>>>>an
>>>>>>impact of more than 20 Gs cause enough additional
>>>>>>
>>>>>>stress to measurably increase the chance of
>>>>>>death in an accident?
>>>>>>
>>>>>>As opposed to that 20 pounds of silk over your
>>>>>>head
>>>>>>allowing you to float down?
>>>>>
>>>>>EXACTLY! If you are more likely to
>>>>>be in a impact where the extra 20
>>>>>pounds is the difference between life and death,
>>>>>than to be in a situation where parachuting is
>>>>>the only option, then wearing a chute is
>>>>>something to consider.
>>>>>
>>>>>So how many chute saves have there been compared
>>>>>to fatal accidents where the pilot almost
>>>>>survived? If a 20 pound chute adds 4% to impact morbidity,
>>>>>and lifesaving use of the chute only happens one time
>>>>>for every 50 impact crashes, then there are things
>>>>>to
>>>>>consider.
>>>>>
>>>>>I'm not talking about situations where wearing or not
>>>>>wearing seems pretty clear. Competitions, aerobatics,
>>>>>test
>>>>>flights, formation flight may be
>>>>>pretty hard to argue. And pattern tows, winch launches
>>>>>in unsoarable weather seem the same way.
>>>>>
>>>>>But what about ridge soaring alone on a
>>>>>day away from MTRs, nobody else around, in a
>>>>>well established sturdy glider?
>>>>>
>>>>>I wonder, because I have a parachute, and I tend to
>>>>>fly in an isolated area, with no MTRs and no
>>>>>company. And I read Kempton Izuno's stuff about
>>>>>wearing a chute on a wave day and wondering
>>>>>about being dragged at 40 knots along the ground
>>>>>if he bailed.
>>>>>
>>>>>Sure, if you gotta have it to save your life,
>>>>>then you got to have it. But for every chute
>>>>>save, how many impact fatalities have there been?
>>>>>How many of these had a chute as a contributing
>>>>>factor because they increase effective BMI?
>>>>>
>>>>>I don't know the answer. But one part of it comes
>>>>>from the ratio of bailouts to fatal impacts.
>>>>>I'd really like to see stats on that...
>>>>>--
>>>>>
>>>>>------------+
>>>>>Mark J. Boyd
>>>>>
>>>>
>>>>
>>>
>>>
>>>--
>>>
>>>------------+
>>>Mark J. Boyd
>>>
>>
>>
>
>
>--
>
>------------+
>Mark J. Boyd
>