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Path: utzoo!linus!decvax!decwrl!Glacier!oliveb!hplabs!hp-pcd!kas
From: kas@hp-pcd.UUCP (kas)
Newsgroups: net.rec.skydive
Subject: Re: Jumpmaster assisted deployment
Message-ID: <41800044@hpcvlo.UUCP>
Date: Thu, 10-Oct-85 15:06:00 EDT
Article-I.D.: hpcvlo.41800044
Posted: Thu Oct 10 15:06:00 1985
Date-Received: Tue, 15-Oct-85 06:20:50 EDT
References: <571@wjvax.UUCP>
Organization: Hewlett-Packard - Corvallis, OR
Lines: 65
Nf-ID: #R:wjvax:-57100:hpcvlo:41800044:000:3791
Nf-From: hpcvlo!kas    Oct 10 11:06:00 1985



>	DEPLOYMENT TEST ENDED

>	     The Palatka Parachute Center in Forida terminated its
>	experiment with jumpmaster assisted deployments for student
>	jumpers recently after a student trapped a pilot chute and
>	held it until the automatic activation device deployed at
>	about 1,000 feet.  DZ owner/operator Don Yahrling had been
>	conducting the program under a waiver to the Basic Safety
>	Regulations from the USPA Safety and Training Committee.
>	     The jumpmaster assist method involves the jumpmaster
>	extracting the student's hand-deploy pilot chute before
>	climb-out and deploying it immediately after exit.  The
>	method is especially popular in Canada but is employed at
>	very few U.S. DZs.

     Ever since this subject got started, I've had a few nervous thoughts
about it.  The above article has justified my fears.  While no mechanical
system can ever be made 100% fail-proof, I've always thought that static
lines came pretty close, in terms of positive deployment.  Granted, the
static line system as a whole has other undesirable traits, and for this
reason I'm a strong believer in the AFF system.  But quite frankly, I don't
consider the jumpmaster assisted deployment to be an improvement over static
lines.
     An additional problem that I predict will occur (if it hasn't already),
is the pilot chute snagging on some portion of the aircrafts' anatomy, such
as a tail wheel.  If the jumpmaster releases his grip before there is a
sufficient load on the bridle line, that pilot chute is going to get whipped
by the prop-blast straight back into the tail feathers of the airplane.  I
once saw this happen when a static line broke loose prematurely, and the 
apex of the canopy snagged the tail wheel.  Fortunately, the jumper-in-tow
(a first time jumper, no less), had the presence of mind to execute a cut-
away and deploy his reserve.  If he had panicked and dumped his reserve
first, the results would have been catastrophic.  The easy cure for this
problem was to use a stronger tie cord on the end of the static line.  There
is no easy fool-proof cure for the jumpmaster assist method.
     Another potential problem might be accidental release of the pilot
chute in the aircraft, the results of which we're all too familiar with.
This can't happen with static lines.
     I can understand the desire of both students and instructors who want
to use "state of the art" equipment, rather than old military surplus gear.
It eliminates the uncertainty of transitioning from one type of gear to
another.  The advantage to the jumpmaster assist method is that the student
uses the same rig (or one just like it) for his first jump as well as his
first freefall.  I propose that this can still be accomplished by removing
the pilot chute and attaching a static line for the first few jumps, and
then replacing the pilot chute when it's time for the first freefall. 
Attaching a pilot chute is a 30-second job for a rigger who knows how to
do it, so it's no big hassle.  The bridle and/or static line can be secured
with rubber bands or velcro loops to provide enough resistance to prevent
premature pack opening until the jumper is safely below the aircraft.  Thus,
with proper rigging, all the problems mentioned above are eliminated, and
the advantage of positive deployment is gained.
     So, all you jumpers/jumpmasters/instructors/riggers out there who are
using the jumpmaster assist method, what do you think?  Have I overlooked
some major issues?  If not, consider making, or recommending, the changes.

             *
            / \
       |---/---\---|            Ken Scofield    C-9355
       |   Gone    |            Hewlett-Packard PCD
       |  Jumpin'  |            Corvallis, OR
       |-----------|
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