Rob Kells & Steve Pearson
The following article is taken from
an outline we use to do parachute seminars. It is written with the hope
that you will take this information and put it to use in your flying, to
increase your flight safety. This is not about how to repack your parachute.
We suggest that you leave the packing to someone who does it often. Over
the last seven years we have done 25 parachute seminars, and repacked more
than eight hundred parachutes. Over 50% of the systems in the early seminars
were improperly maintained and 10% of these parachutes would not have deployed
under any circumstance! These statistics have improved dramatically over
the years as pilots come back to service their equipment year after year.If
you have not attended a formal parachute seminar we suggest that you do
Our thanks go to Vincene
Muller for badgering us into writing the original article and
to Sherry Thevano for pestering us to update the material. Aviation has
made the world much smaller but it is still hard to miss it if you fall!
Parachute Deployment Sequence
After you are under canopy, stand in
the control bar (if you can find it), or climb to the highest point in
the glider. Let the structure of the glider take as much of the landing
impact as possible. Sometimes, it is possible to direct the descent with
weight shift. Try to steer away from ground obstacles and land into the
for the handle, GRASP the handle,
the deployment bag from the container (with most systems a down-and-out
at about 45 degrees works best),
for clear air,
clear air and into the direction of the spin,
the bridle (reach back to your main support strap to locate it) to clear
the chute from the container and accelerate the deployment sequence.
If the parachute is not open, pull
it back and repeat the throw.
In a paraglider after the deployment
you want to try to fly the glider up to meet the reserve or if you are
unable to do that pull continuously on brake line until you have the canopy
in your hands to avoid downplanning.
If your glider is falling at 60 mph,
(88 feet per second), three seconds is 264 feet; if you take ten seconds
the distance will be 880 feet.
Also, when a glider structurally
fails, it often spins at such a high rate that the pilot is unable to maintain
any visual reference with either the terrain or the broken structure. The
successful execution of the deployment sequence under adverse conditions
will depend on your level of preparation. Do not practice in air deployments!
They can be very dangerous.
is no substitute for repeatedly practicing this procedure in a simulator.
Further, you should grasp the handle
and mentally rehearse the deployment sequence while flying. During parachute
seminars, we time practice deployments in a simulator. Deployment times
range from three to ten seconds. The deployment times have gotten faster
over the years of repeated seminars through practice.
Equipment Selection and Care
This information should not be used
as a guide for repacking parachutes. Regular repacking should be performed
by someone who is both experienced and professionally trained and qualified.
Your parachute is only one part of your safety system. As with any system,
reliability is only as good as the weakest link.
All properly built harnesses are
strong enough to withstand the opening shock of a normal parachute deployment
if they are properly maintained. Most harnesses are not designed to withstand
the opening shock of a hang glider reserve from terminal free fall velocity.
To withstand higher loads and adverse loading conditions - like head down-
the shoulder straps, leg loops and back strap should be joined by a primary
structural reinforcement to the main support straps. If you are interested
in a technical reference on conventional skydiving equipment and parachutes,
Parachute Manual - by Dan Poynter, available from
PO Box 8206-240, Santa Barbara, CA 93118-8206 USA
Several years ago a pilot's aluminum
carabiner failed while he was hooking in for flight! Aluminum Carabiners
are typically rated at 1800 to 2800 kilos (4,000 to 6,000 pounds) ultimate
strength when new, but are susceptible to fatigue from nicks and scratches.
Most steel Carabiners are rated at about 5000 kilos (11,000 lbs.) and are
much more durable. We do not know of any failures of high quality alloy
steel Carabiners, but we suggest that you replace even a steel carabiner
after 3 to 5 years of regular service.
As an extra safety measure, use a
quick link to connect your parachute bridle to your harness main supports
straps. If your carabiner failed, you would retain a secondary link to
your parachute. Also, verify that the locking gate of the carabiner faces
forward when hooking into the glider and that the parachute bridle is on
the back side of the carabiner. This procedure will prevent the parachute
bridle from opening the carabiner gate and disconnecting from the harness
Hang glider harnesses, sails, and parachutes
are constructed primarily of nylon, polyester, Kevlar and/or Spectra. All
of these materials deteriorate with exposure to sunlight. Sunlight is by
far the greatest factor in the decay and depreciation of your equipment.
The rate of deterioration depends on many factors: the type of material,
the finish or coating applied to the yarn fibers, the thickness of the
material and of course, the intensity of the radiation. A lightweight parachute
canopy material will typically loose 50% of its strength after one week
of continuous exposure to sunlight. Fluorescent pigments fade as much as
ten times faster than more stable colors such as dark blue or black. UV
deteriorated stitching in webbing support straps and hang loops may fail
long before webbing becomes unserviceable. You can minimize the adverse
effects of exposure by not setting up until you are prepared to fly and
stowing your glider and equipment in their protective cover bags promptly
after landing. If you fly regularly, and your equipment sees a lot of UV,
have any suspect items inspected by your dealer or the manufacturer. Hang
Glider sails typically have a useful life of between 250 and 750 hours
or more of air time, depending on materials and construction, if they are
properly cared for and maintained.
Paragliders, depending on the fabric
are good for roughly half that long.
Most older parachutes were constructed
with 1 inch tubular nylon bridles. If properly sewn, these bridles have
an ultimate strength of approximately 4,000 lbs., however there are four
documented incidents of successful parachute deployments which subsequently
had a tubular bridle severed by hardware or cables on the glider. Today's
standard bridle is 1 inch flat webbing, usually Type 18 or Type 24 with
an ultimate strength of approximately 2800 kilos (6,000 lbs.). This webbing
style is much less likely to be cut by hardware. The minimum bridle length
for hang gliders should be 25 feet to reduce the likelihood parachute entanglement
with the glider.
Paraglider bridals are typically Five
feet in length and require a structural attachment to the harness that
will bring the pilot down feet first.
Finally, a protective sheath on the
exposed portion of your bridle will reduce wear and tear and UV deterioration.
A sheath is particularly important on Kevlar bridles which are thinner
and loose strength at a much faster rate.
Standard conical parachutes were
the most common configuration used for hang glider reserves in past years.
A variation of the conical configuration is the "Pulled Down Apex". These
designs have a short center line attached to the apex of the canopy to
increase the inflated diameter. PDAs can be made smaller in weight and
bulk without sacrificing decent rate. Since deployment time is a function
of size, PDAs usually open faster. Unfortunately, opening shock is a function
of opening time, so faster opening chutes open harder. When Wills Wing
first tested a PDA design in 1981, the opening load from a deployment at
120 mph with a 300 lb. dummy failed the skydiving test harness. At lower
speeds typical of most hang glider and paraglider deployments, this shock
would be significantly lower, but we recommend that you do not combine
the PDA design with an inelastic Kevlar bridle. A further concern with
PDAs is sensitivity to design and tuning parameters. A rigorous drop test
program is essential for development of a stable, low sink rate, structurally
reliable design. If for example the apex is pulled down too far the canopy
will become unstable and osculate. Some very early parachutes were manufactured
with only 10 lines compared to the twenty or more lines on most designs.
These early chutes should be either refitted with 20 lines by a certified
parachute shop or replaced with a more air worthy design. Also, most modern
canopies use "vtab" reinforcements at the line / skirt junction and additional
panel reinforcement. Most chutes can be upgraded to this configuration
if desired. Any chute which has been exposed to excessive heat or caustic/acidic
liquids should be inspected by a qualified rigger or the manufacturer.
Damaged panels can be repaired or replaced for a nominal charge.
It is very important to realize that
all parachute are not created equal! Different makes of canopies with the
same numbers of gores (panels that make up the parachute) can vary in sink
rate performance by more than fifty percent! Free Flight Enterprises has
discontinued production of the 18 Gore PDA. We feel that too many pilots
are choosing size based on cost and weight, rather than margin of safety.
Many heavy pilots, flying in adverse conditions, have purchased them for
the reasons cited above. A pilot under 150 pounds body weight is within
the recommended weight range of an 18 gore only at low density altitudes
(although there have been many saves with more weight).
Wills Wing and Free Flight have chosen
the conservative path and recommend larger reserves. below is a table that
will allow you to compare the relative sink rate verses test weight data.
||Max Pilot Wt
|20 GORE PDA
||238 Sq. Feet
|22 GORE PDA
||302 Sq. Feet
|24 GORE PDA
||336 Sq. Feet
All modern hand deploy systems are
packed in a bag or diaper to help clear the canopy and lines to the perimeter
of the glider before the opening sequence initiates. Most malfunctions
that we have observed during practice deployments at parachute seminars
are related to poor deployment bag design and/or lack of maintenance (the
rubber bands are brittle or even broken). If your deployment system relies
on rubber bands, they should be replaced at least once every six months;
more often if you live in a hot climate. You must use the recommended size
and type of bands for the bag to function properly. Wills Wing/Free Flight
containers include a separate pocket for protecting and stowing lines,
which also reduces the likelihood of deployment problems normally encountered
with poorly maintained deployment systems.
An accidental parachute deployment
is a very dangerous occurrence. A pin lock system is the most effective
mechanism for preventing an unintentional deployment without compromising
your ability to execute a normal deployment sequence. If you do not have
a pin lock system, have one installed before your next flight. You must
use the proper pins, which are characterized by a curved finger lock and
continuous eye assembly. Cotter pins can jam and effectively make deployment
BALLISTIC AND MECHANICALLY DEPLOYED
Five types of mechanically deployed
parachute systems have been marketed to pilots:
- Rocket deployed systems offer
the best performance and are the only ballistic systems suitable (and currently
marketed) for hang glider pilots. Deployment is very fast without recoil.
Both rocket and parachute are mounted on the harness. Some configurations
have an optional hand deployment sequence in case of mechanical failure,
however this option may compromise the reliability of the primary deployment
Rocket systems have many saves to their
credit, some which probably would have been unsuccessful with hand deployments.
Still, there are significant safety concerns beyond those associated with
hand deploy systems. Proper installation and maintenance is more critical
to reliable performance. Improperly installed rocket systems may be impossible
to activate, or worse, may injure the pilot or bystanders within range
of the rocket. Many pilots opt for an independent dual parachute system-one
rocket and one hand deploy. A dual system also provides an additional margin
of safety in case of parachute entanglement, at the expense of increased
weight and expense.
Spring activated systems deploy
a pilot chute which pulls the main chute out of the container. These systems
have at least two disadvantages: slow deployment (like hand systems) and
remote mounting. Like any remote mounted system, there is a danger that
the glider wreckage could interfere with deployment. Finally, these systems
are bulky and often are mounted on the rear keel which adds to the weight
of the glider and makes it staticly tail heavy. We recommend that you do
not use this type of system.
Projectile systems fire a heavy
slug with a powder charge. The kinetic energy of the slug pulls the parachute
to full line extension. Full deployment is achieved in less than 1.5 seconds.
The advantage of this system is speed; the disadvantages are the high recoil
impulse of the charge, remote mounting, mechanical dependence. These systems
are most suitable to powered ultralight applications which can provide
a suitable mounting structure. We recommend that you do not use this type
Mortar systems use a powder charge
to fire a pressure packed canopy out of a tube like a cannon ball. This
system is also very fast. It has the same disadvantages as a projectile
system: high recoil, remote mounting and mechanical temperament. We recommend
that you do not use this type of system. The energy of projectile, mortar
and rocket systems allow them to deploy through some of the obstructions
presented by a broken glider, which is an advantage over hand deployed
NEW HARNESS INITIAL INSPECTION
The following inspection should
be performed before each and every flight. A thorough harness preflight
is equally as important as a glider preflight. Once familiar with the procedure,
it takes only a few moments.
Inspect the seams on the main suspension
straps and the 3" webbing loops that secure the straps to the harness body,
Inspect the seams on the leg straps,
both sides. If your harness is equipped with adjustable leg loops, check
the folded stop at the end of the loop to make sure it is securely sewn
and will prevent the webbing from slipping through the buckle in the full
Inspect the seams on the shoulder straps
and the webbing loops for the forward support lines to your shoulder and
chest area, both sides. Check the adjustment of the shoulder straps and
lock them as shown in the harness adjustment procedure.
Inspect all other seams; look for any
missed stitching on webbing junctions.
Inspect the carabiner. Nicks and scratches
are stress risers and may cause premature fatigue induced failure.
Inspect all lines to make sure they
are properly routed and securely tied and safetied. The shoulder straps
are secured with a bowline knot , the knee and chest support using a half
hitch with safety. Note that the tail end of the line terminates inside
of the large loop before the overhand safety is tied.
Inspect all the webbing and parapac
for material flaws, cuts or wear.
Check that your parachute is secure
in the container and that the safety lock system is properly installed.
Check the function and adjustment of
the main harness buckles located on the side of the parachute container
Proceed to the appropriate harness adjustment
Bounce up and down in the harness to
test that the parachute container Velcro and safety lock system is secure
and properly installed. A standard Wills Wing container will accommodate
a 20 gore Free Flight parachute. Larger parachutes may require a custom
container. The parachute bridle should be taped or velcroed to the main
support strap to stop it from fluttering in the wind and make it less likely
to tangle. A force of not more than 20 lbs should release the bridle from
any such securing mechanism.
GENERAL HARNESS MAINTENANCE
Leave Your Equipment In The Sun
Ultraviolet light is very harmful
to nylon and polyester materials. For more information, read the section
Ultraviolet Deterioration later in this manual
Your Harness To Extreme Heat
The bed of a pick-up truck or
the trunk of a car may get excessively hot due to the routing of the exhaust
system. Heat is particularly damaging to parachutes.
Acids, gasoline and other solvents may degrade
the structural material in your harness. Do not use harsh detergent or
cleaning agents on your harness. Wash with plain water, using a sponge
or soft brush and a mild detergent applied locally to spots and stains.
Replace it if it is nicked, deeply scratched
or if the locking gate does not function properly. Do not clip your carabiner
into any glider tether point that does not provide a completely free unrestricted
pivot. Torsion or bending loads will significantly reduce its strength.
PREFLIGHT PRECAUTIONS AND SUGGESTIONS
BEFORE EVERY FLIGHT
Perform a complete pre-flight inspection
of your harness. Check for excessive wear. Inspect all knots. Hang check
to make sure the lines are properly routed, your parachute is secure and
that your harness is properly clipped into the glider. Make sure that your
legs are in the leg loops. If for any reason you unclip before flight,
take the time to do another hang check. Taking off unclipped or with an
undetected harness or suspension problem is one of the most frequent and
most dangerous errors made by experienced pilots.
An important part of new harness
orientation is determining the proper hang height above the control bar
base tube. The lower you hang, the more authority you will have in weight
shift control. If you are accustomed to hanging high above the base tube
and you decide to lower your hang position, you may feel a little uncomfortable
at first. For most pilots, the transition takes about 10 hours. Make sure
that your parachute doesn't touch the base tube. Leave at least one inch
of clearance to provide for suspension stretch in accelerated maneuvers.
Practice entry and exit procedures in a simulator, with storage containers
loaded, before your first flight. Familiarize yourself with the emergency
egress system which is usually located adjacent to the zipper, below the
parachute container. On most harnesses a hard lateral pull on the handle
will peel open the Velcro in the event of a zipper jam on landing approach.
Exercise extreme caution when flying
over water or landing in a restricted beach area. If you land in the water,
unhook from the glider and hold the carabiner in your hand to prevent it
from hooking a cable. Do not try to get out of the harness until you are
free from the glider. Most harness body's are padded with closed cell foam
which will provide some flotation.
Most harnesses have a zippered convenience
pouch in the bottom of the parachute container. Do not load this pocket
with anything which might interfere with the parachute. Do not store any
sharp object in the front mounted containers which might be dangerous on
a crash landing. During your hang check, verify that items secured to the
side accessory straps, radio and camera mounts, and ballast containers
cannot snag on the glider flying wires. Install a hook knife on an easily
accessible area of your harness.
Connect the bridle to the back of
the carabiner and tape or Velcro it in place against the main support.
Place a rubber band over the assembly to keep the bridle in the proper
position. Make sure the band is positioned low enough that it doesn't interfere
with the carabiner gate. It is a good idea to use a fabric sheath between
the container and the carabiner to protect the bridle from UV deterioration
, otherwise you should replace it at the same intervals that your mains
It is extremely important to do a
hang check with your feet extended as far as possible in the boot of the
harness while bouncing up and down to make sure the parachute is secure
in the container. If the Velcro on the container starts opening, and you
have recently had your chute repacked, there may be too much air left in
the canopy. Usually sitting on your parachute and harness for a few minutes
will solve this problem. If you are still having trouble, take your parachute
and harness to your dealer-your chute could be improperly packed, too big
for the harness container or have an incompatible deployment bag.
Remember that it is imortant to be proficient
at using your emergency reserve
and to maintain your equipment.
The single most important decision we can take as pilots is
WHEN NOT TO FLY so we can never need to use our reserve.