Figure 4-27. Shove the canopy down into the bag filling the corners.
Figure 4-28. Use the flap of the bag to help control the canopy.
Figure 4-29. The closing flap of the bag is pulled so that the
grommets meet the rubber bands. You should not have to stretch
the rubber bands very far.
Figure 4-30. Make a locking stow.
Figure 4-31. The second locking stow. Note the generous size of
the bight.
Figure 4-32. Keep the stows neat and separate. Here, the weight
and mass of the lines is balanced to prevent line strip.
Figure 4-34. Pull the kill line through the bridle.
Figure 4-33. Pull pilot chute kill line from bottom of bag.
Figure 4-35. Drop the excess line into the pilotchute.
Deployment and Inflation Characteristics
Main canopies have changed dramatically over the last
several years and, consequently, different opening problems
have emerged. Some canopies are inherently hard openers,
while others are inherently slow openers. Accuracy canopies,
with their thick airfoils and large overhanging topskins, fall
into the first category, while thinner airfoils, with flatter trim
and baffled leading edges, tend to fall into the latter.
One of the most common problems encountered is that of
hard openings. Line strip or line dump is the leading cause of
hard openings. This occurs when inadequately-stowed lines
come off of the bag all at once instead of releasing one line
bight at a time in an orderly fashion, and subsequently the
canopy is allowed to inflate prior to line stretch resulting in
sometimes an explosive opening. Securing the lines so that it
takes approximately 12 pounds of force to release each bight
is accomplished with a proper stow band and balancing the
weight and mass of the lines by placing 50 percent of the
line weight and mass on the mid-section of the bag and 25
percent of the weight and mass on each side of the bag. This
alleviates the problem of line strip.
Figure 4-36. Rolling the nose of the canopy.
Figure 4-37. Rubber band on center C-Line attachment tab holding
apex of slider.
There are other methods employed to reduce hard openings,
such as rolling the nose of the canopy to delay the initial
inflation process as the leading edge unfurls. This rolling
technique varies from a single roll to several rolls.
[Figure 4-36] If this does not solve the opening problem,
riggers should contact the manufacturer for advice. Most
manufacturers are very cooperative and have considerable
expertise in working with their products.
The manufacturer may recommend modifying the slider size
or deployment brake settings. Of these options, the easiest to
do is to change the brake setting. Reducing the brake setting
results in less pressure on the canopy during opening, thereby
reducing the opening force. The negative effect of reducing the
brake setting is an increase in opening surge. The new brake
setting must find the balance of these results that best fit the
user. If changing the brake setting does not work, then the
rigger may wish to increase the size of the slider to slow the
openings. This usually means replacing the slider with a larger
one. This has the effect of increasing the drag on the slider and
restricting the canopy inflation. Another effective method of
preventing hard openings is to install a 2-inch diameter rubber
band on the center B or C line attachment tab and stowing the
apex of the slider in a single wrap of that band. [Figure 4-37]
The jumpers’ airspeed also has a significant effect on opening
shock. Jumpers should make a conscious effort to slow down
before putting out their pilot chute, and then assume a slightly
head high attitude in preparation for opening.
As canopies age and accumulate substantial jumps on them,
many begin to develop slow openings, commonly known
as “sniveling.” If the canopy was originally packed with
the nose rolled, reducing the number of rolls may speed up
the openings. However, many times the slow openings are
due to other causes. Probably the main reason for canopies
developing slow openings is increased porosity that occurs
with frequent use. It is especially noticeable on canopies that
have a “lip” or a baffled nose. These particular design features
cause a canopy to open slower for softer openings, which
is a desirable characteristic, but as the canopy fabric wears
and permeability increases, the openings may get too slow.
The effect on fabric that originally had a permeability of 0–3
cubic feet per minute (CFM) or 0–5 CFM, such as PIA-C-
44378, may not be as dramatic. With these canopies, pulling
down the tail by deepening the brake setting speeds up the
inflation of the canopy. The rigger must be careful not to set
the brakes so deeply as to place the canopy in a stall during
opening. If this does not work, then decreasing the size of
the slider or the fabric type of the slider may help speed up
the openings. The size and condition of the pilot chute may
also contribute to the perceived speed of opening.
Another cause is when the canopy gets out of trim due to
the stretch of the suspension lines or shrinkage of steering/
brake lines. The rigger should check the trim of the canopy
against the manufacturer’s specifications and either re-trim
the canopy or re-line it. This may have a pronounced effect of
improving the openings, as well as the flying characteristics.
Main Pilot Chute
Hand deploy pilot chutes are made from either the
PIA-C-44378 (0–3 CFM) (formerly known as F-111 which
is a proprietary brand name that is no longer manufactured.
Currently 0-3 CFM is commonly referred to as Silktique and
Exazta-Chute) fabric or zero porosity (0 CFM) fabric. The
PIA-C-44378 fabric begins as a very low-porosity fabric but,
as it is used, the permeability increases. When this happens,
the drag of the pilot chute decreases. Consequently, the ability
of the pilot chute to “lift” the weight of the canopy decreases
and the speed of the opening is affected. Experience has
shown that pilot chutes made from this type of fabric exhibit
a decrease in performance at around 500 jumps under normal
use. Pilot chutes made from the ZP fabric last considerably
longer than those made from 0–3 CFM fabric. However, there
has been some disagreement concerning the use of the two
different fabrics in pilot chutes. One canopy manufacturer
advocates the use of F-111-type fabric only. They believe
the ZP fabric contributes to hard openings. Most parachutists
like ZP pilot chutes because they last longer. The size of the
pilot chute has a direct correlation to the type of opening
experienced. In the early days of hand deploy chutes, a 36-
inch 0–3 CFM pilot chute was standard on most systems.
As the canopies became smaller and lighter, pilot chutes
became smaller as well. Today, 24-, 26-, 28-, and 30-inch
pilot chutes are all common.
Several factors dictate the size of the pilot chute used. The
first is the weight of the canopy. Another factor is the main
container closing configuration. Some systems are designed
to hold the deployment bag so securely that it requires more
drag to extract it from the container. This type may require
a larger pilot chute than the type of container that allows
unrestricted extraction of the bag. This same problem can
develop when an individual packs an oversized main canopy
into the main container. If a larger deployment bag is used
to hold the additional volume and the bag is forcibly stuffed
into the container, the bag can be restricted from being pulled
smoothly from the container. If the pilot chute is too small, a
pilot chute in tow can result. If the parachutist puts a larger
pilot chute on the system, the bag can be extracted from the
container, but the increased size of the pilot chute contributes
to increased snatch force during the opening sequence. This
results in perceived hard openings.
It should be noted that deployment bags are matched
dimensionally to containers—not to canopies. If the tray of
your container is 12 inches wide, 7 inches long, and 5 inches
thick, the bag should also be those dimensions. Forcing a
larger bag into the container overstresses the flaps, grommets,
stiffeners, and some loop anchors. Conversely, if you put
a smaller canopy than was originally intended into the
container, you should use the same bag and pack the canopy
as wide and “fluffy” as possible. In other words, do not squish
all of the air out of the pack job as you normally would. The
main closing loop should be appropriately shortened.
Using a smaller bag than the container was built for can result
in unsafe conditions as well. In the event of a premature
container opening, the bag may float out before the jumper
has an opportunity to deploy the pilot chute. Some friction
is desirable so that the bag rotates out of the container in
the proper sequence—bridle up, lines down. There is an
exception to this tenet for wingsuiters, who essentially open
in a track. So, the size of the pilot chute and, to some extent,
the deployment bag can have considerable effect on the
opening of the main parachute.
Bridle Length
The length of the bridle has an effect primarily on the
deployment of the main pilot chute itself. In the case of a
throw-out pilot chute, the bridle must be long enough to get
the deployed pilot chute out of the turbulence in the wake of
the jumper’s back. If the bridle is too short, the pilot chute
stays in the parachutist’s burble. The length of the bridle
from the locking pin to the pilot chute averages around 7 feet.
Recent years have seen the growth of the use of the “birdman”
flying suits or wingsuits. Because of the increased surface
area and the decreased free fall speeds, the use of a longer
bridle has become common, with a 9-foot length working
well. Along with the longer bridle, containers have been
modified to allow the bottom to open fully and the main bag
to be extracted rearward towards the feet due to the more
horizontal trajectory of the parachutist. Some manufacturers
have also reoriented the mouth of the main deployment bag
for wingsuiters so that the lines are sitting on the floor of the
container tray rather than the bottom flap. This way the bag
rotates 90° out of the container rather than 180°.
In the case of a pull-out pilot chute, where the jumper actually
pulls the pin, the pilot chute is placed with an arc motion of
the arm in the fast air near his or her head so as to avoid the
burble. The jumper’s grip on the pull-out handle is gradually
released as they rotate into a head-high position, reducing the
size of the burble, and in preparation for opening.
Rubber Bands
The rubber stow bands play an important part in the
deployment sequence and serve two important functions.
First, they hold the mouth of the deployment bag closed
and prevent premature deployment of the main canopy.
Secondly, they hold the line stows securely to allow a clean,
orderly deployment of the lines. With the advent of smaller
diameter lines, such as 550 or 725 Spectra ® and HMA ®,
smaller diameter rubber bands have been developed to
properly secure these lines. If the smaller rubber bands are
not available, many parachutists double stow the larger rubber
bands around the small lines.
Figure 4-38. Rubber bands and Tube Stows®.
Figure 4-39. Line stow length comparison.
Figure 4-40. 3-ring layout.
Figure 4-41. 3-ring middle through large ring.
Figure 4-42. 3-ring small through middle ring.
There are other products, which are designed to replace rubber
bands and last longer, but they have downsides. Rubber bands
other than military standard (Mil Spec) rubber bands may not
break at the desired 40–45 pounds and can lead to bag locks.
Other products may not have enough retention ability and
allow the lines to “dump.” Figure 4-38 shows the various
rubber bands and Tube Stoes®. In addition to the correct rubber
bands, the length of the line stows is important as well. In the
past, 1-inch stows were common, but today 3-inch stows are
recommended by several manufacturers. Figure 4-39 shows
the comparison between the two lengths. The main point to
remember is that the lines must be stowed neatly and securely.
Assembly of the Main Canopy To The
Harness and Container
The rigger should be familiar with the various types of
canopy releases currently in use. In skydiving, the most
common release is the 3-ring release system. It was originally
developed in 1976 for skydiving, but has since become
the dominant release system for intentional jumping, both
civilian and military.
Riggers must be familiar with the assembly of the 3-ring
release since they may have to connect new canopies to the
harness and container or have to disconnect the main canopy to
untangle it after landing. Shown in Figures 4-40 through 4-47
is the correct assembly sequence. The rigger must also be
able to inspect the 3-ring release to determine any wear. In
particular, the following areas need to be inspected:
Figure 4-45. 3-ring housing terminal over loop (rear).
Figure 4-46. 3-ring cable through loop.
Figure 4-47. 3-ring assembled (from front).
Figure 4-48. Harness 3-ring inspection.
Figure 4-43. 3-ring loop over the top ring.
Figure 4-44. 3-ring loop profile view.
• Harness 3-ring attachment—check for wear on the
webbing and any damage to the ring or chipping of
the plating. [Figure 4-48]