Figure 2-22. Type 2 deployment—Lo-Po Reserve.
Figure 2-23. Type 3 deployment—Phantom canopy.
Figure 2-24. Type 4 deployment—Preserve diaper.
Figure 2-26. Type 6 deployment—Sleeve.
Figure 2-25. A) Type 5 deployment—Freebag and B) Type 5
deployment—Speedbag.
Type 3: Ascuitto or Piglet-Style Flat Diaper
This deployment features a full diaper with all lines stowed
left to right or perpendicular to the radial seam. Examples
of this method are the Piglet, Phantom, and Security Aero
Conical (SAC) canopies. [Figure 2-23]
Type 4: Handbury or Preserve Full Diaper
This features a choker-type diaper that wraps around the
canopy skirt. It is locked with three stows and all lines are
stowed on the diaper parallel to the radial seam. Examples of
this method are the Preserve series canopies, Strong Lo-Po
Lite, and the Hobbit square reserve. [Figure 2-24] The military
quarter bag is basically a version of the Type 4 method.
Type 5: Free Bag
With a free bag, the canopy is stowed in the bag, and lines are
either stowed on or in the bag. They were originally used on
the Safety Flyer reserve. This is the dominant and preferred
method for virtually all modern square reserves. [Figure 2-25]
Type 6: Sleeves
The sleeve type includes a fabric tube that encloses the
full length of the folded canopy. Lines are stowed on the
sleeve. They were originally used on early sport canopies,
particularly the Para-Commander. [Figure 2-26] A modern
version, known as a “slag,” is used on some ram-air canopies.
An additional deployment method is the “tail pocket.” This is
a fabric pocket sewn on the tail of a ram-air canopy in which
the lines are stowed. [Figure 2-27]
Figure 2-30. Safety Stow®.
Figure 2-28. Hesitator loops.
Figure 2-29. Para-Flite O-rings.
Figure 2-27. Tail pocket.
Securing the Deployment Device
With all deployment methods, it is necessary to properly
fold or stow the canopy and secure the deployment device
with the lines. The early parachutes utilized hesitator loops
to secure the lines. [Figure 2-28] This method is still used
today in many military systems.
In modern designs that utilize types 1 through 4 and 6,
the preferred method of locking the deployment device is
rubber bands. The specification for standard rubber bands
is MIL-R-1832. Type 1 are made of natural rubber and are
1⁄2" × 2". These were designed for use with the thicker Type
III nylon lines such as on the 28' C-9 canopy. Many of the
newer lightweight, round canopies use smaller diameter and
fewer lines. Consequently, the standard rubber bands do not
work well. Some manufacturers supply smaller, 1¼" diameter
rubber bands to be used with their canopies. It is extremely
important to utilize the correct size rubber bands.
With the introduction of the free bag system in 1977, Para-
Flite, Inc., used a BUNA-N “O” ring to secure the locking
stows. [Figure 2-29] During testing of the free bag system,
they found inconsistent holding and breaking strengths of
rubber bands. They wanted the locking stows to release at a
consistent force to prevent bag lock. The “O” rings provided
this. A couple of years later, the “O” rings were upgraded to
a thicker diameter model. In 1983, Para-Flite, Inc. replaced
the “O” rings with the Safety Stow ®. The Safety Stow® is
a continuous loop of elastic shock cord that runs through a
webbing channel and through two grommets to secure the
first two locking stows. [Figure 2-30] In the event of any
restriction on the locking stow, as the loop stretches, it allows
first one side to release and then the opposite side.
It is important to maintain the rubber bands or Safety Stow®.
Rubber bands are susceptible to heat degradation and may dry
out. If they break prematurely during use, the parachute may
malfunction. Non-mil. specification rubber bands may react to
natural brass grommets and may become gummy and sticky,
causing the lines to stick to the diaper or bag. Rubber bands
should be replaced during routine Inspection and Repack.
[Figure 2-31A and B] The BUNA-N “O” rings should be
replaced with the Safety Stow ®. The Safety Stow ® should
be inspected for broken stitching or internal rubber strands.
[Figure 2-32]
In response to occasional violent openings on ram-air
canopies, Parachute Labs (Jump Shack) in 2003 introduced
the “speed bag” to eliminate “line dump” (line strip). The
lines are retained in rubber bands 25 percent in from the edge
of the bag. This balances the mass of the stows between the
Change 1 (December 2015)
Figure 2-32. Bad Safety Stow®.
Figure 2-31. A) Old rubber bands and B) new rubber bands. They come in 3 sizes: 3⁄8" wide × 1¼" diameter, 3⁄8" wide × 2" diameter
and ¾" wide × 2" diameter.
Figure 2-34. Hand tack floating bridle loop.
Figure 2-33. Pre-sewn round bridles.
bights and center span of the stow. The bag has an additional
flap on the top side that has slots for the rubber bands mounted
on the bottom flap. These two flaps overlap closing the bag
over the canopy. The design was used on main canopies
only for the first three years. Its success led to the release as
a reserve bag in 2006.
Bridles
The bridle is a cord or webbing strap that is used to connect
the pilot chute to the canopy or deployment device. Main
and reserve bridles, while sharing the same function,
operate differently.
Early bridles were simply a length of suspension line tied off
to the two components. It was soon learned that the length
of the bridle affected the function of the pilot chute and
the opening characteristics of the canopy. On most round
emergency and reserve parachute assemblies, the length and
type of the bridle is fixed for optimum performance. The
rigger cannot change the configuration of the bridle without
approval of the manufacturer.
There are two basic types of round canopy bridles. The first
is a tubular nylon bridle that is tied on. The second is a pre-
sewn bridle with loops at each end. The loop of one end is
passed through the attach point on the pilot chute and then
back through itself forming a lark’s head knot. The other
loop of the bridle is then similarly attached to the canopy
apex. [Figure 2-33] With this type, it is essential for the
loop to remain loose to ensure the bridle is free floating and
self-centering around the apex lines. Hand tack the loop to
ensure this. [Figure 2-34]
Square reserve bridles are generally built into the free bag. The
bridle material is usually 2 feet wide or more for high drag. The
original concept of the free bag is to allow the square reserve
Figure 2-36. Bungee collapsible bridle.
Figure 2-37. Kill-line collapsible bridle.
Figure 2-38. Kill-line eye or window.
Figure 2-35. Freebag assistor pocket.
to deploy if the reserve pilot chute is captured resulting in a
horseshoe-type malfunction. The high-drag bridle would then
pull the reserve bag off the parachutist’s back and allow the
canopy to deploy free from the bag. In the late 1980s, assistor
pockets were added to some bridles for additional drag as
square reserves became bigger and heavier. [Figure 2-35]
Early main bridles were simply longer versions of the reserve
bridles. This was necessary to compensate for the “burble”
created in free fall by the parachutist. In the mid 1970s and
with the advent of the hand deploy pilot chute, the length of
the bridle was critical in order to allow proper extraction of
the locking pin that secured the pack closed.
In recent years and with the almost total use of ram-air
parachutes, the need for collapsible main pilot chutes has
become widespread. As the main canopies have become
smaller and faster, the drag of the inflated main pilot
chute after opening can have an adverse effect on canopy
performance. This problem has been solved through the
use of a collapsible pilot chute/bridle system. There are two
primary designs used to accomplish this.
The first is the “ bungee” collapsible configuration. This
consists of a length of elastic shock cord inside a tape sheath
on the bridle near the pilot chute end. [Figure 2-36] When
relaxed, it holds the apex of the pilot chute collapsed. When the
pilot chute is deployed into the airstream, the airflow inflates
the pilot chute, which deploys the canopy. After opening, the
elastic pulls the apex down again and collapses the pilot chute,
reducing the drag. While this system works, its main drawback
is that certain airspeeds are needed to inflate the pilot chute.
Remember, the primary function of the pilot chute is to initiate
deployment. Collapsing the pilot chute is secondary.
The second type is the “kill-line collapsible” configuration. This
consists of a bridle with a full length channel through which
passes a line of Kevlar® or Spectra®. [Figure 2-37] The bridle
is “cocked” and the lower end of the bridle is collapsed during
packing. This allows the pilot chute to inflate immediately.
During the deployment sequence, as the canopy inflates, the
lower end is stretched to length and the centerline pulls the apex
of the pilot chute down and collapses it. This configuration
has become almost universal in use for skydiving today. The
only drawback is if the user forgets to cock the bridle during
packing. This results in a collapsed pilot chute and a pilot chute
in tow. In the early days of use of the kill-line bridle, this was
a problem but has become less frequent today. Some bridles
have a colored “eye” at the locking pin location to show if it
is cocked and the centerline is set correctly. [Figure 2-38]
The kill-line configuration is used almost exclusively on
tandem systems due to the high speeds involved and the size
of the drogue pilot chutes. Some bridles are made from 2"
Figure 2-39. Tandem main collapsible bridle.
Kevlar® tape and have tubular nylon centerlines. Others are
made from Type 4 square weave with a Spectra centerline.
The advantage of the latter is that it can be cut with a hook
knife in the event of an on-person malfunction. [Figure 2-39]
Another method of collapsing the pilot chute is to install a No.
8 grommet in the deployment bag and allow the bag to float
on the bridle. After the canopy deploys, the bag slides up the
bridle, inverts, and covers the pilot chute. This is commonly
called the “poor man’s collapsible pilot chute system.” The
drawback to this design is the high wear on the bridle and
pilot chute mesh.
Pilot Chutes
A pilot chute is a small parachute that is used to deploy the
main or reserve parachute. In the earliest uses of parachutes,
the parachute was static line deployed. With the advent of
manually operated or “free fall” parachutes, the need for a
pilot chute was quickly recognized.
There are two basic types of pilot chutes. The first is the
spring-loaded design. This uses a collapsible spring, which
is compressed in the parachute container and held closed
with the ripcord. When the ripcord is pulled, the pack opens
and the pilot chute launches into the airstream. The pilot
chute provides drag and pulls the canopy from the pack as
the parachutist or load falls away. During this process, the
pilot chute also provides tension on the lines of the deploying
canopy and helps the opening sequence. Spring-loaded
pilot chutes are used primarily for emergency and reserve
parachutes. In addition, they are used in military free fall and
training systems for the main parachute.
The second type of pilot chute is the “hand deploy” design.
This type consists of the pilot chute canopy but does not have
a spring to launch it. Instead, the parachutist extracts the
folded pilot chute from a pouch or the container and launches
it into the airstream. The pack is held closed by a locking pin
attached to the bridle of the pilot chute. As the pilot chute
inflates, it extracts the pin from the locking loop and pulls
the parachute from the pack. The rest of the opening process
is similar to the spring-loaded pilot chute. This configuration
came into popularity in the mid 1970s and is now the primary
method of deployment in skydiving.
Spring-Loaded Pilot Chutes
Spring-loaded pilot chutes date from the 1920s. However,
it was not until 1940 that the spiral vane pilot chute was
invented. This design used a spiral spring that is easy to
collapse and pack. The most common type of spiral vane pilot
chute used today is the MA-1 model. [Figure 2-40A and B]
This is used in several military parachute assemblies. In the
early days of skydiving, military pilot chutes, such as the
MA-1 and others were popular. Soon commercial designs
were introduced that improved on the MA-1 with better
launch and drag characteristics. These included the Grabber®
and Hot Dog® pilot chutes. Both of these were primarily for
use with main parachutes.
With the advent of the hand deploy pilot chute for the main,
most of the improvement in spring-loaded pilot chute design
has focused on its use in the reserve or emergency parachutes.
This has paralleled the improvements in container design and
the increased use of AADs. Both of these require better pilot
chutes than in the past.
One example for reserve use is the Magnum® pilot chute
designed by National Parachute Industries. [Figure 2-41]
With its unique shape, it provides maximum drag at low
speeds, such as are experienced during cutaways. Its design
has been licensed by other manufacturers for use in their
assemblies. Additional designs include the Vector II reserve
pilot chute and the Stealth pilot chute. The Vector II design is
a “ballute” configuration that eliminates the use of mesh. In
the event of an unstable launch on its side, the mass of fabric
is sufficient to lift the pilot chute and deploy the parachute.
The Stealth pilot chute uses a conventional mesh design but
has a unique spring/cap configuration that allows the pilot
chute to virtually disappear when packed, hence the name.
The MA-1 spring with mesh in place of the vanes, and a
closed canopy instead of the scalloped canopy provides the
best of both worlds: a spring that does not lock up on itself
and high drag without the possibility of snag.
Hand Deploy Pilot Chutes
The hand deploy pilot chute was introduced in 1976. There
are two types of hand deploy designs. One is the throw-out
pilot chute (TOP) configuration. This is the type where
the pilot chute pulls the locking pin located on the bridle.
[Figure 2-42] The original design had the pilot chute pouch
Figure 2-40. A) MA-1 pilot chute and B) high-drag pilot chute with large hole mesh.
mounted on the belly band. Today, the primary location is an
elastic/Spandex® pocket mounted on the bottom of the main
container (BOC). [Figure 2-43] Most of the difficulties of this
design have to do with pilot chute in tow due to misrouting
of the bridle or failure of the pin to extract.
The second type is the pull-out pilot chute (POP) configuration.
This design has the pilot chute packed in the container, which
is locked with a straight locking pin attached to a short lanyard
and handle. [Figure 2-44A and B] This handle is usually
mounted on the bottom corner of the main container. The
parachutist grasps the handle and pulls the locking pin from
the locking loop and puts the pilot chute into the airstream. The
handle is usually attached to the bottom of the pilot chute and
as the chute enters the airstream, the jumper loosens his grip
on the handle allowing it to be pulled from his or her hand.
This makes for a positive deployment. The main drawback to
this system is losing the handle due to it being dislodged while
moving around in the aircraft or in the air. Fortunately, the
handle does not go far and is easy to obtain because it is on a
short lanyard that is tucked up under the side flap. .
Automatic Activation Devices (AADs) and
Reserve Static Lines (RSLs)
Safety considerations have led to the development of AADs
and reserve static line (RSL) systems. These devices allow
for automatic deployment of the main or reserve parachutes
in the event of an emergency.
Automatic Activation Devices
AADs are devices that activate the parachute automatically.
Modern systems combine a barometric sensor with a rate
of descent sensor so that the system is fully automatic once
turned on and calibrated. The activation may be by either
pulling the ripcord pin(s) or cutting the locking loop(s),
Figure 2-41. Magnum pilot chute.
Figure 2-42. TOP bridle/pin configuration.
Figure 2-43. BOC pocket location.
causing the pilot chute to release. Most older models use
a mechanical or pyrotechnic pin pulling technique. Newer
models use a pyrotechnic loop cutting design.
For many years, AADs were primarily used by the
military and student parachutists. The designs were bulky,
expensive, and, to a degree, inconsistent. The installations
themselves were cumbersome and awkward. In the early
1990s, a new generation of AADs became available. The
CYbernetic Parachute RElease System (CYPRES ®) uses
modern parachute release technology. It is small, reliable,
computer based, and uses a pyrotechnic loop cutter. It has
an auto-off feature that turns the unit off after 14 hours
of operation to conserve power. It also has the ability to
calibrate the unit for operation at altitudes other than the
calibrating ground level. Based on these concepts, other
companies have developed similar systems and as a result,
changed the approach to the design and use of AADs.
Today, a good many sport parachutists use an AAD and
some countries (rightly or wrongly), mandate their use by
all parachutists.
The following describes the operation and installation
requirements of the CYPRES ® model AA. Other designs,
such as the Vigil ®, are compatible with these installation
requirements.
Operation
The CYPRES ® system is a barometrically controlled
microprocessor that activates a pyrotechnic cutter that cuts
the container locking loop. When calibrated to ground
level, the barometric sensor activates the unit firing the
cutter when the descending parachutist reaches an altitude
of approximately 750 feet above ground level (AGL) and
exceeds a rate of descent of 115 feet per second (fps).
The CYPRES® consists of three parts:
1. Battery and processing unit
2. Control unit
3. Cutter [Figure 2-45]
Figure 2-45. CYPRES® AAD.
Figure 2-44. A) POP handle with pilot chute and B) POP handle and lanyard.
Figure 2-46. CYPRES® container pouch.
Figure 2-47. CYPRES® control unit vinyl pocket.
Figure 2-48. CYPRES® cutter location.
The processing unit is generally located in a stowage pouch
installed in the reserve container of the parachute system.
[Figure 2-46] The control unit is contained in a vinyl pocket
located either under the pin protector flap or in the upper back
pad area. [Figure 2-47]
The cutter(s) may be located at the base of the pilot chute
or on a flap over the pilot chute. [Figure 2-48] Each
parachute system has its own particular requirements, and
it is imperative that the rigger have the appropriate manuals
for installation.