Pilot Chute Life Span

Q:

 

How long does a main pilot chute last?

A:
The main pilot chute and bridle are busy items on a modern parachute. The system, which is integrated with the main deployment bag, begins with the pilot chute handle and ends at the attachment ring on top of the main canopy. The pilot chute and bridle must be compatible with the rig’s external pilot chute pouch, the closing system of the main container and—to some degree—the weight of the main canopy. A rig manufacturer will supply the pilot chute and bridle as part of its harness-and-container system.

Pilot chute design and fabric have changed a lot over the last 20 years. Now, for the most part, manufacturers have settled on an envelope (aka the pilot chute’s canopy—the inflatable part) made from zero-porosity nylon and, for the bottom half, nylon marquisette mesh. Bridles are generally 1-inch wide. Bridles for non-collapsible pilot chutes are most commonly single-ply, type-4 nylon square-weave webbing. Bridles for collapsible pilot chutes (which deflate as the deployment bags release the canopies) are two-layered—either a layer of type-4 and a layer of type-3 nylon tape or two layers of type-3 tape—sandwiching a free-sliding inner bridle, called a “kill-line,” made of Spectra® cord. Very importantly, limiter tape or tapes inside the envelope prevent the apex from extending past the point of maximum drag (in other words, collapsing inside-out).

A variety of reasons might cause you to cha-nge or reconfigure your pilot chute and bridle:

  • Significant upsizing or downsizing of your main canopy
  • To upgrade canopy performance by switching from a non-collapsible to a collapsible pilot chute
  • To speed up or slow down the opening
  • Change in skydiving discipline or habits
  • Wear and tear

The common question—when to replace—usually refers to the last point, wear and tear. This depends on a number of factors, such as the material and construction of the system and its use environment. Dirt—particularly dirt with a high silicone or mineral content—accelerates wear on the moving parts of a collapsible pilot chute and degrades the envelope, as well.

Inspections
Fully inspect your collapsible pilot chute after your first 10 or so jumps (for manufacturing defects), then again at 200 jumps and every 100 jumps afterward. To do a thorough check, pull the inner kill-line out from one, then the other, end of the bridle, which allows you to inspect its entire length for wear. Look closely at the exit points of the outer bridle, which are often reinforced with a brownish-yellow Kevlar® tape that degrades severely with use. Look at the handle attachment and stitching on the reinforcement tapes both on the outside and the inside of the apex of the pilot chute. Examine the security of the limiter tape. Also look closely at the stitching that attaches the closing pin to the bridle. The fabric in the eye of the pin should never show wear; if it has, the inner edge of the eye could be cutting through it.


Duct tape is probably not the best solution to pilot chute problems.

Look very carefully at the stitches in the fabric that holds the pin to the bridle, and inspect the loop of attachment webbing inside the steel eye for any damage.

This photo, taken through the mesh with the pilot chute cocked and tension on the handle, shows the limiter tapes loaded (stretched taut) with some slack in the inner kill-line, which is appropriate.

When inspecting the equator of the pilot chute, look for fabric stress along the seam. This mesh separation isn’t severe.

The mesh separation at the base of this pilot chute is getting worrisome.

The internal kill-line bridle will develop “the fuzzies” over time. This one is about halfway through its useful life.
Look at the handle attachment from the inside of the envelope and the outside. The ends of the zig-zag will always fray a little. Don’t be concerned about a half-inch or less of fraying.

An important test is to pull the handle with the pilot chute fully cocked and look through the mesh to determine that the limiter tapes load (are stretched taut) before the inner kill-line: What you should see are taut limiter tapes and a “lazy-S” in the kill-line. If the kill-line is too short, your pilot chute will not fully inflate. If the kill-line is too short or very fuzzy or if the Kevlar® reinforcment is wearing through, you need to visit your rigger for advice. Likewise, report any fraying more than a half-inch long at the ends of any of the zig-zag stitching throughout the pilot chute assembly.

The pilot chute envelope takes a lot of abuse from dirt, sun and even sweat, so look at it every time you pack, and include it in your 100-jump inspection. Also, the quality and durability of the mesh varies from manufacturer to manufacturer. Follow the equator seam and look for strains in the fabric or breaks in the seam stitching.

Besides Wear
A couple of issues require you to consider your pilot chute beyond its overall maintenance and condition. First, if you have a non-collapsible pilot chute, you’ll probably want to replace it with a collapsible one. An inflated pilot chute markedly degrades a main canopy’s performance during flight. It took jumpers a while to become reliable about cocking their pilot chutes (the neglect of which causes pilot-chute-in-tow malfunctions) during each pack routine, but it’s pretty much habit with everyone now and can be verified on most systems during the pin check. (You do get pin checks, right?) By this point in the game, better openings and landings and less stress on the main canopy offset the odds of forgetting to reset the pilot chute during packing.

You’ll also want to be aware of a very perplexing malfunction that appeared on the scene only a few years ago—several jumpers experienced pilot chutes in tow after their curved closing pins pierced their bridles and locked their containers closed—and the jury’s still out on exactly what the problem is. One manufacturer, whose rigs had two reported occurrences, reported being unable to duplicate the problem in testing but modified both its bridle construction and recommended packing procedure. Another company, whose gear had one reported occurrence, also modified its bridle. If in doubt, check with your manufacturer and consider how to place the closing pin so it doesn’t contact the surface of the bridle while it’s being extracted. Some special-use equipment might require an extra-long bridle so the pilot chute can clear an extra-big burble, such as with gear used for AFF students (typically using bigger, heavier canopies) or wingsuiting.


A pin piercing the main-canopy bridle, locking the container closed.

Stowing the bridle taut with the pin directly underneath could increase the possibility of this malfunction.

To help prevent a container lock, pack with some slack in the bridle as shown, keeping the pin to one side.

Pilot chute size can affect opening speeds and perceived opening shock, which is something to discuss with your canopy’s manufacturer. However, keep in mind that the pilot chute is designed for the container and matched with its pouch. A pilot chute that is too big may be hard to pack and extract, stressing the material and stitching on the pouch. One that is too small may self-extract at an inconvenient moment, causing a dangerous situation for you and those you’re jumping with. Typically, the manufacturer will supply big pilot chutes with containers sized for big mains and small pilot chutes for containers sized for small mains, with pockets sized to fit, as well.

When changing pilot chutes, it’s usually best to select original equipment and order by the serial number on your rig. There are also some great after-market pilot chutes out there, but coordinate with the pilot chute manufacturer and the harness-and-container manufacturer for advice before ordering. Be very careful about switching pilot chutes from rig to rig, and look carefully at the relationships between the point where the bridle interfaces with the deployment bag and the placement of the closing pin along its length. Another thing to consider is that more and more, pilot chute handles also interface with retaining mechanisms at the mouth of the stowage pouch.

Pilot chutes don’t last forever, and some failures can be pretty serious. As with the rest of your equipment, understand how yours works, inspect it regularly and replace it correctly when the time comes.

—Kevin Gibson | D-6943
Master Rigger
Orange, Virginia

Comments

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

Chris Davis
Thu, 12/14/2017 - 13:27

Do you know what the pilot chutes have been made of in the late 1990s? The information is for a novel I'm writing.

Webmaster
Mon, 01/29/2018 - 12:09

Pilot chutes are constructed from F-111 nylon or zero porosity nylon materials. - Jim Crouch, Director of Safety and Training

Post new comment

Please provide your full name. We will not post responses from anonymous sources.
The content of this field is kept private and will not be shown publicly.
Type the characters you see in this picture. (verify using audio)
Type the characters you see in the picture above; if you can't read them, submit the form and a new image will be generated. Not case sensitive.