Powered Parachutes - Articles - Scary Parachutes
by By Betty Pfeiffer and Gary Douris

Gary Douris of Free Flight Enterprise and Betty Pfeiffer of High Energy Sports, Inc. represent the major American emergency parachute manufacturers for paragliding and hang gliding.  In this article they join forces for the purpose of exposing unsafe parachute construction with the hopes of saving lives. 

Scary Parachutes

By Betty Pfeiffer and Gary Douris

Although US pilots continue to be very lucky in successful deployment results, we must learn from the rest of the world where some pilots have suffered the disastrous consequences of unsafe systems.  As we see parachutes utilizing "unconventional" manufacturing techniques show up in our shops or at parachute clinics, we have been in the uncomfortable position of having to inform pilots of associated structural problems.

In this article we will illustrate some of the most obvious areas of "marginal construction".  If you suspect your parachute may be utilizing this construction, simulate a practice deployment, and look at your parachute.  (You may as well practice a deployment as long as you are taking your parachute out of your harness).  If you find questionable construction have the parachute inspected by a qualified person.

Emergency reserve parachute is often your last ditch effort to get out of a terrible situation.  You rely on it to safe your life without falling apart in the process.  For the purpose of this article we will not distinguish between catastrophic failures and probable damage from malfunctions or asymmetrical openings.  We will not discuss deployment systems but focus strictly on easy to identify inadequate parachute construction.  A qualified skilled parachute inspector will go into much more detail when examining your parachute for airworthiness.

Cardinal Rule #1  If your parachute lines fall off of your parachute, the parachute will not do you much good.

Unacceptable line attachment at the bridle:

Problem:  Line is folded and sewn with a single stitch zig zag.  Usually the end of each line is melted so it will not ravel.

Sharp edges on the lines can cut fibers.  More important is that the zig zag is only one stitch crossing from the line to the folded end.    If the end of the line catches on wreckage you can easily lose lines.  At the very least this construction should us three stitches for each zig and each zag.

Problem:  One Line is attached to the skirt of the parachute looped around the bridle and secured with a bar tack then attached to the skirt of the parachute.

Your lines are only ½ as strong as they would be if each line were individually attached to the parachute.  If you lose one line you will most likely lose 2 attachments points instead of just one.

The true story of the 10 line parachute:  Years ago when hang glider pilots only cared about "surviving" a deployment, a 10 line parachute emerged.  It packed up very small and looked quite good except for one small detail, it would not open when tested from an airplane.  The designers finally did get it to open by throwing it off the back of a pick-up truck while driving down the runway.  Moral of the story:  Know how your parachute was tested!

Unacceptable line attachments at the skirt of the parachute:

Problem:  Line is sewn directly onto the seam using single stitch zig zag.

Problem:  Line is sewn directly onto the seam without a v-tab to distribute the load in the event of a peeling action (line over, inversion, and temporary partial inversion).

Problem:  V-tab is sewn with single needle and the stitches go past the skirt band into a single layer of parachute material (point loading).

Problem:  Line Attachment loops are attached only to the top surface of the canopy.  (They should be sandwiching the parachute seam).

Problem:  Line Attachment Loops are sewn with two lines of straight stitching.  (They should be using a double stitch zig-zag pattern).

Problem:  Sewing on the line attachment loops extends past the reinforced area onto the single layer of parachute material (point loading).

Cardinal rule #2:  If your parachute falls apart you will come down faster than you wish.

Unacceptable canopy construction  

True Story:  Years ago when parachutes for hang gliding were rare, parachute designers at one company were given the following specifications:  The parachute must be light weight, low bulk, easy and fast to build and use no more than $50 of materials.  The internal code name for these parachutes was "meat-saver".  The parachute was designed to save the person but would probably break some bones in the process.

Problem:  No reinforcement in the skirt or on the apex.  The parachute material is simply folded and sewn.

Problem:  No reinforcement tape in the radial seams.

Problem:  Uneven line lengths fluctuating 4" or more on a round parachute.

Problem:  Uneven gore widths or lengths on a standard round parachute.

Problem:  Parachute "domes" attached to the skirt with 8 to 18 stitches at the seam and no reinforcement.

The problems listed above are meant to give you some direction when evaluating your parachute for airworthiness.  Many of the lessons we have learned come from tests performed on our own parachutes and some from drop tests performed on questionable chutes brought into our shops.

As we continue to monitor hang gliding and paragliding accidents, keep abreast of failure modes in which pilots resort to deploying their parachutes, we continue to refine and improve our safety instructions and products.  When we are confronted with known construction problems we feel it is our responsibility to speak up.

A word about certification: Pilots must be proactive in determining if international certification programs for hang gliding and paragliding parachutes are indeed testing what they claim to be testing.  If you have any question over the testing procedures used to test your equipment, be sure to ask the manufacturer specific questions. 

We believe that with the sophisticated instrumentation available for testing today, good objective results are clearly available and a good certification program will fashion itself after standard parachute tests.  Throwing parachutes off an 800' bridge clearly does not tell us what we need to know about airworthiness of a parachute.

Fly Safely,

 Gary Douris and Betty Pfeiffer

Side Bar:

Parachute truisms that are no longer true

1.        You must always air out your parachute before it gets repacked. 

This was true with the old silk parachutes but no longer a requirement with today's synthetic materials.

2.        Never fold your parachute in the same place two repacks in a row.  The material will break down.

The coating used on today's materials is far superior so this is not an issue.

3.        Never sit on your parachute.

Today we want you to sit on your parachute especially right after it is re-packed.  In this way you can better squeeze the air out and reduce the risk of an accidental deployment.

4.        Parachute rubber bands melt because of the grommets on the deployment bag heat up.

The biggest reason rubber band melted on the old deployment bags was the chemical reaction of the brass grommet with the rubber.  Today manufacturers know better than to use brass grommets.