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Rob Kells & Steve Pearson
Wills Wing USA

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 so immediately.

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

  1. LOOK-GRASP-PULL-LOOK-THROW-PULL
  2. LOOK for the handle, GRASP the handle,
  3. PULL the deployment bag from the container (with most systems a down-and-out at about 45 degrees works best),
  4. LOOK for clear air,
  5. THROW towards clear air and into the direction of the spin,
  6. PULL the bridle (reach back to your main support strap to locate it) to clear the chute from the container and accelerate the deployment sequence.

  7. If the parachute is not open, pull it back and repeat the throw.

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 wind.

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.

There 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.

Harnesses
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, we recommend:
The Parachute Manual - by Dan Poynter
, available from
Parachuting Publications, PO Box 8206-240, Santa Barbara, CA 93118-8206 USA
1-800-PARAPUB

Carabiners
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 during deployment.

Ultraviolet Deterioration

  1. 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.
  2. Paragliders, depending on the fabric are good for roughly half that long.
Bridles

  1. 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.
  2. Paraglider bridals are typically Five feet in length and require a structural attachment to the harness that will bring the pilot down feet first.
  3. 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.
Canopy Design
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.

Model Square Area Test Wt Decent FPS Max Pilot Wt
20 GORE PDA 238 Sq. Feet

250 Pounds 19.5 F.P.S. 180 Pounds
22 GORE PDA 302 Sq. Feet

350 Pounds 19.4 F.P.S. 250 Pounds
24 GORE PDA 336 Sq. Feet 450 Pounds 20.5 F.P.S. 320 Pounds

Deployment Bags
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.

Pin Locks
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 impossible.

BALLISTIC AND MECHANICALLY DEPLOYED PARACHUTES

Five types of mechanically deployed parachute systems have been marketed to pilots:

  1. 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 system.
  2. 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.

  3. 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.

  4. 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 of system.

  5. 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 systems.

NEW HARNESS INITIAL INSPECTION AND PREFLIGHT

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.

  1. Inspect the seams on the main suspension straps and the 3" webbing loops that secure the straps to the harness body, both sides.
  2. 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 loose position.
  3. 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.
  4. Inspect all other seams; look for any missed stitching on webbing junctions.
  5. Inspect the carabiner. Nicks and scratches are stress risers and may cause premature fatigue induced failure.
  6. 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.
  7. Inspect all the webbing and parapac for material flaws, cuts or wear.
  8. Check that your parachute is secure in the container and that the safety lock system is properly installed.
  9. Check the function and adjustment of the main harness buckles located on the side of the parachute container
  10. Proceed to the appropriate harness adjustment instruction.
  11. 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 PRECAUTIONS

Do Not 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

Avoid Exposing 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.

Keep Your Harness Clean
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.

Inspect Your Carabiner
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 are replaced.

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.

Apr 1 2004   Top Top