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Reserve Deployment Articles - reprints

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Fred Wilson
Joined: 10 Dec 2014
Posts: 45
PostPosted: Fri Mar 23, 2012 04:46 am    Post subject: Reserve Deployment Articles - reprints Reply with quote

Angelo Crapanzano passed away, so his website and articles no longer exist.

The Conar Metamorfosi it is now in production by Moyes. See: http://ozreport.com/16.159.0

I have copied them from the Internet Archive Wayback Machine to http://www.hanggliding.org/viewtopic.php?t=25614

This to update my Parachute Repack and Deployment Website re links, info etc at: http://www.hpac.ca/pub/?pid=102

The French and Italian Versions are proving to be a bit more difficult to find.
When i do track them down, I well post them here. French on the French Language side of the Forum.
- especially if non members can see and read them.

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Fred Wilson
Joined: 10 Dec 2014
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PostPosted: Fri Mar 23, 2012 04:47 am    Post subject: Reply with quote

Emergency Parachute Deployment Sequence for Hang Glider Pilots

Once you have decided to deploy your parachute you must follow the following sequence of operations as calmly, yet as quickly as possible.

1 - look at the deployment handle

2 - pass your thumb through the handle and close your fist around it

3 - open the container by pushing the handle aggressively to extract the pod

4 - aggressively throw the parachute towards clear air

5 - get your feet out of your harness

6 - stabilise your wing by controlling eventual oscillations

7 - firmly hang onto the wing and prepare for touch down

Explanations are necessary:

Looking at the deployment handle is vital so that you will be certain to get hold of it on your first attempt. A second try will cost precious time.

Hooking the thumb through the handle is the only way that guarantees you will get hold of it, especially when flying with gloves. Practice the first two steps of the deployment procedure frequently during regular flight so that it becomes second nature. Be careful not to cause an accidental deployment.

Pushing the deployment handle allows the container to be opened progressively and completely, and to extract the pod using the least possible effort.

Aggressively throw the pod to bring the bridles and lines to extension as quickly as possible. If your hang glider is tracking more or less straight, it is desirable to throw backwards. In case of an asymmetric structural failure you will probably be spinning: throw the pod in the direction of your spin and outwards: the centrifugal force will help get the parachute away from you and your wing. If you are falling inverted, the situation is more difficult, but rules still apply: if the wing is tracking more or less straight, throw backwards, and if spinning, throw forward and outwards. A special case is if you are in a continuous tumble, i.e. a situation when your wing, more or less intact, turns continuously forward around a horizontal axis; in this case one must throw as aggressively as possible, laterally outwards, and down along the axis of rotation. Remember that your decision to pull and throw your parachute will also very much depend on your height above ground. If you are very high above ground you have time to try to regain control of your wing, or to wait for several seconds - pod in hand - for the most favourable moment. If you are close to the ground, every millisecond is precious: act immediately. Remember that a very fast rotation can be extremely violent and ultimately lead to your unconsciousness.

Get your feet out of your harness so you’re ready to absorb the landing impact.

Stabilise the wing if you have enough time. If, after deployment of your parachute, you are thrown to the rear of your wing, you will likely encounter a violent spin, which you must stop by getting your weight closer to the nose of the hang glider. Hang on tight to your wing; climb up if possible, getting your feet onto the control bar, or onto the keel if your wing is inverted. Prepare yourself for landing by staying focused and relaxed and absolutely do not attempt to shield yourself from the impact with your hands. Your sink rate will be more or less equivalent to the jump height you have calculated for your parachute. If your wing is not too badly broken up, you can try reducing your sink rate by pushing the control bar forward with your feet trying to bring the nose up as high as possible. Be leery of harnesses with dorsal plates that reduce the ability of your spine to flex to absorb impact. Remember that you will not be able to control your tracking direction while falling and that you will not have a choice where you will touch down.

Angelo Crapanzano - metamorfosi
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Fred Wilson
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PostPosted: Fri Mar 23, 2012 04:48 am    Post subject: Reply with quote

Emergency Parachute Deployment Sequence for Paraglider Pilots

Once you have decided to deploy your parachute you must follow the following sequence of operations as calmly, yet as quickly as possible:

1 - look at the deployment handle

2 - pass your thumb through the handle and close your fist around it

3 - open the container by pushing the handle aggressively to extract the pod

4 - aggressively throw the parachute towards clear air

5 - pull in the C risers of your paraglider to disable it

6 - prepare yourself for the landing impact and performance of a PLF

Explanations are necessary:

Looking at the deployment handle is vital so that you will be certain to get hold of it on your first attempt. A second try will cost precious time.

Hooking the thumb through the handle is the only way that guarantees you will get hold of it, especially when flying with gloves. Practice the first two steps in the deployment procedure frequently during regular flight so that it becomes second nature. Be careful not to cause an accidental deployment.

Pushing the deployment handle allows the container to be opened progressively and completely, and to extract the pod using the least possible effort.

An aggressive throw brings the parachute to full line extension in minimum time. The parachute must be thrown into clear air to reduce the chance of entanglement with the paraglider. If the paraglider still has forward speed in a more or less uniform direction, it is desirable to throw the parachute down and back. In the probable case that your paraglider is spinning with an asymmetric closure, throw the pod in the direction you are spinning and outwards from the centre of rotation: centrifugal force will assist in getting the parachute away from you and your wing. If you are wrapped in your glider, all effort must be made to find open air before throwing. Remember that your decision to pull and throw your rescue parachute will also very much depend on your height above ground. If you are very high above ground you have time to try to regain control of your paraglider, or let it sort itself out with your pod in hand, waiting for the most favourable moment. If you are close to the ground, every millisecond is precious: act immediately. Remember that a very fast rotation can ultimately lead to your unconsciousness.

Pulling in the C risers, if you have enough height, will disable forward movement of your paraglider, otherwise it may have the opportunity to interfere with your parachute reducing its stability and increasing your sink rate. If you hold the Cs in one hand (always above the quick-links to be sure to do it symmetrically), you can use the other hand to turn yourself to best face in the direction which would best facilitate PLF at landing. If your lines are twisted - impossible to pull in the C - you can pull in as much brake line as possible to collapse your wing; be careful to pull in both brakes symmetrically to avoid inducing your glider to spin which is highly dangerous once your parachute has been deployed.

Prepare for landing by maintaining your composure and focus. Stay as flexible and agile as possible, and absolutely do not place your hands out in front to help cushion your impact - focus your attention on the proper PLF sequence. Come what may, always remember that your sink rate corresponds to the equivalent jump height you have calculated. Force yourself to practice PLFs and remember that you cannot steer yourself once your parachute has been deployed and you no longer have any choice where you will touch down.

Angelo Crapanzano - metamorfosi
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Fred Wilson
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PostPosted: Fri Mar 23, 2012 04:49 am    Post subject: Reply with quote

Parachute design criteria & use Lecture


by Angelo Crapanzano — metamorfosi - Translated by Maxim de Jong - Thin Red Line Equipment Inc.

Emergency parachutes for free flight do really work. Since 1977, when Jim Handbury had the idea of
attaching an emergency parachute to a hang glider and it’s pilot, thousands of pilots’ lives have been saved.

The important thing about parachutes is to have one when you need one.

The second most important thing is that it works when you need it to.

In some countries, especially among paragliders, a large number of pilots still do not fly with a parachute.
Rather than make it mandatory to carry a reserve parachute (which is quite useless because it’s almost impossible to enforce),
it’s more important to change the outlook of pilots. Instructors should institute the use of helmet and
back protection from the very first practice sessions at the training hill, and use of a parachute as of the first flight.
This way, new pilots learn to regard these items of safety equipment as indispensable,
and those who fly without, instead of being seen as ‘cool’, should come to be regarded as poor fools.

There is much discussion about emergency parachutes, and for those who are not professional in the field,
it is very difficult to sort out the claims forwarded by the ‘experts’.
Since we speak here of a critical safety issue, it is necessary for all questions to be given a satisfactory answer.
Instead of just giving my own solutions to the various problems surrounding use of emergency parachutes,
I think it best to provide an overview of all points so that each pilot can formulate his or her own thoughts and judgement.

Much as I have made every effort to remain objective, this article is the synthesis of thoughts I have formulated in my 20 years of experience in this field. At any rate, I have tried to emphasise the problems rather than highlight my own solutions to them. Other experts may not necessarily agree on certain points; this only highlights the fact that an emergency parachute is the resulting compromise of solutions to performance requirements, which frequently oppose one another. This is the source of the different theories since not everyone will agree which factors are more or less important than another.

"Reliability", in its general sense, is surely the most fundamental characteristic of an emergency parachute:
it’s almost useless to have a parachute if there is little chance that it will work properly.
Every emergency system must be quite simple to be able to function properly all the time and,
preferably, not giving the pilot the opportunity to make a mistake in its use.
This may seem obvious, but in reality it’s quite difficult to achieve a high degree of reliability because
a parachute is often installed in a harness which was not specifically designed for it and use of an
emergency parachute occurs in a complex environment with many, ever-changing, variables.
A special care must be taken to consider any possible complications.

Murphy’s Law says: "anything that can go wrong, soon or later will go wrong".
This isn’t a pessimist’s outlook by any means; it’s simply logic and is the way it is in real parachute deployments.

I have seen many cases where the parachute was rendered completely useless solely because of small,
seemingly insignificant details: release pins that were just too long, hook Velcro sticking to parachute lines,
deployment handles too difficult to grab in a spin, apparently minor mistakes in repacking, etc…
Actually, one can say that the degree of reliability of a parachute is the balanced sum of all its characteristics.

The "perfect parachute" should provide (in order of appearance):

Reasonable price
Minimum weight and encumbrance
Ease of mounting
No risk of accidental deployment
Easy extraction
Pod which will not open untimely
Ease of throw
Correct deployment sequence
Guaranteed opening
Rapid opening
High structural integrity
Small opening shock
Low sink-rate
Geometry facilitating PLF
Ease of repack
Ease of maintenance
Long life span
Guaranteed specifications

Let’s analyse each of the key points one by one:

Reasonable price: That’s the natural request: ‘the less it costs the happier the pilot is", especially
since it’s something he have to have, but will never use (at least that’s what any pilot hopes!).
In reality, even price is a safety factor, because if the price is too high, more pilots will decide to do without.
The bottom line is that the biggest mistake you can make is to fly without a parachute because any parachute is better than none at all.

Minimum weight and encumbrance: At first sight this doesn’t seem so much important,
but these attributes allow a parachute to deploy more rapidly, make it easier to throw and
easier to mount on a harness such that it won’t impede the pilot’s movements.
Also, heavier equipment contributes to fatigue and encumbrance at launch, which is certainly a significant safety consideration.
If safety equipment provides minimal encumbrance there is a greater chance that a pilot will always carry it along, even if he thinks will never use it.

Ease of mounting: Many times impressive contortions are required to stow a good parachute in a good harness with acceptable results.
This is quite a serious problem, which really demands standardisation of systems between parachute and harness manufacturers.
First and most importantly will be to decide whether the deployment handle and the bridle are part of the parachute, or part of the paragliding harness.

No risk of accidental deployment: Unintentional deployments are too frequent, and in my opinion,
it is unacceptable to have safety equipment which can cause problems during a routine flight.
Deployment handles which protrude too far, Velcro, solitary deployment pins, or pins
that are too short, and four-flap style containers can cause accidental deployments.
The container must be designed to minimise the possibility of accidental deployment and,
prior to every flight, the pilot must verify the parachute is securely stowed.

Easy extraction: It must be easy to remove the parachute from its harness-mounted container, that’s
obvious, but this once again poses a serious problem in compatibility between harness and parachute.
The shape of the deployment handle is very important: it should be semi-rigid and easy to hook a
thumb through to guarantee a secure grasp when needed (especially with gloves,
- it's much easier and safer to grab the handle with your thumb then closing the fingers than the contrary!).
It often happens that the parachute is too difficult, or even impossible, to extract from it’s container (especially for less aggressive persons) because of too much Velcro, or deployment pins which are too long.
In certain cases, if the pilot is in a spin, it’s not even realistic to grab the handle of many parachute systems.
After having mounted a parachute on a harness, it’s vital to do a hang check to verify that the deployment
handle is truly easy to grab and that the parachute can be pulled from the container with minimal effort
and in any variety of pilots position and circumstances. Seems obvious, but almost no one actually does it!

The positioning of the parachute system in paragliding, the shape of the deployment handle and
the length of its connecting strap to its pod are very important.

Ventral position: often one must attach the parachute before each flight.
The handle is highly visible and reachable with both hands when one is seated upright,
but it blocks the view and the handle becomes almost impossible to grab during a spin
when the harness has been adjusted for a partially reclined flying position.

Lumbar position: symmetrical, elegant and easy to manufacture, but one that is susceptible to accidental deployments.
The deployment handle is not visible during flight and there are definite problems in grabbing the handle, especially during a spin.
The longer length of the strap connecting handle to pod, makes a controlled throw difficult.
Also, if the deployment handle detaches itself from the Velcro on the harness, it is almost impossible to grab in flight.

Inferior position: same problems as with the lumbar position with the added concern that the
parachute is highly exposed to trauma at launch and landing which may be lead to accidental
deployment at launch, especially if the pilot uses both hands to get comfortable in the harness after launch.
Furthermore, the parachute in this position reduces the amount of space available to the back protection system exactly where it is needed most.

Lateral position: the handle is always within reach, even during spins.
Use of Velcro is practical, but does not make for a stable container mounting system:
it’s best to choose a container integrated, or sewn, into the harness.
Some pilots think that the asymmetry in mounted weight may enhance asymmetric collapses.
It is possible to make the strap connecting handle to pod very short, and if the handle is
poorly positioned it may get hooked by a steering toggle in flight, causing an accidental deployment.

Dorsal position: the parachute is reasonably well protected from mishaps at launch and the
deployment handle is quite visible on the shoulder, but the connecting strap needs to be quite long.
The routing of the bridles is problematic for the throw if you use the correct hand to deploy and may
actually block the throw if you use the hand opposite to the deployment handle (which is quite a natural reflex).

In hang gliding, both the side and frontal position are good:

Front position: the handle is easy to catch with both hands while the parachute offers some protection
in case of crash but obliges to stay higher over the control bar; of course the handle is quite exposed
and could get tangled in a bad takeoff or in the instrumantes if monted on the speed bar.

Side position: better aerodynamic because the parachute is behind the arm and,
if the container is properly designed, the handle is easy to get with both hands.
Unfortunately often side containers are badly designed and the handle is difficult to get or could get tangled with the side wires.

Important: Do a hang check and actually verify the extraction of the pod
from the container plus the necessary control of the pod for a proper throw.
Too much Velcro, the wrong type of release pins, or pins too long, is able to impede or even entirely prevent
correct pod extraction while a too long handle impedes to control the throw direction and could also get tangled.
Be aware that it is entirely possible to mount a good parachute on a good harness in a very dangerous way!
If you encounter any problem extracting the pod from hte harness get a professional check your system.

Pod which will not open untimely: Once the pod is extracted from the container it is fundamental it does not open until the parachute has actually been thrown. If the pod opens before this time there is a much greater chance for the parachute to hook on something causing malfunction. If necessary, the pilot must be able to wait, pod in hand, for the right moment to throw.

Ease of throw: This is a very important factor which depends on the weight and encumbrance of the parachute, but above all, on harness/container geometry, and the position, orientation and shape of the deployment handle. If the strap connecting the handle to the pod is too long, or if it’s attached to the pod at a single point, it becomes very difficult to control the throw and the parachute may snag the hang glider frame or, even more likely, wrap itself among the paraglider lines. Double handles, which have been relatively popular some years ago, are especially prone to tangle in paraglider lines impeding parachute deployment. Hook Velcro, found on many deployment handles, can be responsible for a variety of deployment problems and has been the cause of at least one death.

Ballistic and pneumatic systems have been used to assist deployment. The advantage of these systems is that they allow optimal positioning of the deployment handle and bring the parachute to full line extension very quickly. The disadvantages are that it is impossible to choose the direction of deployment, and system complexity is significantly greater which reduces reliability. Another disadvantage is that deployment sequence is normally "canopy-lines-bridle" which is not the best one.

Choice of correct throw direction contributes to a more rapid deployment and helps avoid a host of serious problems which may lead to malfunction - it is vital that pilots learn to follow the correct deployment procedure.

Correct deployment sequence: To reduce the possibility of malfunction during deployment of the parachute, and to reduce the risk of interference with the hang glider or paraglider, one must guarantee that the deployment sequence will be ‘bridle-lines-canopy’ and that the pod will not open until it has been thrown. If the pilot has not succeeded in an aggressive throw and one falls at more or less the same speed as the closed pod, it becomes mandatory that the pod opens with very little line tension.

To check if your pod correctly and easily opens, put it on the ground then try to lift it by the bridle and lines: the deployment sequence must be staged "bridle-lines-canopy" and you must not be able to lift the pod from the ground.
To check if your pod may open before being throw, hold the parachute from hte handle and shake it vigorousely.
If one of these test goes wrong get a professional check yur parachute.

The cumulative length of bridle, lines, and parachute canopy must be less than the line lengths of the paraglider. If this is not the case, the parachute may interfere with the leading edge of the paraglider impeding, or at least delaying, full deployment. This penalises parachutes with a larger surface area since, generally speaking, a parachute’s sink-rate and stability suffer badly when the length of the parachute lines become less than the diameter of the canopy.

For hang gliders, to keep the parachute away from the wing, the bridle must extend past the hang glider’s leading edge. But paradoxically, much as it is required that the bridle is long and that longer lines improve stability and parachute sink-rate, it is necessary to have a short sum of bridle plus lines to get a fast deployment. Is a compromise necesssary?... maybe not Smile

Guaranteed opening: It must never be forgotten that anything attached to an emergency parachute is something that can snag. As such, the pod must never be attached to the parachute canopy, and pilot chutes must never be used regardless of configuration. For the same reason, canopy vents increase the possibility of fouling during the deployment sequence. In a real life emergency, it is shown that one falls at relatively low speed, and the pod, still closed, falls faster than the pilot. It is precisely this difference in speed that extends the emergency parachute lines facilitating its ultimate deployment from the pod. Any factor slowing the fall of the pod in this scenario leads to delayed deployment.

Once line and canopy extension occur, and nothing has snagged, the possibility that a round parachute will not open correctly is negligible. One cannot say the same of more complex parachutes like those with vents, those that are steerable or asymmetrically vented, and especially those parachutes of the Rogallo style which are highly susceptible to even the smallest mistake in packing or interference during the deployment sequence.

Rapid opening: In the mountains the majority of one’s flight time is spent relatively close to terrain, exactly where the possibility of tumbling and collapses are the highest. Furthermore, in case of a collapse at high elevation above the ground (without structural failure), a paraglider pilot must always focus on regaining control of his wing, avoiding use of an emergency parachute unless all else fails or little elevation remains. In real accidents one drops at relatively low speeds, often less than 10 m/s, because the broken hang glider or collapsed paraglider greatly slow the descent.
Rapid deployment of an emergency parachute is then indispensable at these low speeds and altitudes.

Everybody always speaks of 'opening speed', but it is the ‘vertical opening distance’ (the vertical distance necessary for the parachute to open) which really counts for us! This opening distance largely depends on sink-rate at time of deployment: a lower sink-rate usually requires a greater opening distance. The most difficult situation for deployment with a paraglider is the negative spin (no forward speed and low vertical speed), whereas, for example, a spiral dive autorotation (high forward and vertical velocities) speeds up parachute deployment. The bottom line is that the parachute must open correctly at any speed. Note that if the parachute opening tests are made with forced opening (pod still attached when the load is released) and starting from 0 speed, the opening distance is shown to be almost precisely a function of the opening time squared, i.e. doubling the opening time requires basically 4x the opening distance.

High structural integrity: A parachute designed specifically to withstand the opening shock associated with terminal velocity is no doubt desirable but, to reduce the opening shock to an acceptably safe level for the pilot, it is necessary to increase the opening time, which increases the vertical opening distance. This is not at all desirable for free flight application.

Years of accumulated experience suggest the choice of the following compromise: set structural standards for paraglider lines and hang glider hang-loops high enough to essentially exclude the pilot can separate from his paraglider or hang glider, and test emergency parachute equipment for structural integrity to roughly 150 km/h.
Remember it takes significant time and distance to reach high speed: if terminal velocity is 180 km/h (chosen value by skydivers), it takes 6.1 seconds (151 m fall) to reach 150 km/h in free fall, while to reach 170 km/h takes 9.1 seconds (283 m).
It is wrong to say that ACPUL tests parachutes in free fall and DHV does not: for paragliders, ACPUL makes one test dropping an 80 kg weight for 5 seconds (reaching, considering friction on the load used, approximately 165 km/h) while DHV drops a minimum weight of 100 kg from 85 m (providing a top velocity of 142 km/h). The ACPUL tests load the parachutes with 9 % more energy, but DHV makes the test three times with the same parachute, in which process the parachute lines lose elasticity - we leave it to you to judge which test is more severe.

To provide perspective, the American TSO certification for sky diving and military parachutes, requires the same parachute to be submitted to 60-odd deployments with a 77 kg load, frequently at 240 km/h (double the energy roughly of the European free-flight certifications). The European CEN certification for emergency parachutes has not yet been officially completed and as such I prefer not to provide comments.

Small opening shock: This is a continuation of the same issue as structural integrity: reduction of opening shock is inextricably linked to an increase in opening distance. It is worth remembering that a pilot can withstand an opening shock of well over 20G since he is subjected to this force for only a very short time. Also worth remembering is that the opening shock is proportional to the velocity squared: for example, giving the same parachute, the opening shock at 150 km/h is 9 times greater than the opening shock at 50 km/h.

Stability: A high level of stability is vital since the ultimate impact force when a pilot touches down often depends more on the pilot’s swinging to and from than on the actual sink-rate of the parachute. In this context one must take note that, generally speaking, high porosity fabric makes for a more stable parachute and a lower opening shock, but does this directly at the cost of sink-rate and opening distance. The best results are certainly achieved by designing a parachute specifically for the intended application. A common misconception is that classic style round parachutes are more stable and oscillate less than pull down apex ones. Stability is often influenced by seemingly insignificant factors and is always heavily influenced by the close proximity of the glider and, in paragliding, by the exact position of the center of gravity of the pilot with respect to the emergency parachute canopy. This center of gravity position is mainly determined by the location of bridle attachment points on the harness and the bridle geometry.

Low sink-rate: It is of course possible to improve (i.e. reduce) the sink-rate for a parachute of a given size by designing it with the highest possible aerodynamic drag coefficient (a modern, high drag parachute of 20 m2 may have the same sink-rate of a silk parachute of 80 m2). However, to obtain a better sink-rate for the same pilot weight on the same parachute design, the only possibility is to use a larger size parachute. A seemingly obvious choice made by many, however, a larger size requires a greater opening distance, more weight, more volume, greater encumbrance to extract from the container and accurately throw, and a higher price.

A larger size of the same design has longer lines and requires a larger volume of air for inflation: at high speed the vertical opening distance required by a parachute is related to the square root of the surface area (doubling the surface area increases 1.41 times the opening distance). However, in real life deployments at very low speed, other factors and especially the parachute weight, strongly influence this formula: in my opinion a reasonable estimate would be that a parachute of the same model, but twice the surface area could require almost twice the opening distance in the most difficult sytuations.
A larger size of the same design brings you down slower according to the square root of the surface area (doubling the surface area reduces 1.41 times the sink-rate), but the impact energy (which is what we are actually interested in) goes with power two of sink-rate thus, with a parachute of half surface, you'll hit the grond twice as hard.

It is difficult to visualize a sink-rate given in m/s. A good system to gain a feeling for sink-rate is to use the ‘equivalent jump height’ instead of sink-rate. Since, in this case, friction of the falling pilot is negligible, the kinetic energy (mv2/2) equals the potential energy (mgh): this provides us an equivalent jump height of h=v2/2g. For example, a sink-rate of 6 m/s is roughly equivalent to jumping from a wall of 1.8 m height (from a standing up position). If one knows the equivalent jump height of a parachute model with a particular pilot weight, it is very easy to calculate the equivalent jump height with your own weight because it's directly proportional, i.e. doubling the pilot weight doubles the equivalent jump height which gives double the energy of impact.

In hang gliding your landing position is heavily affected by the wreckages of the glider, but in paragliding it's easy to simulate how will you land under canopy. Hang yourself in your harness from a rope tied to the inverted V bridle with your feet at the equivalent jump height corresponding to your weight with your parachute; check your position and imagine to cut the rope.

if your neck is forced down your V bridle is too short.
if you feel you'll fall backward then your leg straps are too short or the parachute connection is not in the correct place (have it moved forward by a professional or change harness)
if you are in a good vertical position but you feel you would hurt yourself falling from that heigh, then the your parachute is too small for you: get a parachute with a better sink-rate (or bigger or a different design).

If you feel perfectly confident you could even have a friend cutting the rope and let you fall (don't forget to wear the helmet and possibly have a mattress below). Don’t do this test if you have any doubt concern at all of hurting yourself and don’t place too much confidence in back protection: rigid style back protectors can allow expose your spine to an impact force of 40 G in a fall of only 30 cm! - more than enough to collapse vertebrae and put you in a wheelchair for life!

It's obvious that the greater the sink-rate the greater the risk of injury. However, given the same parachute design, the more we reduce the sink-rate the longer it takes for the parachute to open and then we must concern ourselves that the parachute may not open in time during a low elevation deployment.
A lower sink-rate makes it easier to disable the paraglider to reduce its interference with the parachute; however, this procedure requires some altitude and experience to be successful. It should be the responsibility of instructors to teach newcomers to our sport the correct procedures for disabling the paraglider and how to properly execute a PLF (Parachute Landing Fall), which is not only useful during a parachute landing...

The controversy over sink-rate is essentially a philosophical problem: Alain Zoller - Swiss Federation test pilot - with considerable experience deploying parachutes in simulated accidents, prefers a good sink-rate, while Andy Hediger - renowned Paratech test pilot - who has performed at least 5 deployments in real accidents, prefers flying with a parachute which opens very fast. To allow everyone to decide for themselves, pilots must be clearly informed what sink-rate they will get with their weight on a particular make and model of parachute, very carefully remembering that what is acceptable for a young karate champion would be totally inappropriate for an elderly pilot in poor physical condition.

These are the maximum sink-rates allowed by the different certification organisations. To easily compare them I have listed the equivalent jump heights for 60, 80 and 100 kg pilot loads.

60kg . . . . . . . 80kg . . . . . . . 100kg

2.02 . . . . . . . . 2.69 . . . . . . . . 3.36 . . . . DHV: 6,8 m/s at 70 kg

1.15 . . . . . . . . 1.54 . . . . . . . . 1.92 . . . . ACPUL: 5,5 m/s at 80 kg

1.63 . . . . . . . . 2.17 . . . . . . . . 2.71 . . . . TSO: 6,4 m/s at 77 kg

The DHV and ACPUL values are specifically for parachutes intended for emergency use for free flight. The TSO values are for military parachutes and emergency parachutes for skydivers. I have added the TSO standards for comparison and because it’s the certification which has been most heavily tested and is universally accepted in skydiving.

At first glance it seems that DHV accepts very high sink-rates, but it is important to consider we’re speaking of maximum values here: as for DHV, a very heavy pilot would purchase a larger parachute, certified for a higher weight. With the ACPUL certification, even if one is very light, he cannot purchase a smaller parachute to reduce weight, encumbrance and opening distance because the smaller size cannot be certified. Sink-rate changes dramatically with pilot weight and it is not possible to have one parachute for all pilots. In this regard I have long proposed to CEN (the new European Certification Standard) that all parachutes should have a label with a number which, when multiplied with the weight of the pilot, gives the equivalent jump height. As such, everyone would be able to choose an appropriate size parachute and be aware of the results and requirements of one’s choice. The impact force at the ground heavily depends on wind speed: roughly speaking, a 20 km/h breeze would result in double the impact force as one would experience in calm conditions, and a wind speed of 40 km/h would result in a impact of 5 times larger than calm conditions almost regardless of the sink-rate of the particular model emergency parachute (but with wind on a flat surface one will hit the ground at an angle...).

DHV and ACPUL differ considerably also when it comes to their choice of acceptable parachute opening times: their respective tests do not resemble one another in any way and, as such, are not comparable. However, in broad strokes, ACPUL requires an opening time of under 4 seconds in a rapid autorotation and under 6 seconds in a parachutal phase. DHV requires the parachute to open in less than 60 vertical meters when the load (simulating the pilot) and the parachute are dropped in free fall, side by side, at the same time.

The DHV test pushes the manufacturers to design a pod with high drag (like a drogue chute connected to the pod) but, in my opinion, this is wrong because would go against a good result in most real emergency situations.
In a real accident normally the pod falls faster than the pilot thus a slow falling pod would highly increase the opening time. Furthermore there is always the possibility that both pilot and pod fall down at the same speed. In this case the only available force to open the pod is the aerodynamic drag of the lines but drag goes with speed power two: half speed, one quarter drag. In my opinion it's important to have a pod with low drag (i.e.a fast terminal velocity) to reduce the chances to have pilot and pod falling at the same speed and, in case it happens, to have as much as possible drag on the lines to open the pod. Another important consideration is that anything attached to the pod increases the possibility of entanglement.

Steerability: The ability to steer a parachute away from an obstacle, or to face oneself into the wind, would be an evident advantage. For hanggliders this is simply not possible because the long bridle removes any possibility of use of a directional control mechanism. For paragliders it is possible to use round steerable parachutes, providing a glide of less than 1 once the paraglider is released. Of course if hte paraglider is not released there is a huge loss in glide performances and, with sufficient altitude, it is probably only possible to get oneself facing into the wind.

A Rogallo style emergency parachute is a different matter: deployment is rapid and it has a glide angle close to 3:1, but to avoid serious problems of interference between the two ‘wings’ it becomes almost mandatory to cut away from the paraglider. This involves, of course, a serious risk of entanglement and a remarkable complexity in procedure, especially if one takes into account other details such as disconnection of the speed system. In my opinion, given the likelihood of deployment at lower elevations, the real benefits are minimal compared to the theoretical benefits and are possibly overshadowed by the system’s disadvantages.

Geometry facilitating PLF (Parachute Landing Fall): Certainly one of the most important issues on paragliding. However this depends on the location of the attachment points of the parachute on the harness, and not on the parachute itself. Our legs are very efficient shock absorbers: a fall of only 50 cm on the back, without suitable back protection, may easily put us in a wheelchair, while such a fall landing on one’s feet is absolutely insignificant. Suspend yourself with your harness, 2 meters above the ground from a variety of anchor points corresponding to possible attachment locations for your emergency parachute bridles, and imagine cutting the rope and performing a PLF from this height. The best points of attachment for the parachute bridle are the specifically intended shoulder location common on most paragliding harnesses. Use steel quick-links instead of knots or girth hitches, which cause the webbing of the bridle to melt through under high impact loads. There are two bridle styles to attach the parachute to the harness: inverted V, and H. If the inverted V bridle is too short the pilot could have problems with his neck. Conversely, since the shoulders are not likely to be at the same height at the time of the opening shock, use of an H bridle may result in the parachute opening into a ‘Mae West’ malfunction. Both cases offer drawbacks, however they are both extremely improbable.

For hang gliders, it’s best to anchor the parachute bridle directly to the main harness carabiner so that during the descent under parachute, the parachute supports the weight of the glider and the pilot will have some possibility of movement. If the parachute is attached to the pilot, the opposing aerodynamic forces of parachute and glider will trap the pilot in a likely undesirable position and, as unfortunately happened to Brad Koji, the bridle or control bar can hook under the pilot’s chin. Watch for harnesses with large stiffeners in the back: can prevent your back from bending to absorb shock upon landing, thus leading the possibility of crushed vertebrae.

The use of a swivel to avoid the parachute winding up in case the hangglider is spinning is controversial and, in my opinion, mainly depends on parachute design: personally I do not like it but other renowed manufactures are highly in favour.

Ease of repack: Ease of repack is a fundamental characteristic of an emergency parachute as is its capacity to function even if it has not been perfectly packed. The layout must be such to preclude the possibility of significant packing errors. It is vital to provide good packing instructions with the parachute and that no one with inadequate experience shoulders the responsibility of parachute repacking. Attention: Rogallo style parachutes must in all circumstances be packed by true experts.

Ease of maintenance: Maintenance, and especially timely repacks, must be easy to perform and be well-explained in a comprehensive owner’s manual precluding chance of error. Packing a parachute every 3 or 4 months facilitates faster deployment and provides the best way to do a safety check on the system so that one is always confident it will work when needed. When buying a parachute do not discount the possibility that lines and/or bridle may be easily replaced because they may be easily damaged.

Long life span: Parachutes are constructed of synthetic materials which, while of impressive strength, deteriorate over time. The canopy nylon is very susceptible to UV radiation: left in the sun, the canopy can lose up to half of its strength in one week only and, as such, must be effectively protected. Take note that many weaves of container material allow light (and hence UV) to filter through to the parachute. For safety rasons, regardless if it has been used or not, it is best to retire a parachute after 10 years, or use it as secondary parachute only.

Guaranteed specifications: A parachute’s specifications must be printed on the canopy to allow the pilot to verify its suitability. These specifications must be guaranteed by the reliability of the manufacturer, or better yet, by a certification system which is both serious and comprehensive of everything (which, in my opinion, does not yet exist).

Personal Thinking

Having provided this review, I leave it to the individual to carefully weigh the information, and upon final evaluation, decide the best compromise for oneself.

One might think that I have written much of the above to justify certain design choices I have already made. Others would think that the above reflections have naturally led me to the parachute which I have designed providing the best compromise in my opinion. Everyone can think what they will, but I wish to here explain the reasons for my personal design choices.

There is a profound difference between tests performed for certification, tests performed for demonstrative purposes and real life emergency parachute deployments:

In the first case one wishes to verify that the parachute falls within parameters established, more or less arbitrarily, by some individual or organisation.
In the second case one wishes to show that the parachute works well and brings you softly to the ground.
In the third case one wishes to save one’s life.

An emergency parachute is needed when one’s life is in the balance and, in my opinion, must offer the greatest probability to perform properly in the scenarios which have been shown to be the most common, the most important of which is low altitude above ground.

In the owner’s manual of all my parachutes I provide the formula to calculate sink-rate using your own personal body weight (of course this formula is not applicable to other parachutes): the equivalent jump height which I advise using a CONAR model is between 1.3 meters with an absolute maximum of 1,8 meters.

Until now (January 2003), there have been 265 confirmed deployments of my parachutes in real life accidents, and for sure many others I have not been made aware of. With the exception of minor scratches, in these accidents a total of six pilots were injured:

torn knee ligaments in a pilot who landed in a boulder slope
broken ankle of a pilot who landed in a wind of 70 km/h (when five friends died at Cornizzolo - Italy due to a huge thunderstorm)
broken jaw when a pilot hit their face on a fence post at landing
a broken wrist when a paragliding pilot at Feltre - Italy, was dragged back up the slope in ridge lift after the parachute was deployed
two broken ribs in a Brazilian pilot who came down on the roof of a house
heavy cuts on the nose of a pilot who came in, face first, at almost 3000 m in the mountains of Owens Valley - California.

A German pilot died at Castelluccio di Norcia, in Italy, because he added a deployment handle extension with "hook" Velcro to the existing deployment handle. This Velcro hooked on the lines before opening of the pod and the parachute could never deploy.

Of these 265 deployments, roughly half were made below 100 m AGL, and possibly a quarter below 50 m. We encountered three cases of free fall (the firs two of them with the Classic model and the last one with a Conar):

at Laragne, in France, Derek Austin broke the keel of his hang glider and unfortunately was not able to throw his parachute before reaching very high speed; when he finally did deploy his parachute, the lines separated leading to his death.
Andy Hediger in Zillertal, Austria, after all lines of his prototype paraglider broke, threw his parachute at a speed which was probably much higher than the 138 km/h measured by his barograph (recording data in 4 second intervals). He landed safely after a descent of more than 2000 vertical meters with an average sink-rate of 5.5 m/s.
Flavio Bezerra, a Brazilian pilot at Sao Conrado in Rio de Janeiro, forgot to hook-in at takeoof, hung from the base bar fom a while, then he let go and threw the parachute after a few seconds of free fall. The parachute opened perfectly and the pilot landed unscratched.

Derek was the president of the safety commission of the British Association: he was my friend and in a sense I feel responsible for his death. If I had chosen a different compromise, perhaps he would still be with us. But then again, what would have become of the Karl Reicheggers, Robbie Whittals, Andrea Patruccos and others who threw their parachute less than 30 meters from the ground and the parachute opened just in time to save them?

Several years ago, the British Association compiled a general accident statistics showing that when an emergency parachute functioned correctly, it saved a pilot’s life in 97% of deployments. In the remaining 3% were included cases where the parachute did not deploy properly or quickly enough, and further included a solitary case where the pilot died of the speed at impact under a fully open canopy.

This proves emergency parachutes in free flight do indeed work; there is always the possibility of improvement (a 3% failure is quite high anyway...) and the developmental process must continue and that's what I've done with the Conar design. Nonetheless, I believe the most useful step to take involves convincing all pilots that the parachute is not an accessory, but an indispensable piece of equipment and it0s mandatory to learn how to use it.

Even though an emergency parachute cannot provide a 100% guarantee, and as such should be seen not as a guarantee but as another possibility, one must never forget:
Aviation has made the world much smaller but it is still hard to miss it if you fall!

Angelo Crapanzano — metamorfosi
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Fred Wilson
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Posts: 45
PostPosted: Fri Mar 23, 2012 04:51 am    Post subject: Reply with quote


Practice, Practice, PRACTICE!

Of all the pilots I know who have come down under canopy, not one has ever thought it would happen to him (her).
The consensus is that practicing deployments on the ground, attending parachute clinics, looking and
reaching for the deployment handle each flight, imagining and repeating your deployment sequence at home
and talking to pilots who have come down under canopy all help prepare you for a safer deployment.

Remember: even under the best conditions your parachute may not work so above all else...FLY SAFELY.

By practice, I mean practice practice practice deploying in order to MINIMIZE your deployment times...
- so I refer you to videos like these:

Over a grassy hill: http://www.youtube.com/watch?v=hE1df-w_S5g

At Woodside, over a forest: http://youtu.be/NDwbcWQHfqw

Over Manilla Launch (start at the 2:45 mark.) http://www.youtube.com/watch?v=NQOUjCTCtAk

As far as I know there have been only three comparative test results between emergency parachute, all of them for paragliding.

(A new DHV comparative Test Report was published recently, after Angela passed away.
- See: http://www.apcoaviation.com/news/news/2009/APCO%20Mayday%20review.pdf - Tnx.)

The first one was made by the Spanish magazine "Parapente" in February 1996, using an hot air balloon and an 86 kg mass.

In November 1996 these test were repeated by FIVL, the Italian Federation, more or less in the same way but from an higher height, using a helium balloon and an 80 kg mass.

The third test is much more recent and was made by the French magazine "Vol Libre" in December 1999. In this case they used a real paraglider in flight with a pilot flying weight of 97 kg.

The fourth comparison has been requested from the American market: http://www.highenergysports.com/hg_flight.htm
- a comparative test between the manufacturers declared data (it cannot be considered by the DHV as a true or complete comparison.)

The Conar parachute entered into production in January 1999; that's why our Classic model was tested in the first two comparative tests.

To judge a parachute many other factors should be considered beside performances: reliability, strength, ease of deployment and opening time... just to tell the most important.

cont... spreadsheets and followup articles to further spreadsheets at:

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Fred Wilson
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PostPosted: Wed Aug 29, 2012 11:04 pm    Post subject: Reserve Parachute Packing Courses Reply with quote

Does anyone here know anyone who has taken the APPI Rescue Packer Certification Course? http://appifly.org/?Rescue-Packer

I would sure like to know details about this offering. Tnx! (I've seen some amateurish sessions lately.
- A far, far cry from what Vincene Muller and Muller Windsports puts on!

One of the best clinics each year in Canada is the Paragliding Reserve Chute Deployment Training put on by Muller Windsports
See: http://www.youtube.com/watch?v=DAETwwhvkR

How many chute clinics have you been at where pilots hung straight and steady?
Doesn't Vincene's course look like much more realistic and relevant training?

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Fred Wilson
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PostPosted: Thu Aug 30, 2012 08:24 am    Post subject: Reply with quote

Again, IMHO the #1 most important factor in deployment times is PRACTICE. Period. Little or nothing to do with make or model.
Though having the proper chute for the right harness / container is an often forgotten item in the shopping list.

Regular repacks are a good idea, but for me this is just an excuse to get pilots to PRACTICE. Period.

A plug for Betty Pfeiffer here also. http://www.highenergysports.com/

Betty Pfeiffer wrote:
Essentially our position is that we want rubber bands that stretch easily.
We use #61. If you want a better bite just keep the loop through the d-bag rubber band attachment loop loose.
We do not advocate double wrapping the rubber bands.

Do your club a big, big favour and bring her out for one of your chute clinics.
She spends one and a half full days on it... unlike most of us who allocate a few short hours.
She spends time on harness inspections, and plenty of time on practicing deployments. One terrific, in fact: World Class seminar.

The Betty Pfeiffer Reserve Parachute Clinic: a quick outline of what I cover.

A video of Betty Pfeiffer and her ultra professional clinic: repacking one of her High Energy Sports Pull Down Apex Quantum 330 chutes.
Part 1: http://www.youtube.com/watch?v=PpoVTkMLrwo
Part 2: http://www.youtube.com/watch?v=CLdBEYYschc

- follow the manual procedure for your chute and/or get advice/help from the experts.

Parachute Deployment and Repack Articles Website

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Fred Wilson
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PostPosted: Fri Sep 14, 2012 11:55 am    Post subject: Reply with quote

Importance of having a backup carabiner
See: http://www.youtube.com/watch?v=tduUi9GuYAs

SHPF Ratho and Repack Clinic 2012 practicing Reserve Deployments using a Zip Line.
See: http://www.youtube.com/watch?v=H1xVbnetKig
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Fred Wilson
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PostPosted: Fri Jan 29, 2016 07:23 am    Post subject: Reserve Deployment Clinic Videos. Reply with quote

The Hang Gliding Federation of Australia has posted a whole series of videos dedicated to reserve parachutes, including some from their clinics.

See their dedicated channel at: https://www.youtube.com/channel/UCFlb68K990pnWXI914-i39w/videos

Hang Gliding Parachute Deployment Practice Live, In-Flight with cutaway of the chute after successful in air deployment
Auckland Gliding Club's airfield, Drury, New Zealand
See: https://www.youtube.com/watch?v=jNuU2ntbBI0 while we work the bugs out of embedding this.

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