FREQUENTLY ASKED QUESTIONS / DISCUSSION TOPICS
Welcome to the Frequently Asked Questions (FAQ page). Below, I have tried to answer the most common questions or address issues that visitors to this site may have. If you find that your question is not answered on this page, please email me or call me during business hours on 0431 646 723.
Things happen and sometimes situations or incidents may seem similar. As a general rule though I expect every situation and set of gear to be slightly different. Those differences, even if they are small, can have a cumulative negative outcome. Therefore I will always encourage people to talk to an instructor or rigger about the challenge being discussed.
The following discussion points have come from the myriad of conversations I have participated in over the years.
MICROLINE Vs SPECTRA
Spectra comes in various grades. Spectra 900 which is a bit erratic in its wear profile and Spectra 1000 which is what we use in parachute construction. When PD first started using Spectra, they called it Microline, and still do for that matter.
Other companies did some tests on what they thought to be PD’s Microline. Supposedly this was in an effort to discredit the new material. The challenge was they were testing the inferior Sprectra 900 while PD was and still is using the much superior Spectra 1000 under their name of Microline. Note that this number has nothing to do with strength.
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SOFT LINKS vs SOLID LINKS
In recent years there has been a growing trend towards not using metal links for harness canopy attachment in preference for soft non metallic links.
The concept of a soft link has been around for many many years. Their history goes back to sailing days when they were used for securing lines and tackle on sailing ships. They were also popular as part of securing or lifting cargo because, being non metallic, they didn’t rust. Also the vessel’s rope people could make them up easily.
In parachuting we have done away with as much metal as possible for a range of reasons such as weight reduction, avoiding corrosion and reduced wear to nylon components.
But they need to be connected correctly or they won’t hold. That is why it is imperative to “lock” them off correctly. Only a few weeks before I wrote this I came across a chap who didn’t lock them off after changing risers and found himself sitting under a canopy attached only by the steering lines.
The soft links I produce are made from 1,000 lb Spectra 1000. They have been tested to over 1,500 kg or 3,300 pounds. Considering a hard 4G opening at best puts around 640 kg or 1,400 lbs on the system, and allowing for the front risers to take two thirds of the aerodynamic load, there is a considerable safety margin. (The front third of an aerofoil takes by far the majority of the load in flight.)
Even though they are quite strong and do a great job, they are a non metal item subject to more rapid wear than their metal equivalent. Therefore it is also wise to replace the soft links each time a canopy receives a new line set.
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PIN ROUTING ON CLOSING FLAP
Over the past two decades I have seen two complete about faces on how the bridle cord should routed so as to avoid total malfunctions and achieve a clean deployment. What approach is best? In regard to the bent pin orientation, which is more important, a happy or sad face? Does it matter?
If you have any reservations, and before changing anything in your procedure, check the manufacturer’s manual. Before any product is released to the public it is exhaustively tested. Therefore you are at least your starting point is what the manufacture suggests.
There are two challenges that I have come across. The first one in whether or not the pilot chute can extract the pin smoothly and cleanly. With some placements of the bent pin in a smiley configuration and the bridle set up in a way I see people do it all the time, the bridle can cause the pin to turn and lock over the bridle as it attempts to turn and extract the pin. This has caused some embarrassing “pilot chute in tow” moments.
Riggers, depending on the production manual or their own packing preferences can make a bridle with the curved pin sitting either up or down, to the left or right depending on which side they expect the pin to be inserted into the loop. This is where some thoughtful experimenting on the ground can make a lot of difference.
The second concern is to ensure the bridle cord cleanly extracts the bag from the container. A whipping bridle cord, flicking around, can be a challenge. It can catch flaps. Rare? Yes, but it can.
The again, if the bridle comes out the bottom and then pins the loop as has always been the standard with Racers, the bridle then has to lift the flaps before it can lift the bag. But in doing so it is clearing the way for the bag to leave.
All these ideas work and work well but sometimes things happen. It could be the packing method or it could be the mix of pin orientation, bridle cord replacement and body position at time of deployment.
A good subject to discuss with packers, riggers and instructors.
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PILOT CHUTE SIZE, WEAR / TEAR AND REPLACEMENT
An often overlooked piece of equipment is the trusty old pilot chute. Packed correctly they are reliable and almost always fail safe. As I often tell people, there are over 500 ways to pack a pilot chute and at least 499 of them work. But like any piece of equipment, it can wear out through repeated use.
We toss it out in 170Kph airflows where this tiny frail piece of fabric can exert over 120lbs (50kg) of drag and act as a sky hook of sorts for your canopy to deploy from. This ability to exert a reasonable force is why it is okay to have a reasonably tight loop.
On the other hand, it does need to be big enough to do the job. According to Dan Poynter, below 150kts it should be at least 3% of the area of your main and around 2% if your opening speed is above 150kts. Using this rule of thumb we get the numbers outlined in the table.
But don’t go too small or it just won’t work, least of all on a hop and pop or in an aircraft emergency exit where you are both low and sub terminal.
And then there is the question of F-111 or ZP. ZP creates that little more drag for its size but it can also slip out of the BOC pocket easier. Therefore a lot of people prefer the F-111 which also loses its permeability faster than ZP, so once again, don’t go too small.
Keep an eye on the mesh, as it is likely to wear first especially if it is allowed to be dragged only the ground, through twigs or near any sharp edges.
Poynter talks about pilot chutes having a service life of 300 jumps but I have seen them working effectively with over 1,000 jumps. So keep an eye on it. Don’t take it for granted and you should continue to have an effective tool to hang your main canopy in the sky.
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STALL vs COLLAPSE OF A CANOPY
When I first heard someone ask what the difference was between a canopy collapse and a stall, I was both surprised and intrigued. After a few pondering moments I realised that while aircraft pilots go through a great deal of training in aerodynamics and principles of flight, in skydiving, we generally only touch on the subjects during initial training.
In essence a stall is caused by a loss of aerodynamic lift, either by excessive curving of the canopy causing the centre of lift to move too far forward and the smooth airflow over the wing turns into turbulence. The canopy then either mushes backwards or stalls.
A canopy collapse is where the wing stops being a wing and resembles a less than useful bag of washing. This can be induced either by a excessive flight control or by turbulent air associated with body or “payload” position under the canopy.
It is certainly worth doing some reading on principles of flight and aerodynamics, especially if you want to understand more about what is happening when you are swooping. Ask your pilot for the title of a good book. They will probably recommends ones from their flying lesson days. The only challenge that we add to the mix, – and for us, it is a big one – we suspend the payload a long way below the wing. This means you need to read a few books and articles on canopy design that are respectful of the aerodynamics involved. Short, dumbed-down articles are not sufficient for a good understanding.
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HOW TO PACK A PILOT CHUTE
In general I tell people that there are over 500 ways to pack a pilot chute and at least 499 of them will work. Often people talk about the emphasis that Brian Germain, an American canopy manufacturer, puts on his method of packing a pilot chute.
What many of the 500 methods don’t take into account are the potential challenges of various forms of a total malfunction. For example if the bridle cord gets snagged on exit, it may pull on the pilot chute in the BOC (Bottom Of Container) compressing the contents in such a way that no amount of force can extract it up until the point that the pocket fails.
The essence of what Brian does, and I whole heartedly endorse it, is to get all the “chunky” bits of the pilot chute and bridle as close to the opening or mouth of the BOC pocket. In this way if you pull progressively on the bridle cord, the bridle and pilot chute should easily come out. If it comes out easily you have just removed a series of possible horseshoe scenarios that may impact your jumping success.
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WATCH THOSE BRAKE LINES
So often we take our gear for granted. Most of the time this won’t hurt us, but sometimes life and lack of altitude catch up with us. May people feel that if the canopy survives opening all we have to worry about are other people running into us.
When was the last time you looked at your brake lines?
The rule of thumb is we should replace our suspension lines about every 500 jumps and our steering or brake lines twice as often. Every 250 jumps. The reasons for this are two fold and fairly obvious. These are the lines we work the most whether we are doing lazy turns or yahooing around the sky having fun. Secondly, they are also the lines we need to stay in tact while we flare for landing.
Regardless of the size of your canopy, give some thought to what might happen if you snap a steering line while you are in deep brakes as you flare for landing.
At best it will be a sudden turn with a bit of a roll along the ground. At its worst, it could be fatal.
So, check those lines closely. Look at the wear on the line, look inside the spliced or finger trapped eyes for wear caused by the other lines, toggles or guides. As you swoop in the only questionable component should be your judgement, not your gear.
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HOW WOULD YOU EXPLAIN THAT DECISION TO THE CORONER?
I know I am responsible for the decisions I make. I have always known that. And over the years in various activities I have lost many friends due to poor decisions. But until recently that was the limit of my perspective. While I was revalidating my rigger rating I was given a little more perspective.
As I arranged the slider in the mouth of a square reserve the examiner asked me how I would explain my slider arranging decisions to the coroner. In a flash I was mentally standing in the witness box answering questions on why I pack parachutes certain ways. In all cases I follow the manuals as closely as possible considering that mating various canopies and containers can cause some conflicts allowed in the vagaries of the wording in some manuals.
Now days I pass the concept on to anyone touching equipment belonging to someone else, and this includes doing pre-boarding pin checks. Why do you look or don’t look at something? Why do you fold something a certain way? What evidence is there that what you are doing something is the best way to do it? And if it isn’t the best way, why not? How would you explain your decisions to the Coroner?
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TURNING THE RINGS ON YOUR RISERS
Ever noticed how some people turn the middle ring on their cutaway system and wondered why? On the other hand did you see people doing it and started doing it yourself with no real knowledge of why this action is now a habit?
Well, the origin of this practice goes back to the 80s a year or so after Bill Booth’s 3 ring cutaway system became the preferred cutaway system. Some jumpers noticed that a few of the rings were distorting and becoming oval through frequent use. A potentially embarrassing situation.
Closer examination found that a production run of rings had not been fully heat processed and were not as strong, or hardened, as they should have been to meet their specifications. This resulted in a bulletin being circulated either recommending the replacement of the large ring, testing it for hardness with a Rockwell hardness test or at the very least rotating them a quarter turn each jump. Thus the practice began. Should we stop doing it since all gear now well and truly meets specifications? Probably doesn’t matter one way or another. On the other hand one skydiver said that that it forces her to at least look at her cutaway system each jump.
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3 RING MONTHLY SERVICE
“How often do you do your monthly 3 ring service?” All too often the answer I get is, “I don’t!”
Considering how quickly dust and dirt can build up inside the cutaway cable housings, I would suggest monthly is a good frequency for the suggested monthly service.
If you are unsure about what to do in the service, do the first one or first few under the supervision of an instructor or a rigger. And if need be, take photos of both cables where they go through the riser loops and any other place you may not be sure such as RSL or Collins Lanyard placements.
Some manuals used to talk about applying a light oil to the cables and giving it a good wipe. Later on Silicone was suggested as the preferred cleaner and lubricant. Either way, while it is important to spray the cables and get the dirt off, it is also most important to wipe all the oil or silicone off the cables. The very fine layer that remains is enough lubrication. Any more will attract dust.
The other action that needs to happen is to work the webbing at the bottom of the riser. Often riggers come across systems where, for a variety of possible reasons, the cutaway handle is pulled and the riser still takes the weight of the harness and container. This non-cutaway has occurred to people cutting away from under an open but damaged canopy.
To prevent the webbing from developing a memory, simply twist and massage the bottom halves of the riser around the two rings. It has been found that moisture and dirt followed by a bit of sun can allow a form of mud to fill the spaces in amongst the webbing fibres almost as solid as sun dried clay bricks.
Checked monthly you will at least keep the 3 ring system happy and functional. This also gives you the time, since you aren’t on a 5 minute call, to have a good look at the rest of the system.
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REGULARLY CHECK THE RACs AND SBs
If you own a set of gear that you use for skydiving it is always a great idea to check the Australian Parachute Federation’s RACs and Safety Bulletins on a regular basis. Sometimes something will happen to a piece of equipment and it may be something that every owner should know about. In these situations the manufacturer will release a report about the situation and recommendations or required modifications so as to avoid the situation happening to you.
These are easily found on the APF’s web site.
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BUYING A RIG? THEN GET THE MANUALS
We all like to have a good rig and when buying one, we also like a good deal. Sometimes the two come together. On the other hand some times people inflate the price of tired or out of date equipment believing that it is worth a lot more than it is.
If you are looking for gear, generally the guidance of your instructor can be very useful and appropriate for your needs. Apart from that, keep in mind that if you don’t get the current great deal being offered, there will be another one in the not too distant future.
If you know the equipment you want or what is being suggested, download the manuals from the manufacturer so that there won’t be any surprises. And then have a look on the APF’s web site for RACs ands SBs that relate to what you are getting. Sometimes there may be mandatory modifications, testing of materials and components or, in some cases, some gear may have a finite life, or even be banned.
Value wise, Main canopies deteriorate at about as dollar a jump. Harness container assemblies are similar while reserve canopies tend to hold their value. Of course this can often be affected by what is considered popular at the moment.
But to summarise, be sure you know what you are getting into before you hand over any cash.
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CAN YOU FINGER TRAP LINES?
Of course you can. It is a simple process. The catch is that you need to make sure they don’t slip until the load is applied. Many people look at a finger trapped line and think the sewing, or bartack, is what is holding the line together and taking the load. It isn’t. The strength comes from the finger trapping of the outer sheath of the line locking tight over the inner line. The sewing only holds it in place.
Often with things like kill lines, so as to ensure they remain adjustable, only one of the two finger traps are sewn. The other finger trap is knotted with a single overhand knot in the finger trapped portion of the line.
Can you finger trap?
Yes but probably but don’t try doing a reline yourself unless you are a rigger. On the other hand you can certainly give a kill line a go. Just make sure you show it to an instructor or rigger before you try it out.
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TIME FOR A RELINE?
Relining canopies is a major part of the rigging world these days. Looked after canopies tend to last at least a few thousand jumps where lines tend to either become too worn or internally damaged after around 500 jumps.
Spectra 1000 or Microline suspension lines shrink due to the heat being exerted on them. Therefore an easy way to check if the line shrinkage is excessive is to measure the outside A line against the trim chart for the canopy. These are generally available from the manufacturer on the Internet. Often after 400 to 500 jumps you will notice that the A5 line has shrunk, possibly as much as 100 - 125 mm, or 4” - 5”. This can have a massive impact on the canopy’s flight characteristics. After a reline often people say their old canopy flies like a new one.
Vectran lines on the other hand don’t shrink sufficiently to be noticeable. On the other hand they do experience wear that renders them substantially weaker. Therefore the feeling is to replace Vectran lines at 500 jumps, even though the canopy will still feel like it is flying well. Failure to do so may have a line snap on opening.
With steering lines and the wear they experience, it is often prudent to replace steering lines below the cascades every 250 jumps. This is because they experience a lot of operational control wear in flight as well as during the opening.
Will I, won’t I? While you are thinking about the value of whether or not you should replace steering lines, just consider the effect of a steering line breaking while you are swooping, at worst, or in deep brakes a few feet off the ground.
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SUNLIGHT AND YOUR CANOPY
Remember being told that if you left your canopy in the sun it would loose half of its strength in a week. That means or translates to 7 days x 10 hours (on average) x 60 minutes or 4200 minutes. By comparison 1,000 jumps at 2 minutes for a canopy ride and a 2 minute walk back to the packing area works out to 4,000 minutes.
Does this suggest that a canopy will only last 1,000 jumps? A most interesting arithmetic comparison. Hmmm…?
Canopies these days generally last several thousand jumps. This means that either the numbers are wrong or people do a lot of jumping on overcast days. And what about CRW canopies?
The reality is that the UV part of sunlight does do harm and this damage can vary depending on the colour of the fabric, location on the canopy and the intensity of the sun. It is also testimony to just how over engineered most canopies are.
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IS IT TIME TO REPLACE YOU PILOT CHUTE’S KILL-LINE?
What is the condition of the kill line in the centre of your bridle cord? If it is getting a little furry then it is degrading. You might like this more because, unlike a new one, it will stay cocked longer due to the friction. The packing process can cause it to gradually un-cock as new lines slides through the bridle more easily. So, this then begs the question of, ‘Should it be replaced if it is wearing or thinning out?’
What is the worst that can happen if a kill line fails? You end up landing with an inflated pilot chute. Most of the time this will be no problem. Then again as it will be adding drag to your canopy, it will slow it down and reduce performance. Performance you may need one day in a tight situation especially on smaller canopies.
Overall, I would suggest that if there is any doubt, you should replace the kill line. Also it is a lot easier to replace the line before it breaks than afterwards.
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CHECK YOUR GROMMETS!
Every time a reserve is repacked the rigger of the packer should go around the system and check all webbing, fabric, stitching and the grommets.
The reason the grommets need to be checked is that they can work loose. Less of a problem with stainless steel ones, but still something that needs to be monitored. The process is straight forward, if the grommet turns in location or if you can get your finger nail under the grommet’s edge then it needs to either be replaced or reset. That is a rigger job.
If the grommet is through a plastic stiffener, feel the stiffener, through the fabric, and check it for cracks. It may need replacing as well. This is also a for a rigger.
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The idea of a slider bumper is to protect the lines, where they attach to the risers via metal links, from slider grommet impacts. The damage is two fold. Firstly the link damages the grommets and secondly, the damaged grommet then wears the lines faster
While they are a great idea, if you are not going to go to soft links, there are two points I would like you to keep in mind. Firstly, if you jump in hot weather, you can probably ignore the first one. In cold weather, if you use common pvc tubing, the edges of the tubing can become very hard and sharp and actually increase the rate of wear on the lines. You can avoid this by using a silicone rubber tubing. More expensive in the short term but cheaper than a new line set.
Secondly, you do need to make sure that the links are looked after. This means both setting the rapide link correctly in the first place and then checking it periodically. The correct setting for a rapide link is to close it off with your fingers and, once it is neat, you give the locking nut a tightening quarter turn. No more or you risk stripping the thread and initiating a failure.
Conversely, if you don’t check the links regularly, they can work loose and fail.
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THE PERFECT RIG. DOES IT EXIST?
Once upon a time creating the perfect rig may have been considered possible but these days it certainly doesn’t seem possible. In the old days we would jump out, build a few formations, track away from each other, open our roundies or slow and large square canopies, do a little CRW and then try and impress people by landing close to the centre of the pit or packing area without giving any real thought to the approach direction.
These days, sometimes we want to go real fast close to the ground, or we want to have something that will always open on heading because we have a hundred plus friends around us, or we want to track or do an angle jump. And that is apart from those of us who want to fly like a bird for three minutes in a wing suit and still have a clean opening.
And did I mention CRW or canopy flocking? They have their own specific needs.
There is no such thing as a perfect rig. Some may come close. Some people end up with multiple rigs to satisfy their taste for multiple disciplines. And in saying this I can hear many people say they can’t afford multiple rigs.
You have to do your research and select carefully for the disciplines you want to pursue. Make a list of the disciplines you want to follow and then make a list of the pros and cons for the equipment needed in each of these disciplines. You could end up with a gear bag with both Lightning and Valkyrie main canopies.
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WHAT IS THE LIFE OF A RESERVE CANOPY?
(or anything else for that matter)
To this question there is no simple and definite answer as there are numerous factors that can dictate the service life. In short it is dictated by the legal bodies that look after or manufactured the reserve canopy, or any piece of emergency equipment.
The first one who can set a limit is the manufacturer. They can state how long they believe the piece of equipment should last. These limits can range from a few years up to, ‘indefinitely as long as it passes regular inspections and structural tests.’
Then there is the official body like the APF, USPA or BPA that dictates how you are to jump and manage the equipment. They can, and do on occasion, make certain stipulations or even ban a particular piece of equipment.
And then there are the memos that come out from manufacturers after the item has been sold. Sometimes flaws are found and modifications need to be made urgently to ensure dangerous situations don’t repeat themselves. This is where the APF’s SBs and RACs come into play.
Nothing lasts for ever but sometimes it is important to say how long something should be used. Check your manuals, check the APF web site and look at the SBs and RACs and you should have a better understanding of the life of each component of your skydiving assembly.
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WHO OWNS THE RIG’S PACKING CARD?
So often when a rig is sold off in the component parts, such as main, reserve, harness/container, people forget about giving the packing card any consideration. This generally means that the details about the history of the reserve canopy and the canopy itself are separated when the card is left in the container’s packing card pocket.
Next time you are sitting around talking with fellow skydivers, ask them what should happen to the packing card when a set of gear is broken up. Most will have never given it a thought. Some will say to leave it in the container while the correct people will say it stays with the reserve canopy as a historic record of the canopy.
On this point, if the old card is full, the new one should be sewn to the old one so as to maintain a more complete operational history of the reserve canopy.
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SUGGESTED READING FOR WOULD-BE PACKERS, RIGGERS, OR ANYONE WANTING TO KNOW MORE ABOUT THEIR EQUIPMENT
More knowledge is better than less. While some people say ignorance is bliss, in any form of aviation, ignorance can be fatal. I remember saying decades ago that you don’t want to find yourself whistling through 1,500 feet in free fall wishing you had learnt how to properly tie a bowline. Therefore it is wise to put together a bit of a library. If you are considering becoming a Packer A or Rigger, I would suggest the following as a good starting point.
- APF Operation Regulations - APF
- APF Regulatory Schedules - APF
- Dan Poynter’s Parachute manual, volumes 1 & 2 - Paragear
- Dan Poynter’s Rigging course - Paragear
- Master Rigger’s guide - USPA
- FAA Parachute Manual - FAA
- BPA Riggers Manual - BPA
- BPA Riggers Training manual - BPA
- Familiarise yourself with the RAC & SB section of the APF web site.
On the APF web site you will also find manuals and and booklets on canopy control, malfunction management and what is considered a safe approach to participating in this great sport of ours.
Also, the process for getting a Packer A, B or Rigger rating is to contact an appropriate examiner such as your chief instructor and get the exam for the rating. The idea is that you use the exam as a study guide before you sit a final exam. The great thing is, as a study guide, it also helps you become aware of how to look information up important information on equipment operation and maintenance.
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HYDROGEN EMBRITTLEMENT! SOUNDS SCARY?
If an effort to cut down on rust Chromium can be added to various alloys to reduce the amount of oxidisation or rust. Then again some people take a short cut by just having hardware chrome plated. After all it looks just as shiny.
The catch is that, done poorly, when the hardware in dipped in the chromium salt solution and taken out, a condition can occur where thermal and chemical reactions between the metal and the chrome allows hydrogen bubbles to form in the metal fitting. The result is a considerable weakening of the fitting. Sometimes this effect can be so bad that a dropped piece of hardware will actually shatter.
These days hydrogen embrittlement is rarely used and therefore not much of a problem. If you want something that won’t rust and be shiny, just go to stainless steel hardware.
More subjects will be added as time permits so have a look at this page on a regular basis
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