Two Canopies Out

[FOF 6]

What should you do if you find yourself in the air with two canopies out?

In the mid-1990's Performance Designs conducted a series of test jumps on behalf of the Parachute Industry Association to study this situation. The results of these tests were published in a document titled the "Dual Square Report."

I was just reading a thread in the "Incidents" forum about a fatality that occurred several months ago involving a possible main-reserve entanglement. Several people began discussing dual-deployment situations and how they should be handled. One person suggested that people read the Dual Square Report for more information about this subject. Another person replied by stating "all those tests were done with very large F-111 canopies and don't apply to smaller ZP canopies that are in use today."

During the past few years I have occasionally heard and read similar remarks about the Dual Square Report. I'm concerned about these remarks because first of all, they are not accurate, and second, they may cause people to disregard some very useful information.

The dual square test jumps conducted by Performance Designs included small, zero-porosity, elliptical-type main canopies as well as small reserves. In fact, a variety of configurations were tested including small main / small reserve; small main / large reserve; and large main / small reserve. In addition, different deployment scenarios were tested including ones where the main canopy was deployed first, followed by the reserve; ones where the reserve canopy was deployed first, followed by the main; and others where both canopies were deployed simultaneously.

It is true that some jumpers are now using smaller reserves and significantly smaller mains than those that were available when PD conducted these tests. A few of today's main canopies have performance characteristics that are quite different from those being used at the time. However, the PD tests are still the most extensive series of dual square tests performed to this day. The information gained from these jumps remains valid and useful. In fact, the majority of canopies in use today are the same or at least very similar to those used during the tests.

In the last ten years a number of articles have been written based on information from the Dual Square Report, and it has also been the basis for the recommendations published in certain manuals. Since the Dual Square Report was based directly on the test results, reading the original report in addition to these other articles and manuals can be very informative.

A lot of people will probably be discussing dual deployments during Safety Day next weekend. Although they do not occur very frequently, we should all know as much as possible about these situations and be prepared to handle one if it does occur. I strongly encourage everyone to read the Dual Square Report thoroughly and carefully, and understand the information it contains. Even if you have read it before, a thorough review can be very beneficial. We all need to make our own decisions in this sport, just as in life, but if at all possible they should be informed decisions.

The Dual Square Report can be found in the "Articles" section at the bottom of this page: http://performancedesigns.com/canopyinfo.asp .

[jsaxton 0]

Thank you for clarifying this. The information in the "Dual Square Report." and the training methods that derived from that are responsible for a number of us being here today.

[KindredSpirit 0]

That was a very informative article. Thanks for the link.

"Kicking gravity's ass since 2003!"

[speedy 0]

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I strongly encourage everyone to read the Dual Square Report thoroughly and carefully, and understand the information it contains. Even if you have read it before, a thorough review can be very beneficial.

Which is something I will do now for the 4th time. I still end up in arguments about what the report recommends with people.

For instance, side by side? Cutaway or not?

Thanks for reminding

Dave

Fallschirmsport Marl

[FOF 6]

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I still end up in arguments about what the report recommends with people.

For instance, side by side? Cutaway or not?

I can see why there might be some discussion about this. The Dual Square Report states that either landing the side-by-side or cutting away the main could be the proper response, depending on whether or not the side-by-side feels stable and controllable. The report also notes that canopy type and wing loading can be a factor in this decision:

"The jumpers also did not feel comfortable landing heavily loaded side by sides, especially when a highly elliptical canopy is involved."

In some emergency situations there is clearly one procedure that's the best course of action: if you have a line-over, cut away and deploy your reserve. In other cases the best solution is not always as clear. Imagine having a bad spot at a DZ surrounded by trees. You might be able to make it back to the airport, but you'll be cutting it close. There's a field right below your feet that looks big enough to land in, but it's much smaller than any place you've ever landed in before. What should you do?

We should all be ready to follow standard, accepted emergency procedures when necessary, but we also must be ready for situations that require us to use our own judgment. This is especially true of dual-square situations, particularly the side-by-side.

[krkeenan 0]

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***
For instance, side by side? Cutaway or not?

I recently had a side-by-side. It's intuitive that landing a single reserve is better than trying to handle two canopies. The thing to remember is that if you cutaway the main and anything at all from it snags the reserve on its way out, you are in a bad situation.

So, the best thing to do is to position the canopies so that when the main leaves, it - and all of its parts (risers, toggles, etc.) are going as much as possible directly away from the reserve. The optimum configuration for this is called a downplane. When you turn two attached canopies directly away from each other, they will both pitch downward until they are both diving toward the ground. They will fly stably like this, though with a somewhat high rate of descent. Anyway, this is the optimum time to release the main. The lift vectors for both canopies are straight apart from each other, so when you cutaway, the main flies directly away with no tangle hazard.

What I did was a variation on that. Since I was a little bit low, I didn't want to have the canopies diving at the ground. With the canopies side-by-side, I just pulled a little front riser on the main in the direction away from the reserve. This made the main move to a position about 45 degrees from the reserve. I could see that the lines and all were clear, and the force pulling on the lines (lift vector) was clearly well away from the reserve. When I pulled the handle, the main and risers sprang instantly away, leaving me with a normal reserve ride.

I think the downplane method is more positive, but without some CRW experience and generally having one's shit together, it would be hard for someone to get right the first time. I think the 45 degree method that I described is preferable.

Kevin

======================
Seasons don't fear the Reaper,
nor do the Wind, the Sun, or the Rain...

[tdog 0]

How high were you when you initiated the front riser on the main? What caused the two out?

[krkeenan 0]

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How high were you when you initiated the front riser on the main? What caused the two out?

I was jumping a demo canopy with - I believe - an uncocked pilot chute. I foolishly assumed it was cocked when I got it from the packer. I pulled a little low anyway, and by the time I realized that the PC wasn't doing anything and I couldn't figure out where it even was after looking around, I was down to dumping the reserve. As the reserve started pulling me upright, I looked up and saw both canopies deploying simultaneously. It was pretty freaky. The sliders even came down right next to each other. Luckily, they both opened just fine without interferring with each other.

I was at about 8-9 hundred feet by then, and the ground looked a bit too close for a downplane.

I did get a t-shirt from the maker of the demo canopy, who asked, "So, other than the opening, how did you like it ?"

kk

======================
Seasons don't fear the Reaper,
nor do the Wind, the Sun, or the Rain...

[Orange1 0]

Would just like to maybe post something... a lot of the discussion so far is jumpers with a lot of jumps.
I had a long chat to my CI after the previous long thread about 2-outs and came away pretty sobered. He strongly believes that there are things newer jumpers should not even be thinking about attempting. I know it's in the sticky, but again any low jump number guys reading this, PLEASE check with your instructors on what they think the appropriate procedures for you are in this situation.

Skydiving: wasting fossil fuels just for fun.

[FOF 6]

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I had a long chat to my CI after the previous long thread about 2-outs and came away pretty sobered. He strongly believes that there are things newer jumpers should not even be thinking about attempting. I know it's in the sticky, but again any low jump number guys reading this, PLEASE check with your instructors on what they think the appropriate procedures for you are in this situation. (Orange1)

That's an important point. Some possible solutions to dual square situations are not mentioned in the Dual Square Report, and others are specifically discouraged, because the test jumps demonstrated that they could potentially worsen the situation or because there was an easier and/or potentially less risky solution. The report was intended to provide guidance for all skydivers, not just highly skilled and experienced ones.

Low-time jumpers should always seek an instructor's advice if they have questions about handling these situations. Instructors should also consider the information in the Dual Square Report when giving such advice.

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It's intuitive that landing a single reserve is better than trying to handle two canopies. (krkeenan)

That concept is completely valid to a certain extent, and you've provided some good information based on your own experience with a personal side-by-side. Other experienced jumpers have also had success following similar procedures. However, I'm not convinced that the procedure you described is always "the best thing to do," as you stated. Landing a stable, controllable side-by-side should still be considered a valid option. Making any special effort to "separate" the canopies before cutting away may also not be necessary:

"Cutting away from a side-by-side that does not want to return to a biplane seems to be a safe action as long as no equipment problems exist, and the canopies are not entangled. It must be noted that RSL's were not used in any of these tests. Great caution must be used when cutting away in that scenario due to the varied styles and applications of RSL's."

The PD tests indicated that side-by-sides involving mismatched canopies or highly loaded ones are less likely to be controllable or easily landed. Students and novice jumpers are more likely to be jumping canopies of similar size and planform, with relatively light wing-loadings. If they have something over their head that is flying and controllable, they may be better off sticking with it. Jumpers who do fly highly-loaded canopies or elliptical-type mains should realize that more skill and better decision-making abilities may be required of them in these situations.