Skydive SAFETY – The CRUX
Dan's Dan's Thought for the Day...
Is 'Right of Way' a useful or safe idea to teach in skydiving?
Canopy Collision Part 1 here
In March of 2017 I posted a review of a canopy collision that took place at Skydive Arizona on December 30, 2016. The post included two videos, one shot by a participant in the collision and one shot by an outside observer. The videos (here) make it pretty clear what happened and I hoped they would spur discussion about traffic management.
Before going on, though, let me caution the readers about a few things. One, some of the comments to my post are stated in a way that suggests the commentator knew what was actually going on in the heads of the two who collided. We don't know, and this kind of baseless assertion seriously diminishes the usefulness of the Forum.
Two, if you watch closely there was traffic to both right and left of the overtaking canopy. Lens distortion makes it hard to know just where it was in the final seconds before the collision, but it may have affected the decision making of the top canopy pilot. We could argue endlessly about whether or not the top pilot could have avoided the collision. The fact is that he did not come up with a solution to the problem fast enough to avoid it.
the low canopy was almost entirely responsible for the collision
Three, the landing area is tight even without heavy traffic. Nevertheless, this collision could have occurred anywhere because it essentially was caused by one parachute turning into the path of another, which is the ultimate cause of almost every canopy collision.
Finally, Skydive Arizona does have a lot of guidelines because we have a lot of visitors from drop zones that apparently don't. Breaking the rules isn't a grounding offense in most situations. In this particular case I doubt if either collision participant was actively thinking about those guidelines. In all likelihood the bottom jumper let established habits override the guidelines, and the other was trying to deal with that.
I found it worrisome that several people staunchly defended the concept that “Low Canopy has Right of Way” overrides all other considerations under canopy. In this case the low canopy was almost entirely responsible for the collision and the event never would have occurred if that person had flown in a safe, predictable manner. I want to review the concept of Right of Way and challenge whether it is even a useful or safe idea to teach in skydiving when expressed as an absolute. If we are going to retain the concept we need to understand the origins and the exceptions.
Technically the term Right of Way has nothing to do with navigation by boat, car, parachute, or other conveyance. It is a legal term to describe access to property. For example, if my land is surrounded on all sides by someone else's land, I can be granted a legal Right of Way to my land. Similarly, if tradition allows the public to cross private land at a specific place, a Right of Way exists.
At some point the phrase was adopted to nautical traffic, although technically the proper phrasing is “give way” as “In situation X, vessel 1 gives way to vessel 2.” But to be absolutely clear, the rules about who gives way in traffic have a lot of exceptions, all based on common sense. Ultimately they are intended to minimize confusion and de-conflict traffic problems, but they are not in any way absolute rules. Here are some examples:
'A powered vessel gives way to a sailing vessel.' Unless the powered vessel is actively fishing, or needs a deep channel that the sailboat does not. And any sailor with an iota of experience and common sense knows that sailing a yacht in front of a massive container ship is a sure way to be run down, regardless of your unpowered status.
Between two sailboats, the default rule is that 'a vessel on a port tack gives way to one on a starboard tack'. For those who aren't sailors, that means if the wind is coming over your left side, you give way to a boat that has the wind coming over its right side. In fact this is probably where the phrase “right of way” comes from because the boat on the starboard tack is to the right of a line drawn back to front through the boat on the port tack, and vice versa. Eventually this was applied to cars: if two cars were approaching a crossroads, the one to the right had ‘right of way.’
Obviously this didn't work very well with cars, or we would not need four-way stop signs or roundabouts. But for the purposes of this discussion, we're much more like sailboats than we are like cars or powerboats.
To further confuse things, if we go back to sailing there are many more exceptions to the rule. A windward vessel gives way to leeward. Shallow draft gives way to deep draft in a narrow channel. An overtaking vessel gives way to the slower vessel, ideally passing to the rear if they are on different courses. But most importantly for applying these guidelines to skydiving, the vessel being overtaken is obliged to maintain course and speed, or if it must maneuver, clearly signal its intention!
all flight in the landing pattern must be predictable!
Parallels in skydiving would be that a canopy over open area should give way to one over obstacles, higher to lower, and so on. But regardless of the guidelines, it is understood that the root rule is: all flight in the landing pattern must be predictable! Without predictable flight no set of guidelines or rules can prevent collisions. This collision came down to that: an unnecessary and unpredictable turn into the path of an overtaking canopy.
Let's also get over the idea that all parachutes are similar in handling characteristics and therefore a blanket rule can keep them safely separated. For example, USPA asks Group Member Drop Zones to separate “high performance” landings from - presumably - ordinary landings. What does that mean? A Valkyrie at 2.4 on a straight approach is going as fast as a Sabre 2 at 1.2 coming out of a 180. It's too much to ask skydivers to sort themselves by canopy type, wing loading, and flying style other than by a general designation of high performance landing areas.
In Skydive Arizona's case, we limit one landing area to turns of 90 or less, and nowhere do we allow turns over 180. (Except when the jumper exits on a pass dedicated to HP landing.) However, we do ask that people refrain from S turns or flying at an angle across the final approach. This is something we should expect of everyone, and if everyone does it, there should be minimal problems with a fast parachute finding a clear lane next to a slow parachute. In the collision in question, the low parachute failed in the most basic of navigation duties: maintain course and speed and make your intentions clear.
the low parachute failed in the most basic of navigation duties: maintain course and speed and make your intentions clear
This is a cultural issue. Older skydivers or those taught by older skydivers may have been taught that right-of-way is absolute, taught without the essential caveat “maintain course and speed, make intentions clear.” It may also involve drop zone culture; wide open DZs without much traffic seem to neglect canopy control skills and DZs where people don't travel much may spend little time teaching their jumpers what to look out for when they visit a big DZ. We used to teach people to fly in deep brakes and perform S-turns to fine tune their landing point. Now we know this is dangerous in traffic and we don't teach it any more.
There is no reason a big seven cell can't safely land in the same area as a tiny, ultra-high performance canopy, but not when using obsolete rules of the road. The low person does not have the right to turn into the path of an overtaking canopy, period. Finally, low or high, never assume you know where all the traffic is. The assumption you should make is that there is overtaking traffic above and behind, in your blind spot, and you must fly predictably to minimize the chances of them colliding with you.
In a way it is like tracking off from a formation. If you are higher than someone below you in the same quadrant, it is your job to not fly over them. But at the same time, it is their job to track straight and give a good wave-off before deploying. At no time should we be looking behind us; our job on break-off is to avoid anyone ahead and below. Easily done if they are tracking straight!
Bryan Burke made his first jump in 1978. In the years since then he has done just about every job in skydiving - instructor, organizer, event coordinator, drop zone manager, and of course, Safety and Training Advisor. He has been with Skydive Arizona since 1989. Most of his off-DZ time is spent reading, running rivers, or riding motorcycles in remote places.
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