What is the risk of a single skydive?
What is the risk of a single skydive?
I've seen many articles that compares the risk of skydiving with other sports or activities like cycling or driving. However, they are very ambiguous in terms of how the risk was calculated (number of jumps, number of km driven, etc). Here is an example:
Image taken from here.
So, how much is the risk of a single jump?
How does that compares with a common activity like driving a car?
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I think that those stats are all supposed to be per "instance" — per jump, per flight, per trip, per boxing match, etc. Some of the activities further down in the original image have annotations like "per mile" or "per flight hour", but none of the sporting ones do.
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– hobbs
Sep 14 '18 at 23:27
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I think this is a risk that you cannot assess that way. Statistically, it may be 1:100,000 for a large (infinite) number of samples. However, for a bloody beginner with zero experience, the risk on the first jump likely is more like 1:100 or worse. Risk -- for everything -- goes down drastically after the first few attempts due to having better experience and being less nervous. And then, ironically, after some years, and despite experience it drastically goes up again due to becoming careless (because hey, I know what I'm doing!).
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– Damon
Sep 15 '18 at 9:46
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As an ex hang glider pilot, I have to dispute that image anyway. It probably was true for hang gliding back in the 70s, but not any time recently.
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– Graham
Sep 16 '18 at 6:32
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The image states something about likelihood, likelihood of what? Accident? Major accident? Fatal accident?
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– Mast
Sep 16 '18 at 8:45
3 Answers
3
Puzzled by this question I did my own research and found numbers that allows to get a good comparison for year 2016:
According to the United States Parachute Association (USPA), there were 3.2 million jumps in 2016 and 21 fatalities. Therefore, the chances of dying in a single jump were 1 in 152,381.
For a comparison with driving, we can use data from the Insurance Institute for Highway Safety. According to which, in the United States there were on average 1.16 deaths per 100 million vehicle miles traveled.
Crunching those numbers, the chances of dying by driving one km are 1 in 138,103,448. Therefore, to equal those chances to one skydive you have to drive 906 km.
Summarising
In 2016, a single skydiving jump in the US represented the same risk of death as driving 906 km (566 miles).
[UPDATE] Demographics
Many have pointed in that there might be an important component of the risk related with age, experience and how careful a skydiver is.
To approach to an understanding in that regard I've compiled the 147 fatal accidents in the USPA database that happened from 2008 as a result of solo jumps (i.e. not-tandem).
This data do not allow to infer real demographics trends, because I don't know how many total jumps were in each demographic group (I only know how many lead to a fatal accident). However, the visualization of some aspects of the data can be informative.
In the following figure each dot is a fatal accident, and it is plotted based in the numbers of jumps the person involved have performed before the accident (vertical axis) and the age of the person (horizontal axis).
It is clear that the bulk of casualties happen to fairly experienced skydivers (100+ jumps). So, as expected, the more you jump the more chances of dying you have. Note that the vertical axis is logarithmic (so to distinguish between people with relatively small jump counts).
This may lead to think that the first 100 jumps are quite safe, but we can not jump to that conclusion: If you check how many death are there for different jump numbers, you have the following picture
In this plot, the first bar counts deaths during jumps 1 to 50, the second bar for jumps 51 to 100 and so on.
So now it seems that most deaths are in the first 50 jumps. However, that does not mean that the first 50 jumps are more dangerous, because there were many more jumps corresponding to jump number 1 to 50 than jumps number 900 to 950. So, however informative, this have no real statistical value. And the trend suggesting that jumps become less dangerous as you gain experience might be just an artifact due to the fact that there are more beginner skydivers than experienced ones.
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@ Camilo Rada that's brilliant. As an ex skydiver, it fits, in my opinion. Now I've always said jumping is probably about as dangerous as motorcycles or maybe less so. Thing is when you jump, most of the risk of death is from a failure to perform when required, like after a malfunction (the probability of a double malfunction is pretty microscopic) whereas on a motorcycle, the risks are all around you and many are out of your control.
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– John K
Sep 14 '18 at 19:54
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That's actually a decent way to put a number on it. There's always the apples to oranges problem between driving and aviation. One measures stats in miles, the other in hours. So figuring that I drive around 1200 miles a week, that's equivalent to about 2 jumps/week in risk. I just might take up skydiving now!
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– TomMcW
Sep 14 '18 at 21:15
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@JohnK So what you're saying is, you should skydive to work instead of riding a motorcycle... ;-)
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– Michael
Sep 14 '18 at 23:07
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Interesting take but selection bias is strong in this answer. Teenagers have three times the driving fatality rate of those 20 and older; few teens skydive. Drivers come from every walk of life; the top ten demos (70%) for skydivers are military, self-employed, engineers, skydiving professionals, health professionals, computer engineers, management, business/finance, sales/marketing, and aviation. Not surprising since the sport is fairly expensive and completely discretionary. Correcting for demographics would give a completely different answer.
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– Pilothead
Sep 15 '18 at 7:44
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Would be interesting to know if the chances of dying are the same in the 1st and 1000th jump. But then, n = 21 isn't enough for that.
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– DonQuiKong
Sep 15 '18 at 14:13
Here is another way to understand risk perception in skydiving vs driving.
In skydiving, equipment malfunction is the cause of 50% of deaths. The highly regulated automobile industry would never stand for this. It would be deemed unnecessary and engineered out of the products. Collisions, landing problems, and other account for the other 50%.
In driving, almost none of the fatalities are equipment related as it doesn't even rate a one percent causality. Drunk driving, speeding, distractions and weather cause nearly all traffic fatalities.
In other words, if you are a careful driver you can eliminate virtually all risk of death from your own driving. If you are a careful skydiver, at best you can only eliminate half the risk.
My guess is that few skydivers jump drunk, or exhausted and just trying to get home, or in a downpour. The 900km risk comparison might be fifty times too generous when applied to conscientious people, which I would assume skydivers already are. 45,000km might be more reasonable given the <1% vs 50% equipment failure ratio, and this is more than two years of driving for the average person. This is also more in line with general perception of risk.
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I agree with the general sentiment, but I’m wondering: How many of the skydiving equipment failures could be avoided by careful inspection? How many occur because the equipment is operated wrongly or used in the wrong circumstances?
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– Michael
Sep 15 '18 at 9:55
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@Michael I think this is the point. Cars don't have to be inspected every time you use them; they are pretty much idiot proof. Safety equipment costs about $2k per car, and that doesn't count all the engineering to make cars durable and reliable. Automatic chute deployment is one step skydiving is taking in this direction.
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– Pilothead
Sep 15 '18 at 16:30
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"In other words, if you are a careful driver you can eliminate virtually all risk of death from driving." Sorry, this is just not true. No amount of care will eliminate much of the risk to you from other people who are drunk, speeding, or distracted.
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– David Schwartz
Sep 15 '18 at 21:36
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@DavidSchwartz You are correct. I should have said "risk of death from your own driving". Fixed.
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– Pilothead
Sep 15 '18 at 23:59
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I think you are stretching the numbers a lot for the sake of the argument. From one side, as you already acknowledge, there is a lot of risk in driving that you cannot avoid by being careful. The the 50% stat is based on one year only (n=24), the same article say 11 to 50%. And lastly and more important those are MAIN parachute malfunctions. Arguably, a careful skydiver should be able to deploy the reserve and land safely if the main parachute malfunctions.
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– Camilo Rada
Sep 16 '18 at 16:25
You jump with a main chute and a reserve chute. The odds for either one of these failing are roughly 1 in 1000. This give approx a 1:1,000,000 chance both fail and you fall to your death.
That’s the risk of a parachute failure. It does not account for risks associated with jump plane crashes, mid air collisions during the ride up, free fall or canopy deployment, improper landing, etc
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Or a car accident on the way to or from the airfield. As per above answer, if you drive 10 KM to the airfield and another 10 KM back, then 50 such trips equal the risk of a single skydive.
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– dotancohen
Sep 14 '18 at 21:42
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@Carlo Felicione the failure probability of a professionally inspected, packed and rarely used reserve is a fraction of the rate for a repetitively user packed main where most malfunctions are due to packing errors and canopy wear and tear. I'd say the probability of a random double mal is quite a bit better than 1 in 1 mil.
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– John K
Sep 15 '18 at 0:57
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Reference for 1 in 1000 odds for both main and reserve parachute malfunction please. One in 150k jumps results in death, and equipment malfunction causes half of those. One in a million is more than three times too rare.
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– Pilothead
Sep 15 '18 at 7:58
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Like most aviation related risks, most people want to know the risk of random failures beyond the person's control, which filters out many performance related failure modes. When I was jumping in the late 70s it was expected you'd have a mal by 5-700 jumps and the average experienced jumper with a couple thousand had had 2 or 3. The fatalities generally follow screw ups in handling the malfunction. Try to find a case of a reserve, PROPERLY DEPLOYED, failing and it's vanishingly rare. Unlike bikes where you can be taken out by other drivers at any time, in jumping it's almost all on you.
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– John K
Sep 15 '18 at 13:10
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I don't think the math is as simple as this. Aren't there some main chute malfunctions that prevent a clean cutaway, and therefore cause risk of the backup chute failing to deploy properly even if it was otherwise fine?
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– Wayne Conrad
Sep 16 '18 at 0:15
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