By Tim Pfeiffer, taken from USHPA
Have you ever heard someone say, "Paragliding isn't any more dangerous than driving." By the way some pilots drive on the way to launch this may be true, but on average it appears that pilots are three to six times more likely to die flying than driving. Putting this in perspective, riding a motorcycle is 16 times more likely to result in a fatality than driving. However, fatalities don't begin to tell the story of the risks involved in paragliding. Most of us who have been flying for a few years have grown weary of the steady stream of broken bones and visits to friends in the hospital.
It's easy to say that aviation is just inherently risky, but why then is commercial aviation the safest way to travel? Commercial aircraft are exposed to many of the same risks as paragliders. The difference is that in commercial aviation the risks are deliberately and thoughtfully managed. Not just crashes, but incidents are thoroughly investigated to learn what went wrong and how to do better next time. Accident reporting helps identify the sources of risk, but risk management is needed to keep the risks in line with the joy of flying.
While we manage risk continuously in our everyday lives, we are not particularly good at it. We tend to judge risk based on fear, which may or may not be a good indicator of risk. For example, most people have a natural fear of heights, so if we use our fear of heights to guide our risk assessment, we should fly very close to the ground. Also, it is human nature to underestimate risks; something termed "optimistic bias" in the language of risk analysis. And who could be more optimistic than a group of people who think they can fly strapped to some nylon by skinny little stings.
To begin replacing our fear-based risk assessment with managed risk, it is helpful to understand the relationship between risk and probability. A useful definition of risk states that risk is the probability of an event multiplied by the consequences. Probability is a number between 0 and 1, with one being a sure thing and 0 being impossible. So if the consequence is very large, like a serious life altering injury, the risk will be high even if the probability is very small. Alternatively, if the consequences are minor, the risk is small even if the probability is very high.
So how does this help us make sound piloting decisions? Let's say you are flying along and could fly to the next field or land in a closer field. You think you can make it, but if you encounter some head wind there is a chance you could come up short. Of course, if you come up short, you could have to walk a couple of hundred yards. Most of us need the exercise, so the consequences are minor and even given the considerable probability of not making your expected glide, the total risk is small -- go for it. On the other hand, change the field to a narrow canyon with raging rapids and power lines. Now, consider the risks. Even if the probability of not making your glide is extremely small, the extreme consequences make for relatively high risks.
Understanding the definition of risk is great for risks we know and understand, but the vast majority of failures, paragliding injuries or space shuttle disasters, result from unknown risks. Recently a relatively inexperienced pilot visited a popular coastal ridge soaring site. The wind was light and no other pilots were flying. He attributed the lack of pilots to the conditions being less than soarable. Figuring that being a new pilot a sled ride would be good practice, he chose to fly. The result was broken bones and a harrowing helicopter rescue. What went wrong? The pilot thought he had assessed the risks and certainly didn't feel a simple sled ride involved a large risk. This pilot learned about the unknown risk the hard way. Later the pilot was subjected to a chorus of pilots questioning why he would even think of flying that site in those conditions and stories of other luckless pilots who had tried the same thing he did. Which makes the point, that most unknown risks are not unknown by everyone. Ask your friend with the cast if they understood the risks behind the decisions leading up to their crash. Chances are, something they did not anticipate hurt them, but given the proper knowledge they could have anticipated and avoided the crash. Through experience and communication we can reduce the unknown risks, but never eliminate these risks.
We can't possibly be expected to understand and analyze every risk, so how can we manage risks that we don't even know exist. Fortunately managing unknown risks is no more complicated than accounting for the known risks. An engineer designing a building or airplane part analyzes the known risks, then accounts for possible unknown risks by adding a factor of safety. Depending on the consequences of failure and how well the risks are understood, this factor of safety is typically 2 to 5 times the calculated value. Because of the universal application of this concept in engineering, building collapses and catastrophic mechanical failures in aircraft are exceedingly rare. This same concept can be applied to piloting decisions.
Let's return to our discussion of gliding to the next field. If the consequences involve only a short walk, there is not much need for an extra margin for safety. In fact, this would be a good time to test your glide angle estimation skills. Make a note of how far your estimated glide varied from reality. With a stack of estimates under varying conditions in your experience bank, you are ready for the next step. Estimating your glide when you absolutely positively cannot come up short. What was your worst estimate ever? Let's say you estimate that you can glide four times further than the width of Death Canyon, but there was that time you came up with only a half of your estimated glide. Just like the engineer designing the aircraft part this worst case glide should be your base estimate. Using your worst-case estimate, you can glide twice as far as the canyon is wide. This could be considered a factor of safety of two. Is a factor of two enough? Consider the consequences and the unknown risks that could possibly be involved. Also, is there some compelling reason to cross the canyon. For most of us who plan a few thousand more flights, a factor of two involves far too much risk.
The only way to completely eliminate the risks of flying would be not to fly. Since for most of us this is not a desirable option, we must learn to manage the risks and find a balance between risks and the experience of flight. Learning to manage risks is just like any other skill involved in flying. It must be learned and mistakes will be made. The trick is to learn from the mistakes without paying too high a price. Considering the consequences and leaving room for the inevitable mistake keeps the price down. Often the only difference between an incident and an accident is altitude. The inevitable mistakes and incidents will be learning experiences rather than setbacks. Learning about what can happen on full speed bar with lots of altitude is one way to gain experience; without lots of altitude it is a good way to stop gaining experience. An even better way to gain experience is to learn from the mistakes of others. The history of aviation is filled with pilots who gave their bones and lives to learning the hard lessons. Making the same mistake again dishonors the memory of the pioneers who made the dream of flight a reality.
The old cliche could never be truer; judgment comes from experience, experience comes from lack of judgment.
Totally unscientific top nine list of risks
- Long drives - It is just as blown out after a 20-hour drive as after a 20-minute drive.
- Hot wings - it's not the wing it's the pilot.
- Relevant experience - It's what you don't know that's going to hurt you.
- Health and physical fitness - Those extra pounds are extra force during a hard landing.
- Landing - The second most common way to get hurt.
- Launching - The most common way to get hurt.
- Complacency - It always hits when you least expect it.
- Attitude - The best way to get hurt is to think you can't.
- Altitude - It's not the air that's going to hurt, it's the impact with the ground.
