Accidents

I love flying. Like most pilots who have been involved in aviation for any period of time I have witnessed some accidents and heard stories of hair raising escapes. Along the way I have lost some friends. The point of this article is to take a closer look at how accidents occur and more importantly how they can be averted.

The accidents which do occur are really only the tip of the iceberg. For each accident there are dozens, perhaps hundreds of “close shaves” which had the potential to result in an accident. First let’s dispense with the “it won’t happen to me” syndrome. I consider myself fairly bright, cautious and a better than average pilot but I will readily admit to perhaps more than my fair share of close shaves. There simply is not a select group of aviators so diminished in mental capacity as to represent the sole source of supply for accidents.

But what is it that separates the close shaves from the accidents. Is it perhaps luck, or is it in reality good management. The ideas embodied here are wide spread throughout the general aviation community but have been slow to filter through to our free flying community. Once you have read them I think you will agree that avoiding accidents has little to do with luck and everything to do with good management.

The primary concept to understand is that of “cascading chains of causation”. While pilot error is the primary cause of almost all accidents an accident rarely ever stems from a single pilot error. What usually happens is that a pilot makes an initial bad decision or technical flying mistake. This then places the pilot and aircraft in a situation where a more challenging decision or technically difficult flying is required. If this situation is not correctly assessed and the problem dealt with increasingly difficult decisions and technically challenging flying are required. The resultant increase in pilot workload makes further errors more likely. If this process continues on unchecked then an accident may occur.

Consider the following typical accident scenario. A hang glider pilot is setting up for a landing in strong winds. He decides on the distant smaller landing paddock surrounded by trees because it is near a road and easier for pick up, instead of the large closer open one which involves a 300m carry out. The pilot safely arrives over the centre of the chosen paddock with plenty of altitude and proceeds to lose height as usual with a series of 360 turns. Due to inattention the pilot drifts downwind of the landing paddock. By the time he notices he’s rapidly drifting downwind he has a marginal glide back over the trees to the chosen paddock. At this point he elects to try to glide back into the chosen paddock rather than land in the alternate paddock immediately below. The pilot knows a little theory and speeds up to achieve best glide into the headwind. Unfortunately he does not have the skills to adequately control the glider at high speed. After hitting a few bumps the glider gets the speed wobbles and the pilot has to slow down. The glide initially looks OK until the glider enters some sink. The glide now looks very marginal, nonetheless the pilot stays in prone and presses on reasoning that they will probably “hit some lift after the sink like there always is”. The pilot does not speed up to get through the sink because he doesn’t want to increase his sink rate, which he wrongly reasons will worsen his glide angle. A tree landing is now a strong possibility. The pilot elects to continue on in prone and try to sneak over the trees. Sadly he has insufficient skills and pushes out too far, stalls and clips a tree. A wingtip snags a branch and the glider is turned downwind. The pilot now faces a situation where he is stalled, travelling at high speed downwind, and still in prone. Now in a state of panic he effectively abandons control of the glider. Instead of pulling in to get the glider flying and then attempting to crank it around into the wind he lets the glider continue downwind and doesn’t even flare before the A frame hits the ground. The pilot does not use wheels because they are for beginners so even though the wings are level the glider noses in hard. The pilot, still in prone and hanging onto the uprights breaks both before his helmet slams into the keel and snaps it. Fortunately he emerges unscathed.

Later in the pub, over a couple of cleansing ales, this pilot admits to having made a mistake by drifting behind the trees and being unable to make it back to the landing paddock. In fact he made a linked chain of about 13 different mistakes – perhaps this was his lucky number as similar situations in real life have not always had such happy endings.

Let’s consider these mistakes and what the pilot might have done at each point. First the pilot chooses to fly in strong winds when perhaps lighter winds would have been more appropriate given his lack of skill at high speed flight in the windy and potentially turbulent conditions. He also selects a landing paddock surrounded by trees for the sake of a convenient pick up when the more forgiving large open paddock might have been a better choice. Next the pilot decides to lose height by using 360s because this is the way he always lands. This fails to take account of the strong winds which make downwind drift likely. Linked S turns probably would have been a better choice in the prevailing conditions. Next the pilot fails to note he is drifting downwind early enough to correct the drift by simply flying into wind. Once the precarious downwind position has been noted the pilot elects to try to glide back instead of choosing an alternate paddock. Due to insufficient skill the pilot is unable to fly at the best speed to penetrate the headwind. The pilot hits some sink and elects to continue hoping for lift, even though he knows the glide is marginal, instead of choosing an alternate landing site. The pilot selects an inappropriate airspeed to fly through the sink where he should speed up for best glide. Up until this point the pilot has had options for a safe landing. From this point on a crash is likely but the pilot still has the opportunity to maintain control over the glider to minimise the impact. With a tree landing now a strong possibility the pilot stays in prone and tries and squeak over the trees instead of accepting the tree landing. A crash has now become probable but the pilot still remains in prone. Prone is an extremely bad position to be in during a crash as it makes a head first impact likely and prevents a proper flare. The pilot then stalls the glider and as a result loses control. A crash is now almost inevitable. The pilot is now so panicked that he fails to attempt to get the glider flying again and pointed back into the wind, nor does he flare and slow the glider as much a possible before impact. Without wheels the glider inevitably noses in whereas it might have rolled and absorbed some of the impact if they were fitted. Finally the pilot fails to curl up in a ball and try to let the glider and his strongest bits (legs, pelvis and chest) take the impact, instead allowing his head and arms to bear the brunt of the force. Fortunately he read an article on the importance of helmets and his investment in a good one quite possibly saves his life.

At every point until final impact the pilot has had options available and decisions to make. At each stage the “cascading chain of causation” can be nipped in the bud to minimise the consequences of previous errors. As time passes and further wrong decisions are made the options reduce and become less appealing, more flying skills are called upon and the pilot’s workload increases. Eventually increasing pilot workload may lead to the condition known as sensory overload which could be summarised in layman’s terms as panic or brain failure. This is not a good state of mind for a pilot. An ordinary decision made in good time is generally better than a perfect decision made too late or no decision at all.

Hopefully this article will give you a new perspective on so called accidents and perhaps the ability to turn them into mere close shaves or better still no more than single instances of pilot error, promptly corrected before the situation gets out of control. We are all human and will make mistakes. Without the opportunity to make mistakes we will learn little and develop slowly if at all as pilots. What we must not do is let pilot error continue to the point where you need to be the worlds best pilot to get yourself out of the situation you have just put yourself in. You may just find you’re not up to it. To finish here are some flying truisms which are both amusing and educational.

Good judgement is the product of experience. But what is experience – simply the product of bad judgement!

Take offs are optional; landings are mandatory.

The four most useless things in aviation: runway behind, altitude above, fuel in the truck, and the last five seconds,

The superior pilot uses their superior judgement to avoid having to use their superior skills.

Flying hang gliders is fun
Flying hang gliders is not inherently safe
It can be made safe by the way you go about it
Your own fate is in your own hands. – Erik Fair

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