By Paul Klemond
Lots of pilot wisdom is shared in the European magazines and elsewhere, but there's not much shared understanding of big collapses in print here in the US. After I took a big collapse and crashed in Mexico two years ago, I started asking some great pilots for help in understanding what happened and how I could have prevented it. Joe Gluzinski, Dave Bridges, Chris Santacroce, Robbie Whittall and others shared their valuable insight with me. I think more pilots should know about big collapses. I'm not the most qualified to write this, but I have the time so here it is.
This article is not the complete story. Please, do not go out and induce big collapses just to see what happens. Steve Roti points out that intentional pilot-induced collapses aren't the same as the real thing because the pilot is ready for them, and there's no way to simulate the nasty air that causes real collapses and that can make recovery problematic. Fly in strong thermal conditions enough and sooner or later you'll mother nature will demonstrate big collapse conditions for you.
What I'll present here is no substitute for the kind of instruction and practice one gets at an SIV or advanced maneuvers clinic, taught by a qualified instructor. I seize every opportunity I can to attend these clinics, especially after I buy a new wing. I really don't enjoy the adrenaline of doing a radical maneuver, but it's worth it to me: it builds the reflex piloting responses that are totally critical when something very unusual happens while you're flying. The instructor advice is priceless and may save your life. So go attend these clinics if you at all can.
This article is meant to get you thinking about big collapses, to spur you to seek out the understanding and skills you need to fly safely and avoid big collapses, failing that, to recover from them without making them worse.
Conditions
Big collapses are most likely to happen in strong thermal conditions. If you don't normally fly in such conditions, then don't expect to dive into it when you're on vacation. Most sites have some challenging conditions from time to time, but the gnarliest air is usually found in serious desert and mountain sites like the Owens, Chelan, Elsinore, King Mountain, Valle de Bravo's El Penon, Igualla, etc. If you don't often fly in such places, recognize that you're not born with the skills to fly safely there. Take some extra time in moderate conditions to develop your "bump tolerance" and skills. A little humility may save your life. Make your own decisions.
Prevention
99% of collapses can and should be prevented. (Maybe only 92% if you fly in the Owens a lot.) Let's discuss prevention.
WING LOADING: Are you light on your wing or heavy? Are you near the bottom of your wing's certified weight range, or near the top? It's generally true that lighter-loaded wings are more prone to collapses than heavier-loaded wings. Consider flying a wing on which you are more than half-way into the weight range. Carrying water ballast is an option but it poses certain problems, such as increased energy that needs to be dissipated at landing, and inconvenience. Lighter-loaded wings sometimes behave slower or more gently during stalls and spins, but they often reopen more slowly after a collapse. It's better to avoid the stalls, spins and collapses in the first place by flying a heavier-loaded wing.
AWARENESS: It's worst to suffer a collapses when you're not mentally prepared. This is easy! Just be paranoid ALL THE TIME. At any moment you could suffer a collapse. Think about prevention and contingencies, and you're already one step closer to preventing or handling a collapse. As this new mindset become instinct, you'll enjoy flying again. Until then, don't be complacent and caught by surprise.
If you're using your speed bar or your trimmers are out and fast, be aware that you're new angle of attack generally _increases_ your risk of collapse or front tuck. Be paranoid and use active piloting, the next preventative technique.
ACTIVE PILOTING: Use your brakes to feel, anticipate and prevent a collapse from happening. Robbie Whittall told me to pretend my hands are each 5-kg weights: when the pressure gets light, pull down to maintain 5-kg of pressure. When it gets heavy, let up to restore 5-kg of pressure. The faster you react to changes in pressure this way, the more actively you are piloting. This should prevent a lot of collapses.
Some pilots believe that everyone should be able to actively pilot by constantly feeling the wing through brakes alone. Other pilots (like me) rely additionally on a visual check, looking up at the wing frequently to see what it's doing. Whether you look up or not, this isn't the whole story - it's a starting point for you to practice and seek out knowledge of active piloting.
WEIGHT-SHIFTING: Some pilots relax too much and forget that weight-shifting is a very important part of active piloting. Don't just let the air throw you around like a sack of potatoes. As your harness rolls left and right, roll your hips left and right to keep your upper body stable and your weight distributed under both carabiners. Later I'll talk about what to do with your weight if you do take a collapse. But short of that happening, roll your hips to keep both sides pressurized as you take the ups and downs.
Most thermalling pilots I talk to prefer looser harness straps and loose or no cross-bracing - they're better able to feel what the wing is doing, and they have more room to shift their weight. (Some wings require certain harness width and cross-bracing as a certification or safety requirement - learn about your particular wing before changing your harness settings.) It might be hard at first to give up the secure feeling of a tight harness. Maybe loosen it gradually, flight by flight. I've never heard of any pilot falling out of a closed harness, even a loose one. Don't go overboard. But do consider a looser harness setting and see if you don't prefer it.
LEVEL FLYING: Collapses often happen near thermals, but that doesn't mean you're always working the thermal when you find it. A lot of big collapses occur during straight and level flight. When you're working a thermal (turning in it), the half of the wing on the inside of the turn is highly pressurized and very unlikely to collapse. The half on the outside of the turn may collapse but it is unlikely to be a large collapse, and is usually manageable. So, to avoid big collapses, it's preferrable to work thermals whenever possible. "Turn or be turned," as my friend Mark Heckler says. Weight shift hard into your turns, to keep that inside half highly pressurized. Actively pilot the outside half. And when you must fly straigh and level, be aware of the increased likelihood of collapses.
There's a lot more that someone could write about prevention, such as reading terrain for example. I hope someone writes about it because I'd like to know more too!
Handling Big Collapses
OK let's say you've mastered the prevention practices but you still get hit with that 0.1% case, the monster collapse. Here's where some pilots make mistakes that actually make matters worse. Let's look at what to avoid, and what to consider.
First, what's the difference between a big collapse and a not-so-big collapse? That depends entirely on the wing and the load beneath it. Your wing will have its own behavior. If you want to fly strong thermic conditions, you need to learn how your wing behaves after different degrees of collapses, big and small. (DO NOT go out and induce _big_ collapses just to see what happens! Work with your instructor to build your skills safely.) Every wing has a threshold: small collapses which are manageable, and big collapses which are not. What does "manageable" mean? Keep reading.
Most pilots know the collapse-victim's mantra: "Steer, then Clear." This is meant to help you prioritize your actions: don't focus on reinflating the collapsed side until you've regained steering control of the inflated flying side, and avoided a collision. This is generally good advice -- but it does have its limits! This is precisely where some pilots run into trouble.
A collapse is manageable when you are able to steer your wing, via brakes and weightshift, before the collapsed side reinflates. Sometimes this is not possible. After a big collapse, only a small portion of your wing will still be inflated. This small portion will almost certainly "dive" forward under the new load of your entire weight. Maybe the wing will enter a spiral. As with all collapses, you should shift your weight hard to the good (inflated) side of your wing. This should be automatic, reflex. Simultaneously, as you apply brake to regain steering control, you must beware: this new tiny wing of yours has a HIGH (EARLY) stall point. It is very common and very easy to cause it to stall, which will manifest itself as a negative spin.
Some pilots say you can feel this through the brakes before it happens: the brake pressure may suddenly go from heavy to light, precipitating the spin. I know I cannot feel this on my wing. Watching the wing might help. Better advice I think is to simply admit that you're better off NOT steering the wing since you can't safely do so without risking the stall/negative spin. No one can make this decision for you. If you can safely steer, you should. If you can't, you shouldn't. What else can you do?
"Let the wing fly - it wants to fly." Every wing is different, but most non-competition wings are designed to reinflate after even the biggest collapses. When this happens, you will regain steering. More good advice I got from Robbie Whittall: if you don't recognize exactly what your wing is doing, raise your hands, watch the wing and wait until you do recognize exactly what your wing is doing before trying corrective input. (Maybe you know better for your wing. I sure don't for mine.)
Clearly recovering from big collapses can require a lot of altitude. Remember the two points about "awareness" and "level flying"?
Be aware of your altitude above the terrain at all times, before collapses happens. Lateral clearance is critical too: collapses will often fling you horizontally. Those who've taken big collapses tend to avoid "scratching" - flying in ultra close to the terrain - in thermic or turbulent conditions. Be prepared to throw your reserve if necessary. Two years ago, I survived without throwing my reserve, but I felt very lucky and very stupid not to have thrown it. How will you know when you need to throw yours? I don't think anyone can answer that for you. You can't predict or visualize all the different weird wing troubles you might have.
Some macho pilots make fun of people who throw their reserves, saying they should have just worked it out. Not me. Make no mistake, throwing your reserve commits you to a course frought with its own significant risks. Before you're in the air having a problem, you should talk to your instructor and others you trust, and set your own course of action. Be aware every moment you spend below 300' AGL or whatever height you think makes sense, below which you don't really have time to analyze, ponder or decide. I hope these ideas spur some discussion that will eventually help us all avoid serious problems. May we all fly for a long time and never have any big collapses!