“Collapse” is one of the most-cited fears of inquiring minds. “But can’t that paraglider wing collapse?” they ask. Of course it can. But it turns out that the dreaded collapse has more bark than bite and most are easily avoidable. Even when it happens it’s rarely more than a surprising sight. There are, of course, exceptions.
see also Weight Shift, fury of a dust devil video, Active Piloting, Attending a Maneuvers Clinic, Mid-Day Collapse Accident with video and diagram, and Reserve Parachutes.
Gaining a mastery of the wing can dramatically reduce the chances of a collapse in the first place. But that mastery comes through sound training and experience. Not just experience boating around in smooth air, but exposing yourself to lower levels of turbulence and maneuvering. Don’t think you can read about this here, in the Bible, or anywhere else and just go do it, either. Steep maneuvering in a paraglider is risky beyond its appearances, especially for those who tend to jump ahead of their capabilities.
Some good news: the wing is built to open and fly. Quickly. So even if part of it does fold down, once it’s reloaded, normal lift returns pronto. Higher performance wings are notorious for getting their long, skinny tips caught in the lines (a cravat) and can be more challenging to recover.
What’s surprising is how easily most wings can be controlled with up to half of their area folded up. In most cases, if the pilot minimizes brake pull, lets the remaining wing accelerate briefly and then steer, it’s quite flyable, even landable like that.
Two rules should followed by new pilots:
- Rule 1. Never have NO brake pressure, always have about pressure 2 or what many instructors call quarter brakes (about the weight of your arms). The wing is far more collapse resistant with some brake pressure but, beyond about pressure 3, the benefit goes away since you lose brake authority by being too slow.
- Rule 2. if you feel something unusual, do the default action: reduce brakes, reduce power, then steer. Risk and reward has the refrain “Hands Up, Power Off” which means “Reduce Brakes, Reduce Power”.
You’re cruising along when bumps begin—how much brakes to pull? First, reduce pressure then go to pressure 2. If something unusual happens, reduce brakes a bit reduce power a bit, then steer. Remember, the vast majority of complications from collapses are not the fold itself, but rather the pilot’s abrupt and excessive reaction to it.
See also the Bump Scale for a standard reference to turbulence strength.
Active Piloting
Here is a complete article on Active Piloting.
There’s more than meets the eye but the skill is primal for those who want to really be able to master their craft. It’s much more than riding the brakes and must be learned over time. Depending on your wing, immediate responses may be in order, almost jabbing at the brakes. You learn by seeing how much pull it takes to reduce the wing’s forward darting when it hits a sharp bump.
I’ve seen numerous accidents and collapses that were aggravated by the pilot’s attempt at using brakes when the best action would have been simply reducing brake pressure to about pressure 2 (see brake pressures) and concentrating on direction.
You can do a lot to avoid collapses in the first place. Staying out of turbulence is the best prevention. Keeping the wing from going forward too much is the next best thing. The further forward your wing goes, the more likely a collapse is.
Free flyers in strong thermal conditions get collapses a lot, relatively speaking, so avoid such conditions. A good start is to only fly in the first 3 and last 3 hours of the day. Don’t fly in rotors—downwind of obstructions and remember that stronger wind means stronger mechanical turbulence.
Don’t fly too slow. Speed is life especially once you’re already in turbulence. If you’re getting bounced around a lot hold pressure 2, as mentioned above, but reduce it if you feel the airflow on your face decrease or the wing goes back. One you give up too much speed, those brakes are nearly worthless. Except for heavily reflexed wings, have the trimmers set to slow and do not use the speedbar. Flying faster can dramatically aggravate a fold since the extra airspeed will tend to pull it under farther.
As an aside, cruising along in turbulence under power leaves you more susceptible to going parachutal—a rarity in free flight but more common in motoring, and another reason to remember “reduce brakes, reduce power, then steer” if you feel something unusual.
You are most susceptible to collapses when 1) lightly loaded, 2) accelerated, 3) hands up, 4) descending power off.
High Performance vs Reflex
High performance wings (higher than DHV 1-2 or equivalent), especially when lightly loaded, will behave the worst during large folds—they are more susceptible and less likely to recover cleanly. Their higher certification, in fact, comes significantly from how long they take to recover from various upsets. These long, skinny wings are favored by cross-country pilots for their great glide at the expense of higher risk. Don’t think that skill alone will make them safe—it will make a difference but some awesome pilots have died in the thermic cauldron called “big-air.” Small folds,
Some instructors prefer calling them folds, asymmetric tip folds or asymmetric wing folds.
Turbulence means a downward vertical gust that causes all or part of the leading edge to fold under. It then blows back and lift is lost. Depending on severity, the glider will turn towards the folded portion since the open part is lifting.
If the whole leading edge folds under, it’s called a frontal collapse. If a tip folds it’s called an asymmetric collapse or asymmetric tip fold.
During the fast half of a slow/fast task at the 2005 USPPA competition, at about 1.5 meters high, I hit turbulence. 40% of the left wing folded as my left side brake went limp. It only took a couple inches of brake with my right hand to steer and keep it tracking down the lane. This technique allowed me to keep from hitting the ground and within the 5 meter wide lane.
Another important response to turbulence is to get off the speedbar. I didn’t since I had no idea how bad it was! It happened while nearly fully accelerated, trimmers at 3/4 out in moderately turbulent air: a very, very, VERY susceptible condition.
Photo by fellow competition pilot Stan Kasica.
A Reflex style wing courtesy www.FlyParamania.com
These wings load the A’s and B’s very heavily with the trimmers set to fast. They are less prone to collapse in that condition because the leading edge is less subject to “blow down,” where relative wind aggravates the collapse as the leading edge is blown down and back, taking more of the wing as it goes. The effect is seen in all three of these pictures and the video below.
But any wing, going real fast, will be wilder on the recovery. So even the reflex wings will frequently earn (or deserve) a DHV 2 or performance rating at their faster settings.