Deadly Spiral Dives!


Spiral dives in a paraglider can be deadly. There have been two fatal ones in our area in the last year. Pilots entered them intentionally or accidentally and before they knew it, they were locked in descending at a high speed. Only awareness of what was happening and aggressive action could have saved them.
A spiral dive is the strongest tool that a pilot posseses to descend quickly.  Sink rates of over 4000 feet per minute (fpm) can be reached in tight spiral dives. However, with these tight spirals comes strong g-forces; the body’s blood can leave the brain and unconsciousness can result.   Furthermore if a glider becomes spiral stable, it will continue diving towards the ground with no pilot input needed to continue this death spiral. Actively flying pilots need much altitude to exit a tight spiral dive.
If you need to descend quickly, there are several safer options. Here is a hierarchy for descending with a paraglider. Use the safer techniques first and reserve the more powerful ones only for dire situations:
1) Fly away from the lifting air: 200 fpm.
2) Big ears: 400 fpm
3) Big ears + speedbar: 600 fpm. First pull ears, then engage the speedbar. Engaging the speedbar first then adding ears could cause a frontal
4) B-line stall: 1700 fpm. If the lift is extreme, do a B-line stall with care since you are stalling the wing and giving up immediate control.
5) Assymetric spirals: 2000 fpm. Enter and leave spirals before great g-forces can build up.
6) Spiral dive: 4000 fpm.  This is a last, desperate option – loss of control is possible as you fly towards the ground approaching 40 mph!
All of these descent tools should be practiced the first time under the close guidance of an instructor. The last three (B-line stalls, asymmetric spirals and spiral dives) should be practiced at a safety clinic over water with an instructor.  When you upgrade your wing to one of higher rating, you should practice these descent techniques again.

If you are wondering how your wing typically exits from spirals, look the DHV’s web site at http://www.dhv.de. The DHV test pilots have found that, in exiting a spiral, higher performance wings typically continue turning through 180 to 360 degrees even if you do everything correctly!

Granger Banks, a USHPA advanced tandem instructor (USHPA #???), has been offering safety clinics since 1992. Contact him at granger@parasoftparagliding.com.