Twin Bowls Top Landing

By Steve Roti

At first glance the Twin Bowls launch area may look like an easy place to top land. Don't be fooled -- it's actually a tricky spot, and the stronger the soaring conditions the riskier it is to top land there. Here's why:

1. Twin Bowls is primarily a thermal soaring site, not a ridge soaring site. The launch area is right in the path of thermals rising from the bowl and tracking up the ridge above launch. That means the possibility of thermal turbulence close to the ground when launching and landing.

2. Mechanical turbulence is an increasing problem as the trees get taller in front of the launch area. When we started paragliding there in 1993 the trees were tiny, but now in 2000 some of the trees are in the 20-30 foot range which causes significant texture and eddies in the air coming up and over the area where pilots are launching and landing.

3. There's a wind and lift gradient above the launch area that gets more severe the further back you go. In other words the wind is stronger and has a larger vertical component 100 feet above the launch area than it does 50 feet above. When the glider encounters the gradient it pitches forward and the ground rushes up at the pilot.

4. The terrain makes setting up a top landing approach difficult. The ground south of the launch is lower and north of the launch it's higher and tree-covered. The east end of the launch is lower than the west end and narrower too.

5. The wind can cause problems too. When there's a north component in the wind coming up and over the launch area the trees north of launch create additional mechanical turbulence that can combine with the other sources of turbulence mentioned above to make the air downright nasty.

What does this mean to me? It means that Twin Bowls is an advanced top landing spot in moderate to strong soaring conditions. When I first started flying Twin Bowls I didn't start top landing right away -- I waited a year and a half before doing my first one there, and I had plenty of prior experience top landing at other sites. I've been fortunate in that all my top landings at Twin Bowls so far have been safe.

Not everyone else has been as fortunate. Between 1998 and 2000 there have been three top landing accidents involving newer pilots that resulted in Life Flight evacuations. One injury was a broken leg, the second was a fractured vertebra, and the third a dislocated elbow. (In addition, there was another Life Flight evacuation of a pilot who crashed immediately after launching.) That's quite a few accidents at one launch site in just three years, and it should cause newer pilots to ask themselves "Is it possible to top land at Twin Bowls safely?"

Each pilot will need to answer this question for themselves, but before deciding consider this list of Do's and Don'ts.

  1. Do choose the right conditions (lighter soaring conditions with the wind from the west or southwest).

  2. Do plan your approach carefully, try to land in the western-most half of the launch area.

  3. Do give yourself a margin of safety so you can fly over the front of the launch area into the bowl if the approach doesn't work out as planned.

  4. Do practice active piloting as you come in to land because more likely than not you'll encounter some degree of turbulence in soarable conditions.

  5. Do put your landing gear (your legs!) down and ready to land below 50' AGL because you might descend that last 50' faster than you expect and you'll be better off if you land on your feet.

  6. Don't try to teach yourself how to top land at Twin Bowls. There are easier and better places to learn how to top land -- you need to have strong top landing skills before trying it at Twin Bowls.

  7. Don't tell yourself that you must top land -- remember that top landing is optional and the standard LZ for Twin Bowls is on the valley floor.

  8. Don't try to top land when the wind is strong or has a north component in it.

  9. Don't make sharp turns close to the ground.

  10. Don't try to force a top landing or let yourself get suckered into doing it just because others are. Remember that it's better to be using your legs hiking out from the valley floor than it is to be in the hospital with a broken leg.

This list is not exhaustive, but is intended to give you some idea of the risks involved. Remember that conditions vary tremendously over the course of a flying day, and can sometimes change dramatically in just a few minutes. If you're in doubt about the wisdom of top landing at Twin Bowls, the prudent thing to do is to land in the standard LZ.

Additional comments

From Mike Steed:

  • The entire approach path should be in windward air; avoid the downwind side of the launch area which is where the gradient and turbulence is worst. If you can't get down on the windward side, that should tell you something!
  • Be courteous of other pilots and who want to launch or spectators who are standing in the intended landing area.

From Steve Forslund (originally posted on the CPC mailing list):

This was not supposed to sound like a how to, just some thoughts on what works for me. One of the most important skills in top landing is knowing when not to. The launch at Twin Bowls is changing every year, as the trees grow up in front it is now possible to have 8-10 mph at launch, but up in the lift band it may be blowing 20 mph or more. I think this may be encouraging us to launch and fly on days that have a lot more base wind than conditions that used to be flown when the trees out front were shorter and fewer. The flat top lends itself to going back and avoiding the lift band, but while this works I generally only use this on L&V days and keep a good eye on streamers and trees for any boomers coming through. I prefer (especially with wind) to work my way down at the front of launch or further out front, if I can not do this with out extreme measures close to the ground then it is obvious I should land elsewhere. The advantage is that you learn how strong it really is. LOOK A GIFT HORSE IN THE MOUTH! If there is a lot of lift around and you have a small LZ that you can manage to drop into, it may not be fun.