|15 minutes before Craig died, he was making sure I got a safe launch.|
Craig and I were passionate about photographing the beautiful cliff areas that Craig had been finding and pioneering over the past several years. We were at the Indian Creek launch with a film crew. We scouted the area on Sunday. On Monday we were there to shoot launches. The film crew spent most of the PM setting up and adjusting the camera on a crane. Kevin and Dave made non-filmed flights to the bottom LZ early in non-soarable conditions and came back up.
Overcast conditions delayed us. About 1 1/2 hours before sunset, the clouds had cleared and the crew was ready. Kevin launched without incident. Wind was lighter. Dave launched on my Trapezoid Predator and popped his nose severely, wings stayed level. He pulled in immediately and dove away. I launched next with a camera mount 30 inches below the rear of the keel on a 185 Dream. I felt and heard the mount drag on the rock as I launched, so I knew I had popped my nose. I pulled in and few away into the first soarable air of the day. I climbed in smooth lift to as much as 300 feet above launch. In about 10 minutes or so, I watched Craig come off the cliff right wing first with considerable yaw rotation left. He descended falling-leaf style, nose against the cliff for about 200 feet. Then something broke and the glider folded causing him to accelerate to great speed into the rocks of the scree field about 400 feet below launch.
This cliff launch site has a "bull nose" or rounded edge. I think that this easy-looking launch run caused us to think of it as a more normal type of launch in which you run down a slope to gain airspeed to start the wing's generating lift and eventually lift off. It can work that way in little or no wind if you have enough running room, but with significant wind(more than 5 mph) at a sheer cliff the normal launch technique is not reliable.
The wind is always parallel to the surface its flowing over, whether shallow slope or steep cliff. On a tall sheer cliff the wind is straight up and has momentum. We cannot expect wind that has great momentum going straight up to curve in at launch just because the cliff edge is rounded. Mostly, it continues upward with some currents at times flowing in at launch.
Craig understood this. When he helped visiting pilots launch these cliffs, he would stand in front of them at the cliff edge with a streamer on a stick. He would hold it high and low on the right and left to show the pilot what the air flow was at the edge. He would make recommendations as to when it looked bad or when it looked like the airflow had settled in to a good condition. Because he launched last, he had no pilot to do that for him. I think he believed he could do it alone using the two permanent streamers he had set on the sides.
The video shows that Craig started his run from about 3 feet behind the spot that Craig and I had agreed was the best place to start. As he ran, his glider banked left until the left tip hit the ground and stopped as it contacted a small rock obstruction at the cliff edge. At this time he was about 4 steps into his run with much speed. With the left tip stopped, much of that forward energy turned into yaw rotation making it impossible to fly away.
Reserve chute was out of the container, but still in the deployment bag at the impact site.
Launching a steep cliff in soarable conditions.
His wing started a slight roll oscillation within the limits of the side wires just before he started. It went left, then right and he started his run just as it was going left again. With the right wing up in faster air and the left wing down, it quickly became a self-aggravating and unrecoverable unwanted roll.
The streamer just behind Craig turned tail just as he started running. I feel that the unlucky non-uniform parcel of air at the cliff edge was a major factor.
I feel that the obstruction that stopped the left tip is the most significant factor, because it made a bad situation an impossible one. It might have been possible to dive and turn away from the cliff if the tip had slid off the edge.
The extra distance from the edge where Craig started gave the wing more time to roll before he arrived at the edge. This is not insignificant.
I now think that the risk of trying to launch steep cliffs in anything but very light winds is an unacceptable one.
I think it is possible to launch steep cliffs in soarble conditions if there are lull cycles in which the wind is reliably light for a long enough period. While waiting at the edge for a lull, the glider should be secured with an anchored climbing rope with carabiner(removed just before launch).
The procedure for launching a cliff is to start no more than 3 steps back(in very light, preferably no wind) and build momentum while keeping the wing level. We need to essentially throw ourself and the glider off the cliff and quickly pull in to dive for flying speed. The run is not for building airspeed. No human is strong enough to run fast enough on level ground (while carrying a glider) to achieve flying airspeed. We just need to get off the cliff cleanly and pull the nose way down for airspeed. It is essentially the same as a balloon-drop launch. We start with zero airspeed and dive to get the glider flying.
Keeping your wing level is the big problem if there is any wind at all. Since the glider is not flying until you are off the cliff and diving, there is no weight-shift control. Your only roll control is through your stance on the ground and your “muscling” of the control frame.
Yaw control is also essential. If one wing gets over the edge slightly before the other, that wing can go up and the other down in a self-aggravating manner. It is impossible to overcome this with the inadequate leverage of the relatively short control frame as compared to the span of the glider.
Even if you do get off a windy sheer cliff with wings level, the nose punches into a wall of upward moving air while the tips are still in cliff-edge air that is not moving up. This creates the powerful nose-popping effect that surprised Dave and I, and I'm sure also had an effect on Craig's launch.
We must learn the lessons from this terrible loss of a great guy who was an expert at this. When several factors conspire at once, the chance of a good outcome is greatly reduced. Unless you are prepared to accept increased risk, stick to windy-cliff sites that have been proven safe by lots of use over the decades.