Re: REFLECTOR: Velocity, Accident & Thermals

[CBrock5000@aol.com]

What I am about to describe here is extremely important in landings and 
takeoffs of all aircraft, and I hope brings up a general discussion 
worthwhile to all. As a hang glider pilot for 16 years, I have learned to 
respect thermal activity. I was really surprised the first time I discussed 
this with my CFII, MEI and he didn't have a very good understanding of 
thermals and I have found since then, neither do most pilots. When you fly a 
"non powered" aircraft like a high performance hang glider, you learn which 
parts of the day and terrain will produce the "hottest" thermals. The wind 
that was described on final in this accident sounds like thermal activity. 
How powerful are thermals? Hang glider pilots look for these thermals to gain 
massive amounts of altitude. Many times while hang gliding on hot days near 
hot terrain like large rock formations, shopping malls, etc. I have been in 
thermals that registered 2000 fpm on my variometer. Due to our precision 
flying inside the core a resulting altitude gain of 4000-10000 feet is not 
uncommon. It is a bit funny to be standing on a hot mountain launch site with 
tourists asking why you are dressed out in neoprene and layered clothing and 
ski gloves. They have a hard time believing the altitude gain until they 
stand around and watch for a while and see one advanced hang glider pilot 
after another ascend out of sight. If you miss the circle of the core the 
other side of the thermal is usually just as strong in the opposite downward 
direction. It is well known that these high tech double surface competition 
hang gliders can be tumbled over due to extreme thermals. I know of several 
pilots that were in strong thermals that were tumbled. Imagine the power to 
tumble over a hang glider instantly in mid air, with glider, pilot, 
parachute, cross country gear, gps, vario, water back pack, etc. weighing in 
at 260-350 pounds .... Powerful. So what do WE do when landing, especially 
during hot sunny days? Keep the speed up during downwind, base and final, get 
into ground effect, bleed off the energy, flare, land and lock it down. Yes, 
in a velocity this takes extra runway, and yes I will not even try flying the 
velocity on a hot mid day for some time. I cringe when I read about test 
flights by new velocity pilots during hot days, because of thermals. 
Beginning hang glider pilots are only allowed to practice in a pasture field 
in early morning and late evening hours when thermals are usually less 
strong. And this rule follows them all the way to the first 40 hours or so of 
mountain launches.....smooooth, cool air. For those of us that haven't been 
flying canard type aircraft for many hours I suggest only flying for some 
time in the safest conditions; cool mornings and evenings, long runways, etc. 
Let's remember these are high performance aircraft and should be handled with 
respect. These ideas are not meant in any way to pass judgment on the pilot 
in this accident, just information I have been thinking about for some time 
in regard to my flying whenever my plane is ready. Chris Brock XL-RG, 
Knoxville, TN.