On Saturday, June 5, 2004 7:59:47 PM UTC-5, Ed Byars wrote:
I sent the following to our magazine nine months ago and didn't receive an
acknowledgement or receipt. I guess it was not suitable for them so I
thought I would share it with ras to maybe provoke some safety discussion..

efb10-11-03-rev.6-5-04

You may be interested in my latest crotch strap experience.

I'm still analyzing my June 2003 accident and the cause. More later on this.
The role of the crotch strap is significant and worthy of mention.

The last half dozen gliders I've had I added a crotch strap (usually
available from Wings & Wheels), which easily clicks into the bottom, front
or 5th slot of the standard Gadringer belt hardware. I secure the other end,
which terminates with the belt into a triangular link, with a quarter inch
hole that I bolt to the seat pan with a large "wood" washer behind the seat
pan. My gliders are Experimental category so this is legal.

I always heard that the main purpose of a crotch strap was to keep the lap
belt across the upper thighs and prevent it sliding up to the stomach area.
I have since learned better.

It of course depends on the direction of the accident loads and the
direction of the inertia of the body as to how all restraint straps come
into play.

Many glider accidents involve "dropping in" vertically wherein the tailbone
(in the L-1, L-2 area) or higher are damaged so the belts don't help much..
You seldom see accidents with lap belt overload, but it happens. I have a
sad memory of helping remove a dead friend from an inverted Ventus cockpit
where the lap belts on both sides had pulled lose from the seat pan.
Fortunately rare but it happens.

In my "incident" the nose of the glider hit hard ground at about a 60 plus
degree angle. The "load" was about along the longitudinal axis of the
glider. Since in our modern gliders (ASW-28 in my case) we recline (sit
supine), the inertia of my body was toward the nose with only the crotch
strap to resist. Actually Waibel designed the seat pan to take some of this
forward load against the bottom of the thighs. In this seating the knees are
bent more upward.

The nose of the glider (along with my feet) was crushed in a calculated
energy-absorbing manner. Thank you Gerhardt Waibel! I think his design and
the crotch strap saved my knees.

I was conscious and lucid until the helicopter dropped me off at the
Medical College of Georgia Trauma Center.

After that I really was not with it for a couple of weeks, but after that
time I suddenly noticed that my groin area was still quite swollen. I
realized that my crotch area had sustained a significant load and that all
things considered had kept my body from moving more forward and no doubt
helped minimize the leg/knee damage. I had no shoulder strap or lap belt
marks or soreness.

Since my guess is that a significant number of glider accidents impose loads
and body reactions similar to mine, I recommend a crotch strap. Trying to
distribute the load to the pelvic area by wearing an athletic "cup" may be
good for some flights, but for some flights there are other disadvantages..
Many contest pilots regularly wear a male external catheter and I don't
think both would work. With just the crotch strap I always had to be
careful that the strap was adjusted somewhat to the right, was not too
tight, and did not interfere with the flow from the catheter that was to the
left.

I suggest reading Chip Bearden's posting which appeared in the
rec.aviation.soaring newsgroup on Nov.20 1998 which outlines a more complex
but better seat belt design.

I hope this discussion will create more thought about glider accident
safety.

Ed Byars

Ed,
Over the last Winter, I purchased and installed a crotch belt for my LS8-18 using the convenient cross-enforcement rib molded into the seat pan. I've flown with it all season without having issues with the catheter tubing. The lap belts stay low on the hip area while they were riding up toward the belly without a crotch strap. I fully agree with your recommendations. Flying the New Castle ridge last week I found the belting now keeps the body better connected with the seat pan with less "floating".
Herb, J7