TOST vs. Schweizer Hooks on Tow Planes.

Currently operating 3 tow planes, all with Schweizer hooks installed. I would love to get access to some concrete information on the issues with the Schweizer hooks, comparison between the two, and any concerns with the TOST system. My goal is to likely switch over the fleet, having personally experienced a situation with a glider losing directional control on tow, and causing momentary upset to the towplane. In my opinion, the TOST system is superior, and tangible information is the best way to present this opinion to the other parties involved in our operation.

https://groups.google.com/d/topic/re...xRo/discussion

There was a lively discussion concerning the two tow hook options. It's worth reading before everyone chimes in here.

Paul A.
Jupiter, FL

Originally Posted by Jason Scott

Currently operating 3 tow planes, all with Schweizer hooks installed. I would love to get access to some concrete information on the issues with the Schweizer hooks, comparison between the two, and any concerns with the TOST system. My goal is to likely switch over the fleet, having personally experienced a situation with a glider losing directional control on tow, and causing momentary upset to the towplane. In my opinion, the TOST system is superior, and tangible information is the best way to present this opinion to the other parties involved in our operation.

In the FAA Advisory Circular, Date 3/3/08 AC No 43.13-2b, Page 76, Par 808 states as follows:

“ WHEN THE GLIDER UNDER TOW OPERATES ABOVE A CERTAIN ANGLE TO THE TOW PLANE, THE RING MAY SLIDE UPWARDS ON THE HOOK, CAUSING EXCESSIVE LOAD ON THE HOOK AND DIFFICULTY IN RELEASING THE TOW ROPE RING.”

The Soaring Society of America thru their Soaring Safety Foundation, Tow Pilot Training Course additionally acknowledge IN RED as follows:

“If at any time the nose of the tow plane is pulled uncontrollably by the glider to a dangerously high or low pitch attitude, - PULL THE RELEASE! “

It goes on to say:

“Depending on the installation of the tow hitch, it may be possible for the release mechanism to become jammed due to the excessively high position of the glider, (American style hook). “

Here we have two "authorities" acknowledging the problem which has been a contributing factor to the death of tow pilots in the past. This condition has existed for a few decades at least with knowledge of and a lack of interest in correcting the matter. If this is not 'concrete" enough then I don't know what would be.

Every report I have read notes a "delay in releasing" on the part of the tow pilot. I would submit that there was no delay in the attempt, rather a mechanism which is meant to release but will not as noted in the above documents.

My letter to the FAA recommended at a MINIMUM that there be blanket permission for a qualified A&P IA to invert the Schweizer hook AND to allow for the increase in the length of the release handle, increasing the mechanical advantage and allowing for access to the tow pilot in the upright and seated position. It is absurd to have it down on the floor and with a 5-1 mechanical advantage which has been shown to be inadequate to affect a release. The TOST system would be preferable especially if you consider that you may not tow any glider with a max gross weight of 1500 lbs with the Schweizer hook as this system is limited to a 1200 lb rope.

The push back will be the cost of the Tost system and while you're at it don't forget to improve the position and mechanical advantage of the release handle. But If you don't value the life of your tow pilots...

Walt Connelly
Former tow pilot (7K tows)
Now happily flying helicopters

" The push back will be the cost of the Tost system"
Push back is not about cost, push back is about the lack of information on legally installing the Tost system on all current towplanes in light of you wanting the FAA to ban all Schweizer hooks. As I said to you last time this came up, if you want to make towing safer collect and make available STCs and successful 337s for Tost hook installations. Instead of whining to a higher power for a solution that screws clubs be the solution that helps clubs.

I question why the FAA would care if a Schweizer release was mounted
inverted.Â* I would also bet that it would be a very simple 337 which
would allow the modification.

That said, when I installed Garmin G5 instruments in the 180 to replace
the vacuum instruments, I found that I could not move the vacuum
attitude indicator to the right hand panel as a backup. According to
Garmin's installation manual the instrument had to be moved one position
left and one row down.Â* That's what the STC called for.Â* What a bunch of
crap.

On 5/1/2019 7:57 AM, wrote:

" The push back will be the cost of the Tost system"
Push back is not about cost, push back is about the lack of information on legally installing the Tost system on all current towplanes in light of you wanting the FAA to ban all Schweizer hooks. As I said to you last time this came up, if you want to make towing safer collect and make available STCs and successful 337s for Tost hook installations. Instead of whining to a higher power for a solution that screws clubs be the solution that helps clubs.

--
Dan, 5J

Originally Posted by

" The push back will be the cost of the Tost system"
Push back is not about cost, push back is about the lack of information on legally installing the Tost system on all current towplanes in light of you wanting the FAA to ban all Schweizer hooks. As I said to you last time this came up, if you want to make towing safer collect and make available STCs and successful 337s for Tost hook installations. Instead of whining to a higher power for a solution that screws clubs be the solution that helps clubs.

Your characterization of my "whining" to a higher power speaks of one unconcerned with safety. I pointed out clearly the glaring knowledge of a problem which has resulted in the death of tow pilots. The FAA AO acknowledges the problem as does the SSA/SSF (which is a joke). The SSA is a toothless tiger along for the ride while collecting dues and selling magazines in my Constitutionally protected opinion. The FAA has the teeth if they choose to chew.

I'm more concerned with saving lives than anything else having been a second or two from losing mine. If your mechanics can't find the appropriate STCs and 337s perhaps you need to find another mechanic.

I've been contacted by one tow pilot who has acknowledge my actions which influenced his facility to make the changes I recommended. By his acknowledgement it saved his life shortly thereafter. I've heard from commercial operators who experienced this event and realized the potential. They did the work needed to make the changes to a safer, more accessable system.

Have a nice day.

Walt Connelly
Former tow pilot
Now happily flying Whirlybirds.

Mr. Connelly, for my own knowledge where does the 1500/1200 lb. limitation on the Schwiezer system come from. Ive tried to find a reference in the past but couldnt find one.

To respectfully add to the debate, I'd challenge anyone in favor of ousting the Schwiezer system if they feel the same way about aero tow with a Tost c.g. hook? Here the superior Tost system has been perhaps miss used and this installation has caused more glider accidents and fatalities than Schwiezer release on tow plane accidents.
I appreciate the position of the "hands off" crowd, what I'd like to see is if those in favor of banning the Schwiezer system on the tow plane also believe they should be beholden to a regulation or policy affecting the method by which they are towed in their glider (when it's their expense).
These two items would have the single biggest impact on soaring safety that I can think of at the lowest cost and highest participation level if it were either a regulatory or insurance requirement. The problem is pilots are cheap and nobody thinks it will happen to them.

-Doug

On Wednesday, May 1, 2019 at 9:59:05 AM UTC-4, wrote:
Mr. Connelly, for my own knowledge where does the 1500/1200 lb. limitation on the Schwiezer system come from. Ive tried to find a reference in the past but couldnt find one.


There are numerous mentions on RAS regarding the placarded #1200 limit on Pawnee. Ex:

https://groups.google.com/d/topic/re...aK4/discussion

PA

Does anyone know the limits on these STC'd hooks? They claim to be better than Schweizer hooks, but don't list any numbers to substantiate it. (I've emailed an inquiry to them.)

https://pacificaerialtowhooks.com/

On Wednesday, May 1, 2019 at 12:02:59 PM UTC-4, Paul Agnew wrote:
Does anyone know the limits on these STC'd hooks? They claim to be better than Schweizer hooks, but don't list any numbers to substantiate it. (I've emailed an inquiry to them.)

https://pacificaerialtowhooks.com/

If you read the documents section on that website it says 1200 lbs max. http://pacificaerialtowhooks.com/wp-...ev_IR__ICA.pdf . Page 203.