Tow Plane Upsets......

I have been towing for about two and a half years and have logged over 6,500 tows. Having recently experienced a couple of rather violent glider kiting incidents, one at about 300 feet AGL I decided to investigate the experiences of other tow pilots in these circumstances. I have spent several hours reading posts about gliders kiting and upsetting the tow plane, many of the posts deal with creating an automatic release that will recognize the actions of the glider and release without input from the tow pilot. Nice idea, some really creative approaches and the bottom line is anything can be done if you have enough money and can get the FAA to buy into it and give approval.

Lots of opinions and ideas as to why these things happen. Bottom line is that they do happen, they have resulted in loss of tow pilot lives and the causes are well known.

Of my two most recent experiences one was with a 67 year old licensed private pilot, glider only, no other pilot ratings who at 2000 feet tried to release, “slipped back in the seat pulling back on the stick and going vertical.” I took a stab at the release to no avail, the pressure was too great and I soon found myself at about 75 degrees nose down at full power. The natural instinct at this point is to pull back the power and try again to release. He managed to release before I could try for a second time and I recovered. If this has to happen to you, 2000 feet is a good place to be. My understanding is that this was his first tow in more than a year. Something to think about.

My second experience in the same week was with a 15 year old student on her 3rd solo pattern tow. At about 250 to 300 feet I started a turn from the downwind drift to the right. I felt a tug on my tail pulling my nose to the left. After a few seconds I tried again to turn to the right knowing that she was behind me to the right. Could not see her, no mirror on the right. (much easier if she was a little to the left) The second time the pull of my tail to the right and nose to the left was a bit more violent…..followed by a very hard tug of my tail UP and to the right. We could not have been much more than 300 feet when I found myself nose down and trying to release….again the pressure was too much to overcome and I needed to retard the throttle. Before I could make a second attempt at release I heard a loud BANG as the rope broke, I regained control and recovered just above the trees. (glad that I had made a pit stop before I started towing). She made it back to the field and didn’t seem at all concerned……I shall withhold my comments at this point.

I had to straighten out the Schweizer hook which was off to the right about 30 degrees before I could make the last 8 tows of the day.

While I have concerns with both of these pilots my major concern is that the difficulty of actuating the release when the glider kites is well documented. To make matters worse, the release in the tug I was flying, although a bit more manually accessible than the other two I fly requires that the pilot pull it back and push down to fully actuate the release. Not an easy thing to do under the circumstances. The other two release handles are down on the floor to the left and for someone of my height, sitting on a cushion and trying to grab the release is very difficult. It would seem to me that an easy fix would be to simply make a longer handle curved up so one could both see and feel for it in an emergency. A longer handle would also provide a bit more mechanical advantage although having read many of the posts I am not sure this would overcome the pressure on the Schweizer hook. Of course I hear all the noise about needing to apply for a 337 and get FAA approval….next I will need approval to put a cushion on the seat or to have an inspection after washing the airplane.

So, the fixes appear to be going to a Tost hook or inverting the Schweizer hook which I understand can be done with an available STC. In my case I would also like to see a more accessible release handle…would (or should) an STC be required for this? This would be the short term fix I would like to see. If the handle was made from the same stock as the current device, just a foot or so longer it would seem that this should be able to be done without a long drawn out approval process.

I love flying, enjoy the gliderport environment and people but I am NOT willing to give up my life. When the glider kites things happen very fast. Unless your hand is on the handle (not feasible in my circumstances) you will not be able to release before the pressure gets too great. If it happens much lower than I experience it will be lights out. So remember my glider pilot friends….fly well….the life you save might be your tow pilot.

Walt Connelly

Hi Walt I am a tow pilot but don't have nearly as many tows. I do have a lot of total time and an A&P/IA.

I've given it a lot of thought and research. I won't tow with anything but a Tost tow hook for the exact reasons of your difficulty releasing. Of the three Pawnee's I tow with the releases are within easy reach from a normal seating position. I am adding a Tost hook to my personal Cub for tow pilot training . I intend to put the tow release within easy reach of my left hand near the throttle. There's a lot of leeway on where to put the release. An STC isn't really needed as installing a tow hook system is outlined in AC 43-13.

Just some of my thoughts. Hope they help.

Walt,

Our Pawnees have Tost releases. Schweizer hooks were removed about 30 years ago after an upset accident. The release cable is within a few inches reach of the throttle lever.

The release cable runs along the floor near the flap handle to a pulley attached to the floor that turns the cable 90 degrees upwards and then it attaches to the bottom of the instrument panel directly in front of the throttle quadrant. Reach forward and pull the cable, the glider is gone.

Release handles mounted to the floor are an accident waiting to happen, as are Schweizer hooks. As you have now experienced!

Originally Posted by Dave Springford

Walt,

Our Pawnees have Tost releases. Schweizer hooks were removed about 30 years ago after an upset accident. The release cable is within a few inches reach of the throttle lever.

The release cable runs along the floor near the flap handle to a pulley attached to the floor that turns the cable 90 degrees upwards and then it attaches to the bottom of the instrument panel directly in front of the throttle quadrant. Reach forward and pull the cable, the glider is gone.

Release handles mounted to the floor are an accident waiting to happen, as are Schweizer hooks. As you have now experienced!

Thank you for your input Dave....it is quite obvious that this problem is well known and that there are things that can (AND WILL) be done to mitigate the difficulty of releasing in an emergency. While nothing is fool proof our current situation is FOOLISH. Until you experience it, until you try to pull the handle it will not be obvious to you. It is now beyond obvious to me. The discussions going forward will be what we can do and why....NOT what we can't do. It CAN be corrected...It WILL be corrected. I love aerobatics, just not at 200-300 feet AGL in a non aerobatic airplane.

Walt

Originally Posted by Charles Longley

Hi Walt I am a tow pilot but don't have nearly as many tows. I do have a lot of total time and an A&P/IA.

I've given it a lot of thought and research. I won't tow with anything but a Tost tow hook for the exact reasons of your difficulty releasing. Of the three Pawnee's I tow with the releases are within easy reach from a normal seating position. I am adding a Tost hook to my personal Cub for tow pilot training . I intend to put the tow release within easy reach of my left hand near the throttle. There's a lot of leeway on where to put the release. An STC isn't really needed as installing a tow hook system is outlined in AC 43-13.

Just some of my thoughts. Hope they help.

Thank you Charles.....this is the kind of response I am looking for especially from an A&P/IA.

Walt

On Sunday, April 23, 2017 at 8:43:12 PM UTC-4, Walt Connelly wrote:
I have been towing for about two and a half years and have logged over
6,500 tows. Having recently experienced a couple of rather violent
glider kiting incidents, one at about 300 feet AGL I decided to
investigate the experiences of other tow pilots in these circumstances.
I have spent several hours reading posts about gliders kiting and
upsetting the tow plane, many of the posts deal with creating an
automatic release that will recognize the actions of the glider and
release without input from the tow pilot. Nice idea, some really
creative approaches and the bottom line is anything can be done if you
have enough money and can get the FAA to buy into it and give
approval.

Lots of opinions and ideas as to why these things happen. Bottom line
is that they do happen, they have resulted in loss of tow pilot lives
and the causes are well known.

Of my two most recent experiences one was with a 67 year old licensed
private pilot, glider only, no other pilot ratings who at 2000 feet
tried to release, “slipped back in the seat pulling back on the stick
and going vertical.� I took a stab at the release to no avail, the
pressure was too great and I soon found myself at about 75 degrees nose
down at full power. The natural instinct at this point is to pull back
the power and try again to release. He managed to release before I
could try for a second time and I recovered. If this has to happen to
you, 2000 feet is a good place to be. My understanding is that this was
his first tow in more than a year. Something to think about.

My second experience in the same week was with a 15 year old student on
her 3rd solo pattern tow. At about 250 to 300 feet I started a turn
from the downwind drift to the right. I felt a tug on my tail pulling
my nose to the left. After a few seconds I tried again to turn to the
right knowing that she was behind me to the right. Could not see her,
no mirror on the right. (much easier if she was a little to the left)
The second time the pull of my tail to the right and nose to the left
was a bit more violent…..followed by a very hard tug of my tail UP and
to the right. We could not have been much more than 300 feet when I
found myself nose down and trying to release….again the pressure was too
much to overcome and I needed to retard the throttle. Before I could
make a second attempt at release I heard a loud BANG as the rope broke,
I regained control and recovered just above the trees. (glad that I had
made a pit stop before I started towing). She made it back to the field
and didn’t seem at all concerned……I shall withhold my comments at this
point.

I had to straighten out the Schweizer hook which was off to the right
about 30 degrees before I could make the last 8 tows of the day.

While I have concerns with both of these pilots my major concern is that
the difficulty of actuating the release when the glider kites is well
documented. To make matters worse, the release in the tug I was flying,
although a bit more manually accessible than the other two I fly
requires that the pilot pull it back and push down to fully actuate the
release. Not an easy thing to do under the circumstances. The other
two release handles are down on the floor to the left and for someone of
my height, sitting on a cushion and trying to grab the release is very
difficult. It would seem to me that an easy fix would be to simply make
a longer handle curved up so one could both see and feel for it in an
emergency. A longer handle would also provide a bit more mechanical
advantage although having read many of the posts I am not sure this
would overcome the pressure on the Schweizer hook. Of course I hear all
the noise about needing to apply for a 337 and get FAA approval….next I
will need approval to put a cushion on the seat or to have an inspection
after washing the airplane.

So, the fixes appear to be going to a Tost hook or inverting the
Schweizer hook which I understand can be done with an available STC.
In my case I would also like to see a more accessible release
handle…would (or should) an STC be required for this? This would be
the short term fix I would like to see. If the handle was made from the
same stock as the current device, just a foot or so longer it would seem
that this should be able to be done without a long drawn out approval
process.

I love flying, enjoy the gliderport environment and people but I am NOT
willing to give up my life. When the glider kites things happen very
fast. Unless your hand is on the handle (not feasible in my
circumstances) you will not be able to release before the pressure gets
too great. If it happens much lower than I experience it will be lights
out. So remember my glider pilot friends….fly well….the life you save
might be your tow pilot.

Walt Connelly




--
Walt Connelly

Walt, I "feel your pain". It has been long reported that a Schweizer hook is difficult if not impossible to release under abnormal situations such as yours. A lot of tow pilots claim if that if the stick hits a stop, pull the release now! Another item I've always been acutely aware is the co-location of the flap handle and the release handle. Do you in a stressful time have the ability to grab the release NOW! Perhaps a Tee handle on a heavy cord in your lap would be quicker and provide more leverage. I like Dave's comment in favor of switching to Tost releases

It seems to require a dead towpilot before a club gets rid of Schweitzer
tow
hooks.

Originally Posted by George Haeh

It seems to require a dead towpilot before a club gets rid of Schweitzer
tow
hooks.

George, we are a commercial operation, not a club. BUT if there are not three Tost hooks ordered tomorrow when we open for business and arrangements made to properly position the release handle I will terminate my employment.

Walt

Originally Posted by

Walt, I "feel your pain". It has been long reported that a Schweizer hook is difficult if not impossible to release under abnormal situations such as yours. A lot of tow pilots claim if that if the stick hits a stop, pull the release now! Another item I've always been acutely aware is the co-location of the flap handle and the release handle. Do you in a stressful time have the ability to grab the release NOW! Perhaps a Tee handle on a heavy cord in your lap would be quicker and provide more leverage. I like Dave's comment in favor of switching to Tost releases

Wes,

There will be Tost hooks and release handle modifications post haste on all three of our tugs or I will commence my full retirement. There is NO logical reason why a longer handle cannot be fabricated and installed....FAA or NO FAA.

Walt