Towing Accident Rate vs GA?

[Jamie Shore]

I know that I can review the NTSB database and answer this myself but I am hoping that someone else has already done the homework.

Two Questions
1. What is the accident, incident and/or fatality rate of towing gliders vs GA?
2. Same question but comparing glider flying in general to GA.

I don't recall ever hearing statistics for #1 above. Tom Knauff has referred to statistics that suggest flying gliders is slightly more dangerous than GA(maybe it was comparing gliders to driving your car).

Thanks,
Jamie Shore

[[email protected][_2_]]

I thought glider flying was 4 times more dangerous then GA. Our
annual death toll is low likely because there are so few participants,
flying relatively low hours(for the most part.) No idea about
towing #'s, but we seem to lose a tow pilot or two a year, how many
tow pilots are there? Couple thousand? With 30000 glider pilots in
the US, less than half that as members of the SSA(some of them are
inactive life members, and people that renew because they are going to
fly this year...), I'd guess 5,000 'active' glider pilots, even at
15,000 active pilots the numbers per participant are up there. I'm
not advocating for anything just pointing out that gliding is more
dangerous than it appears.
On Jan 25, 7:40*am, Jamie Shore > wrote:
> I know that I can review the NTSB database and answer this myself but I am hoping that someone else has already done the homework.
>
> Two Questions
> 1. What is the accident, incident and/or fatality rate of towing gliders vs GA?
> 2. Same question but comparing glider flying in general to GA.
>
> I don't recall ever hearing statistics for #1 above. Tom Knauff has referred to statistics that suggest flying gliders is slightly more dangerous than GA(maybe it was comparing gliders to driving your car).
>
> Thanks,
> Jamie Shore

[Doug Greenwell]

At 13:45 25 January 2011, wrote:
>I thought glider flying was 4 times more dangerous then GA. Our
>annual death toll is low likely because there are so few participants,
>flying relatively low hours(for the most part.) No idea about
>towing #'s, but we seem to lose a tow pilot or two a year, how many
>tow pilots are there? Couple thousand? With 30000 glider pilots in
>the US, less than half that as members of the SSA(some of them are
>inactive life members, and people that renew because they are going to
>fly this year...), I'd guess 5,000 'active' glider pilots, even at
>15,000 active pilots the numbers per participant are up there. I'm
>not advocating for anything just pointing out that gliding is more
>dangerous than it appears.
>On Jan 25, 7:40=A0am, Jamie Shore wrote:
>> I know that I can review the NTSB database and answer this myself but
I
>a=
>m hoping that someone else has already done the homework.
>>
>> Two Questions
>> 1. What is the accident, incident and/or fatality rate of towing
gliders
>=
>vs GA?
>> 2. Same question but comparing glider flying in general to GA.
>>
>> I don't recall ever hearing statistics for #1 above. Tom Knauff has
>refer=
>red to statistics that suggest flying gliders is slightly more dangerous
>th=
>an GA(maybe it was comparing gliders to driving your car).
>>
>> Thanks,
>> Jamie Shore
>
>

I don't know about the US, but I was recently sent some figure from a UK
AAIB (Air Accident Investigation Branch Report)

On an hourly basis, the UK accident rates over a 10 period were:

light aircraft:
174.4 reportable accidents per million hours
10.6 fatal accidents per million hours (3 out of 85 fatal accidents
involved a glider tug)

light helicopters:
128.8 reportable accidents per million hours
15.9 fatal accidents per million hours.

gyroplanes:
1,422.4 reportable accidents per million hours
400.0 fatal accidents per million hours (!!)

microlights:
347.0 reportable accidents per million hours
17.9 fatal accidents per million hours.

gliders (based on BGA statistics):
322.4 reportable accidents per million hours
24.0 fatal accidents per million hours.

So on an hourly basis, gliding in the UK is about twice as dangerous as
GA, but about as dangerous as microlighting (... and don't even think
about a gyro plane!)

However, average flight times for gliders are short (about 13mins -
probably since the majority of training in the UK is done on winch
launches), so accidents per movement is probably a better indicator of
safety -

70.7 reportable accidents per million launches
5.3 fatal accidents per million launches.

I don't have the data for average GA flight duration, but I'd bet it's
rather longer than 13min - even if it's only half an hour, that brings
the accident rate per movement to a comparable level to gliding

Doug

[Andy[_1_]]

On Jan 25, 8:47*am, Doug Greenwell > wrote:

> I don't have the data for average GA flight duration, but I'd bet it's
> rather longer than 13min - even if it's only half an hour, that brings
> the accident rate per movement to a comparable level to gliding

Not sure that's valid unless you know the nature of the GA flight.
That half hour could have one takeoff and one landing or it could have
been spent circuit bashing (performing multiple takeoffs and
landings).

Andy

[Doug Greenwell]

At 18:23 25 January 2011, Andy wrote:
>On Jan 25, 8:47=A0am, Doug Greenwell wrote:
>
>> I don't have the data for average GA flight duration, but I'd bet
it's
>> rather longer than 13min - even if it's only half an hour, that
brings
>> the accident rate per movement to a comparable level to gliding
>
>Not sure that's valid unless you know the nature of the GA flight.
>That half hour could have one takeoff and one landing or it could have
>been spent circuit bashing (performing multiple takeoffs and
>landings).
>
>Andy
>
fair point - this is the trouble with comparing accident records of any
sort ... what's a good indicator for one activity doesn't give a clear
picture for another. I guess you'd have to drill down into accident
rates by flight phase - which I'm sure someone somewhere must have done.


Still the odds look pretty good to me ... I have more heart-stoppingly
near-death experiences in one days cycling than in a years flying, and the
proportion of mad b*&%$&s actually trying to kill you is far lower :-)

Doug

[T[_2_]]

On Jan 25, 5:45*am, " >
wrote:
> I thought glider flying was 4 times more dangerous then GA. *Our
> annual death toll is low likely because there are so few participants,
> flying relatively low hours(for the most part.) * * No idea about
> towing #'s, but we seem to lose a tow pilot or two a year, how many
> tow pilots are there? *Couple thousand? *With 30000 glider pilots in
> the US, less than half that as members of the SSA(some of them are
> inactive life members, and people that renew because they are going to
> fly this year...), I'd guess 5,000 'active' *glider pilots, even at
> 15,000 active pilots the numbers per participant are up there. *I'm
> not advocating for anything just pointing out that gliding is more
> dangerous than it appears.
> On Jan 25, 7:40*am, Jamie Shore > wrote:
>
>
>
> > I know that I can review the NTSB database and answer this myself but I am hoping that someone else has already done the homework.
>
> > Two Questions
> > 1. What is the accident, incident and/or fatality rate of towing gliders vs GA?
> > 2. Same question but comparing glider flying in general to GA.
>
> > I don't recall ever hearing statistics for #1 above. Tom Knauff has referred to statistics that suggest flying gliders is slightly more dangerous than GA(maybe it was comparing gliders to driving your car).
>
> > Thanks,
> > Jamie Shore

I am not aware of any tow pilot or tow plane losses in the last few
years during tow or as a result of glider actions on tow.
I am aware of tow plane/pilot losses caused either by a 3rd aircraft
interaction (Colorado) or a midair back in the traffic pattern after
release and during landing. Not related to the act of towing.

T

[Jim Logajan]

T > wrote:
> I am not aware of any tow pilot or tow plane losses in the last few
> years during tow or as a result of glider actions on tow.
> I am aware of tow plane/pilot losses caused either by a 3rd aircraft
> interaction (Colorado) or a midair back in the traffic pattern after
> release and during landing. Not related to the act of towing.

I am aware of one. There was a tragic accident about 16 months ago at our
glider club in which our tow pilot (and club president) and was killed
during a tow. The NTSB released a probable cause just last month (and
the local paper had a story also):

http://www.ntsb.gov/ntsb/GenPDF.asp?id=WPR09FA414&rpt=fi
http://www.registerguard.com/csp/cms/sites/web/updates/25708653-55/henderson-glider-report-crash-plane.csp

I knew him somewhat, but not deeply. He never struck me as someone who was
cavalier about safety, so the mistakes that were made are doubly sad.

I note that the NTSB did not fault the student glider pilot for
inadvertently moving out of position due to the distraction. I suppose
other than making sure your mental facilities are unimpaired, clubs with
SGS 2-33's might want to make doubly sure that the back door is properly
secured prior to any launch - particularly with low time pilots.

[T[_2_]]

On Jan 25, 8:22*pm, Jim Logajan > wrote:
> T > wrote:
> > I am not aware of any tow pilot or tow plane losses in the last few
> > years during tow or as a result of glider actions on tow.
> > I am aware of tow plane/pilot losses caused either by a 3rd aircraft
> > interaction (Colorado) or a midair back in the traffic pattern after
> > release and during landing. Not related to the act of towing.
>
> I am aware of one. There was a tragic accident about 16 months ago at our
> glider club in which our tow pilot (and club president) and was killed
> during a tow. The NTSB released a probable cause just last month (and
> the local paper had a story also):
>
> http://www.ntsb.gov/ntsb/GenPDF.asp?id=WPR09FA414&rpt=fihttp://www.registerguard.com/csp/cms/sites/web/updates/25708653-55/he...
>
> I knew him somewhat, but not deeply. He never struck me as someone who was
> cavalier about safety, so the mistakes that were made are doubly sad.
>
> I note that the NTSB did not fault the student glider pilot for
> inadvertently moving out of position due to the distraction. I suppose
> other than making sure your mental facilities are unimpaired, clubs with
> SGS 2-33's might want to make doubly sure that the back door is properly
> secured prior to any launch - particularly with low time pilots.

Thank you for the information. That accident did not appear on any
discussion forums as others do so I missed it.
Valid points for any doors, canopies, or latches on any glider with
more than one entry point. A 2-33, Grob 103, or ASK-21.

More argument for Tost tow assemblies.

It appears the NTSB concentrated on the tow pilots medical report.

T

[mattm[_2_]]

On Jan 26, 12:41*am, T > wrote:
> On Jan 25, 8:22*pm, Jim Logajan > wrote:
>
>
>
> > T > wrote:
> > > I am not aware of any tow pilot or tow plane losses in the last few
> > > years during tow or as a result of glider actions on tow.
> > > I am aware of tow plane/pilot losses caused either by a 3rd aircraft
> > > interaction (Colorado) or a midair back in the traffic pattern after
> > > release and during landing. Not related to the act of towing.
>
> > I am aware of one. There was a tragic accident about 16 months ago at our
> > glider club in which our tow pilot (and club president) and was killed
> > during a tow. The NTSB released a probable cause just last month (and
> > the local paper had a story also):
>
> >http://www.ntsb.gov/ntsb/GenPDF.asp?id=WPR09FA414&rpt=fihttp://www.re......
>
> > I knew him somewhat, but not deeply. He never struck me as someone who was
> > cavalier about safety, so the mistakes that were made are doubly sad.
>
> > I note that the NTSB did not fault the student glider pilot for
> > inadvertently moving out of position due to the distraction. I suppose
> > other than making sure your mental facilities are unimpaired, clubs with
> > SGS 2-33's might want to make doubly sure that the back door is properly
> > secured prior to any launch - particularly with low time pilots.
>
> Thank you for the information. That accident did not appear on any
> discussion forums as others do so I missed it.
> Valid points for any doors, canopies, or latches on any glider with
> more than one entry point. A 2-33, Grob 103, or ASK-21.
>
> More argument for Tost tow assemblies.
>
> It appears the NTSB concentrated on the tow pilots medical report.
>
> T

Hmm, very interesting report. I thought we were about to launch on
the
annual extended discussion of Schweitzer hooks and gliders.

However, I will point out that a student pilot's actions are
considered
to be up to the instructor's judgement, even if the student is flying
solo. The instructor must have suitably trained the student to handle
the flight before turning them loose, and must supervise all their
flights
until their checkride. I think that's part of the NTSB attitude in
the
report, although they don't mention the instructor.

-- Matt

[T[_2_]]

On Jan 26, 7:53*am, mattm > wrote:
> On Jan 26, 12:41*am, T > wrote:
>
>
>
>
>
> > On Jan 25, 8:22*pm, Jim Logajan > wrote:
>
> > > T > wrote:
> > > > I am not aware of any tow pilot or tow plane losses in the last few
> > > > years during tow or as a result of glider actions on tow.
> > > > I am aware of tow plane/pilot losses caused either by a 3rd aircraft
> > > > interaction (Colorado) or a midair back in the traffic pattern after
> > > > release and during landing. Not related to the act of towing.
>
> > > I am aware of one. There was a tragic accident about 16 months ago at our
> > > glider club in which our tow pilot (and club president) and was killed
> > > during a tow. The NTSB released a probable cause just last month (and
> > > the local paper had a story also):
>
> > >http://www.ntsb.gov/ntsb/GenPDF.asp?id=WPR09FA414&rpt=fihttp://www..re......
>
> > > I knew him somewhat, but not deeply. He never struck me as someone who was
> > > cavalier about safety, so the mistakes that were made are doubly sad.
>
> > > I note that the NTSB did not fault the student glider pilot for
> > > inadvertently moving out of position due to the distraction. I suppose
> > > other than making sure your mental facilities are unimpaired, clubs with
> > > SGS 2-33's might want to make doubly sure that the back door is properly
> > > secured prior to any launch - particularly with low time pilots.
>
> > Thank you for the information. That accident did not appear on any
> > discussion forums as others do so I missed it.
> > Valid points for any doors, canopies, or latches on any glider with
> > more than one entry point. A 2-33, Grob 103, or ASK-21.
>
> > More argument for Tost tow assemblies.
>
> > It appears the NTSB concentrated on the tow pilots medical report.
>
> > T
>
> Hmm, very interesting report. *I thought we were about to launch on
> the
> annual extended discussion of Schweitzer hooks and gliders.
>
> However, I will point out that a student pilot's actions are
> considered
> to be up to the instructor's judgement, even if the student is flying
> solo. *The instructor must have suitably trained the student to handle
> the flight before turning them loose, and must supervise all their
> flights
> until their checkride. *I think that's part of the NTSB attitude in
> the
> report, although they don't mention the instructor.
>
> -- Matt- Hide quoted text -
>
> - Show quoted text -

The student did as trained.. was distracted.. noticed he was out of
position with tow in sight.. attempted to recover to proper position..
lost sight of tow and released and returned to the field.

What else is the instructor to do?

Nothing mentioned of the instructor in the final report. If it was an
"unsupervised solo", it might have been mentioned.

IIRC from other threads, only the insurance company requires the
instructor to be on the field for direct supversion. Not the FARs.

T

[Jim Logajan]

mattm > wrote:
> However, I will point out that a student pilot's actions are
> considered
> to be up to the instructor's judgement, even if the student is flying
> solo. The instructor must have suitably trained the student to handle
> the flight before turning them loose, and must supervise all their
> flights
> until their checkride. I think that's part of the NTSB attitude in
> the
> report, although they don't mention the instructor.

I know the instructor (and I knew the tow pilot and have met the glider
pilot.) The CFIG in fact had flown three flights with me while I was a
glider student. Of the three CFIGs in the club I flew with, he provided the
most detailed feedback and critiques. In fact whereas my primary instructor
considered me ready for solo, but had to travel on the weekend I hoped to
solo, he stepped in and flew three flights with me. But he did not sign me
off for solo. So I would judge his standards higher than the average CFIG
(he happens to be chief pilot for a businesss and pilots a company King Air
for them.)

[bumper[_4_]]

From the NTSB report,

"Examination of the tow airplane tail hook assembly revealed that the
mounting plate was bent upward and the
heads of two connecting bolts were in contact with the base of the
rudder. The tail hook was intact and remained attached to the mounting
plate. The hook was in the locked position, closed around the tow
ring. The release cable remained attached to the hook and was
continuous to the cockpit release handle. Functional testing of the
tail hook assembly revealed no anomalies, and the assembly functioned
appropriately."

I'm really surprised at the above part of the NTSB report - - my take
is a bit different. I visited the yard where the wreckage was stored,
some weeks after the accident, as I happened to be there on other
business. I was not allowed to take pictures but did examine the
wreckage and in particular, the tow hook assembly. I'm not an expert
on aviation wreckage examination, I am trained in auto accident
investigation.

There were two Schweizer tow hooks mounted to a flat plate, with an
additional mounting hole for a third hook, all side-by-side ( I
understand multiple tow hooks are sometimes used for banner towing.)
The multiple hook mounting plate was attached to the aircraft via what
looked to be an alluminum bar, guessing 1/4" thick by 1.5" wide and
extending back maybe 8" from the rudder post spring mount . . . you
would be correct if you concluded this bar offered minimal resistance
to vertical loads without bending. As the NTSB says, the bar was bent
upwards and had impacted the lower part of the rudder, deforming
bending the bottom bow of the rudder up in the process. Though this
jammed the rudder, given the low altitude and nose down attitude pre-
crash, the jammed rudder probably was not causal.

The upward bend and position of the tow hooks inserted a significant
amout of slack in the tow release cable forward of the hook. This
slack, along with the new geometry or position of the tow hook with
respect to the release cable (i.e. now would be pulling upward on the
release toggle instead of forward as necessary to release the hook),
looked to me like it would have been impossible to release the tow
hook/s from the cockpit, even with no load on the hook. Otherwise the
hook appeared to be functional, just not by the cable (note that I did
not touch or try to operate the hook by hand - - I was only allowed to
look, not touch).

From what I saw, I believe the tow hook installation was inadequate
and unsafe. If it was causative, it was doubtless not the only cause
of this accident, though. It may well be that even if the mount had
been designed with the cutomary strength common in tow planes (rather
than just being adequate for banner towing) that a kiting glider would
still have resulted in the same tragic outcome.

I'm posting this as I think the NTSB overlooked and/or glossed over
the role the bent tow hook mount may have played, and in doing so
missed an opportunity for us to learn from this. As we know even a
properly installed upright Schweizer hook can be difficult to release
with upward loading. If the mount is inadequate (that aluminum bar
comes to mind) and bends up easily, unless the Bowden cable is
installed in such a way that the cable stays in line with the hook
(i.e. perpendicular to the release toggle) and, unless there's a way
for the release lever or mechanism in the cockpit to take up any extra
slack that my be induced by the bent mount, I'd say there's no hope of
releasing whatsoever - - even if the tuggie is right on it.

bumper

[Andy[_1_]]

On Jan 27, 2:03*am, bumper > wrote:
> From the NTSB report,
>
> "Examination of the tow airplane tail hook assembly revealed that the
> mounting plate was bent upward and the
> heads of two connecting bolts were in contact with the base of the
> rudder. The tail hook was intact and remained attached to the mounting
> plate. The hook was in the locked position, closed around the tow
> ring. The release cable remained attached to the hook and was
> continuous to the cockpit release handle. Functional testing of the
> tail hook assembly revealed no anomalies, and the assembly functioned
> appropriately."
>
> I'm really surprised at the above part of the NTSB report - - my take
> is a bit different. I visited the yard where the wreckage was stored,
> some weeks after the accident, as I happened to be there on other
> business. I was not allowed to take pictures but did examine the
> wreckage and in particular, the tow hook assembly. I'm not an expert
> on aviation wreckage examination, I am trained in auto accident
> investigation.
>
> There were two Schweizer tow hooks mounted to a flat plate, with an
> additional mounting hole for a third hook, all side-by-side ( I
> understand multiple tow hooks are sometimes used for banner towing.)
> The multiple hook mounting plate was attached to the aircraft via what
> looked to be an alluminum bar, guessing 1/4" thick by 1.5" wide and
> extending back maybe 8" from the rudder post spring mount . . . you
> would be correct if you concluded this bar offered minimal resistance
> to vertical loads without bending. As the NTSB says, the bar was bent
> upwards and had impacted the lower part of the rudder, deforming
> bending the bottom bow of the rudder up in the process. Though this
> jammed the rudder, given the low altitude and nose down attitude pre-
> crash, the jammed rudder probably was not causal.
>
> The upward bend and position of the tow hooks inserted a significant
> amout of slack in the tow release cable forward of the hook. This
> slack, along with the new geometry or position of the tow hook with
> respect to the release cable (i.e. now would be pulling upward on the
> release toggle instead of forward as necessary to release the hook),
> looked to me like it would have been impossible to release the tow
> hook/s from the cockpit, even with no load on the hook. Otherwise the
> hook appeared to be functional, just not by the cable (note that I did
> not touch or try to operate the hook by hand - - I was only allowed to
> look, not touch).
>
> From what I saw, I believe the tow hook installation was inadequate
> and unsafe. If it was causative, it was doubtless not the only cause
> of this accident, though. It may well be that even if the mount had
> been designed with the cutomary strength common in tow planes (rather
> than just being adequate for banner towing) that a kiting glider would
> still have resulted in the same tragic outcome.
>
> I'm posting this as I think the NTSB overlooked and/or glossed over
> the role the bent tow hook mount may have played, and in doing so
> missed an opportunity for us to learn from this. As we know even a
> properly installed upright Schweizer hook can be difficult to release
> with upward loading. If the mount is inadequate (that aluminum bar
> comes to mind) and bends up easily, unless the Bowden cable is
> installed in such a way that the cable stays in line with the hook
> (i.e. perpendicular to the release toggle) *and, unless there's a way
> for the release lever or mechanism in the cockpit to take up any extra
> slack that my be induced by the bent mount, I'd say there's no hope of
> releasing whatsoever - - even if the tuggie is right on it.
>
> bumper

Amazing the NTSB overlooked the tow hook installation and completely
disregarded the most likely probable cause - that the tug had an
unrecoverable upset caused the glider being out of position.

This report, and one for a tow fatal at Peoria, AZ, seem to show that
NTSB is completely unfamiliar with the tug upset scenario.

The combination of a 2-33 which requires considerable forward stick
pressure to maintain position on tow, a distracted glider pilot, and a
****ty tug tow hook was a sure set up for another dead tow pilot.

Andy

[Darryl Ramm]

On Jan 27, 1:03*am, bumper > wrote:
> From the NTSB report,
>
> "Examination of the tow airplane tail hook assembly revealed that the
> mounting plate was bent upward and the
> heads of two connecting bolts were in contact with the base of the
> rudder. The tail hook was intact and remained attached to the mounting
> plate. The hook was in the locked position, closed around the tow
> ring. The release cable remained attached to the hook and was
> continuous to the cockpit release handle. Functional testing of the
> tail hook assembly revealed no anomalies, and the assembly functioned
> appropriately."
>
> I'm really surprised at the above part of the NTSB report - - my take
> is a bit different. I visited the yard where the wreckage was stored,
> some weeks after the accident, as I happened to be there on other
> business. I was not allowed to take pictures but did examine the
> wreckage and in particular, the tow hook assembly. I'm not an expert
> on aviation wreckage examination, I am trained in auto accident
> investigation.
>
> There were two Schweizer tow hooks mounted to a flat plate, with an
> additional mounting hole for a third hook, all side-by-side ( I
> understand multiple tow hooks are sometimes used for banner towing.)
> The multiple hook mounting plate was attached to the aircraft via what
> looked to be an alluminum bar, guessing 1/4" thick by 1.5" wide and
> extending back maybe 8" from the rudder post spring mount . . . you
> would be correct if you concluded this bar offered minimal resistance
> to vertical loads without bending. As the NTSB says, the bar was bent
> upwards and had impacted the lower part of the rudder, deforming
> bending the bottom bow of the rudder up in the process. Though this
> jammed the rudder, given the low altitude and nose down attitude pre-
> crash, the jammed rudder probably was not causal.
>
> The upward bend and position of the tow hooks inserted a significant
> amout of slack in the tow release cable forward of the hook. This
> slack, along with the new geometry or position of the tow hook with
> respect to the release cable (i.e. now would be pulling upward on the
> release toggle instead of forward as necessary to release the hook),
> looked to me like it would have been impossible to release the tow
> hook/s from the cockpit, even with no load on the hook. Otherwise the
> hook appeared to be functional, just not by the cable (note that I did
> not touch or try to operate the hook by hand - - I was only allowed to
> look, not touch).
>
> From what I saw, I believe the tow hook installation was inadequate
> and unsafe. If it was causative, it was doubtless not the only cause
> of this accident, though. It may well be that even if the mount had
> been designed with the cutomary strength common in tow planes (rather
> than just being adequate for banner towing) that a kiting glider would
> still have resulted in the same tragic outcome.
>
> I'm posting this as I think the NTSB overlooked and/or glossed over
> the role the bent tow hook mount may have played, and in doing so
> missed an opportunity for us to learn from this. As we know even a
> properly installed upright Schweizer hook can be difficult to release
> with upward loading. If the mount is inadequate (that aluminum bar
> comes to mind) and bends up easily, unless the Bowden cable is
> installed in such a way that the cable stays in line with the hook
> (i.e. perpendicular to the release toggle) *and, unless there's a way
> for the release lever or mechanism in the cockpit to take up any extra
> slack that my be induced by the bent mount, I'd say there's no hope of
> releasing whatsoever - - even if the tuggie is right on it.
>
> bumper

I guess this largely depends on what exact post-crash functional
testing of the release mechanism that the NTSB did. Did they test with
the tow hook loaded up with a rope at appropriate (high) angles?

Does anybody know if the aluminum (or could it be duralium - either
way it sounds surprisingly weak to bending) mount was a part of a kit
or was custom fabricated? Was it installed via a 337 for glider towing
or banner towing only? (There are no STC for tow hooks on Pawnees
AFAIK so it would have been a 337).

Especially if others are flying with a similar setups we need to try
hard to help prevent another tow release accident. Maybe this is
something the SSA could followup on with the NTSB folks involved. Its
a tragedy that the tow pilot was killed, and I'd hate to see something
missed even if there are other impairment factors here.

When aerotowing I get towed mostly behind Pawnees that have
retractable tow ropes and rope guillotines. That big handle is going
to work if needed. The soaring community is dependent on towplanes and
all our great tow pilots who support us and its very sad to see
accidents like this happening.

Darryl

[Ramy]

On Jan 27, 6:56*am, Andy > wrote:
> On Jan 27, 2:03*am, bumper > wrote:
>
>
>
>
>
> > From the NTSB report,
>
> > "Examination of the tow airplane tail hook assembly revealed that the
> > mounting plate was bent upward and the
> > heads of two connecting bolts were in contact with the base of the
> > rudder. The tail hook was intact and remained attached to the mounting
> > plate. The hook was in the locked position, closed around the tow
> > ring. The release cable remained attached to the hook and was
> > continuous to the cockpit release handle. Functional testing of the
> > tail hook assembly revealed no anomalies, and the assembly functioned
> > appropriately."
>
> > I'm really surprised at the above part of the NTSB report - - my take
> > is a bit different. I visited the yard where the wreckage was stored,
> > some weeks after the accident, as I happened to be there on other
> > business. I was not allowed to take pictures but did examine the
> > wreckage and in particular, the tow hook assembly. I'm not an expert
> > on aviation wreckage examination, I am trained in auto accident
> > investigation.
>
> > There were two Schweizer tow hooks mounted to a flat plate, with an
> > additional mounting hole for a third hook, all side-by-side ( I
> > understand multiple tow hooks are sometimes used for banner towing.)
> > The multiple hook mounting plate was attached to the aircraft via what
> > looked to be an alluminum bar, guessing 1/4" thick by 1.5" wide and
> > extending back maybe 8" from the rudder post spring mount . . . you
> > would be correct if you concluded this bar offered minimal resistance
> > to vertical loads without bending. As the NTSB says, the bar was bent
> > upwards and had impacted the lower part of the rudder, deforming
> > bending the bottom bow of the rudder up in the process. Though this
> > jammed the rudder, given the low altitude and nose down attitude pre-
> > crash, the jammed rudder probably was not causal.
>
> > The upward bend and position of the tow hooks inserted a significant
> > amout of slack in the tow release cable forward of the hook. This
> > slack, along with the new geometry or position of the tow hook with
> > respect to the release cable (i.e. now would be pulling upward on the
> > release toggle instead of forward as necessary to release the hook),
> > looked to me like it would have been impossible to release the tow
> > hook/s from the cockpit, even with no load on the hook. Otherwise the
> > hook appeared to be functional, just not by the cable (note that I did
> > not touch or try to operate the hook by hand - - I was only allowed to
> > look, not touch).
>
> > From what I saw, I believe the tow hook installation was inadequate
> > and unsafe. If it was causative, it was doubtless not the only cause
> > of this accident, though. It may well be that even if the mount had
> > been designed with the cutomary strength common in tow planes (rather
> > than just being adequate for banner towing) that a kiting glider would
> > still have resulted in the same tragic outcome.
>
> > I'm posting this as I think the NTSB overlooked and/or glossed over
> > the role the bent tow hook mount may have played, and in doing so
> > missed an opportunity for us to learn from this. As we know even a
> > properly installed upright Schweizer hook can be difficult to release
> > with upward loading. If the mount is inadequate (that aluminum bar
> > comes to mind) and bends up easily, unless the Bowden cable is
> > installed in such a way that the cable stays in line with the hook
> > (i.e. perpendicular to the release toggle) *and, unless there's a way
> > for the release lever or mechanism in the cockpit to take up any extra
> > slack that my be induced by the bent mount, I'd say there's no hope of
> > releasing whatsoever - - even if the tuggie is right on it.
>
> > bumper
>
> Amazing the NTSB overlooked the tow hook installation and completely
> disregarded the most likely probable cause - that the tug had an
> unrecoverable upset caused *the glider being out of position.
>
> This report, and one for a tow fatal at Peoria, AZ, seem to show that
> NTSB is completely unfamiliar with the tug upset scenario.
>
> The combination of a 2-33 which requires considerable forward stick
> pressure to maintain position on tow, a distracted glider pilot, and a
> ****ty tug tow hook *was a sure set up for another dead tow pilot.
>
> Andy- Hide quoted text -
>
> - Show quoted text -

I am actually not surprised. The NTSB is notorious for missing the
point and opportunities to learn lessons. All they need to find is
some alcohol or drug in the blood and balme it on it and they are
done. Just like in car accidents. Otherwsie they conclude a pilot
error due to loss of control. I bet Bumper's investigation by just
looking at the tow hook was more thorough than the NTSB investigation.

Ramy

[Alex Potter]

On Thu, 27 Jan 2011 15:38:19 -0800, Ramy wrote:

> I am actually not surprised. The NTSB is notorious for missing the point
> and opportunities to learn lessons. All they need to find is some
> alcohol or drug in the blood and balme it on it and they are done. Just
> like in car accidents. Otherwsie they conclude a pilot error due to loss
> of control. I bet Bumper's investigation by just looking at the tow hook
> was more thorough than the NTSB investigation.

Do you not have a govermental organisation like our AAIB in Leftpondia?

<http://www.aaib.gov.uk/sites/aaib/publications/formal_reports.cfm>

Their investigations and reports seem very thorough.

--
Alex

[Andy[_1_]]

On Jan 27, 6:24*pm, Alex Potter > wrote:
> On Thu, 27 Jan 2011 15:38:19 -0800, Ramy wrote:
> > I am actually not surprised. The NTSB is notorious for missing the point
> > and opportunities to learn lessons. All they need to find is some
> > alcohol or drug in the blood and balme it on it and they are done. Just
> > like in car accidents. Otherwsie they conclude a pilot error due to loss
> > of control. I bet Bumper's investigation by just looking at the tow hook
> > was more thorough than the NTSB investigation.
>
> Do you not have a govermental organisation like our AAIB in Leftpondia?
>
> <http://www.aaib.gov.uk/sites/aaib/publications/formal_reports.cfm>
>
> Their investigations and reports seem very thorough.
>
> --
> Alex

NTSB performs a similar function to AAIB but they are not only
responsible for air accidents, but all accidents in the national
transportation system, which includes road and rail. They seem to
investigate major accidents thoroughly. Their investigation staff may
be spread too thin to investigate accidents that don't have a
significant impact on public safety. Just speculation of course but it
does seem consistent with the standard of investigation that I have
seen for accidents that I knew something about before the report was
published.

Andy

[150flivver]

On Jan 28, 6:55*am, Andy > wrote:
> On Jan 27, 6:24*pm, Alex Potter > wrote:
>
>
>
> > On Thu, 27 Jan 2011 15:38:19 -0800, Ramy wrote:
> > > I am actually not surprised. The NTSB is notorious for missing the point
> > > and opportunities to learn lessons. All they need to find is some
> > > alcohol or drug in the blood and balme it on it and they are done. Just
> > > like in car accidents. Otherwsie they conclude a pilot error due to loss
> > > of control. I bet Bumper's investigation by just looking at the tow hook
> > > was more thorough than the NTSB investigation.
>
> > Do you not have a govermental organisation like our AAIB in Leftpondia?
>
> > <http://www.aaib.gov.uk/sites/aaib/publications/formal_reports.cfm>
>
> > Their investigations and reports seem very thorough.
>
> > --
> > Alex
>
> NTSB performs a similar function to AAIB but they are not only
> responsible for air accidents, but all accidents in the national
> transportation system, which includes road and rail. *They seem to
> investigate major accidents thoroughly. *Their investigation staff may
> be spread too thin to investigate accidents that don't have *a
> significant impact on public safety. Just speculation of course but it
> does seem consistent with the standard of investigation that I have
> seen for accidents that I knew something about before the report was
> published.
>
> Andy

This NTSB report is an embarrassment. How many stone cold sober tow
pilots could recover an upset at 200feet? I haven't flown a 150hp
Pawnee but I've heard it has trouble getting out of its own way in
benign circumstances much less a kiting glider at 200 feet and a
release system that may have been compromised.

[Alex Potter]

On Fri, 28 Jan 2011 04:55:21 -0800, Andy wrote:

> NTSB performs a similar function to AAIB but they are not only
> responsible for air accidents, but all accidents in the national
> transportation system, which includes road and rail. They seem to
> investigate major accidents thoroughly. Their investigation staff may
> be spread too thin to investigate accidents that don't have a
> significant impact on public safety. Just speculation of course but it
> does seem consistent with the standard of investigation that I have seen
> for accidents that I knew something about before the report was
> published.

In the UK, we split the functions between the RAIB, AAIB and the police,
for railways, aviation and road transport respectively.

Both of the AIBs publish extensively documented, detailed reports, after
thorough investigations. I've tried, and failed, to find similarly
detailed reports on the NTSB web site. Are there any?

--
Alex

[Andy[_1_]]

On Jan 28, 10:58*am, 150flivver > wrote:
> *How many stone cold sober tow
> pilots could recover an upset at 200feet? *

My guess is none. You have to recognise the problem, find the release
handle which is poorly placed in all the Pawnees I have flown, pull
it, hope the hook load is not so high that the rope can't be dumped,
and then recover from the dive.

Andy

[sisu1a]

> Both of the AIBs publish extensively documented, detailed reports,
after
> thorough investigations. I've tried, and failed, to find similarly
> detailed reports on the NTSB web site. Are there any?

If you're sufficiently rich/important, a little more effort is put
into trying to figure out what really happened. Fosset's NTSB is a
good example: http://www.ntsb.gov/ntsb/brief2.asp?ev_id=20081007X17184&ntsbno=SEA07FA277&akey=1
....not sure how it compares to RAIB/AIB reports though.

-Paul

[Gilbert Smith[_2_]]

Andy > wrote:

>On Jan 28, 10:58*am, 150flivver > wrote:
>> *How many stone cold sober tow
>> pilots could recover an upset at 200feet? *
>
>My guess is none. You have to recognise the problem, find the release
>handle which is poorly placed in all the Pawnees I have flown, pull
>it, hope the hook load is not so high that the rope can't be dumped,
>and then recover from the dive.
>
>Andy

I have survived one of these upsets, fortunately at about 400ft.
The effect on both the tow plane and the glider when the rope came
tight was an instantaneous transition from horizontal to vertical.

My first reaction was to shut the throttle, and I guarantee that this
would be yours also. The second was to release the rope, but the
glider pilot had already pulled his release.

Recovery from the dive is the #1 problem. If you are too low you will
likely pull the tug to horizontal and flick-roll into the deck, or
simply go straight in.

[Gilbert Smith[_2_]]

Darryl Ramm > wrote:

>On Jan 27, 1:03*am, bumper > wrote:
>> From the NTSB report,
>>
>> "Examination of the tow airplane tail hook assembly revealed that the
>> mounting plate was bent upward and the
>> heads of two connecting bolts were in contact with the base of the
>> rudder. The tail hook was intact and remained attached to the mounting
>> plate. The hook was in the locked position, closed around the tow
>> ring. The release cable remained attached to the hook and was
>> continuous to the cockpit release handle. Functional testing of the
>> tail hook assembly revealed no anomalies, and the assembly functioned
>> appropriately."
>>
>> I'm really surprised at the above part of the NTSB report - - my take
>> is a bit different. I visited the yard where the wreckage was stored,
>> some weeks after the accident, as I happened to be there on other
>> business. I was not allowed to take pictures but did examine the
>> wreckage and in particular, the tow hook assembly. I'm not an expert
>> on aviation wreckage examination, I am trained in auto accident
>> investigation.
>>
>> There were two Schweizer tow hooks mounted to a flat plate, with an
>> additional mounting hole for a third hook, all side-by-side ( I
>> understand multiple tow hooks are sometimes used for banner towing.)
>> The multiple hook mounting plate was attached to the aircraft via what
>> looked to be an alluminum bar, guessing 1/4" thick by 1.5" wide and
>> extending back maybe 8" from the rudder post spring mount . . . you
>> would be correct if you concluded this bar offered minimal resistance
>> to vertical loads without bending. As the NTSB says, the bar was bent
>> upwards and had impacted the lower part of the rudder, deforming
>> bending the bottom bow of the rudder up in the process. Though this
>> jammed the rudder, given the low altitude and nose down attitude pre-
>> crash, the jammed rudder probably was not causal.
>>
>> The upward bend and position of the tow hooks inserted a significant
>> amout of slack in the tow release cable forward of the hook. This
>> slack, along with the new geometry or position of the tow hook with
>> respect to the release cable (i.e. now would be pulling upward on the
>> release toggle instead of forward as necessary to release the hook),
>> looked to me like it would have been impossible to release the tow
>> hook/s from the cockpit, even with no load on the hook. Otherwise the
>> hook appeared to be functional, just not by the cable (note that I did
>> not touch or try to operate the hook by hand - - I was only allowed to
>> look, not touch).
>>
>> From what I saw, I believe the tow hook installation was inadequate
>> and unsafe. If it was causative, it was doubtless not the only cause
>> of this accident, though. It may well be that even if the mount had
>> been designed with the cutomary strength common in tow planes (rather
>> than just being adequate for banner towing) that a kiting glider would
>> still have resulted in the same tragic outcome.
>>
>> I'm posting this as I think the NTSB overlooked and/or glossed over
>> the role the bent tow hook mount may have played, and in doing so
>> missed an opportunity for us to learn from this. As we know even a
>> properly installed upright Schweizer hook can be difficult to release
>> with upward loading. If the mount is inadequate (that aluminum bar
>> comes to mind) and bends up easily, unless the Bowden cable is
>> installed in such a way that the cable stays in line with the hook
>> (i.e. perpendicular to the release toggle) *and, unless there's a way
>> for the release lever or mechanism in the cockpit to take up any extra
>> slack that my be induced by the bent mount, I'd say there's no hope of
>> releasing whatsoever - - even if the tuggie is right on it.
>>
>> bumper
>
>I guess this largely depends on what exact post-crash functional
>testing of the release mechanism that the NTSB did. Did they test with
>the tow hook loaded up with a rope at appropriate (high) angles?
>
>Does anybody know if the aluminum (or could it be duralium - either
>way it sounds surprisingly weak to bending) mount was a part of a kit
>or was custom fabricated? Was it installed via a 337 for glider towing
>or banner towing only? (There are no STC for tow hooks on Pawnees
>AFAIK so it would have been a 337).
>
>Especially if others are flying with a similar setups we need to try
>hard to help prevent another tow release accident. Maybe this is
>something the SSA could followup on with the NTSB folks involved. Its
>a tragedy that the tow pilot was killed, and I'd hate to see something
>missed even if there are other impairment factors here.
>
>When aerotowing I get towed mostly behind Pawnees that have
>retractable tow ropes and rope guillotines. That big handle is going
>to work if needed. The soaring community is dependent on towplanes and
>all our great tow pilots who support us and its very sad to see
>accidents like this happening.
>
>Darryl

There is a simple test: tie the tow rope to a tree, work the tow plane
up to full power, then pull the release. I bet there are a lot of
PA18s and the like which fail this test today.

[kirk.stant]

On Feb 1, 9:07*am, Gilbert Smith > wrote:
> Darryl Ramm > wrote:
> >On Jan 27, 1:03*am, bumper > wrote:
> >> From the NTSB report,
>
> >> "Examination of the tow airplane tail hook assembly revealed that the
> >> mounting plate was bent upward and the
> >> heads of two connecting bolts were in contact with the base of the
> >> rudder. The tail hook was intact and remained attached to the mounting
> >> plate. The hook was in the locked position, closed around the tow
> >> ring. The release cable remained attached to the hook and was
> >> continuous to the cockpit release handle. Functional testing of the
> >> tail hook assembly revealed no anomalies, and the assembly functioned
> >> appropriately."
>
> >> I'm really surprised at the above part of the NTSB report - - my take
> >> is a bit different. I visited the yard where the wreckage was stored,
> >> some weeks after the accident, as I happened to be there on other
> >> business. I was not allowed to take pictures but did examine the
> >> wreckage and in particular, the tow hook assembly. I'm not an expert
> >> on aviation wreckage examination, I am trained in auto accident
> >> investigation.
>
> >> There were two Schweizer tow hooks mounted to a flat plate, with an
> >> additional mounting hole for a third hook, all side-by-side ( I
> >> understand multiple tow hooks are sometimes used for banner towing.)
> >> The multiple hook mounting plate was attached to the aircraft via what
> >> looked to be an alluminum bar, guessing 1/4" thick by 1.5" wide and
> >> extending back maybe 8" from the rudder post spring mount . . . you
> >> would be correct if you concluded this bar offered minimal resistance
> >> to vertical loads without bending. As the NTSB says, the bar was bent
> >> upwards and had impacted the lower part of the rudder, deforming
> >> bending the bottom bow of the rudder up in the process. Though this
> >> jammed the rudder, given the low altitude and nose down attitude pre-
> >> crash, the jammed rudder probably was not causal.
>
> >> The upward bend and position of the tow hooks inserted a significant
> >> amout of slack in the tow release cable forward of the hook. This
> >> slack, along with the new geometry or position of the tow hook with
> >> respect to the release cable (i.e. now would be pulling upward on the
> >> release toggle instead of forward as necessary to release the hook),
> >> looked to me like it would have been impossible to release the tow
> >> hook/s from the cockpit, even with no load on the hook. Otherwise the
> >> hook appeared to be functional, just not by the cable (note that I did
> >> not touch or try to operate the hook by hand - - I was only allowed to
> >> look, not touch).
>
> >> From what I saw, I believe the tow hook installation was inadequate
> >> and unsafe. If it was causative, it was doubtless not the only cause
> >> of this accident, though. It may well be that even if the mount had
> >> been designed with the cutomary strength common in tow planes (rather
> >> than just being adequate for banner towing) that a kiting glider would
> >> still have resulted in the same tragic outcome.
>
> >> I'm posting this as I think the NTSB overlooked and/or glossed over
> >> the role the bent tow hook mount may have played, and in doing so
> >> missed an opportunity for us to learn from this. As we know even a
> >> properly installed upright Schweizer hook can be difficult to release
> >> with upward loading. If the mount is inadequate (that aluminum bar
> >> comes to mind) and bends up easily, unless the Bowden cable is
> >> installed in such a way that the cable stays in line with the hook
> >> (i.e. perpendicular to the release toggle) *and, unless there's a way
> >> for the release lever or mechanism in the cockpit to take up any extra
> >> slack that my be induced by the bent mount, I'd say there's no hope of
> >> releasing whatsoever - - even if the tuggie is right on it.
>
> >> bumper
>
> >I guess this largely depends on what exact post-crash functional
> >testing of the release mechanism that the NTSB did. Did they test with
> >the tow hook loaded up with a rope at appropriate (high) angles?
>
> >Does anybody know if the aluminum (or could it be duralium - either
> >way it sounds surprisingly weak to bending) mount was a part of a kit
> >or was custom fabricated? Was it installed via a 337 for glider towing
> >or banner towing only? (There are no STC for tow hooks on Pawnees
> >AFAIK so it would have been a 337).
>
> >Especially if others are flying with a similar setups we need to try
> >hard to help prevent another tow release accident. Maybe this is
> >something the SSA could followup on with the NTSB folks involved. Its
> >a tragedy that the tow pilot was killed, and I'd hate to see something
> >missed even if there are other impairment factors here.
>
> >When aerotowing I get towed mostly behind Pawnees that have
> >retractable tow ropes and rope guillotines. That big handle is going
> >to work if needed. The soaring community is dependent on towplanes and
> >all our great tow pilots who support us and its very sad to see
> >accidents like this happening.
>
> >Darryl
>
> There is a simple test: tie the tow rope to a tree, work the tow plane
> up to full power, then pull the release. I bet there are a lot of
> PA18s and the like which fail this test today.

Another test is to tie the rope to something above the tail of the
towplane to simulate the angle you might get in an upset and try
activating the release. What you are trying to simulate is the force
of the towring on the moving arm of the Schweitzer. We tried it on
our Pawnee and I was surprised that it wasn't as hard to do as I
thought it would be - even with the tail ballasted to add tension to
the rope. But it did take a hefty pull.

This is a GOOD thing to demonstrate and let all your tow-pilots
practice before the season starts!

Better solution is to invert the release (there is a 337 for that mod)
or go to a Tost.

I too have had an upset - fortunately a minor one - when a solo
student botched a soft release in a 2-33 during a pattern tow. Pulled
the tail up on my Pawnee, but he released before I could get to the
release handle and the upset was only about 10 degrees or so. Got my
attention, though!

Kirk
Icing up in St Louis...

[150flivver]

On Feb 1, 1:07*pm, "kirk.stant" > wrote:
> On Feb 1, 9:07*am, Gilbert Smith > wrote:
>
>
>
> > Darryl Ramm > wrote:
> > >On Jan 27, 1:03*am, bumper > wrote:
> > >> From the NTSB report,
>
> > >> "Examination of the tow airplane tail hook assembly revealed that the
> > >> mounting plate was bent upward and the
> > >> heads of two connecting bolts were in contact with the base of the
> > >> rudder. The tail hook was intact and remained attached to the mounting
> > >> plate. The hook was in the locked position, closed around the tow
> > >> ring. The release cable remained attached to the hook and was
> > >> continuous to the cockpit release handle. Functional testing of the
> > >> tail hook assembly revealed no anomalies, and the assembly functioned
> > >> appropriately."
>
> > >> I'm really surprised at the above part of the NTSB report - - my take
> > >> is a bit different. I visited the yard where the wreckage was stored,
> > >> some weeks after the accident, as I happened to be there on other
> > >> business. I was not allowed to take pictures but did examine the
> > >> wreckage and in particular, the tow hook assembly. I'm not an expert
> > >> on aviation wreckage examination, I am trained in auto accident
> > >> investigation.
>
> > >> There were two Schweizer tow hooks mounted to a flat plate, with an
> > >> additional mounting hole for a third hook, all side-by-side ( I
> > >> understand multiple tow hooks are sometimes used for banner towing.)
> > >> The multiple hook mounting plate was attached to the aircraft via what
> > >> looked to be an alluminum bar, guessing 1/4" thick by 1.5" wide and
> > >> extending back maybe 8" from the rudder post spring mount . . . you
> > >> would be correct if you concluded this bar offered minimal resistance
> > >> to vertical loads without bending. As the NTSB says, the bar was bent
> > >> upwards and had impacted the lower part of the rudder, deforming
> > >> bending the bottom bow of the rudder up in the process. Though this
> > >> jammed the rudder, given the low altitude and nose down attitude pre-
> > >> crash, the jammed rudder probably was not causal.
>
> > >> The upward bend and position of the tow hooks inserted a significant
> > >> amout of slack in the tow release cable forward of the hook. This
> > >> slack, along with the new geometry or position of the tow hook with
> > >> respect to the release cable (i.e. now would be pulling upward on the
> > >> release toggle instead of forward as necessary to release the hook),
> > >> looked to me like it would have been impossible to release the tow
> > >> hook/s from the cockpit, even with no load on the hook. Otherwise the
> > >> hook appeared to be functional, just not by the cable (note that I did
> > >> not touch or try to operate the hook by hand - - I was only allowed to
> > >> look, not touch).
>
> > >> From what I saw, I believe the tow hook installation was inadequate
> > >> and unsafe. If it was causative, it was doubtless not the only cause
> > >> of this accident, though. It may well be that even if the mount had
> > >> been designed with the cutomary strength common in tow planes (rather
> > >> than just being adequate for banner towing) that a kiting glider would
> > >> still have resulted in the same tragic outcome.
>
> > >> I'm posting this as I think the NTSB overlooked and/or glossed over
> > >> the role the bent tow hook mount may have played, and in doing so
> > >> missed an opportunity for us to learn from this. As we know even a
> > >> properly installed upright Schweizer hook can be difficult to release
> > >> with upward loading. If the mount is inadequate (that aluminum bar
> > >> comes to mind) and bends up easily, unless the Bowden cable is
> > >> installed in such a way that the cable stays in line with the hook
> > >> (i.e. perpendicular to the release toggle) *and, unless there's a way
> > >> for the release lever or mechanism in the cockpit to take up any extra
> > >> slack that my be induced by the bent mount, I'd say there's no hope of
> > >> releasing whatsoever - - even if the tuggie is right on it.
>
> > >> bumper
>
> > >I guess this largely depends on what exact post-crash functional
> > >testing of the release mechanism that the NTSB did. Did they test with
> > >the tow hook loaded up with a rope at appropriate (high) angles?
>
> > >Does anybody know if the aluminum (or could it be duralium - either
> > >way it sounds surprisingly weak to bending) mount was a part of a kit
> > >or was custom fabricated? Was it installed via a 337 for glider towing
> > >or banner towing only? (There are no STC for tow hooks on Pawnees
> > >AFAIK so it would have been a 337).
>
> > >Especially if others are flying with a similar setups we need to try
> > >hard to help prevent another tow release accident. Maybe this is
> > >something the SSA could followup on with the NTSB folks involved. Its
> > >a tragedy that the tow pilot was killed, and I'd hate to see something
> > >missed even if there are other impairment factors here.
>
> > >When aerotowing I get towed mostly behind Pawnees that have
> > >retractable tow ropes and rope guillotines. That big handle is going
> > >to work if needed. The soaring community is dependent on towplanes and
> > >all our great tow pilots who support us and its very sad to see
> > >accidents like this happening.
>
> > >Darryl
>
> > There is a simple test: tie the tow rope to a tree, work the tow plane
> > up to full power, then pull the release. I bet there are a lot of
> > PA18s and the like which fail this test today.
>
> Another test is to tie the rope to something above the tail of the
> towplane to simulate the angle you might get in an upset and try
> activating the release. *What you are trying to simulate is the force
> of the towring on the moving arm of the Schweitzer. *We tried it on
> our Pawnee and I was surprised that it wasn't as hard to do as I
> thought it would be - even with the tail ballasted to add tension to
> the rope. * But it did take a hefty pull.
>
> This is a GOOD thing to demonstrate and let all your tow-pilots
> practice before the season starts!
>
> Better solution is to invert the release (there is a 337 for that mod)
> or go to a Tost.
>
> I too have had an upset - fortunately a minor one - when a solo
> student botched a soft release in a 2-33 during a pattern tow. *Pulled
> the tail up on my Pawnee, but he released before I could get to the
> release handle and the upset was only about 10 degrees or so. *Got my
> attention, though!
>
> Kirk
> Icing up in St Louis...

I fly a towplane with the release on the floor and you push down on
the handle to release. The one upset I had was luckily at around 1500
feet when the glider kited. The negative g plastered me against the
ceiling and I physically could not reach down far enough to affect a
release.

[Jamie Shore]

The following extracts come from multiple years of SSF(Soaring Safety
Foundation) Safety Reviews. See the reports for more details on each
of the
accidents.

http://www.soaringsafety.org/prevention/reports.html

The SSF does not know how many hours or flights were flown by gliders/
tow
planes so the following is raw data and not statistics.

ACCIDENTS INVOLVING TOW PLANES

2009
During FY09, one accident involving tow aircraft occurred resulting in
fatal
injuries to the pilot. The tow-plane was towing a Schweizer glider
when it
crashed shortly after takeoff.

2008
During FY08, one accident involving tow aircraft occurred resulting in
no
injuries to the pilot. As noted above, tow-plane was involved in a mid-
air
collision with the glider it had just released.

2007
During FY07, one accident involving tow aircraft occurred resulting in
fatal
injuries to the pilot. As noted above, the glider released after
noticing a
problem with the towplane. The towplane departed the right side of
the
runway and crashed while attempting to avoid trees.

2006
During FY06 only a single accident directly involved a towplane. As
noted
below, the towplane was preparing to launch when it was struck by a
landing
glider. The pilot of a Piper Pawnee (PA-25-235) was uninjured when
the
airplane was struck by a landing Grob 103 glider. The glider pilot
received
minor injuries while the passenger was uninjured. *NTSB SEA06LA163A
and
SEA06LA163B.

2005
During 2005, three accidents involving tow aircraft occurred during
the
landing phase of flight. One commercially rated and two privately
rated
pilots received no injuries as a result of these accidents, but all
three
airplanes were substantially damaged during the event.

2004
During 2004, five accidents involving tow aircraft occurred during
the
take-off phase of flight. As a result of these accidents, two pilots
were
fatally injured, two pilots received no injuries, and one pilot and
one
passenger received minor injuries. Additionally, two tow aircraft
were
destroyed and three were substantially damaged during these events.

2000-2003
Not available on the above SSF link.

1999
During 1999, four accidents involving tow aircraft were reported to
the
National Transportation Safety Board. Two of these accidents occurred
in-flight while the remaining events were divided between the takeoff
and
landing phases of flight. As a result of these accidents, two pilots
were
fatally injured and two aircraft were destroyed.

1998
During 1998, three accidents involving tow aircraft occurred during
the
takeoff phase of flight. As a result of these accidents, one pilot
was
fatally injured and two pilots received minor injuries. Additionally,
two
tow aircraft were substantially damaged and a third was destroyed.