Towing Accident Rate vs GA?

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 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

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 we

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

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

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

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

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?...09FA414&rpt=fi
http://www.registerguard.com/csp/cms...rash-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.

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?...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

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?...ihttp://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

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