Cle Elum crash on NTSB

On Oct 29, 12:22*pm, Martin Gregorie
wrote:
Both show what we are exhaustively trained against: assuming that you're
OK once you've pushed over to a normal gliding attitude. You're not of
course, because you'll be too slow and, unless you reacted IMMEDIATELY
and got the stick far enough forward for a zero G push-over you'll be
below stall speed, from where any turn will spin immediately.

The rule of thumb[*] is to push over until your dive attitude is as steep
as you were going up and then hold the attitude without attempting to
turn until you've reached the landing approach speed you'd chosen for the
day. Then, and only then you decide whether you've space to land ahead or
whether you need to turn.

Yes, I agree with this, except there's no need to push. Simply keeping
the stick roughly in the middle will allow the nose to fall through as
the speed drops, without any danger of stalling, and with the wing
operating at an efficient (low drag) angle of attack.

Easing the stick forward enough to get zero G is OK too, but
unnecessary. Negative G is likely to be counterproductive and actually
cause more drag and therefore bleed off more energy than a small
amount of positive G.


[*] unless, of course, its a low break where you'd become a lawn dart if
you used the above technique. Off a winch you'll always have plenty of
specs ahead, so a shallower recovery attitude is OK once you're
comfortable above stall speed and anyway you won't need to turn.

I don't agree.

Assuming you maintain a low drag angle of attack, you'll arrive back
at the release height with the same speed you had on the way up. We
know you made the pull up into the climb from just above ground level,
with an adequate safely margin from stalling, and with lower speed
than you had in the climb. There's no reason at all that you can't
safely pull out of the dive, starting from the cable break height,
even if the cable broke just as you were entering full climb.

At 05:54 30 October 2011, Bruce Hoult wrote:
On Oct 29, 12:22=A0pm, Martin Gregorie
wrote:
Both show what we are exhaustively trained against:
assuming that you're
OK once you've pushed over to a normal gliding attitude.
You're not of
course, because you'll be too slow and, unless you reacted
IMMEDIATELY
and got the stick far enough forward for a zero G push-over
you'll be
below stall speed, from where any turn will spin
immediately.

The rule of thumb[*] is to push over until your dive attitude
is as steep
as you were going up and then hold the attitude without
attempting to
turn until you've reached the landing approach speed you'd
chosen for the
day. Then, and only then you decide whether you've space
to land ahead or
whether you need to turn.

Yes, I agree with this, except there's no need to push. Simply
keeping
the stick roughly in the middle will allow the nose to fall
through as
the speed drops, without any danger of stalling, and with the
wing
operating at an efficient (low drag) angle of attack.

That is incorrect and sounds positively dangerous - the speed
will drop off to well below the stall speed before the nose comes
down sufficiently for the airspeed to increase due to gravity. You
are, in effect, doing a steep stall, which is means that the
aircraft goes through a phase of not being positively controlled!


Easing the stick forward enough to get zero G is OK too, but
unnecessary. Negative G is likely to be counterproductive and
actually
cause more drag and therefore bleed off more energy than a
small
amount of positive G.


While there may be slightly less drag with neutral control rather
than with the elevator pointing down, this is a moot point. you
may save a little potential energy, but this will be at the expense
of airspeed and it will take longer to regain it than if you push
the stick over. The idea is to rectify the "unusual" undesirable
attitude before it becomes an issue. Near the ground, airspeed is
everything.


[*] unless, of course, its a low break where you'd become a
lawn dart if
you used the above technique. Off a winch you'll always
have plenty of
specs ahead, so a shallower recovery attitude is OK once
you're
comfortable above stall speed and anyway you won't need
to turn.

I don't agree.

Assuming you maintain a low drag angle of attack, you'll arrive
back
at the release height with the same speed you had on the way
up. We
know you made the pull up into the climb from just above
ground level,
with an adequate safely margin from stalling, and with lower
speed
than you had in the climb. There's no reason at all that you
can't
safely pull out of the dive, starting from the cable break height,
even if the cable broke just as you were entering full climb.


Again, I'd rather have the positive control that pushing the stick
forwards (obviously without being a lawn-dart) gives than
wallowing about at less that 100' agl.
I'm totally with Martin and the BGA (and all of the winch qualified
instructors!) on this. If I demonstrated this laissez-faire attitude
to winch launch failures (in the UK at least), I would not be
allowed to fly solo!

This explains it in much more detail (and with greater authority)
than I can he
http://www.gliding.co.uk/bgainfo/saf...ts/safewinchbr
ochure-0210.pdf

On Oct 30, 6:58*am, Paul Tribe wrote:
At 05:54 30 October 2011, Bruce Hoult wrote:On Oct 29, 12:22=A0pm, Martin Gregorie
wrote:
Both show what we are exhaustively trained against:

assuming that you're









OK once you've pushed over to a normal gliding attitude.
You're not of
course, because you'll be too slow and, unless you reacted
IMMEDIATELY
and got the stick far enough forward for a zero G push-over
you'll be
below stall speed, from where any turn will spin
immediately.

The rule of thumb[*] is to push over until your dive attitude
is as steep
as you were going up and then hold the attitude without
attempting to
turn until you've reached the landing approach speed you'd
chosen for the
day. Then, and only then you decide whether you've space
to land ahead or
whether you need to turn.

Yes, I agree with this, except there's no need to push. Simply
keeping
the stick roughly in the middle will allow the nose to fall
through as
the speed drops, without any danger of stalling, and with the
wing
operating at an efficient (low drag) angle of attack.

That is incorrect and sounds positively dangerous - the speed
will drop off to well below the stall speed before the nose comes
down sufficiently for the airspeed to increase due to gravity. You
are, in effect, doing a steep stall, which is means that the
aircraft goes through a phase of not being positively controlled!





Easing the stick forward enough to get zero G is OK too, but
unnecessary. Negative G is likely to be counterproductive and
actually
cause more drag and therefore bleed off more energy than a
small
amount of positive G.

While there may be slightly less drag with neutral control rather
than with the elevator pointing down, this is a moot point. you
may save a little potential energy, but this will be at the expense
of airspeed and it will take longer to regain it than if you push
the stick over. The idea is to rectify the "unusual" undesirable
attitude before it becomes an issue. Near the ground, airspeed is
everything.













[*] unless, of course, its a low break where you'd become a
lawn dart if
you used the above technique. Off a winch you'll always
have plenty of
specs ahead, so a shallower recovery attitude is OK once
you're
comfortable above stall speed and anyway you won't need
to turn.

I don't agree.

Assuming you maintain a low drag angle of attack, you'll arrive
back
at the release height with the same speed you had on the way
up. We
know you made the pull up into the climb from just above
ground level,
with an adequate safely margin from stalling, and with lower
speed
than you had in the climb. There's no reason at all that you
can't
safely pull out of the dive, starting from the cable break height,
even if the cable broke just as you were entering full climb.

Again, I'd rather have the positive control that pushing the stick
forwards (obviously without being a lawn-dart) gives than
wallowing about at less that 100' agl.
I'm totally with Martin and the BGA (and all of the winch qualified
instructors!) on this. If I demonstrated this laissez-faire attitude
to winch launch failures (in the UK at least), I would not be
allowed to fly solo!

This explains it in much more detail (and with greater authority)
than I can hehttp://www.gliding.co.uk/bgainfo/saf...ts/safewinchbr
ochure-0210.pdf

Addressing the two previous posts which are somewhat misguided.

The minimum height loss in a winch launch failure is determined by the
airspeed at the top of the ballistic trajectory. The proper action is
that which maintains as much airspeed as possible. The airspeed over
the top is greatest if the recovery is flown at slightly negative G
but zero G is 99% as good and is readily teachable without a G-
Meter.

Why zero G? The glider has no induced drag and is therefore losing
airspeed at the minimum rate. It is also impossible to stall a glider
whose wings are not producing lift regardless how low the airspeed
goes - stall is determined by AoA, not airspeed.

If the pilot is very skilled, or uses an AOA indicator, the wing may
be gently reloaded to an angle of attack corresponding to best L/D
starting at the top of the trajectory for even less height loss.
Otherwise, it's better to go for greater stall margin by diving to
about 1.5 x Vs before starting to level out.

Pushing the nose down to a dive angle equal to the climb angle at the
rope break is easy to teach and provides a large stall margin but
burns up height. If the landing is to be made ahead, this is fine -
especially on large airfields where the maximum height at which a
landing ahead is possible is large. On smaller airfields, max land-
ahead height will be much lower so retaining enough height for a
circle to land maneuver has to be considered.

Now commenting on the BGA Condor derived video.

Fully developed 4-turn spins to impact are rare - especially with
modern, spin-resistant gliders. Far more common is a 180 degree
rolling dive into terrain starting with a stall and wing drop. These
unfortunate pilots could have simply stopped the roll with ailerons
then recovered from the dive. Check the ASI. If airspeed is swiftly
increasing, you're not in a spin.

Modern gliders require full-aft stick to spin. If the entry is with
less than full-back stick - likely in inadvertent situations - the
resulting incipient spin will instantly transition into a spiral dive
which, to a less than spin-current pilot, will look and feel like a
spin. If the pilot delays spiral dive recovery - or worse, applies
spin recovery controls - the result is the all too familiar
unsurvivable dive into terrain.

I will not comment on any of the important technical discussion points
above - I know enough to say I don't know squat. The comment about
"the natural progression' of increasing soaring pilot knowledge...Joe
Growing Pilot to always/continually/actively..." seems very apt.

What I can say, knowing a few people in the "arts", is that they find
it *VERY* easy to get someone to be in a commercial or a film. Our
whole culture pushes us to want to be "... world-famous for 15
minutes..." (Andy Warhol). Couple that with a financial incentive
and the desire to try something that pushes our envelope can be
overwhelming. The non-technical producers/directors push for what
they see in their mind's eye - which is exactly what they are paid to
do. They also push for getting it done quickly before they run out of
money, light or both.

The producer/director pushes the responsibilty for the safety of the
stunt on the stunt pilot. The onus is now on the stunt pilot, which
is exactly what the glider pilot was in this situation, to tell the
director what needs to happen, coupled with "no" or "wait a minute -
let's think this through." But people want to please and not get
yelled at by the director/producer for not being cooperative, wasting
time/money, or whatever else is important at that moment. Have you
ever been on a set? There sure seems to be a lot of yelling going on
and what seems to be angry words. Maybe "Hollywood" types are used to
this environment but pilots are not in their realm. The entire
aviation community is a hierarchy in a military sense. The FAA tells
the examiner what to do (how to examine). The examiner tells the CFIG
what to do (to get his rating). The CFIG tells me what to do (for a
bi-annual). And the producer/director tells everyone what to do. It
is in a pilot's human nature to salute and get the job done. "Ours is
not to question why..."

I am reminded of the biography "Hollywood Pilot" of Paul Mantz (http://
en.wikipedia.org/wiki/Paul_Mantz). Fascinating read. While he did do
a few spur of the moment crazy things (like flying into an active
volcano and having his engines sputter), he more often than not took a
great amount of time thinking through what he was going to do. He had
experts around him to advise him. Importantly, he had enough
credibility to make the producers/directors wait for him rather than
the other way around. The unfortunate Cadillac commercial glider
pilot seems to have had neither the needed experts nor credibility.
Or he may just have wanted to please, salute and go forth. Paul Mantz
did die due to his trade in the original "Flight of the Phoenix", so
even the pinacle of the trade can fail at what they do best.

Its a dangerous aviation world out there. Unnecessary risks seem more
and more reckless as I grow older.

Thanks, John

At 15:56 30 October 2011, Bill D wrote:
On Oct 30, 6:58=A0am, Paul Tribe wrote:
At 05:54 30 October 2011, Bruce Hoult wrote:On Oct 29, 12:22=3DA0pm,
Mar=
tin Gregorie
wrote:
Both show what we are exhaustively trained against:

assuming that you're









OK once you've pushed over to a normal gliding attitude.
You're not of
course, because you'll be too slow and, unless you reacted
IMMEDIATELY
and got the stick far enough forward for a zero G push-over
you'll be
below stall speed, from where any turn will spin
immediately.

The rule of thumb[*] is to push over until your dive attitude
is as steep
as you were going up and then hold the attitude without
attempting to
turn until you've reached the landing approach speed you'd
chosen for the
day. Then, and only then you decide whether you've space
to land ahead or
whether you need to turn.

Yes, I agree with this, except there's no need to push. Simply
keeping
the stick roughly in the middle will allow the nose to fall
through as
the speed drops, without any danger of stalling, and with the
wing
operating at an efficient (low drag) angle of attack.

That is incorrect and sounds positively dangerous - the speed
will drop off to well below the stall speed before the nose comes
down sufficiently for the airspeed to increase due to gravity. You
are, in effect, doing a steep stall, which is means that the
aircraft goes through a phase of not being positively controlled!





Easing the stick forward enough to get zero G is OK too, but
unnecessary. Negative G is likely to be counterproductive and
actually
cause more drag and therefore bleed off more energy than a
small
amount of positive G.

While there may be slightly less drag with neutral control rather
than with the elevator pointing down, this is a moot point. you
may save a little potential energy, but this will be at the expense
of airspeed and it will take longer to regain it than if you push
the stick over. The idea is to rectify the "unusual" undesirable
attitude before it becomes an issue. Near the ground, airspeed is
everything.













[*] unless, of course, its a low break where you'd become a
lawn dart if
you used the above technique. Off a winch you'll always
have plenty of
specs ahead, so a shallower recovery attitude is OK once
you're
comfortable above stall speed and anyway you won't need
to turn.

I don't agree.

Assuming you maintain a low drag angle of attack, you'll arrive
back
at the release height with the same speed you had on the way
up. We
know you made the pull up into the climb from just above
ground level,
with an adequate safely margin from stalling, and with lower
speed
than you had in the climb. There's no reason at all that you
can't
safely pull out of the dive, starting from the cable break height,
even if the cable broke just as you were entering full climb.

Again, I'd rather have the positive control that pushing the stick
forwards (obviously without being a lawn-dart) gives than
wallowing about at less that 100' agl.
I'm totally with Martin and the BGA (and all of the winch qualified
instructors!) on this. If I demonstrated this laissez-faire attitude
to winch launch failures (in the UK at least), I would not be
allowed to fly solo!

This explains it in much more detail (and with greater authority)
than I can
hehttp://www.gliding.co.uk/bgainfo/saf...ments/safewin=
chbr
ochure-0210.pdf

Addressing the two previous posts which are somewhat misguided.

The minimum height loss in a winch launch failure is determined by the
airspeed at the top of the ballistic trajectory. The proper action is
that which maintains as much airspeed as possible. The airspeed over
the top is greatest if the recovery is flown at slightly negative G
but zero G is 99% as good and is readily teachable without a G-
Meter.

Why zero G? The glider has no induced drag and is therefore losing
airspeed at the minimum rate. It is also impossible to stall a glider
whose wings are not producing lift regardless how low the airspeed
goes - stall is determined by AoA, not airspeed.

If the pilot is very skilled, or uses an AOA indicator, the wing may
be gently reloaded to an angle of attack corresponding to best L/D
starting at the top of the trajectory for even less height loss.
Otherwise, it's better to go for greater stall margin by diving to
about 1.5 x Vs before starting to level out.

Pushing the nose down to a dive angle equal to the climb angle at the
rope break is easy to teach and provides a large stall margin but
burns up height. If the landing is to be made ahead, this is fine -
especially on large airfields where the maximum height at which a
landing ahead is possible is large. On smaller airfields, max land-
ahead height will be much lower so retaining enough height for a
circle to land maneuver has to be considered.

Now commenting on the BGA Condor derived video.

Fully developed 4-turn spins to impact are rare - especially with
modern, spin-resistant gliders. Far more common is a 180 degree
rolling dive into terrain starting with a stall and wing drop. These
unfortunate pilots could have simply stopped the roll with ailerons
then recovered from the dive. Check the ASI. If airspeed is swiftly
increasing, you're not in a spin.

Modern gliders require full-aft stick to spin. If the entry is with
less than full-back stick - likely in inadvertent situations - the
resulting incipient spin will instantly transition into a spiral dive
which, to a less than spin-current pilot, will look and feel like a
spin. If the pilot delays spiral dive recovery - or worse, applies
spin recovery controls - the result is the all too familiar
unsurvivable dive into terrain.


Yesterday(Saturday) I did my 5 year instructor test in a DG1000 with short
wing tips and maximum aft Cof G.In that configeration it is very easy to
spin,just pulling in a normal thermal turn will cause it to spin in less
than 90degrees.This is not the configeration that you would normally use
but it is an example of the characteristics of this glider;a good ship but
it bites.

On Oct 30, 1:13*pm, Jonathon May wrote:
At 15:56 30 October 2011, Bill D wrote:





On Oct 30, 6:58=A0am, Paul Tribe *wrote:
At 05:54 30 October 2011, Bruce Hoult wrote:On Oct 29, 12:22=3DA0pm,
Mar=
tin Gregorie
wrote:
Both show what we are exhaustively trained against:

assuming that you're

OK once you've pushed over to a normal gliding attitude.
You're not of
course, because you'll be too slow and, unless you reacted
IMMEDIATELY
and got the stick far enough forward for a zero G push-over
you'll be
below stall speed, from where any turn will spin
immediately.

The rule of thumb[*] is to push over until your dive attitude
is as steep
as you were going up and then hold the attitude without
attempting to
turn until you've reached the landing approach speed you'd
chosen for the
day. Then, and only then you decide whether you've space
to land ahead or
whether you need to turn.

Yes, I agree with this, except there's no need to push. Simply
keeping
the stick roughly in the middle will allow the nose to fall
through as
the speed drops, without any danger of stalling, and with the
wing
operating at an efficient (low drag) angle of attack.

That is incorrect and sounds positively dangerous - the speed
will drop off to well below the stall speed before the nose comes
down sufficiently for the airspeed to increase due to gravity. You
are, in effect, doing a steep stall, which is means that the
aircraft goes through a phase of not being positively controlled!

Easing the stick forward enough to get zero G is OK too, but
unnecessary. Negative G is likely to be counterproductive and
actually
cause more drag and therefore bleed off more energy than a
small
amount of positive G.

While there may be slightly less drag with neutral control rather
than with the elevator pointing down, this is a moot point. you
may save a little potential energy, but this will be at the expense
of airspeed and it will take longer to regain it than if you push
the stick over. The idea is to rectify the "unusual" undesirable
attitude before it becomes an issue. Near the ground, airspeed is
everything.

[*] unless, of course, its a low break where you'd become a
lawn dart if
you used the above technique. Off a winch you'll always
have plenty of
specs ahead, so a shallower recovery attitude is OK once
you're
comfortable above stall speed and anyway you won't need
to turn.

I don't agree.

Assuming you maintain a low drag angle of attack, you'll arrive
back
at the release height with the same speed you had on the way
up. We
know you made the pull up into the climb from just above
ground level,
with an adequate safely margin from stalling, and with lower
speed
than you had in the climb. There's no reason at all that you
can't
safely pull out of the dive, starting from the cable break height,
even if the cable broke just as you were entering full climb.

Again, I'd rather have the positive control that pushing the stick
forwards (obviously without being a lawn-dart) gives than
wallowing about at less that 100' agl.
I'm totally with Martin and the BGA (and all of the winch qualified
instructors!) on this. If I demonstrated this laissez-faire attitude
to winch launch failures (in the UK at least), I would not be
allowed to fly solo!

This explains it in much more detail (and with greater authority)
than I can
hehttp://www.gliding.co.uk/bgainfo/saf...ments/safewin=
chbr
ochure-0210.pdf

Addressing the two previous posts which are somewhat misguided.

The minimum height loss in a winch launch failure is determined by the
airspeed at the top of the ballistic trajectory. *The proper action is
that which maintains as much airspeed as possible. *The airspeed over
the top is greatest if the recovery is flown at slightly negative G
but zero G is 99% as good and is readily teachable without a G-
Meter.

Why zero G? *The glider has no induced drag and is therefore losing
airspeed at the minimum rate. *It is also impossible to stall a glider
whose wings are not producing lift regardless how low the airspeed
goes - stall is determined by AoA, not airspeed.

If the pilot is very skilled, or uses an AOA indicator, the wing may
be gently reloaded to an angle of attack corresponding to best L/D
starting at the top of the trajectory for even less height loss.
Otherwise, it's better to go for greater stall margin by diving to
about 1.5 x Vs before starting to level out.

Pushing the nose down to a dive angle equal to the climb angle at the
rope break is easy to teach and provides a large stall margin but
burns up height. *If the landing is to be made ahead, this is fine -
especially on large airfields where the maximum height at which a
landing ahead is possible is large. *On smaller airfields, max land-
ahead height will be much lower so retaining enough height for a
circle to land maneuver has to be considered.

Now commenting on the BGA Condor derived video.

Fully developed 4-turn spins to impact are rare - especially with
modern, spin-resistant gliders. *Far more common is a 180 degree
rolling dive into terrain starting with a stall and wing drop. *These
unfortunate pilots could have simply stopped the roll with ailerons
then recovered from the dive. *Check the ASI. *If airspeed is swiftly
increasing, you're not in a spin.

Modern gliders require full-aft stick to spin. *If the entry is with
less than full-back stick - likely in inadvertent situations - *the
resulting incipient spin will instantly transition into a spiral dive
which, to a less than spin-current pilot, will look and feel like a
spin. *If the pilot delays spiral dive recovery - or worse, applies
spin recovery controls - the result is the all too familiar
unsurvivable dive into terrain.

Yesterday(Saturday) I did my 5 year instructor test in a DG1000 with short
wing tips and maximum aft Cof G.In that configeration it is very easy to
spin,just pulling in a normal thermal turn will cause it to spin in less
than 90degrees.This is not the configeration that you would normally use
but it is an example of the characteristics of this glider;a good ship but
it bites.





A couple observatons based on 44 years of auto launching.

Bill D's last post makes the most sense to me.

My guess is that the rope did not rear release. Unless there is little
to no tension on the rope they will not rear release. The rope has to
"blow" back a good ways and having a draggy parachute makes this more
likely. But even with the chute pulling back and little rope tension
it is interesting how far to the rear the rope angle is when it rear
releases. (I can send pics of this to anyone interested.) The rope
either broke or was released under tension.

Jonathan May's observations ring a bell with me regarding spin
characteristics. About 10 years ago I was flying with the winner of
the SSA sweep stakes in a DG-1000. I was in the back seat observing
the front seater working a thermal when, presto, we were pointing
straight down (at a comfortable altitude). Curious, I took over and
reentered the thermal to see what happened. It became clear
immediately that the ship did not like the combination of slow speed,
a little pro rudder and top aileron. As has been observed in prior
posts, modern ships are more tolerant of this sort of sloppy flying,
the Duo for example, but there are exceptions. Recovery from the
upsets were immediate and straight forward with standard control
movements, but 200' isn't enough altitude if you find yourself pointed
earthwards.

Each decade I seem to add another 10 knots to the pattern speed as an
antidote for geezerazation. As long as I can get the Duo speed down to
60 knots over the fence I have a cushion in the pattern for sort of
thing that might have figured in this accident.

Karl Striedieck

I agree - except that:

A Tost release will let go when the cable vector is approximately 85-87
degrees to the longitudinal axis. Amount of tension will affect how hard
it releases, not whether it will release.

So- in this case, with the very short rope it is quite possible
geometrically that the cable would back release at around 180 foot into
the climb. Even allowing for a perfectly straight rope with no catenary,
and the glider in level flight - the release angle would have been
reached by 226 feet.

If the glider is climbing in the normal steep climb - at ~40 degrees to
the ground, the geometry for release happens at 171 feet. So the release
height was , as far as I can tell entirely predictable.

Having experienced a cable break at such low height I can vouch that you
have to push over well past the normal flying attitude and WAIT while
the airspeed builds, and the brown stuff gets closer. Once you have
recovered a safe airspeed there is precious little height left for
anything other than landing in whatever is directly in front of you.

Trying to level off at the top will have you down somewhere in the 30kt
airspeed, and any glass such as a DG1000 is not going be able to turn at
that kind of speed. Even my Kestrel loses it's manners below 34kt...


On 2011/10/31 4:43 AM, Karl Striedieck wrote:
On Oct 30, 1:13 pm, Jonathon wrote:
At 15:56 30 October 2011, Bill D wrote:





On Oct 30, 6:58=A0am, Paul Tribe wrote:
At 05:54 30 October 2011, Bruce Hoult wrote:On Oct 29, 12:22=3DA0pm,
Mar=
tin Gregorie
wrote:
Both show what we are exhaustively trained against:

assuming that you're

OK once you've pushed over to a normal gliding attitude.
You're not of
course, because you'll be too slow and, unless you reacted
IMMEDIATELY
and got the stick far enough forward for a zero G push-over
you'll be
below stall speed, from where any turn will spin
immediately.

The rule of thumb[*] is to push over until your dive attitude
is as steep
as you were going up and then hold the attitude without
attempting to
turn until you've reached the landing approach speed you'd
chosen for the
day. Then, and only then you decide whether you've space
to land ahead or
whether you need to turn.

Yes, I agree with this, except there's no need to push. Simply
keeping
the stick roughly in the middle will allow the nose to fall
through as
the speed drops, without any danger of stalling, and with the
wing
operating at an efficient (low drag) angle of attack.

That is incorrect and sounds positively dangerous - the speed
will drop off to well below the stall speed before the nose comes
down sufficiently for the airspeed to increase due to gravity. You
are, in effect, doing a steep stall, which is means that the
aircraft goes through a phase of not being positively controlled!

Easing the stick forward enough to get zero G is OK too, but
unnecessary. Negative G is likely to be counterproductive and
actually
cause more drag and therefore bleed off more energy than a
small
amount of positive G.

While there may be slightly less drag with neutral control rather
than with the elevator pointing down, this is a moot point. you
may save a little potential energy, but this will be at the expense
of airspeed and it will take longer to regain it than if you push
the stick over. The idea is to rectify the "unusual" undesirable
attitude before it becomes an issue. Near the ground, airspeed is
everything.

[*] unless, of course, its a low break where you'd become a
lawn dart if
you used the above technique. Off a winch you'll always
have plenty of
specs ahead, so a shallower recovery attitude is OK once
you're
comfortable above stall speed and anyway you won't need
to turn.

I don't agree.

Assuming you maintain a low drag angle of attack, you'll arrive
back
at the release height with the same speed you had on the way
up. We
know you made the pull up into the climb from just above
ground level,
with an adequate safely margin from stalling, and with lower
speed
than you had in the climb. There's no reason at all that you
can't
safely pull out of the dive, starting from the cable break height,
even if the cable broke just as you were entering full climb.

Again, I'd rather have the positive control that pushing the stick
forwards (obviously without being a lawn-dart) gives than
wallowing about at less that 100' agl.
I'm totally with Martin and the BGA (and all of the winch qualified
instructors!) on this. If I demonstrated this laissez-faire attitude
to winch launch failures (in the UK at least), I would not be
allowed to fly solo!

This explains it in much more detail (and with greater authority)
than I can
hehttp://www.gliding.co.uk/bgainfo/saf...ments/safewin=
chbr
ochure-0210.pdf

Addressing the two previous posts which are somewhat misguided.

The minimum height loss in a winch launch failure is determined by the
airspeed at the top of the ballistic trajectory. The proper action is
that which maintains as much airspeed as possible. The airspeed over
the top is greatest if the recovery is flown at slightly negative G
but zero G is 99% as good and is readily teachable without a G-
Meter.

Why zero G? The glider has no induced drag and is therefore losing
airspeed at the minimum rate. It is also impossible to stall a glider
whose wings are not producing lift regardless how low the airspeed
goes - stall is determined by AoA, not airspeed.

If the pilot is very skilled, or uses an AOA indicator, the wing may
be gently reloaded to an angle of attack corresponding to best L/D
starting at the top of the trajectory for even less height loss.
Otherwise, it's better to go for greater stall margin by diving to
about 1.5 x Vs before starting to level out.

Pushing the nose down to a dive angle equal to the climb angle at the
rope break is easy to teach and provides a large stall margin but
burns up height. If the landing is to be made ahead, this is fine -
especially on large airfields where the maximum height at which a
landing ahead is possible is large. On smaller airfields, max land-
ahead height will be much lower so retaining enough height for a
circle to land maneuver has to be considered.

Now commenting on the BGA Condor derived video.

Fully developed 4-turn spins to impact are rare - especially with
modern, spin-resistant gliders. Far more common is a 180 degree
rolling dive into terrain starting with a stall and wing drop. These
unfortunate pilots could have simply stopped the roll with ailerons
then recovered from the dive. Check the ASI. If airspeed is swiftly
increasing, you're not in a spin.

Modern gliders require full-aft stick to spin. If the entry is with
less than full-back stick - likely in inadvertent situations - the
resulting incipient spin will instantly transition into a spiral dive
which, to a less than spin-current pilot, will look and feel like a
spin. If the pilot delays spiral dive recovery - or worse, applies
spin recovery controls - the result is the all too familiar
unsurvivable dive into terrain.

Yesterday(Saturday) I did my 5 year instructor test in a DG1000 with short
wing tips and maximum aft Cof G.In that configeration it is very easy to
spin,just pulling in a normal thermal turn will cause it to spin in less
than 90degrees.This is not the configeration that you would normally use
but it is an example of the characteristics of this glider;a good ship but
it bites.





A couple observatons based on 44 years of auto launching.

Bill D's last post makes the most sense to me.

My guess is that the rope did not rear release. Unless there is little
to no tension on the rope they will not rear release. The rope has to
"blow" back a good ways and having a draggy parachute makes this more
likely. But even with the chute pulling back and little rope tension
it is interesting how far to the rear the rope angle is when it rear
releases. (I can send pics of this to anyone interested.) The rope
either broke or was released under tension.

Jonathan May's observations ring a bell with me regarding spin
characteristics. About 10 years ago I was flying with the winner of
the SSA sweep stakes in a DG-1000. I was in the back seat observing
the front seater working a thermal when, presto, we were pointing
straight down (at a comfortable altitude). Curious, I took over and
reentered the thermal to see what happened. It became clear
immediately that the ship did not like the combination of slow speed,
a little pro rudder and top aileron. As has been observed in prior
posts, modern ships are more tolerant of this sort of sloppy flying,
the Duo for example, but there are exceptions. Recovery from the
upsets were immediate and straight forward with standard control
movements, but 200' isn't enough altitude if you find yourself pointed
earthwards.

Each decade I seem to add another 10 knots to the pattern speed as an
antidote for geezerazation. As long as I can get the Duo speed down to
60 knots over the fence I have a cushion in the pattern for sort of
thing that might have figured in this accident.

Karl Striedieck






--
Bruce Greeff
T59D #1771 & Std Cirrus #57

On Oct 30, 11:16*pm, BruceGreeff wrote:

If the glider is climbing in the normal steep climb - at ~40 degrees to
the ground, the geometry for release happens at 171 feet. So the release
height was , as far as I can tell entirely predictable.

No argument here. However there is still a question left unanswered.
If the pilot had intended to do a 180 turn back, and had intended to
make that turn back as close to the far end of the runway as possible,
then why would a 40 deg pitch climb have been used? The glider would
have had plenty of time to reach rope limiting altitude if only a
shallow climb had been made. The shallow climb, in conjunction with a
speed higher than normal, but less than winch limit speed, would have
ensured release under pilot control and with the glider at maximum
possible energy.

I wonder if the video will ever be released. It's likely to be far
more informative than the eye witness reports.

Andy

On Oct 30, 8:43*pm, Karl Striedieck
wrote:
On Oct 30, 1:13*pm, Jonathon May wrote:









At 15:56 30 October 2011, Bill D wrote:

On Oct 30, 6:58=A0am, Paul Tribe *wrote:
At 05:54 30 October 2011, Bruce Hoult wrote:On Oct 29, 12:22=3DA0pm,
Mar=
tin Gregorie
wrote:
Both show what we are exhaustively trained against:

assuming that you're

OK once you've pushed over to a normal gliding attitude.
You're not of
course, because you'll be too slow and, unless you reacted
IMMEDIATELY
and got the stick far enough forward for a zero G push-over
you'll be
below stall speed, from where any turn will spin
immediately.

The rule of thumb[*] is to push over until your dive attitude
is as steep
as you were going up and then hold the attitude without
attempting to
turn until you've reached the landing approach speed you'd
chosen for the
day. Then, and only then you decide whether you've space
to land ahead or
whether you need to turn.

Yes, I agree with this, except there's no need to push. Simply
keeping
the stick roughly in the middle will allow the nose to fall
through as
the speed drops, without any danger of stalling, and with the
wing
operating at an efficient (low drag) angle of attack.

That is incorrect and sounds positively dangerous - the speed
will drop off to well below the stall speed before the nose comes
down sufficiently for the airspeed to increase due to gravity. You
are, in effect, doing a steep stall, which is means that the
aircraft goes through a phase of not being positively controlled!

Easing the stick forward enough to get zero G is OK too, but
unnecessary. Negative G is likely to be counterproductive and
actually
cause more drag and therefore bleed off more energy than a
small
amount of positive G.

While there may be slightly less drag with neutral control rather
than with the elevator pointing down, this is a moot point. you
may save a little potential energy, but this will be at the expense
of airspeed and it will take longer to regain it than if you push
the stick over. The idea is to rectify the "unusual" undesirable
attitude before it becomes an issue. Near the ground, airspeed is
everything.

[*] unless, of course, its a low break where you'd become a
lawn dart if
you used the above technique. Off a winch you'll always
have plenty of
specs ahead, so a shallower recovery attitude is OK once
you're
comfortable above stall speed and anyway you won't need
to turn.

I don't agree.

Assuming you maintain a low drag angle of attack, you'll arrive
back
at the release height with the same speed you had on the way
up. We
know you made the pull up into the climb from just above
ground level,
with an adequate safely margin from stalling, and with lower
speed
than you had in the climb. There's no reason at all that you
can't
safely pull out of the dive, starting from the cable break height,
even if the cable broke just as you were entering full climb.

Again, I'd rather have the positive control that pushing the stick
forwards (obviously without being a lawn-dart) gives than
wallowing about at less that 100' agl.
I'm totally with Martin and the BGA (and all of the winch qualified
instructors!) on this. If I demonstrated this laissez-faire attitude
to winch launch failures (in the UK at least), I would not be
allowed to fly solo!

This explains it in much more detail (and with greater authority)
than I can
hehttp://www.gliding.co.uk/bgainfo/saf...ments/safewin=
chbr
ochure-0210.pdf

Addressing the two previous posts which are somewhat misguided.

The minimum height loss in a winch launch failure is determined by the
airspeed at the top of the ballistic trajectory. *The proper action is
that which maintains as much airspeed as possible. *The airspeed over
the top is greatest if the recovery is flown at slightly negative G
but zero G is 99% as good and is readily teachable without a G-
Meter.

Why zero G? *The glider has no induced drag and is therefore losing
airspeed at the minimum rate. *It is also impossible to stall a glider
whose wings are not producing lift regardless how low the airspeed
goes - stall is determined by AoA, not airspeed.

If the pilot is very skilled, or uses an AOA indicator, the wing may
be gently reloaded to an angle of attack corresponding to best L/D
starting at the top of the trajectory for even less height loss.
Otherwise, it's better to go for greater stall margin by diving to
about 1.5 x Vs before starting to level out.

Pushing the nose down to a dive angle equal to the climb angle at the
rope break is easy to teach and provides a large stall margin but
burns up height. *If the landing is to be made ahead, this is fine -
especially on large airfields where the maximum height at which a
landing ahead is possible is large. *On smaller airfields, max land-
ahead height will be much lower so retaining enough height for a
circle to land maneuver has to be considered.

Now commenting on the BGA Condor derived video.

Fully developed 4-turn spins to impact are rare - especially with
modern, spin-resistant gliders. *Far more common is a 180 degree
rolling dive into terrain starting with a stall and wing drop. *These
unfortunate pilots could have simply stopped the roll with ailerons
then recovered from the dive. *Check the ASI. *If airspeed is swiftly
increasing, you're not in a spin.

Modern gliders require full-aft stick to spin. *If the entry is with
less than full-back stick - likely in inadvertent situations - *the
resulting incipient spin will instantly transition into a spiral dive
which, to a less than spin-current pilot, will look and feel like a
spin. *If the pilot delays spiral dive recovery - or worse, applies
spin recovery controls - the result is the all too familiar
unsurvivable dive into terrain.

Yesterday(Saturday) I did my 5 year instructor test in a DG1000 with short
wing tips and maximum aft Cof G.In that configeration it is very easy to
spin,just pulling in a normal thermal turn will cause it to spin in less
than 90degrees.This is not the configeration that you would normally use
but it is an example of the characteristics of this glider;a good ship but
it bites.

A couple observatons based on 44 years of auto launching.

*Bill D's last post makes the most sense to me.

My guess is that the rope did not rear release. Unless there is little
to no tension on the rope they will not rear release. The rope has to
"blow" back a good ways and having a draggy parachute makes this more
likely. But even with the chute pulling back and little rope tension
it is interesting how far to the rear the rope angle is when it rear
releases. (I can send pics of this to anyone interested.) The rope
either broke or was released under tension.

Jonathan May's observations ring a bell with me regarding spin
characteristics. About 10 years ago I was flying with the winner of
the SSA sweep stakes in a DG-1000. I was in the back seat observing
the front seater working a thermal when, presto, we were pointing
straight down (at a comfortable altitude). Curious, I took over and
reentered the thermal to see what happened. It became clear
immediately that the ship did not like the combination of slow speed,
a little pro rudder and top aileron. As has been observed in prior
posts, modern ships are more tolerant of this sort of sloppy flying,
the Duo for example, but there are exceptions. Recovery from the
upsets were immediate and straight forward with standard control
movements, but 200' isn't enough altitude if you find yourself pointed
earthwards.

Each decade I seem to add another 10 knots to the pattern speed as an
antidote for geezerazation. As long as I can get the Duo speed down to
60 knots over the fence I have a cushion in the pattern for sort of
thing that might have figured in this accident.

Karl Striedieck

To be more specific, I wasn't saying the DG1000 or other gliders
wouldn't depart into a spin, I was saying it is difficult to make them
stay in a spin without pro-spin controls. Almost all gliders will
spin but few will stay in a spin for long without active pilot
assistance. Left to themselves, they quickly transition into spiral
dives.

That's the gotcha.

If the glider has transitioned into a spiral dive, and the pilot does
nothing or uses spin recovery controls, it's going to get nasty -
especially at low altitudes.

Bill D wrote..........
If the glider has transitioned into a spiral dive, and the pilot does
nothing or uses spin recovery controls, it's going to get nasty -
especially at low altitudes.

I believe the way to distinguish between a spin or a spiral is to take
a quick peek at the airspeed indicator. If it is reading 60 knots or
more, you are in a spiral, not a spin and need to roll the wings level
and pull the nose up to the horizon. If you apply spin recovery
controls (stick forward and opposite rudder) you will find yourself
going straight down right now!
Cheers,
JJ