SAFETY ALERT

On 8/22/2011 5:50 PM, Cookie wrote:

- Show quoted text -

Ramy do you really need "reminding" to realize that low passes are
dangerous?

So a guy gets killed doing a low pass....Do you need the SSA, FAA,
NTSB, and whoever else to tell you "Don't do that".

It's not obvious to me the low pass was the cause of the Idaho fatality,
and given the cursory investigation the FAA can afford, we might never
know. Was it

* a medical problem
* a mechanical failure
* hypoxia
* malfunctioning airspeed indicator
* pilot incompetence with pattern turns

I'm sure others can think of more factors that would have led to
spinning in, even if the pilot did not do a low pass beforehand. And
that is part of the problem with the SSA coming out with "generic"
advice immediately after an accident: it may completely miss the cause,
and lull us into an unfounded complacency.

Cookie and others suggest "Don't do low passes", but that's generic
advice not yet supported by this accident. That advice can stand on it's
own without this accident. We should still strive to understand this
accident, though it will be difficult, instead of assuming it was just a
botched low pass.

We can't do a full investigation ourselves, but we can at least consider
those factors I mentioned. Can we rule out a medical problem? Will
someone inspect the glider for mechanical malfunction? Did he have
oxygen left in the tank, a functioning delivery system, an oximeter,
experience in using oxygen? Is the airspeed system potentially
over-reading? Could he always fly a good pattern, or did he
over-rudder/under-bank at times? Was his glider (HIS glider, not BG's in
general) well tested and benign (no surprises) in it's handling?

There are many ways for things to go wrong, and even after 35 years of
"trying", I still - more infrequently now - discover new ones.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what
you need to know tinyurl.com/yfs7tnz

On Aug 22, 10:02*pm, Eric Greenwell wrote:
On 8/22/2011 5:50 PM, Cookie wrote:

- Show quoted text -

Ramy do you really need "reminding" to realize that low passes are
dangerous?

So a guy gets killed doing a low pass....Do you need the SSA, *FAA,
NTSB, and whoever else to tell you "Don't do that".

It's not obvious to me the low pass was the cause of the Idaho fatality,
and given the cursory investigation the FAA can afford, we might never
know. Was it

* a medical problem
* a mechanical failure
* hypoxia
* malfunctioning airspeed indicator
* pilot incompetence with pattern turns

I'm sure others can think of more factors that would have led to
spinning in, even if the pilot did not do a low pass beforehand. And
that is part of the problem with the SSA coming out with "generic"
advice immediately after an accident: it may completely miss the cause,
and lull us into an unfounded complacency.

Cookie and others suggest "Don't do low passes", but that's generic
advice not yet supported by this accident. That advice can stand on it's
own without this accident. We should still strive to understand this
accident, though it will be difficult, instead of assuming it was just a
botched low pass.

We can't do a full investigation ourselves, but we can at least consider
those factors I mentioned. Can we rule out a medical problem? Will
someone inspect the glider for mechanical malfunction? Did he have
oxygen left in the tank, a functioning delivery system, an oximeter,
experience in using oxygen? Is the airspeed system potentially
over-reading? Could he always fly a good pattern, or did he
over-rudder/under-bank at times? Was his glider (HIS glider, not BG's in
general) well tested and benign (no surprises) in it's handling?

There are many ways for things to go wrong, and even after 35 years of
"trying", I still - more infrequently now - discover new ones.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what
you need to know tinyurl.com/yfs7tnz


Eric,

I am not trying to say what actually happened in any of these recent
accidents...we are just talking about accidents in general..that there
are certain categories of accident that seem to repete...and how to
help prevent them.

* a medical problem
* a mechanical failure
* hypoxia
* malfunctioning airspeed indicator
* pilot incompetence with pattern turns


You give 5 possible potential "causes" for accidents......we can
easily address each...and figure out how each of us could improve our
odds, or prevent the accidents caused by them.


I'm going to start with "malfunctioning airspeed indicator"........A
glider pilot should be able to fly safely without reference to an
airspeed indicator.......I can think of no accident where the cause
should be a malfunctioning airspeed indicator..airspeed indicator does
not seem to be a factor in any of the recent accidents.

Mechanical failure is very very rare..(unless caused by improper
flying)...annual inspections, 100 hour inspections and preflight
inspections insure us against mechanical failure.....the onus falls on
the PIC to insure the aircraft is airworthy. I don't see where
mechanical failure enters into any of the recent accidents.

Hypoxia is a good one.........we all should have received some degree
of training about hypoxia, its symptoms, and effects.
Many of us fly where this is seldon a concern..others use O2 on a
regular basis and better be proficient on this topic.
Again...don't see this relating to any of the recent accidents...

Medical problems.....we supposedly "self certify" and are required to
not fly during peroids of medical defeciency...does everybody do this?

Lastly pilot incompetence...........BINGO! That's the one! I
see this in accident after accident!


Cookie

On 8/22/2011 7:48 PM, Cookie wrote:
On Aug 22, 10:02 pm, Eric wrote:
On 8/22/2011 5:50 PM, Cookie wrote:

- Show quoted text -

Ramy do you really need "reminding" to realize that low passes are
dangerous?

So a guy gets killed doing a low pass....Do you need the SSA, FAA,
NTSB, and whoever else to tell you "Don't do that".

It's not obvious to me the low pass was the cause of the Idaho fatality,
and given the cursory investigation the FAA can afford, we might never
know. Was it

* a medical problem
* a mechanical failure
* hypoxia
* malfunctioning airspeed indicator
* pilot incompetence with pattern turns

I'm sure others can think of more factors that would have led to
spinning in, even if the pilot did not do a low pass beforehand. And
that is part of the problem with the SSA coming out with "generic"
advice immediately after an accident: it may completely miss the cause,
and lull us into an unfounded complacency.

Cookie and others suggest "Don't do low passes", but that's generic
advice not yet supported by this accident. That advice can stand on it's
own without this accident. We should still strive to understand this
accident, though it will be difficult, instead of assuming it was just a
botched low pass.

We can't do a full investigation ourselves, but we can at least consider
those factors I mentioned. Can we rule out a medical problem? Will
someone inspect the glider for mechanical malfunction? Did he have
oxygen left in the tank, a functioning delivery system, an oximeter,
experience in using oxygen? Is the airspeed system potentially
over-reading? Could he always fly a good pattern, or did he
over-rudder/under-bank at times? Was his glider (HIS glider, not BG's in
general) well tested and benign (no surprises) in it's handling?

There are many ways for things to go wrong, and even after 35 years of
"trying", I still - more infrequently now - discover new ones.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what
you need to know tinyurl.com/yfs7tnz


Eric,

I am not trying to say what actually happened in any of these recent
accidents...we are just talking about accidents in general..that there
are certain categories of accident that seem to repete...and how to
help prevent them.

* a medical problem
* a mechanical failure
* hypoxia
* malfunctioning airspeed indicator
* pilot incompetence with pattern turns


You give 5 possible potential "causes" for accidents......we can
easily address each...and figure out how each of us could improve our
odds, or prevent the accidents caused by them.


I'm going to start with "malfunctioning airspeed indicator"........A
glider pilot should be able to fly safely without reference to an
airspeed indicator.......I can think of no accident where the cause
should be a malfunctioning airspeed indicator..airspeed indicator does
not seem to be a factor in any of the recent accidents.

The pilot flies through virga; water enters the airspeed system, causing
it to over-read as he pulls up from his low pass. As he waits for the
airspeed to bleed off to pattern speed while pointed up at 20 degrees,
the glider stalls and spins. This was my first thought, because I
recently had a virga induced airspeed error - my very first, despite
flying through virga and rain several times a year over 35 years of
glider flying. It took me at least a minute to realize I had a problem,
and even longer to decide it was water from the virga.


Mechanical failure is very very rare..(unless caused by improper
flying)...annual inspections, 100 hour inspections and preflight
inspections insure us against mechanical failure.....the onus falls on
the PIC to insure the aircraft is airworthy. I don't see where
mechanical failure enters into any of the recent accidents.

A control rod jams when you try to put the nose down, stall, spin - It's
not something even a person watching on the ground would see, much less
trying to dissect the cause remotely after the fact. I had a control rod
break in the club Blanik that was not inspectable by the PIC. We got
down safely. If we'd spun in, would inspecting the wreck have found
that? Maybe, maybe not. It happens.


Hypoxia is a good one.........we all should have received some degree
of training about hypoxia, its symptoms, and effects.
Many of us fly where this is seldon a concern..others use O2 on a
regular basis and better be proficient on this topic.
Again...don't see this relating to any of the recent accidents...

King Mountain Glider Park (the Idaho fatality location) is at 5500';
cloud base on a good day can be 20,000'; 16,000' to 18,000' is normal
for August. We don't know how high he was or for how long, how well his
oxygen system worked, what his pulmonary condition was, and if he
monitored it.


Medical problems.....we supposedly "self certify" and are required to
not fly during peroids of medical defeciency...does everybody do this?

We're not always aware of our medical deficiencies, or may misjudge
their effect.


Lastly pilot incompetence...........BINGO! That's the one! I
see this in accident after accident!

But it shouldn't become a prejudice, or we won't learn from an accident.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

On Aug 22, 9:33*pm, Eric Greenwell wrote:
On 8/22/2011 7:48 PM, Cookie wrote:









On Aug 22, 10:02 pm, Eric *wrote:
On 8/22/2011 5:50 PM, Cookie wrote:

- Show quoted text -

Ramy do you really need "reminding" to realize that low passes are
dangerous?

So a guy gets killed doing a low pass....Do you need the SSA, *FAA,
NTSB, and whoever else to tell you "Don't do that".

It's not obvious to me the low pass was the cause of the Idaho fatality,
and given the cursory investigation the FAA can afford, we might never
know. Was it

* a medical problem
* a mechanical failure
* hypoxia
* malfunctioning airspeed indicator
* pilot incompetence with pattern turns

I'm sure others can think of more factors that would have led to
spinning in, even if the pilot did not do a low pass beforehand. And
that is part of the problem with the SSA coming out with "generic"
advice immediately after an accident: it may completely miss the cause,
and lull us into an unfounded complacency.

Cookie and others suggest "Don't do low passes", but that's generic
advice not yet supported by this accident. That advice can stand on it's
own without this accident. We should still strive to understand this
accident, though it will be difficult, instead of assuming it was just a
botched low pass.

We can't do a full investigation ourselves, but we can at least consider
those factors I mentioned. Can we rule out a medical problem? Will
someone inspect the glider for mechanical malfunction? Did he have
oxygen left in the tank, a functioning delivery system, an oximeter,
experience in using oxygen? Is the airspeed system potentially
over-reading? Could he always fly a good pattern, or did he
over-rudder/under-bank at times? Was his glider (HIS glider, not BG's in
general) well tested and benign (no surprises) in it's handling?

There are many ways for things to go wrong, and even after 35 years of
"trying", I still - more infrequently now - discover new ones.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what
you need to know tinyurl.com/yfs7tnz

Eric,

I am not trying to say what actually happened in any of these recent
accidents...we are just talking about accidents in general..that there
are certain categories of accident that seem to repete...and how to
help prevent them.

* a medical problem
* a mechanical failure
* hypoxia
* malfunctioning airspeed indicator
* pilot incompetence with pattern turns

You give 5 possible potential "causes" for accidents......we can
easily address each...and figure out how each of us could improve our
odds, or prevent the accidents caused by them.

I'm going to start with "malfunctioning airspeed indicator"........A
glider pilot should be able to fly safely without reference to an
airspeed indicator.......I can think of no accident where the cause
should be a malfunctioning airspeed indicator..airspeed indicator does
not seem to be a factor in any of the recent accidents.

The pilot flies through virga; water enters the airspeed system, causing
it to over-read as he pulls up from his low pass. As he waits for the
airspeed to bleed off to pattern speed while pointed up at 20 degrees,
the glider stalls and spins. This was my first thought, because I
recently had a virga induced airspeed error - my very first, despite
flying through virga and rain several times a year over 35 years of
glider flying. It took me at least a minute to realize I had a problem,
and even longer to decide it was water from the virga.



Mechanical failure is very very rare..(unless caused by improper
flying)...annual inspections, 100 hour inspections and preflight
inspections insure us against mechanical failure.....the onus falls on
the PIC to insure the aircraft is airworthy. *I don't see where
mechanical failure enters into any of the recent accidents.

A control rod jams when you try to put the nose down, stall, spin - It's
not something even a person watching on the ground would see, much less
trying to dissect the cause remotely after the fact. I had a control rod
break in the club Blanik that was not inspectable by the PIC. We got
down safely. If we'd spun in, would inspecting the wreck have found
that? Maybe, maybe not. It happens.



Hypoxia is a good one.........we all should have received some degree
of training about hypoxia, its symptoms, and effects.
Many of us fly where this is seldon a concern..others use O2 on a
regular basis and better be proficient on this topic.
Again...don't see this relating to any of the recent accidents...

King Mountain Glider Park (the Idaho fatality location) is at 5500';
cloud base on a good day can be 20,000'; 16,000' to 18,000' is normal
for August. We don't know how high he was or for how long, how well his
oxygen system worked, what his pulmonary condition was, and if he
monitored it.



Medical problems.....we supposedly "self certify" and are required to
not fly during peroids of medical defeciency...does everybody do this?

We're not always aware of our medical deficiencies, or may misjudge
their effect.



Lastly pilot incompetence...........BINGO! * * That's the one! * *I
see this in accident after accident!

But it shouldn't become a prejudice, or we won't learn from an accident.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

Eric, I would think if an airspeed indicator fails because the pitot
is plugged the pilot would know it long before deciding to try a low
pass. Now, flying a low pass with a known-bad ASI is really dumb. I
suspect if the pilot thought anything whatever was wrong with the
glider or himself, he wouldn't have tried the pass.

We know the low pass happened - anything else is speculation. That
pretty much leaves pilot error as the top suspect for now.

Low passes in a BG-12 are certainly possible to do safely - I used to
watch Ross and Kenny do some spectacular ones. However any well
trained pilot has to know it is a maneuver with very low safety
margins.

I remember thinking I wanted to do one. Just going for it seemed dumb
so I practiced at a safe altitude to see how much height I would
gain. With the glider I had, 300 feet was about the max which seemed
to leave no margin at all. I gave up the idea.

On 8/22/2011 9:11 PM, Bill D wrote:


Eric, I would think if an airspeed indicator fails because the pitot
is plugged the pilot would know it long before deciding to try a low
pass.

Maybe, unless he flew through the virga or rain shortly before landing.
I've done that a number of times. My problem occurred at least 10
minutes after flying through the virga.

Now, flying a low pass with a known-bad ASI is really dumb. I
suspect if the pilot thought anything whatever was wrong with the
glider or himself, he wouldn't have tried the pass.

I agree.

We know the low pass happened - anything else is speculation. That
pretty much leaves pilot error as the top suspect for now.

One possibility: the water lies spread out in a horizontal tube in
normal fight, but pulling up lets it slide back to a bend, and Ta-da,
the pitot is now blocked. I think this water might be hard to discover
after the wreckage is moved and lies around for several days.


Low passes in a BG-12 are certainly possible to do safely - I used to
watch Ross and Kenny do some spectacular ones. However any well
trained pilot has to know it is a maneuver with very low safety
margins.

I remember thinking I wanted to do one. Just going for it seemed dumb
so I practiced at a safe altitude to see how much height I would
gain. With the glider I had, 300 feet was about the max which seemed
to leave no margin at all. I gave up the idea.

Now I'm curious - what glider and what initial airspeed did you use?

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm
http://tinyurl.com/yb3xywl
- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what
you need to know tinyurl.com/yfs7tnz

Another real possibility not mentioned is dehydration. Nice high
speed pass, pull, pull, pull, with positive g load, works fine if you
are hydrated, if not then you can drop your blood pressure and grey
out or pass out.

Drink, drink, drink.....

Kevin
192
92

On Aug 23, 5:29*am, kevin anderson wrote:
Another real possibility not mentioned is dehydration. *Nice high
speed pass, pull, pull, pull, *with positive g load, works fine if you
are hydrated, if not then you can drop your blood pressure and grey
out or pass out.

Drink, drink, drink.....

Kevin
192
* 92

More shifting of the blame........again and again...shift the blame!


Cookie

On Mon, 22 Aug 2011 22:02:17 -0700, Eric Greenwell wrote:

Now I'm curious - what glider and what initial airspeed did you use?

That may well apply to anything up to and including early glass and to
selected later gliders too: Juniors and ASK-23 both come to mind.

I checked my Std Libelle's zoom capability yesterday - at 3000 ft and
2800 ft, pulling up at a stabilised 100 kts both times. Each time I
pushed over as the speed came down toward 50 kts. Both went no lower that
42 kts and both gained precisely 300 ft. The rate of speed drop-off below
50 kts is dramatic.

Bottom line: As I'd guessed, I don't think a low pass and pull up is a
safe option in a Libelle.

Re elevator flutter stories: surely you'll only get control surface
flutter if you're over Vne or flying a badly maintained glider? Doing
either is unsafe at any altitude.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

On 8/23/2011 2:30 PM, Martin Gregorie wrote:
Snip...

Re elevator flutter stories: surely you'll only get control surface
flutter if you're over Vne or flying a badly maintained glider? Doing
either is unsafe at any altitude.

Being a strong believer in Murphy, and knowing enough about engineering and
airplane design to be dangerous, and allowing for uncertainties difficult to
convey in short snippets of writing, I - myself - would have used a different
word than 'surely' in the posed question. In any event, you're theoretically
correct...but the pilot in me isn't comfortable pushing that part of the
envelope in close proximity to the ground. There are reasons many (most?)
professional test pilots tend to rank flutter testing toward the top of their
least favorite tests.

And I suppose it's quite possible each case of zoomie-related, contest finish
flutter about which I've read involved flight exceeding Vne and/or 'lousy
maintenance.' If so what might that suggest about some subset of contest
pilots...flagrant disregard of flight limitations? Dubious ability to maintain
precise speed control at high speeds, in thermic turbulence, near to the
ground? Slapdash maintainers of their ships? Hidden pre-existing damage? Etc.
The simple fact of flutter existence in this particular flight regime raises
seriously perturbing questions in my mind.

Without intending to kick a wounded horse (while noting no one so far has
bothered to address most of the *non*-rhetorical questions posed elsewhere
about zoomies), my larger point in posing the questions is to encourage
readers of the thread to examine themselves, their motivations, and their
comfort levels in performing this particular task. Whether individuals decide
to perform zoomies is up to them, and I'm philosophically OK with that.

As I noted elsewhe BTDT; stopped doing them ~1980; have seen (and enjoyed
watching) many since (while simultaneously mentally cringing and
hoping/praying nothing bad happens); wouldn't consider my future significantly
poorer if I never see another one; sincerely hope I don't personally know
(even via RAS) anyone who may be a part of a zoomie gone bad in the future.

And to paraphrase Forrest Gump, that's all I have to say about zoomies in this
thread.

Regards,
Bob W.

On Aug 24, 8:30*am, Martin Gregorie
wrote:
On Mon, 22 Aug 2011 22:02:17 -0700, Eric Greenwell wrote:
Now I'm curious - what glider and what initial airspeed did you use?

That may well apply to anything up to and including early glass and to
selected later gliders too: Juniors and ASK-23 both come to mind.

I checked my Std Libelle's zoom capability yesterday - at 3000 ft and
2800 ft, pulling up at a stabilised 100 kts both times. Each time I
pushed over as the speed came down toward 50 kts. Both went no lower that
42 kts and both gained precisely 300 ft. The rate of speed drop-off below
50 kts is dramatic.

That is exactly what I'd have predicted.

A rough mental calculation of how much height a given airspeed can be
converted to (at zero final airspeed e.g. top of a tail slide) is
speed in knots divided by five, squared.

So 100 knots can be converted to (100/5)^2 = 20^2 = 400 ft

If you still want to have 50 knots at the top then you need to
subtract the height that 50 knots is "worth": (50/5)^2 = 10^2 = 100
ft.

Giving 300 ft net.

(the theoretical frictionless physics says to divide by 4.748 not 5,
but 5 is both easier to work with in your head and closer to what
you'll actually get)

Bottom line: As I'd guessed, I don't think a low pass and pull up is a
safe option in a Libelle.

100 knots is certainly on the slow side. 120 is much better. That
gives you an expected (120/5)^2 - 100 = 476 ft to play with.


Wikipedia says the Std Libelle has a 250 km/h (135 knot) Vne. Is that
incorrect?

http://en.wikipedia.org/wiki/Glasflügel_H-201