Fatal crash Arizona

On Wednesday, May 7, 2014 1:20:44 PM UTC+12, Bill D wrote:
I can assure you that the higher a glider's performance, the safer it is. It's the old, low L/D gliders that can run out of altitude before getting lined up with the runway.

It's a mystery to me why some people think you can "get away with" so much more in old gliders than in those great big heavy clumsy glass ones.

Somewhere in this thread I saw a statement that you could safely turn back from 150 ft in an old glider (which I agree with), but you're a dead man if you try it below 300 ft in glass.

The differences that govern such a thing just aren't that big!

Let's look at some numbers for weight and wing area of typical training gliders (from Wikipedia):

ASK13: 290 kg, 17.5 m^2
Blanik L13: 292 kg, 19.15 m^2

PW6: 360 kg, 15.3 m^2
ASK21: 360 kg, 17.95 m^2
Puchacz: 368 kg, 18.16 m^2
Janus: 365 kg, 17.3 m^2

G103: 390 kg, 17.9 m^2
Duo Discus: 410 kg, 16.4 m^2
DG1000: 415 kg, 17.5 m^2

There's not a lot of difference in the wing areas, with individual variations bigger than the generational differences.

Yes, the glass ones weigh a bit more. How much more?

Someone flying solo in an ASK21 is at about the same all up weight as someone in a ASK13 with a smaller than average instructor in the back seat.

Someone flying solo in a DG1000 is at about the same all up weight as someone in a ASK13 with a largish instructor in the back seat.

We expect students to be able to cope with the flying characteristic differences between having an instructor and not having one -- and to cope with that difference on their first time flying alone!

At 02:06 09 May 2014, Bruce Hoult wrote:
On Wednesday, May 7, 2014 1:20:44 PM UTC+12, Bill D wrote:
I can assure you that the higher a glider's performance, the safer it
is.
It's the old, low L/D gliders that can run out of altitude before getting
lined up with the runway.

It's a mystery to me why some people think you can "get away with" so
much
more in old gliders than in those great big heavy clumsy glass ones.

Somewhere in this thread I saw a statement that you could safely turn
back
from 150 ft in an old glider (which I agree with), but you're a dead man
if
you try it below 300 ft in glass.

The differences that govern such a thing just aren't that big!

Let's look at some numbers for weight and wing area of typical training
gliders (from Wikipedia):

ASK13: 290 kg, 17.5 m^2
Blanik L13: 292 kg, 19.15 m^2

PW6: 360 kg, 15.3 m^2
ASK21: 360 kg, 17.95 m^2
Puchacz: 368 kg, 18.16 m^2
Janus: 365 kg, 17.3 m^2

G103: 390 kg, 17.9 m^2
Duo Discus: 410 kg, 16.4 m^2
DG1000: 415 kg, 17.5 m^2

There's not a lot of difference in the wing areas, with individual
variations bigger than the generational differences.

Yes, the glass ones weigh a bit more. How much more?

Someone flying solo in an ASK21 is at about the same all up weight as
someone in a ASK13 with a smaller than average instructor in the back
seat.

Someone flying solo in a DG1000 is at about the same all up weight as
someone in a ASK13 with a largish instructor in the back seat.

We expect students to be able to cope with the flying characteristic
differences between having an instructor and not having one -- and to
cope
with that difference on their first time flying alone!

I think you are missing the point. The difference between the perceived
attitude of a Discus flying at 45kts (too slow) or 55kts (much better) in a
turn is very small, easy to get wrong.
The perceived attitude difference in a T21 Sedburgh between 35kts (slow)
and 45kts(better) is quite large, easy to spot if you got it wrong. Bearing
in mind that a T21 would not stall until you got it back to 22-25kts made
low turns much more unexciting. The T21 and T31 are the gliders I was
referring to.
When it all turns to ratsh1t in a glass glider it happens that much more
quickly than it ever did in wood.

At 00:13 10 May 2014, Don Johnstone wrote:
At 02:06 09 May 2014, Bruce Hoult wrote:
On Wednesday, May 7, 2014 1:20:44 PM UTC+12, Bill D wrote:
I can assure you that the higher a glider's performance, the safer it
is.
It's the old, low L/D gliders that can run out of altitude before
getting
lined up with the runway.

It's a mystery to me why some people think you can "get away with" so
much
more in old gliders than in those great big heavy clumsy glass ones.

Somewhere in this thread I saw a statement that you could safely turn
back
from 150 ft in an old glider (which I agree with), but you're a dead man
if
you try it below 300 ft in glass.

The differences that govern such a thing just aren't that big!

Let's look at some numbers for weight and wing area of typical training
gliders (from Wikipedia):

ASK13: 290 kg, 17.5 m^2
Blanik L13: 292 kg, 19.15 m^2

PW6: 360 kg, 15.3 m^2
ASK21: 360 kg, 17.95 m^2
Puchacz: 368 kg, 18.16 m^2
Janus: 365 kg, 17.3 m^2

G103: 390 kg, 17.9 m^2
Duo Discus: 410 kg, 16.4 m^2
DG1000: 415 kg, 17.5 m^2

There's not a lot of difference in the wing areas, with individual
variations bigger than the generational differences.

Yes, the glass ones weigh a bit more. How much more?

Someone flying solo in an ASK21 is at about the same all up weight as
someone in a ASK13 with a smaller than average instructor in the back
seat.

Someone flying solo in a DG1000 is at about the same all up weight as
someone in a ASK13 with a largish instructor in the back seat.

We expect students to be able to cope with the flying characteristic
differences between having an instructor and not having one -- and to
cope
with that difference on their first time flying alone!

I think you are missing the point. The difference between the perceived
attitude of a Discus flying at 45kts (too slow) or 55kts (much better) in
a
turn is very small, easy to get wrong.
The perceived attitude difference in a T21 Sedburgh between 35kts (slow)
and 45kts(better) is quite large, easy to spot if you got it wrong.
Bearing
in mind that a T21 would not stall until you got it back to 22-25kts made
low turns much more unexciting. The T21 and T31 are the gliders I was
referring to.
When it all turns to ratsh1t in a glass glider it happens that much more
quickly than it ever did in wood.



All completely correct but there is one even bigger problem, most pilots
when making a low level turn off a launch failure or to modify a
circuit/pattern that has got too low, tend to be looking for/at the place
they intend to land with little or no attention to spare for the ASI,
attitude or slip/skid indicator, that's why these events are so productive
of stall/spin accidents. Training needs to emphasise, GLANCE AT THE ASI
EVERY 2 - 3 SECONDS IN THESE CIRCUMSTANCES. Attitude is un unreliable
indicator very near the ground, even the smallest undulations in the
terrain can give a false impression and just being low can make the
attitude look more nose down than it is.

On 5/6/2014 5:56 PM, Don Johnstone wrote:
Major Snip...

I will stick with my
300ft thank you, I know it works. Low turns, below that height may have
been acceptable in old wooden gliders, the minimum height in T31 and T21
gliders was 150ft, but for modern glass gliders it is just far too low...
Snip...

Volunteers for testing whether a lower-speed/higher-rate glider (T21/T31
certainly qualify) requires less height to execute a course reversal compared
to a higher speed/lower-sink rate modern plastic one? While testing, please do
contact the ground in controlled flight...

...you
only have to look at the accident statistics to see that low final turns
figure to a large degree in accidents so why plan for it?

Because: a) it happens (statistics); and b) (IMO) we reasonably safely can?
(That's certainly NOT the case when practicing the inadvertent departure from
controlled flight in the pattern.) And the skill might be good to have in
one's skill set? I'm not trying to be snarky, but it's the *uncontrolled*
ground contact that jumps out from the death statistics I've seen.

I repeat a controlled descent with wings level is far more likely to have a
better result than hitting the ground in a turn or even worse spinning in
trying to avoid it.

Roger both thoughts...especially that last one!

It's not "merely" the broken rope Joe Glider Pilot needs to be prepared for
as "the" source of an in-pattern prematurely terminated tow. Except for
training flights, I've never had an in-pattern premature tow termination...but
I know of lots of others who "for real" have, with causes including (off the
top of my head) unlatched canopies, passenger idiocy, improperly connected tow
rings and almost certainly more I'm forgetting.

Stuff happens. Prepare - mentally, training, muscle memory - accordionly.

Bob W.

We have a
rule here in the UK, launch failure on aerotow below 300ft a landing should
be made ahead, or slightly to one side. No attempt should be made to turn
back below this height.

As a UK FI(S) and FIC, previously a Full Cat instructor, this is news to me. Where is it expressed?

I thought the rule was to exercise judgement. I always address 'where would you go now' issues with students and on check flights. In most conditions and situations I would turn back from lower than 300 foot.

On Tuesday, May 6, 2014 4:41:23 PM UTC-4, Don Johnstone wrote:
While in no way do I wish to speculate on the cause of this accident or

indeed suggest that my comments in any way address the cause of this

accident.

I feel that comment is needed on some of the things said here. We have a

rule here in the UK, launch failure on aerotow below 300ft a landing should

be made ahead, or slightly to one side. No attempt should be made to turn

back below this height.

The reason is simple, a controlled crash into difficult terrain is likely

to result in a better outcome than an uncontrolled arrival on the airfield.

The important bit to keep intact is the bit you are sitting in, the rest of

the glider does not really matter too much. The best chance of achieving

that is flying to the ground with the wings level. It has only happened to

me once, there was a field ahead but it was full of the Tiger Moth tug that

had landed in the middle. I discovered that there was just enough space for

a Skylark 2 as well. I have no doubt that a turn back would have resulted

in an accident. I was at 250ft agl max.

If there really is nowhere to land ahead you should really ask the

question, "should I be taking a launch".

Frankly I would be horrified to be required to conduct a turn back at

200ft, I would suggest that this is one of those occasions where the danger

of practice is to great to justify.

Sometimes it's hard to face the fact that the glider must be destroyed to survive. Trying to save the device could be a deadly decision.

Again, I don't know what actually happened, best guess, inadvertent unintentional release. Whether he tried to turn back, or just plain didn't get the nose down quick enough during a 90 degree or lesser turn, who knows.

The only way to practice rope breaks at 100' is on a simulator (condor).

Don's suggestion that there is a rigid rule about turn back heights in the UK is a surprise to me (I am an instructor). Select the least bad option at the time. Prepare students for it by (at an earlier stage) saying 'from here I would..'. Later asking 'if the tow fails here, where would you go?'

In most circumstances from 200 foot I would turn back.

Quite right, individual clubs may have had a minimum turn back height as
advice or even a rule, the BGA has not. I write as the ex-National Coach
who produced the BGA Instructor's Manual.

At 02:47 19 July 2014, waremark wrote:
Don's suggestion that there is a rigid rule about turn back heights in
the
=
UK is a surprise to me (I am an instructor). Select the least bad option
at=
the time. Prepare students for it by (at an earlier stage) saying 'from
he=
re I would..'. Later asking 'if the tow fails here, where would you go?'

In most circumstances from 200 foot I would turn back.