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Crunch Alert (USA) - hugely serious but (apparently) non-fatal

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BobW

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Apr 30, 2012, 12:33:58 PM4/30/12
to
Having once 'felt the need' myself, this one undoubtedly has a compelling
story; it will definitely make its way into the NTSB database.

Thank goodness the pilot is (reportedly) OK. SSA member; diamond badge; 2-time
3rd place finisher in Region 9 Regional.

If it happens it must be possible. Let's - as pilots - do what we can to
minimize our chances of 'it' happening...

<Begin cut-n-paste...>
> IDENTIFICATION
> Regis#: 555AP Make/Model: JS1 Description: JONKER SAILPLANE
> Date: 04/29/2012 Time: 1900
>
> Event Type: Accident Highest Injury: None Mid Air: N Missing: N
> Damage: Unknown
>
> LOCATION
> City: TAOS State: NM Country: US
>
> DESCRIPTION
> PILOT ENCOUNTERED RUDDER PEDAL PROBLEM, LOST CONTROL, AND ABANDONED THE
> AIRCRAFT BY PARACHUTE.
>
> INJURY DATA Total Fatal: 0
> # Crew: 1 Fat: 0 Ser: 0 Min: 0 Unk:
> # Pass: 0 Fat: 0 Ser: 0 Min: 0 Unk:
> # Grnd: Fat: 0 Ser: 0 Min: 0 Unk:
>
> WEATHER: K0E0 291855Z AUTO 23006KT 10SM SCT075 21/01 A3004
>
> OTHER DATA
>
>
> FAA FSDO: ALBUQUERQUE, NM (SW01) Entry date: 04/30/2012

<End cut-n-paste...>

Mike the Strike

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Apr 30, 2012, 4:21:08 PM4/30/12
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From Albuquerque Soaring web site...

"Per Billy Hill this evening: today Angel Pala was thermalling with Billy in the area north of Moriarty and south of Lamy when he heard a loud bang, and lost rudder authority (both pedals fell full forward). Evidently the glider behaved like full right rudder. Shortly thereafter the glider entered an inverted spin, and Angel wisely decided he should walk home, and so hit the silk. He landed under parachute, and hiked out, and was taken to a hospital in Santa Fe. He seems to be fine and Billy expects to pick him up when he is released from hospital.

Mike

T

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Apr 30, 2012, 9:28:55 PM4/30/12
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Happy that all is well with the pilot..

But do we know what happened? a mid air? a rudder cable failure?

T

Renny

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Apr 30, 2012, 10:46:35 PM4/30/12
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It was not a mid-air. We are awaiting more information on the
investigation. The good news is that.Angel is now home and is
recovering from his bumps and bruises after landing, via parachute, in
Nowhere, NM........
Thx - 3R

Ramy

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May 1, 2012, 3:39:44 AM5/1/12
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Wow, thank god it happened at altitude!
Isn't it that virtually all our rudder pedals mechanism are spring loaded, and if one cable breaks the result is instantaneously full rudder? I always thought this is a receipt for disaster. A glider without rudder control may still be flyable and even landable, but not with full rudder!

Ramy

Dave Nadler

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May 1, 2012, 7:03:26 AM5/1/12
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What was the altitude AGL ?
Where is the JS1 rudder vented ?

Sure lucky it ended OK for the pilot !
Best Regards, Dave

Mike the Strike

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May 1, 2012, 9:42:52 AM5/1/12
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Reportedly, the problem occurred at about 5,000 ft AGL and the aircraft inverted and entered a flat spin. Angel departed the aircraft about 3,500 to 3,800 feet AGL.

Mike

John Carlyle

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May 1, 2012, 10:43:53 AM5/1/12
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I've often wondered about the amount of altitude loss that occurs when exiting an aircraft in distress. Here it was about 1,500 feet in what would seem to be ideal circumstances - inverted (I have no idea what part centrifugal force was playing in this case).

Doesn't bode well for someone in a deep cockpit in an upright attitude. Maybe it's time to look seriously at DG's NOAH system...

-John

Papa3

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May 1, 2012, 11:00:02 AM5/1/12
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John,

I watched a number of pilots trying to get out of their gliders at Perry on the ground. Between an excess of personal ballast and declining muscle strength, I'd be willing to bet half of them could never get out with any increased lateral or positive, vertical loading.

Related to this, I'm curious why static lines aren't prevalent in the US. It seems all of the European made gliders have a provision for the static line. Any of our Euro friends care to illuminate us on whether use of static lines is common there?

John Carlyle

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May 1, 2012, 11:40:31 AM5/1/12
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Don't know about static lines, but someone on the group (maybe Kirk Stant?) made a suggestion that if all else failed when trying to exit an aircraft in distress, lean all the way forward and pull the ripcord. He said you would get hurt, but you'd also be out. A last resort tip I'm going to remember!

Wearing a parachute I struggle to get out of my LS8 while sitting on the ground. I can't see me making it out in the air with increased lateral or positive vertical loading, but hopefully adrenalin can work wonders if I'm ever unlucky enough to need to exit...

-John

Don Johnstone

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May 1, 2012, 11:51:51 AM5/1/12
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At 15:00 01 May 2012, Papa3 wrote:

>
>I watched a number of pilots trying to get out of their gliders at Perry
>on=
> the ground. Between an excess of personal ballast and declining muscle
>s=
>trength, I'd be willing to bet half of them could never get out with any
>in=
>creased lateral or positive, vertical loading. =20

I think you might find that adrenaline takes over in that situation
>
>Related to this, I'm curious why static lines aren't prevalent in the US.

>=
>It seems all of the European made gliders have a provision for the static
>l=
>ine. Any of our Euro friends care to illuminate us on whether use of
>stati=
>c lines is common there?

Static lines are not used here in the UK for the very good reason that
pilots tend to exit the glider wearing the parachute and walk away. I think
the fitting of a static line loop in the glider was an LBA requirement but
as far as I am aware no one uses it for the reason given above.

If you want a good laugh have a look at this. The demonstrator is
attempting to show that the practice of undoing the chest strap before the
leg straps is unecessary because you won't ever get dragged by the chute.
http://www.youtube.com/watch?v=9Kx-buGUOhw

Dan Marotta

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May 1, 2012, 12:20:49 PM5/1/12
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I was in flight that day and recall hearing a few pilots asking if anyone
had heard from Angel lately. I didn't learn of his misfortune until the
next morning. From descriptions I've heard of the accident, it sounds like
a rudder cable broke. I have not seen the wreck and I'm not a professional
accident investigator, this is just my opinion based on what I've heard.
I've also looked at another JS-1 on the field and there's a frayed rudder
cable.

It seems like all modern gliders use the same or a variation of the same
mechanism for connecting and adjusting rudder cables and pedals. You can
bet that, before my next flight in my LAK-17a, I'll be giving those parts a
very close look.

I was shocked to hear of Angel's accident and am so glad that he survived.



"Don Johnstone" <gp3...@okbloggs.co.uk> wrote in message
news:4fa00882$0$2708$a826...@newsreader.readnews.com...

Greg Arnold

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May 1, 2012, 12:35:25 PM5/1/12
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On 5/1/2012 9:20 AM, Dan Marotta wrote:
> I was in flight that day and recall hearing a few pilots asking if
> anyone had heard from Angel lately. I didn't learn of his misfortune
> until the next morning. From descriptions I've heard of the accident, it
> sounds like a rudder cable broke. I have not seen the wreck and I'm not
> a professional accident investigator, this is just my opinion based on
> what I've heard. I've also looked at another JS-1 on the field and
> there's a frayed rudder cable.


Where on the cable is it frayed? At the rudder? At the pedals?

GM

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May 1, 2012, 1:27:26 PM5/1/12
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>> Static lines are not used here in the UK for the very good reason that
pilots tend to exit the glider wearing the parachute and walk away. <<

Slow learners, eh? ;-)

Don't know what the rules are in other European countries but I Germany, wearing a chute while in training is mandatory. Since a static line chute pulls the rip-chord for you, this is what we exclusively used in our trainers. I have seen two guys bail out of a L13 (wing came off) using static line chutes and both where fully deployed in a very short time after exiting! Each European-designed glider I know of has a hard-point to attach the static line to. Said hard point is marked in red.

Berry

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May 1, 2012, 1:57:01 PM5/1/12
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>
> Wow, thank god it happened at altitude!
> Isn't it that virtually all our rudder pedals mechanism are spring loaded,
> and if one cable breaks the result is instantaneously full rudder? I always
> thought this is a receipt for disaster. A glider without rudder control may
> still be flyable and even landable, but not with full rudder!
>
> Ramy

Some powered aircraft have interconnected controls with springs in the
control circuits. Tailwheel birds with steerable tailwheels have springs
connecting the rudder and tailwheel. A broken cable on those aircraft
can result in a rudder hard over. My homebuilt taildragger has a fixed
tailwheel for that reason (and enough rudder to drag that wheel sideways
when needed)

I think most gliders do not have springs in the rudder control circuit.
I can't remember ever flying a glider with a spring-centered rudder.
However, don't we all fly with just a little pressure on both rudder
pedals? A cable break is going to result in the rudder hard over on the
unbroken side. That is going to result in a rapid yaw and air loads that
will tend to hold the rudder hard over with no way to get it back. I can
see that putting the ship over on it's back pretty quickly. Snap rolls
anyone?

Marc

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May 1, 2012, 2:49:26 PM5/1/12
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On May 1, 9:20 am, "Dan Marotta" <dcmaro...@earthlink.net> wrote:
> It seems like all modern gliders use the same or a variation of the same
> mechanism for connecting and adjusting rudder cables and pedals.  You can
> bet that, before my next flight in my LAK-17a, I'll be giving those parts a
> very close look.

If your serial number is 141 or less, service bulletin
017A.5.52.005A already requires installation
of plastic tubes over the rudder cables where they pass through the
pedal attachment S-tubes, to prevent fraying. The tubes should be
visible, if the fix was applied...

Marc

Mark Mocho

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May 1, 2012, 3:23:03 PM5/1/12
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I spoke to Angel Pala this morning. I have been asked to clear up some
misconceptions and incorrect assumptions floating around.

Angel reported that he was thermalling northeast of Moriarty at around
11,300 msl. He was pushing on the rudder pedals (probably fairly hard
as we do occasionally in strong conditions) when there was a "snap"
and both rudder pedals went forward on the adjustment/positioning rod.
He attempted to pull them back using the adjustment cable, but there
was no tension felt, either on the spring or the rudder slider. The
aircraft rudder deflected and put the glider into a right turn. THERE
WAS NO "INVERTED FLAT SPIN" as previously reported. The glider started
descending in a right turn. Angel attempted to control the turn by
using opposite aileron (slip) but control was insufficient to maintain
direction.

Terrain below was far too rugged to attempt to land with minimal
control, so he decided to exit the aircraft with plenty of altitude.
Angel is a U.S. Army Special Forces veteran with Jumpmaster
qualifications and 90+ jumps, so he wasn't exactly unfamiliar with
parachuting under stressful conditions. He mistakenly disconnected his
seat belts prior to jettisoning the canopy, and was outside looking in
very quickly. He described "floating along next to his aircraft" as a
very weird "surreal" feeling. The glider maintained a fairly flat
right turn as Angel pulled the ripcord. His chute, a ParaPhernalia
"Softie" had been repacked at the factory only a month prior to the
incident. He said the D-ring only extended a few inches before the
canopy deployed from the container. The opening was "heavier" than he
expected (i.e., very rapid) with a harsh opening shock. Angel said
that the opening was so quick tthat a 400 ft. altitude would have been
sufficient, and this is from one who had experience with HALO (High
Altitude Low Opening) jumps.

As he descended under canopy, he had difficulty reaching the steering
toggles. Whether their position was out of reach due to misadjustment
of the harness or the air stream had taken them off their stowed
position has not been determined. Angel used the risers to effect some
directional control. He was able to observe that the glider continued
to the ground in a stable, flat right turn. It impacted the ground
"relatively intact" as he described it. He even heard the impact
before he landed himself.

Realiozing that he would have to hike out, Angel concentrated on
protecting his lower extremities as much as possible, electing to land
in a relaxed PLF rather than attempt to run out the landing. Windy
conditions dragged him briefly before he was able to collapse the
canopy and release the harness. He gathered the canopy and hiked four
miles before getting a ride directly to a hospital in Santa Fe. He
called several people at Moriarty to give basic "I'm OK" messages. He
told me today with some chagrin that his "SPOT" messenger is safe in
his hangar.

He underwent an MRI and other tests, spent the night and was released
on Monday. Billy Hill picked him up and took him back to his home in
Taos. Injuries were relatively minor, with substantial bruising and
some tendon strain to his left shoulder, cuts and scrapes and some
mouth cuts, but he will make a full recovery.

Knowing Angel's sense of humor, we just had to ask some "sensitive"
questions. He reports that a normal catheter stays on, but will fail
under tension loads at the outlet. Good to know.

The FAA and NTSB have been notified and investigations are underway.
The glider will most likely be removed by a professional aircraft
recovery company. It may need to be removed by helcopter to a place
nearby with road access, as there isn't a way to get a vehicle and
trailer to the site. One Sheriff's Deputy who reached the site said
there is about a 75-100 foot bluff between the glider and the nearest
road. He described the trek up the bluff as "a real hump."

Once the aircraft has been recovered and inspected, more information
about the cause of the accident will be released. Until then, it is
inadvisable to speculate.

The Jonker representative and the factory have been in contact with
Angel, and there are no recriminations. Leo Bennetti-Longhini reprts
that Angel is being a true gentleman about the situation and Jonker
will do whatever is needed to identify the cause and effect a
solution. JS-1 owners have been notified of the situation.

Martin Gregorie

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May 1, 2012, 4:01:12 PM5/1/12
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On Tue, 01 May 2012 10:27:26 -0700, GM wrote:

> Don't know what the rules are in other European countries but I Germany,
> wearing a chute while in training is mandatory. Since a static line
> chute pulls the rip-chord for you, this is what we exclusively used in
> our trainers. I have seen two guys bail out of a L13 (wing came off)
> using static line chutes and both where fully deployed in a very short
> time after exiting! Each European-designed glider I know of has a
> hard-point to attach the static line to. Said hard point is marked in
> red.
>
When did those hard points first appear? My glider, built in 1969,
doesn't appear to have one, so I'm curious.


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

Peter von Tresckow

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May 1, 2012, 4:12:01 PM5/1/12
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I have a ring mounted to the bulkhead behind the seat in my Ka-6, and that
was built in '63

Actually on a ride in a K13 in Germany I almost triggered the static line
when walking away from the plane. So you got to remember about that
"feature"

Pete

"Martin Gregorie" <mar...@address-in-sig.invalid> wrote in message
news:jnpfe8$rhm$1...@localhost.localdomain...

John Firth

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May 1, 2012, 4:01:19 PM5/1/12
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At 11:03 01 May 2012, Dave Nadler wrote:
>On Monday, April 30, 2012 4:21:08 PM UTC-4, Mike the Strike wrote:
>> From Albuquerque Soaring web site...
>>=20
>> "Per Billy Hill this evening: today Angel Pala was thermalling with
>Billy=
> in the area north of Moriarty and south of Lamy when he heard a loud
>bang,=
> and lost rudder authority (both pedals fell full forward). Evidently the
>g=
>lider behaved like full right rudder. Shortly thereafter the glider
>entered=
> an inverted spin, and Angel wisely decided he should walk home, and so
>hit=
> the silk. He landed under parachute, and hiked out, and was taken to a
>hos=
>pital in Santa Fe. He seems to be fine and Billy expects to pick him up
>whe=
>n he is released from hospital.
>>=20
>> Mike
>
>What was the altitude AGL ?
>Where is the JS1 rudder vented ?
>
>Sure lucky it ended OK for the pilot !
>Best Regards, Dave
>
I am surprised that the rudder went full over, and slip would not center
it>
Rudder vent?
Does not the JS-1 have an extractor dorsal vent?
WE should test controlability with feet off!
John Firth

sisu1a

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May 1, 2012, 3:04:55 PM5/1/12
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>You can
> bet that, before my next flight in my LAK-17a, I'll be giving those parts a
> very close look.

Always a good idea, especially on a LAK-17a! I won't mention any
names, but a well known fellow around here had his 17a rudder cable
disengage (factory installed incorrect swedge fitting... oops!),
leaving him rudderless a few years ago. Thank goodness there are no
springs in that design, as he was fairly low so was committed to
landing. Titanium testicles and a cool head combined with skill and
luck for a successful outcome.

Glad the JS1 pilot is OK; I hope he buys his rigger a sixpack and
writes this up someday. I also hope this doesn't screw Jonkers...

-Paul

Martin Gregorie

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May 1, 2012, 6:28:22 PM5/1/12
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On Tue, 01 May 2012 15:12:01 -0500, Peter von Tresckow wrote:

> I have a ring mounted to the bulkhead behind the seat in my Ka-6, and
> that was built in '63
>
Interesting. Mine is an H.201 Libelle. I suppose the static line could
simply be secured to the tube behind the seat. This carries the forward
wing pin sockets and doubles as attachment for the shoulder straps so its
plenty strong enough but, on mine anyway, doesn't have a specific static
line anchor point.


> Actually on a ride in a K13 in Germany I almost triggered the static
> line when walking away from the plane. So you got to remember about that
> "feature"
>
:-)

I almost did that after getting out of an ASK-23 at the Wasserkuppe.

Martin Gregorie

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May 1, 2012, 7:09:29 PM5/1/12
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On Tue, 01 May 2012 20:01:19 +0000, John Firth wrote:

> I am surprised that the rudder went full over, and slip would not
> center it
>
I don't think I am, but this would depend on the seating geometry. I've
never seen a JS-1 so have no idea about its seating arrangements.

Here's the general idea. If you fly with knees raised you'll always have
some pressure on the pedals, so if the rudder cable snaps, both pedals
will go forward as described and you'll get full rudder toward the
unbroken cable side.

To let the rudder straighten out it will be necessary to get your feet
off the pedals and keep them off. In some gliders, particularly those
with flat floors, e.g. Discus 1, ASW-19,20 and Pegase, you can probably
pull your knees up and put your feet flat on the floor with your toes
resting against the pedal hinge bar if necessary. In a DG-300 you can
probably pull your knees toward you with your lower legs and heels
resting on the 'shelf' behind the pedals. However, in other gliders where
you fly with raised knees there are problems. If there isn't the space to
put your feet flat on the floor behind the pedal hinges this will be
extremely tiring after the first 5-10 minutes. Would it be possible at
all in an LS7 or 8? I have no idea if there's any foot room between the
front of the under-knee hump and the pedal pivots in these gliders.

> WE should test controlability with feet off!
>
And also see if its possible to take your feet entirely off the pedals
and keep them off for the time it will take to pick a field, lose height,
fly a circuit and land. If this requires holding your legs and/or feet in
the air, can you do that long enough to land the glider without the
effort of doing it being totally distracting?

Don Johnstone

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May 1, 2012, 7:25:01 PM5/1/12
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What glider do you have Martin?

Dave Nadler

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May 1, 2012, 8:49:24 PM5/1/12
to
On Tuesday, May 1, 2012 4:01:19 PM UTC-4, John Firth wrote:
> Rudder vent?

Hole in the rudder to equalize internal pressure.
Sounds like this was NOT the problem here, but
it wouldn't be the first control surface to explode.

BruceGreeff

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May 2, 2012, 9:54:53 AM5/2/12
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My 1970 Std Cirrus had one...
Bruce Greeff
T59D #1771 & Std Cirrus #57

Dan Marotta

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May 2, 2012, 10:09:39 AM5/2/12
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What I saw was approximately 6 inches forward of the forward bulkhead. Just
about where the cable enters the S-tube.


"Greg Arnold" <Soa...@cox.netREMOVE> wrote in message
news:jnp3ce$t5r$1...@dont-email.me...

Dan Marotta

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May 2, 2012, 10:14:01 AM5/2/12
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Thanks, Marc. Mine is S/N 119. I'm towing today (leaving for the airport in 20 minutes) and I'll check that before pulling the tug out of the hangar. "Marc" <marc....@gmail.com> wrote in message news:315ff75b-acc1-4e1a...@t2g2000pbg.googlegroups.com... On May 1, 9:20 am, "Dan Marotta" <dcmaro...@earthlink.net> wrote: > It seems like all modern gliders use the same or a variation of the same > mechanism for connecting and adjusting rudder cables and pedals. You can > bet that, before my next flight in my LAK-17a, I'll be giving those parts > very close look. If your serial number is 141 or less, service bulletin 017A.5.52.005A already requires installation of plastic tubes over the rudder cables where they pass through the pedal attachment S-tubes, to prevent fraying. The tubes should be visible, if the fix was applied... Marc

Dan Marotta

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May 2, 2012, 10:24:51 AM5/2/12
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OUTSTANDING description, Mark. Kudos for Angel's description and your
reporting!


"Mark Mocho" <markm...@gmail.com> wrote in message
news:9bfc48d4-df5f-4479...@nl1g2000pbc.googlegroups.com...

jpg...@gmail.com

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May 2, 2012, 11:35:09 AM5/2/12
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On Tuesday, 1 May 2012 20:04:55 UTC+1, sisu1a wrote:

> Glad the JS1 pilot is OK; I hope he buys his rigger a sixpack and
> writes this up someday. I also hope this doesn't screw Jonkers...
>
> -Paul

Notwithstanding the pilot's impressive account of the incident we don't yet know the underlying cause. I too am hoping and, in my case, betting that Jonker Sailplanes will not be seriously affected in the long term (any more than SH was by their spar problem) providing that they respond promptly and appropriately, as I expect they will. Speaking as one who went ahead with a JS1 order yesterday - after hearing about this accident.

John


Ramy

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May 2, 2012, 3:19:03 PM5/2/12
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I second that. This is the kind of accident reports we need to be able to understand better and learn - detailed and timely, vs NTSB reports which may take long time and typically have no details or worse, incorrect information.
And since the LAK17 was also mentioned in this thread, I would add that I heard of another LAK17 rudder cable disconnect, luckily after touch down, but if I recall correct this was a replacement cable and not factory cable.

I think the obvious lessons so far is to always inspect your glider as much as possible, and of course always fly with parachute!

Ramy

Mike the Strike

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May 2, 2012, 5:21:55 PM5/2/12
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...and while we are talking about rudder cables, years ago I accidentally drilled through a rudder cable when installing a boom microphone. When we pulled the cable out to replace it, we found that the factory had done exactly the same thing a few feet further down the fuselage and half the strands were severed.

Sometime later, I heard of a rudder cable failure on this particular sailplane type and wondered if this were a common manufacturing problem.

Mike

Martin Gregorie

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May 2, 2012, 6:18:35 PM5/2/12
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As I said above, an H.201 Std Libelle.

Bob Whelan

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May 2, 2012, 7:46:10 PM5/2/12
to
On 5/2/2012 1:19 PM, Ramy wrote:
> On Wednesday, May 2, 2012 7:24:51 AM UTC-7, Dan Marotta wrote:
>> OUTSTANDING description, Mark. Kudos for Angel's description and your
>> reporting!
>>
>>
>> "Mark Mocho"<markm...@gmail.com> wrote in message
>> news:9bfc48d4-df5f-4479...@nl1g2000pbc.googlegroups.com...
>>><Major
>>
snip of excellent stuff...>

>
> I second that. This is the kind of accident reports we need to be able to
> understand better and learn -

<Snip>

>
> Ramy

"What Dan and Ramy said." This took a lot of effort and time to research and
compose/write. It's genuinely appreciated.

Thank goodness 'only' a plane was lost. Let's hope a full investigation
manages to uncover 'a smoking gun.'

Bob W.

uline...@yahoo.com

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May 3, 2012, 1:49:05 AM5/3/12
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Martin,
don't know when these hard-points became standard but our club had a factory built K6CR (built in the early to mid '60s) and it had the hard-point already in it. My '64 Libelle has the forward carry-through tube designated as the hard-point, so I would guess that they have been around for a while. What glider do you fly? Did you check in your POH - should be in there.
Uli

Dan Marotta

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May 3, 2012, 10:24:24 AM5/3/12
to
Checked my LAK-17a, S/N 119 yesterday. Cables are in perfect condition and
service bulletin has been complied with.

Thanks, again, for the heads up.


"Bob Whelan" <rfwh...@greeleynet.com> wrote in message
news:jnsh00$bd9$1...@speranza.aioe.org...

Martin Gregorie

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May 3, 2012, 11:12:25 AM5/3/12
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I fly an H.201 Libelle. In the Flight Manual it says:

Page E7 "The cockpit-layout is not suitable for automatic parachutes."

I presume they mean static line 'chutes? The term in German (page
7,German section) is 'automatische Fallschirme'.

Eric

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May 4, 2012, 2:27:50 AM5/4/12
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Nearly all gliders have strong springs on the rudder pedals which
tension the cables. A rudder cable failure will result in the rudder
going over to the other side and there is nothing you can do with your
feet to prevent this (unless you can hook your foot under the pedal on
the unbroken side and pull it forward).

Basil

Ramy

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May 4, 2012, 2:52:08 AM5/4/12
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One must wonder why, and if there was no safer way to design the rudder pedals mechanism so it wouldn't aggravate the situation in a case of cable break.

Ramy

uncl...@ix.netcom.com

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May 4, 2012, 9:19:24 AM5/4/12
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The tension springs are an essential part of the control circuit to avoid flutter. Inspection of cables where they go through the adjustment guides is a standard item on inspection check lists.
It might be smart for everybody to adjust their pedals all the way forward and back and see if the guy who did our inspection nissed something.
UH

Don Johnstone

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May 4, 2012, 6:47:29 PM5/4/12
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>
>The tension springs are an essential part of the control circuit to avoid
>flutter. Inspection of cables where they go through the adjustment guides
>is a standard item on inspection check lists.
>It might be smart for everybody to adjust their pedals all the way
forward
>and back and see if the guy who did our inspection nissed something.
>UH

Not sure that flutter is the reason for the springs. They are necessary to
to tension the cables when the rudder pedals are moved for and aft on some
gliders. Some gliders do not have springs in the cable at all

Martin RSA

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May 10, 2012, 9:32:38 AM5/10/12
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Ramy;814097 Wrote:
> Renny wrote:[color=blue][i]
>
> Wow, thank god it happened at altitude!
> Isn't it that virtually all our rudder pedals mechanism are spring
> loaded, and if one cable breaks the result is instantaneously full
> rudder? I always thought this is a receipt for disaster. A glider
> without rudder control may still be flyable and even landable, but not
> with full rudder!
>
> Ramy

This is sort of true, but not in this case. The spring is just strong
enough to ensure the pedal does not fall forward when the pilot climbs
out. Also, if one spring is off, it is not strong enough to allow yaw to
initiate.

In the accident of the JS1, the glider was in a right hand slip (full
left aileron required). We can assume in this case that the left hand
rudder cable broke. In the accident photo’s the right hand cable is off,
which probably happened during impact.




--
Martin RSA

Greg Arnold

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May 10, 2012, 11:31:08 AM5/10/12
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Are the accident photos online?

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Martin RSA

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May 11, 2012, 1:58:07 AM5/11/12
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Greg Arnold;

Are the accident photos online?[/QUOTE Wrote:
>
>
> Not that I am aware of




--
Martin RSA
Message has been deleted

Mike C

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May 11, 2012, 1:30:45 PM5/11/12
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Saw the photos yesterday. Also inspected the sister ship of the JS1
that had a rudder cable failure at 100 hours. The sister ship has 28
hours and the right rudder cable is beginning to fray with several
strands already worn through due to contact with the sharp edge of the
S tube.
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