You should take a look at this:

http://www.dg-flugzeugbau.de/holm-dg300-e.html

Marc

On 4/7/07 12:34 AM, in article
, "Marc Ramsey"
> wrote:

> You should take a look at this:
>
> http://www.dg-flugzeugbau.de/holm-dg300-e.html
>
> Marc

My German skills are non-existant. Can anyone tell me if the lengthier
German part mentions which serial numbers are affected, because the English
part says the manufacturing error began sometime during the production run.
Presumably that means some of the early DG-300's were built right.

Thanks,
Bullwinkle

On Apr 7, 6:01 am, Bullwinkle > wrote:
> On 4/7/07 12:34 AM, in article
> , "Marc Ramsey"
>
> > wrote:
> > You should take a look at this:
>
> >http://www.dg-flugzeugbau.de/holm-dg300-e.html
>
> > Marc
>
> My German skills are non-existant. Can anyone tell me if the lengthier
> German part mentions which serial numbers are affected, because the English
> part says the manufacturing error began sometime during the production run.
> Presumably that means some of the early DG-300's were built right.
>
> Thanks,
> Bullwinkle

You can try translating the DG webpage with this one:

http://babelfish.altavista.com/babelfish/tr

Just drop the URL into it, and choose "German to English".

-John W

On 4/7/07 5:16 AM, in article
. com, "rasposter"
> wrote:

> On Apr 7, 6:01 am, Bullwinkle > wrote:
>> On 4/7/07 12:34 AM, in article
>> , "Marc Ramsey"
>>
>> > wrote:
>>> You should take a look at this:
>>
>>> http://www.dg-flugzeugbau.de/holm-dg300-e.html
>>
>>> Marc
>>
>> My German skills are non-existant. Can anyone tell me if the lengthier
>> German part mentions which serial numbers are affected, because the English
>> part says the manufacturing error began sometime during the production run.
>> Presumably that means some of the early DG-300's were built right.
>>
>> Thanks,
>> Bullwinkle
>
> You can try translating the DG webpage with this one:
>
> http://babelfish.altavista.com/babelfish/tr
>
> Just drop the URL into it, and choose "German to English".
>
> -John W
>

OK: thanks!

Did that, and to answer my own question: no, no serial number range is
listed. Hopefully that will come out as DG and Elan/AMS continue to work the
problem.

As a summary, much of the longer German portion appears to be heavy duty
mental handwringing over what DG should do with the info that the spars are
weaker: ground the fleet, require a very expensive inspection, or just
impose some restrictions on speeds and weights. Clearly they have done the
latter.

I have to believe that Elan/AMS has sufficient manufacturing records to
determine when they changed their process, either by serial number, or by
date (from which affected serial numbers could be derived). You'd think
they'd keep those records for legal reasons, if no other.

Hoping for further clarification,
Thanks,
Bullwinkle

On Apr 7, 7:28 am, Bullwinkle > wrote:
> On 4/7/07 5:16 AM, in article
> . com, "rasposter"
>
>
>
>
>
> > wrote:
> > On Apr 7, 6:01 am, Bullwinkle > wrote:
> >> On 4/7/07 12:34 AM, in article
> >> , "Marc Ramsey"
>
> >> > wrote:
> >>> You should take a look at this:
>
> >>>http://www.dg-flugzeugbau.de/holm-dg300-e.html
>
> >>> Marc
>
> >> My German skills are non-existant. Can anyone tell me if the lengthier
> >> German part mentions which serial numbers are affected, because the English
> >> part says the manufacturing error began sometime during the production run.
> >> Presumably that means some of the early DG-300's were built right.
>
> >> Thanks,
> >> Bullwinkle
>
> > You can try translating the DG webpage with this one:
>
> >http://babelfish.altavista.com/babelfish/tr
>
> > Just drop the URL into it, and choose "German to English".
>
> > -John W
>
> OK: thanks!
>
> Did that, and to answer my own question: no, no serial number range is
> listed. Hopefully that will come out as DG and Elan/AMS continue to work the
> problem.
>
> As a summary, much of the longer German portion appears to be heavy duty
> mental handwringing over what DG should do with the info that the spars are
> weaker: ground the fleet, require a very expensive inspection, or just
> impose some restrictions on speeds and weights. Clearly they have done the
> latter.
>
> I have to believe that Elan/AMS has sufficient manufacturing records to
> determine when they changed their process, either by serial number, or by
> date (from which affected serial numbers could be derived). You'd think
> they'd keep those records for legal reasons, if no other.
>
> Hoping for further clarification,
> Thanks,
> Bullwinkle- Hide quoted text -
>
> - Show quoted text -


My wife is a native speaker of German. I asked her to read this and
even though she isn't familiar with some of the terminology here is a
summary of generally what it says.

The glider that was inspected which resulted in this discovery is
about 20 years old and they did not report its serial number. At some
point ELAN started manufacturing the wings not to design
specifications. They apparently started using epoxy resins rather
than polyester resins (as were specified) in the affected part of the
spars possibly to reduce the curing times. This was done without
notification let alone approval from Glaser-Dirks. ELAN is aware that
they did this and ELAN does not dispute doing it but says they refuse
to take on any inspection costs. Also, they have been unresponsive to
DG's inquiries regarding this matter.

DG estimates the inspection cost to be around 6,000 euros and repair
cost could easily come to 5,000 euros per wing. DG says to maintain
consistency the inspection and repairs should all be done at the DG
factory in Germany so there will also be shipping costs. DG goes on
to say this option is not really discussion worthy for the pilots.
They rather opted for doing calculations and endurance tests on the
affected parts to prove that they are still sufficiently stable and
that the airplanes can be flown safely at reduced speeds and use.
This is apparently why they decided to just reduce the speeds, take
off weight and limit use. They say the current fleet is about 500
gliders worldwide.

I, for one, bought a DG-300 for its superior strength among other
reasons. We will have to wait for more clarification from DG but at
this point it seems that strength has now been reduced. Since this is
admittedly the fault of ELAN for not following the correct
manufacturing process and not notifying DG that they were altering the
manufacturing process this seems like a negligence issue. I would
hope they would do something to rectify the situation.

Bob
DG-300, S/N 3E-127

On Apr 7, 2:34 am, Marc Ramsey > wrote:
> You should take a look at this:
>
> http://www.dg-flugzeugbau.de/holm-dg300-e.html
>
> Marc

Try this:
http://translate.google.com/translate?u=http%3A%2F%2Fwww.dg-flugzeugbau.de%2Fholm-dg300-e.html+&langpair=de%7Cen&hl=en&ie=UTF-8&oe=UTF-8&prev=%2Flanguage_tools

wrote:
> I, for one, bought a DG-300 for its superior strength among other
> reasons. We will have to wait for more clarification from DG but at
> this point it seems that strength has now been reduced. Since this is
> admittedly the fault of ELAN for not following the correct
> manufacturing process and not notifying DG that they were altering the
> manufacturing process this seems like a negligence issue. I would
> hope they would do something to rectify the situation.

I sold mine several years ago, so I don't really have much of a stake in
this (at the moment, anyway), but when I bought my 303 Acro, the check
wasn't payable to ELAN, it was payable to Glaser-Dirks (which is, of
course, not quite the same company as DG-Flugzeugbau).

When subcontractor spar fabrication "innovations" resulted in our Duo
being grounded, Schempp-Hirth immediately took responsibility, found a
practical inspection and repair protocol, trained repair shops in their
major markets to inspect and repair (and flew SH technicians worldwide
to deal with the rest), and had most of the gliders back in the air in
less than two months without charging the owners a dime.

The situations aren't exactly comparable, but if I ever find myself
buying another new glider, this sort of behavior will no doubt influence
the choice...

Marc

On Apr 7, 11:47 am, Marc Ramsey > wrote:
> wrote:
> > I, for one, bought a DG-300 for its superior strength among other
> > reasons. We will have to wait for more clarification from DG but at
> > this point it seems that strength has now been reduced. Since this is
> > admittedly the fault of ELAN for not following the correct
> > manufacturing process and not notifying DG that they were altering the
> > manufacturing process this seems like a negligence issue. I would
> > hope they would do something to rectify the situation.
>
> I sold mine several years ago, so I don't really have much of a stake in
> this (at the moment, anyway), but when I bought my 303 Acro, the check
> wasn't payable to ELAN, it was payable to Glaser-Dirks (which is, of
> course, not quite the same company as DG-Flugzeugbau).
>
> When subcontractor spar fabrication "innovations" resulted in our Duo
> being grounded, Schempp-Hirth immediately took responsibility, found a
> practical inspection and repair protocol, trained repair shops in their
> major markets to inspect and repair (and flew SH technicians worldwide
> to deal with the rest), and had most of the gliders back in the air in
> less than two months without charging the owners a dime.
>
> The situations aren't exactly comparable, but if I ever find myself
> buying another new glider, this sort of behavior will no doubt influence
> the choice...
>
> Marc


I'm wondering why they have not issued a TN on this. Also, they
certainly know the S/N of the one where this was discovered as well as
any other tested. It seemed like they tested more than one.

In 1986 there was a mass balance issue that could have caused
flutter. They issued a TN and a very specific list of S/N's for
that. You'd think they could do the same here. ELAN seems to have
clammed up and mayby that's where the list needs to come from.
They're probably worried about liability and maybe they should be.

wrote:
> I'm wondering why they have not issued a TN on this. Also, they
> certainly know the S/N of the one where this was discovered as well as
> any other tested. It seemed like they tested more than one.

Issuing a TN would imply that DG is the responsible party. In reality,
I believe that DG still holds the EASA equivalent of the type
certificate for the 300/303, in which case they are the only ones that
can issue an official TN (and they have issued TNs for the 300/303 in
recent years). I too ran the German portion of the notice through a
translator when I first found it, and there were several paragraphs
devoted to convincing the reader that DG is not responsible, don't
expect us to do anything, it's all ELAN's fault, etc.


> In 1986 there was a mass balance issue that could have caused
> flutter. They issued a TN and a very specific list of S/N's for
> that. You'd think they could do the same here. ELAN seems to have
> clammed up and mayby that's where the list needs to come from.
> They're probably worried about liability and maybe they should be.

ELAN has been out of the aircraft business for several years, so I doubt
they'll have anything to say. The relationship between ELAN's former
aircraft business and AMS has never been clear to me. AMS produced and
sold to end-users something less than twenty 303s after they took over
the production rights, so they may get stuck with the liability for those.

But, as far as I know, ELAN was always a subcontractor to Glaser-Dirks
(and briefly DG) and never sold gliders directly to end-users (other
than perhaps acting as the agent for sales in Slovenia). If that is the
case, depending on how the reorganization was structured and German law,
DG may well end up holding the bag for the other 480 or so gliders,
which might explain the rather odd way of issuing a notice...

Marc

On Apr 7, 1:31 pm, Marc Ramsey > wrote:
> wrote:
> > I'm wondering why they have not issued a TN on this. Also, they
> > certainly know the S/N of the one where this was discovered as well as
> > any other tested. It seemed like they tested more than one.
>
> Issuing a TN would imply that DG is the responsible party. In reality,
> I believe that DG still holds the EASA equivalent of the type
> certificate for the 300/303, in which case they are the only ones that
> can issue an official TN (and they have issued TNs for the 300/303 in
> recent years). I too ran the German portion of the notice through a
> translator when I first found it, and there were several paragraphs
> devoted to convincing the reader that DG is not responsible, don't
> expect us to do anything, it's all ELAN's fault, etc.
>
> > In 1986 there was a mass balance issue that could have caused
> > flutter. They issued a TN and a very specific list of S/N's for
> > that. You'd think they could do the same here. ELAN seems to have
> > clammed up and mayby that's where the list needs to come from.
> > They're probably worried about liability and maybe they should be.
>
> ELAN has been out of the aircraft business for several years, so I doubt
> they'll have anything to say. The relationship between ELAN's former
> aircraft business and AMS has never been clear to me. AMS produced and
> sold to end-users something less than twenty 303s after they took over
> the production rights, so they may get stuck with the liability for those.
>
> But, as far as I know, ELAN was always a subcontractor to Glaser-Dirks
> (and briefly DG) and never sold gliders directly to end-users (other
> than perhaps acting as the agent for sales in Slovenia). If that is the
> case, depending on how the reorganization was structured and German law,
> DG may well end up holding the bag for the other 480 or so gliders,
> which might explain the rather odd way of issuing a notice...
>
> Marc


That was my wife's take on it as well. DG has performed these tests
and they are not going to do any more and ELAN isn't saying much.
They said they tested 8 wings and found this problem in 3 of them.
They said they don't know when the change in materials started or
ended, just that it did happen. My guess is the early 300's and late
303's are not affected but without a list of serial numbers who
knows. And maybe it didn't affect all the ones where the epoxy resin
was used.

Perhaps this is all an april fools joke. Or perhaps not. DG has
posted this on their web site but not published a technical note so
therefore the FAA will not publish an AD. At least I don't see how
they could without anything official from DG. Without that do the
operating limitations really change? Will all 300 owners see this?
Probably not and they will continue to operate their aircraft under
the offical operating limitations. When I go to the DG web site to
look for issues pertaining to my 300 I check the TN's. I would not
know about this if I didn't see it here.

I guess an email to DG is in order. I'd like to at least know the
serial number of the glider where this was initially discovered as
well as the numbers on the ones from the other 8 wings tested
indicating the 3 where it was present and the 5 where it wasn't. Like
you said I'll also be sure to let them know if I were to be in the
market for a new glider this sort of behavior would make me not
consider DG and before finding this out I would have considered DG
first.

Bob

On Apr 7, 2:34 am, Marc Ramsey > wrote:
> You should take a look at this:
>
> http://www.dg-flugzeugbau.de/holm-dg300-e.html
>
> Marc

I tried to read the computer translation out of curiosity, it is
dreadful.
To encapsulate:
Most, if not all DG 300 are restricted to a much lower speed and load
envelope due to flaws found in the spar production.
The fibers in the spar caps are not strait or aligned due to
manufactured flaws in the root area, hence the compression strength is
reduced.
The gliders will be able to fly with a reduce flight envelope.
Not fix is possible due to cost.
In a nut shell the value of that glider is substantially reduced.

Udo

The Company ELAN from Slovenia, which produced for Glaser Dirks GmbH
changed the production process without permission of Wilhelm Dirks at an
unknown date. This means that nobody knows which gliders are affected.

Andreas

>> http://www.dg-flugzeugbau.de/holm-dg300-e.html

> My German skills are non-existant. Can anyone tell me if the lengthier
> German part mentions which serial numbers are affected, because the English
> part says the manufacturing error began sometime during the production run.
> Presumably that means some of the early DG-300's were built right.
>
> Thanks,
> Bullwinkle
>

On 7 Apr 2007 10:59:27 -0700, wrote:

>I, for one, bought a DG-300 for its superior strength among other
>reasons. We will have to wait for more clarification from DG but at
>this point it seems that strength has now been reduced. Since this is
>admittedly the fault of ELAN for not following the correct
>manufacturing process and not notifying DG that they were altering the
>manufacturing process this seems like a negligence issue. I would
>hope they would do something to rectify the situation.


DG decided this:
- NO inspection required

If you decide not to perform an inspection, these new limits will
become valid for a DG-300/DG-303 Acro:

- Vne limited from 270 kp/h to 250 kp/h
- Va limited from 200 to 175 kp/h
- Maximum T/O weight limited from 525 to 450 kg
- 6 kg lower limit of mass of non-carrying structure
- aerobatics prohibited

Apart from the max T/O weight (and the prohibition of aerobatics for
the DG-303 Acro) none of this limitations is going to have any
practical influence on aircraft handling, don't you agree?




Bye
Andreas

Ok guys,

I did a bit of research on the issue. Here the key points from DG's
posting with some additional information about DG's and Elan's
history. For those who wonder, I'm a native German speaker :-) :

The issue:
- Elan, who has been producing all DG 300/303 since its launch (up it
being taken over by AMS-Flight in 1999), apparently changed the
production process of the main spar at some unknown point in the past
without Glaser-Dirks (the DG predecessor) approval leading to the
possibility of faulty main spars (not all main spars produced by them
are necessary faulty).
- The glider that initially revealed the faulty main spar as a result
of a servere landing accident is about 20 years old with aprox. 1500h.
- There are about 500 DG-300/303 gliders still flying with an average
age of about 15 years and a total of about 1 million hours.
- No DG 300/303 has ever had a failed wing in flight as a result of
structural failure.
- The required breaking strength of the wing at the time of
certification was 1.725 times the max allowed in flight-load. The
actual certification test to failure was stopped at 2.1 times the max
allowed in-flight load without the wing failing.
- DG does not now how many gliders are affected, out of 8 tested 3 had
a faulty main spar.
- To test the wing is difficult and expensive, the wing has to be cut
open.

Possible solutions:
1. All gliders will be grounded
2. All gliders will have to be inspected within a reasonable time
period and repaired if necessary. The inspection would cost around EUR
6000 per glider, a repair, if necessary can easily reach EUR 5000. All
gliders would have to come to DG's factory in Germany since it would
be near impossible to develop guidelines about what is still
acceptable and what has to be repaired.
3. DG tries, using calculations, tests to failure and load tests on
faulty main spars, to prove that even faulty main spars have enough
strength as a result of the very high structural reserves of the
original design. This approach might allow to continue operating the
glider with reduced operating limits without the need for inspections
and repairs.

DG decided to go the 3. route to avoid having to ground all gliders
and has spent to date about EUR 10,000 to do the required testing.
Based on the suprisingly good results when testing the faulty main
spars they got the following operating limitations approved by the
EASA (European FAA equivalent):

New Operating Limits for all DG-300/303:
- Max speed reduced from 270 km/h to 250 km/h
- Maneuvering speed reduced from 200 km/h to 175 km/h
- MTOW reduced from 525 kg to 450 kg
- No aerobatics (also applies to the DG-300 Acro)

If you want to avoid these limitations you will have to get the glider
inspected and repaired if necessary.

The liability/legal issues/responsability:
The great majority of the affected gliders were delivered by & paid to
Glaser-Dirks which went bankrupt in 1996. The current DG-Flugzeugbau
only took over the Type Certificates and spare part supply but not the
product liability, the actual gliders and faulty main spars were not
manufactured by Glaser-Dirks but by Elan which does not dispute this.

Elan refuses to shoulder any costs related to the investigation of the
faulty main spars and does not respond to any inquiries. All gliders
with faulty main spars produced by Elan are out of warranty.

About 10 gliders were produced by Elan or its successor AMS-Flight and
delivered by the current DG-Flugzeugbau, all these gliders are out of
warranty as well.

AMS-Flight was established in 1999 to continue Elan's existing
aircraft production and took over the entire Elan Flight Division of
Elan as of Sep. 1st, 1999. AMS produced and delivered about 25 gliders
under their own responsibility and claims, that they converted the
production process back to the original specifications. However, they
don't seem to be able to state when and starting with which serial
number they did so. It is likely that the only DG-303s that are still
under warranty are technically ok but nobody knows for sure and only
an inspection will be able to prove that.


Here the companies' time lines & current sales:
1973 - Glaser-Dirks Flugzeugbau GmbH founded, prudction of the DG-100
begins
1978 - Elan founded
1983 - DG-300 introduced and produced by Elan
1996 - Glaser-Dirks Flugzeugbau GmbH goes bankrupt -> DG Flugzeugbau
GmbH buys up key parts of Glaser-Dirks (excluding the product
liability of the DG-300 series), Elan continues to produce the
DG-300/303.
1999 - AMS-Flight established to continue Elan's existing aircraft
production, takes over the entire Elan Flight Division of Elan as of
Sep. 1st, 1999.
2006 - AMS-Flight stops DG-303 ELAN manufacturing. As of February 2006
444 DG-300 ELAN & 67 DG-303 ELAN gliders were produced.
2006 - AMS sales EUR 2.4 million (projected), 40 employees
2006 - DG sales EUR 7 million (delivered 50 planes), 75 Employees


The potential costs of fixing all affected DG-300/303 gliders
Inspection: 500 gliders in service x EUR 6000 per inspection = EUR
3,000,000
Repairs: 188 gliders (3 out of 8) x EUR 5000 per repair = EUR
940,000

Total (without any related costs): EUR 3,940,000 (approx. USD
5,265,000)

Looking at that total you can see that this could potentially bankrupt
either company (with related loss of employment), hence DG's close
look at their legal responibility...

I'm not taking any sides on this, look at above facts and judge for
yourself. Either way there will only be losers in this messy affair...

Markus

Hi guys,

John Giddy pointed out an important restriction I left out in my
summary above (not sure how I missed that, sorry
about that):

- Maximum mass of non-lifting parts is reduced from 246 kg (542 lb) to
240 kg (529 lb)

So the complete set of new restrictions to the operational limits is
as follows:

- Max speed reduced from 270 km/h (146 kt) to 250 km/h (135 kt)
- Maneuvering speed reduced from 200 km/h (108 kt) to 175 km/h (94 kt)
- MTOW reduced from 525 kg (1157 lb) to 450 kg (992 lb)
- Maximum mass of non-lifting parts reduced from 246 kg (542 lb) to
240 kg (529 lb)
- No aerobatics (also applies to the DG-300 Acro)

DG's definition of non-lifting parts is as follows:

- Fuselage (with permanently installed equipment, canopy, and main
pins)
- Cockpit load (Pilot + parachute + equipment <for instance tail fin
battery in baggage compartment instead of in tail fin>)
- Horizontal tail

This means that your max. cockpit load is reduced by 6 kg (13 lb) all
other things being equal.

I just saw that DG apparently just posted the complete English
translation of their German posting:

http://www.dg-flugzeugbau.de/holm-dg300-e.html

I hope this helps,

Markus

>DG... has spent to date about EUR 10,000 to do the required testing.

Are we supposed to be impressed that DG spends this on the fleet?
That is less than it would cost to ship, inspect and repair a single
US-based glider!

On Apr 9, 9:22 am, "Mike Yankee" > wrote:
> >DG... has spent to date about EUR 10,000 to do the required testing.
>
> Are we supposed to be impressed that DG spends this on the fleet?
> That is less than it would cost to ship, inspect and repair a single
> US-based glider!

A quick clarification to my original cost translation after carefully
re-reading the original German post:

The inspection is estimated at EUR 6000 per glider. If a repair is
deemed necessary it can easily reach EUR 5000 PER MAIN SPAR. Since a
glider has 2 wings with 2 spars we'd end up with a worst case scenario
of EUR 16000 per glider and a potential total of some 376 main spars
affected in a fleet of some 500 gliders (initial test showed 3 out of
8 main spars defective).

So the potential total costs for the entire fleet would be:

- Inspection: 500 gliders in service x EUR 6000 per
inspection = EUR 3,000,000
- Repairs: 376 main spars (3 out of 8) x EUR 5000 per
repair = EUR 1,880,000
- Total (without any related costs) = EUR 4,940,000
(approx. USD 6,521,000)

Also note that DG's owner apparently just added some comments below
the original posting related to the considerable discussion going on
especially in German forums.

The extended DG posting: http://www.dg-flugzeugbau.de/holm-dg300-e.html

For those of you who know some German here a link to the discussion on
one of the main forums:
http://www.segelflug.de/cgi-bin/wwwthreads/postlist.pl?Cat=1,5&Board=Flugzeuge

The pictures DG's owner (Friedel Weber) refers to in his comments can
be found here:

http://www.segelflug.de/cgi-bin/wwwthreads/showthreaded.pl?Cat=1,5&Board=Flugzeuge&Number=65186&page=0&view=expanded&sb=5&o=#Post65186

Markus

Markus Graeber wrote:
> On Apr 9, 9:22 am, "Mike Yankee" > wrote:
>>> DG... has spent to date about EUR 10,000 to do the required testing.
>> Are we supposed to be impressed that DG spends this on the fleet?
>> That is less than it would cost to ship, inspect and repair a single
>> US-based glider!
>
> A quick clarification to my original cost translation after carefully
> re-reading the original German post:
>
> The inspection is estimated at EUR 6000 per glider. If a repair is
> deemed necessary it can easily reach EUR 5000 PER MAIN SPAR. Since a
> glider has 2 wings with 2 spars we'd end up with a worst case scenario
> of EUR 16000 per glider and a potential total of some 376 main spars
> affected in a fleet of some 500 gliders (initial test showed 3 out of
> 8 main spars defective).

3 of 8 in a sample that size (8) is playing pretty fairly free and loose
with statistics. Did DG sample gliders they thought would be affected
or did they sample across the entire manufacturing run? The numbers
could be much different.
Also, since they say they've tested 8 gliders, it costs EUR 6000/glider
to test, and they've spent EUR 10,000, I'm assuming they've only tested
wrecked gliders. That, or they hired an accountant from Enron. ;-)




Shawn

On Apr 9, 11:52 am, Shawn > wrote:
>
> 3 of 8 in a sample that size (8) is playing pretty fairly free and loose
> with statistics. Did DG sample gliders they thought would be affected
> or did they sample across the entire manufacturing run? The numbers
> could be much different.
> Also, since they say they've tested 8 gliders, it costs EUR 6000/glider
> to test, and they've spent EUR 10,000, I'm assuming they've only tested
> wrecked gliders. That, or they hired an accountant from Enron. ;-)
>
> Shawn

8 samples implies that they tested 4 gliders including the one that
showed the original defect after a severe landing accident. From what
I understand that original glider was repaired and is airworthy again
(and for sale by the club in Germany that owns it), it probably is the
only one right now with a guarantee that it has no main spar defects
and as such can be operated within the old operating limits...

I would guess they tested whatever they had at hand and of course the
sample might not be representative but all you can go by right now to
get an idea of the extend of the problem; especially since Elan is not
able/willing to provide any more information as to when they did the
change to the wing manufacturing process which can possibly lead to
the main spar defects discovered.

I assume the EUR 10,000 mentioned is the cost of the load test & tests
to destruction they did on affected wings to establish the new
operating limitations.

Markus

Instead of being absolutely straight, the rovings of one spar cap
showed a slightly wave-like pattern. Alarmed by this discovery we
investigated the spar caps of several other DG-300 wings, which were
in for repair in our factory or other approved maintenance shops. We
found a similar, but less severe pattern at some of these wings too.

The most important question right to the beginning:
"Why may DG-300 spars exhibit this wave-like pattern, and is this flaw
also possible at spars of other DG airplanes?"

The answer:
This specific flaw is limited to the DG-300/303 series!
For all DG wings, except for the DG-300 and DG-600, the spar caps are
manufactured in separate a mould, which allows maximum precision for
the roving placement. While the rovings for the DG-600 are placed
directly into the wing mould, they are inserted into a prefabricated
channel which becomes an integral part of the wing structure. This
allows the same precision for the roving placement. Only the
DG-300/303 uses a different manufacturing method (which is also used
by other manufacturers), therefore only the DG-300/303 is prone to the
described manufacturing flaw.


Notice the statement (which is also used by other manufacturers)

After reading all this I am still unsure what is wrong. Can someone
paint (or draw) me a mental picture on what was manufacturered
incorrectly? Also, what is a roving?

Finally, I assume that only DG-300/303's that say ELAN on them are
affected.

- John

Short answer

The spar caps on a sailpane are often made of rovings. Rovings are
long strands of, in this case, uni fiberglass (lots of it) postitioned
at the thickest part of the chord, that extend from the spar roots to
an area usually just short of the tip of a wing. For optimum strength
they must be straight. If there are sections of the material that are
not straight, a percentage of the spar strength is lost. On some
DG300's some of the rovings were not laid in correctly, are not
straight,so there have been reductions on the operating limitations of
the sailplanes for safety reasons.

Mike


On Apr 9, 9:10 pm, "ContestID67" > wrote:
> After reading all this I am still unsure what is wrong. Can someone
> paint (or draw) me a mental picture on what was manufacturered
> incorrectly? Also, what is a roving?
>
> Finally, I assume that only DG-300/303's that say ELAN on them are
> affected.
>
> - John

Mike wrote:

> The spar caps on a sailpane are often made of rovings. Rovings are
> long strands of, in this case, uni fiberglass (lots of it) postitioned
> at the thickest part of the chord, that extend from the spar roots to
> an area usually just short of the tip of a wing. For optimum strength
> they must be straight. If there are sections of the material that are
> not straight, a percentage of the spar strength is lost. On some
> DG300's some of the rovings were not laid in correctly, are not
> straight,so there have been reductions on the operating limitations of
> the sailplanes for safety reasons.

Also, see the pictures at the URL previously posted by Markus
Graeber [shorter form below]:

http://tinyurl.com/yoj2hl



Jack
http://groups.yahoo.com/group/dg-300

On Apr 9, 9:10 pm, "ContestID67" > wrote:
> After reading all this I am still unsure what is wrong. Can someone
> paint (or draw) me a mental picture on what was manufacturered
> incorrectly? Also, what is a roving?
>
> Finally, I assume that only DG-300/303's that say ELAN on them are
> affected.
>
> - John
This is copied from a LAK 17 site. I think it is dated approx.
1996 Note that when you have ripples in the roving it degrades the
compression as a bend can't take compressive forces as well as
something absolutely straight.


THE SAGA OF A CARBON SPAR DESIGN BY JIM MARSKE (1996)

When I went about designing the wing spar for the Genesis 2, I tried
to find design strength values for the carbon rovings to be used in
the spar caps, the manufacturer's data sheet claimed 310,000 psi
tensile strength but gave no compression data. A call to the
manufacturer produced a claim of 100,000 psi in compression. Talking
with others who have constructed carbon wing spars, I was advised to
be careful as such values cannot be obtainable and to back off to
90,000 psi in tension and 60,000 in compression. To satisfy myself, I
had several test strips made up of hand laid-up carbon rovings and
sent them to an independent test laboratory for strength evaluation.
The results of the five test samples were disturbing. In tension the
values ranged from 152,000 to 190,000 psi. In compression the values
ranged from 48,000 to 74,000 psi. The reason why there was so much
scatter and the values lower than expected is that it is almost
impossible to lay the rovings down without zigzag waves every few
inches. You can only pull the tow till its shortest filament pulls
tight and the rest lay in small waves. As a result of this condition,
and to acquire the necessary strength, the G1 prototype spar is fairly
heavy and very stiff. To prove the spars strength, we static loaded it
to +5g's and -3g's. Wing deflection, measured at the tip, was 25
inches at+5g's.
We needed carbon that was stronger and more consistent in strength
values, Therefore, we looked into pulltruded carbon rods, Samples were
ordered and examined, but waves were found in those filaments also, At
about this same time, I found a brief article in Sport Aviation
concerning a carbon rod expounding very straight filament alignment. A
sample rod was obtained and after examination of the filaments, we saw
that they were indeed very straight. Furthermore, the manufacturer
claimed a tensile strength of 315,000 psi and a compressive value of
200,000 psi, which was impressive. When bending the 1 /8 inch diameter
rod to first sign of fracture, it was the tensile filaments that were
failing one at a time. In addition to the high strength properties of
these rods, the automated manufacture of the rod controlled the resin
content, which is not possible in a hand laid-up situation, and
dimensions of the rod assured consistent strength properties.
The next step was to prove that the rod would function as a spar cap,
and that it would carry the required loads without delamination. A
Genesis spar segment of the aircraft center section was made and
tested in the Sportine Aviacija laboratory. No failure occurred during
a load sequence to a load limit of +8.3g's. This load represents an
aircraft design load of 1200 pounds, times a safety factor of 1 .5 as
required by JAR-22. Impressed with these results, the load was
increased past the required load limit of +8.3g's to +1 g's without
incident. Going to +10.5g's we reached the maximum output load of the
test machine, and again no degradation of the rods was observed. This
load was nearly twice the required spars design load of +5.55g's.
Satisfied with the static results, we did not however have a history
of dynamic cyclic endurance testing for this particular rod. Since the
majority of the rods do not span full length of the spar we had
concerns as to what would happen at the end of each rod end in the mid
section of the spar where a stress riser may occur. So we embarked
upon a cyclic endurance test at an elevated load to force an early
failure.
The first run was a 4g positive loading. We hoped for 5,000 cycles but
stopped at 10,000 cycles. We then increased the load to 6g's expecting
a failure in a few hundred cycles; we stopped the test at 5,500
cycles. The test spar was then inverted in the fixture to apply
negative loading. The test lab director insisted that we start at -3g.
We started at -4g's and ran for 5,000 cycles. No degradation was
noted. To finish the test we repeated the static loading test again.
One cycle to +8.33g's and two cycles to -5.33g's. Again no degradation
was visible.
So we asked Klemas, Sportine Aviacija's chief engineer as to just how
many flight hours all this cyclic testing is equivalent to, Klemas
gave me a report on recorded accelerations made on one of their
LAK-12's during 50 hours of flying, which included towing, takeoffs,
landings and ground handling. The accelerations were all counted and
grouped together to form a 50 hour flight period. The cycles were then
multiplied by 200 to find the life of 10,000 flight hours for the
LAK-12.
THE SAGA OF A CARBON SPAR DESIGN continue
This data was then transferred into chart form. I overlaid the Genesis
data on the same chart to obtain a comparison. A diagram of the
results appears below.

picture: Genesis spar test results compared to the LAK-12 spar test
results.



After completing a quick calculation, which still requires further
evaluation, I feel that we have acquired an excess of 5,000 flight
hours (probably 6,000 hours) in positive loading and an excess of
10,000 flight hours in negative loading. I understand that a survey of
various glider clubs around the world responded to an inquiry as to
the maximum flight hours that had been accumulated on any of their
gliders. Only a few gliders had accumulated near 5000 flight hours.
However one Australian club reported nearly 6,000 flight hours.
G2 WING SPAR DEVELOPMENT
As mentioned previously, the Sportine Aviacija facility has an
extensive engineering test lab and experienced engineering staff.
These capabilities in combination with our own engineering efforts
have produced some amazing results in the area of the wing spar
development for the G2.
For example, the main spar on the G1 prototype was constructed in the
usual manner using hand laid-up carbon fiber roving. However
laboratory tests have shown that there is plenty of room for
improvement in this process. So we decided to look into using
prestressed carbon fiber rods as a replacement to the carbon roving
used in the wing spars. These rods alone are five times stronger than
conventional hand laid-up carbon roving.
Using the Sportine Aviacija test lab, we prepared a sample for cyclic
fatigue testing and took it through 10,000 cycles at +4 g's, 5,000
cycles at +6 g's and 5000 cycles at -4 g's. Then as required for
Jar-22 certification, we loaded this same spar sample twice for 10
seconds (once for 3 seconds is all that's required) at +8,3 and -5,3
g's and experienced absolutely no degradation or failure whatsoever,
We then took it to 10 g's and also experience no degradation or
failure. Certification test results like this are practically unheard
of in sailplane development, but that's not to say they shouldn't be.

A short article with some additional information has been posted at the
AMS-Flight web site:

http://www.ams-flight.si/

Marc

www.marskeaircraft.com/carbonrod.html

Another article on rovings vs Graphlite rods. The Genesis 2, LAK 17,
LAK 19 and probably also the LAK 20 use the Graphlite rod design for
their wing spars. I hope Jim Marske doesn't mind that I posted these
but they are out on the net anyway.

DG just posted the preliminary TA which is awaiting approval by the
EASA (European FAA):

http://www.dg-flugzeugbau.de/Data/tn-359-24.pdf

DG also added some more FAQs at the bottom of the web page dealing
with the main spar issue:

http://www.dg-flugzeugbau.de/holm-dg300-e.html

Markus

I wrote this short article on what I think the problem is, based on
the DG advisory and the photos at segelflug.de:

http://www.hpaircraft.com/misc/dg300spars.htm

It is only my guess at what the issues are, please view it with some
skepticism. Please alert me to any factual errors.

Thanks, and best regards

Bob K.

On Fri, 06 Apr 2007 23:34:52 -0700, Marc Ramsey wrote:

> You should take a look at this:
>
> http://www.dg-flugzeugbau.de/holm-dg300-e.html
>
> Marc

Just finished reading this and the related thread. This is a nightmare for
the affected owners and many others in the industry!

However as a suggestion:

Would it be possible to determine if any one aircraft has the defect by
measuring wing deflection under a known load?

From my understanding of the defect, the misaligned fibres would not only
reduce the strength of the spar, but also it's stiffness. By measuring the
deflection of a sample of wings under load and then opening them up to
determine whether they have the defect or not, it might be possible to
draw up a non invasive procedure which can be used to determine if the
defect exists in a particular aircraft, and if it does, to what extent.

Anybody from DG reading this?

Ian

Ian wrote:
> On Fri, 06 Apr 2007 23:34:52 -0700, Marc Ramsey wrote:
>
>> You should take a look at this:
>>
>> http://www.dg-flugzeugbau.de/holm-dg300-e.html
>>
>> Marc
>
> Just finished reading this and the related thread. This is a nightmare for
> the affected owners and many others in the industry!
>
> However as a suggestion:
>
> Would it be possible to determine if any one aircraft has the defect by
> measuring wing deflection under a known load?


I don't know about your deflection suggestion, but how DG handles
this spar-cap situation for all of the DG-300 owners should have a
significant bearing on whether, and how much, the market will
discount all of their products in the future.

A few dollars spent now to shore up what had been a good reputation
can pay big dividends. We shall soon see if DG is to remain a
desirable marque.


Jack

I would think an ultrasonic inspection could get
a good enough picture of the undulations to know
if it's serious. Problem is what deviation from
ideal is acceptable? If anybody knows a glider
pilot who is in the USAF they could check with
the NDI Lab at their base and see if someone
could inspect the spar. Long, long ago I was an
AF NDI Technician and we X-Ray'd car batteries,
mag particle tested cam and crankshafts and would
have jumped at the chance to inspect a glider wing.

Nothing they did could be official, but for peace of

mind it might be something to try. You might get
some new students at your club. I first saw a soaring

site when I was stationed at Zweibrucken AB in Germany.

EASA has now published an emergency AD (saying essentially the same
thing as DG's Tech Note), available at:

http://ad.easa.europa.eu/blob/easa_ad_2007_0100_e_corrected.pdf/EAD_2007-0100-E_1

I know about this only because a friend saw the link on the BGA
website.

As a long-time DG-300 owner, I am extremely disappointed to have heard
NOTHING from Glaser-Dirks about this situation. There is simply no
excuse for this. They have all or most owners' e-mail addresses
already (for their monthly newsletter). This situation cries out for
proactive announcements, explanation, clarification, etc. from the
manufacturer. Instead, we are left to scavenge whatever "information"
we can (possibly not all accurate) from R.A.S. and other sources. DG
did put the Tech Note draft on its website last week but that helps no
one unless they know about it or accidentally stumble across it. What
is missing is any official notification from the manufacturer. I can
abide the limitations required by the AD more easily than I can this
pitiable lack of proper communications and support from Glaser-Dirks.

Almost two weeks ago, when the R.A.S. thread first appeared, I sent an
e-mail inquiry to Glaser-Dirks with copies to the North American
dealers. I received no response. No excuse for that, either.

At 13:18 16 April 2007, Mike Yankee wrote:
>EASA has now published an emergency AD (saying essentially
>the same
>thing as DG's Tech Note), available at:
>
> http://ad.easa.europa.eu/blob/easa_ad_2007_0100_e_corrected.pdf/E
>>AD_2007-0100-E_1
>
>I know about this only because a friend saw the link
>on the BGA
>website.
>
>As a long-time DG-300 owner, I am extremely disappointed
>to have heard
>NOTHING from Glaser-Dirks about this situation. There
>is simply no
>excuse for this.

that would be because Glaser-Dirks went bankrupt several
years ago

Are all DG300 certified "experimental" (in the U.S.) ?
PeterK
"Ian" > wrote in message
...
> On Fri, 06 Apr 2007 23:34:52 -0700, Marc Ramsey wrote:
>
>> You should take a look at this:
>>
>> http://www.dg-flugzeugbau.de/holm-dg300-e.html
>>
>> Marc
>
> Just finished reading this and the related thread. This is a nightmare for
> the affected owners and many others in the industry!
>
> However as a suggestion:
>
> Would it be possible to determine if any one aircraft has the defect by
> measuring wing deflection under a known load?
>
> From my understanding of the defect, the misaligned fibres would not only
> reduce the strength of the spar, but also it's stiffness. By measuring the
> deflection of a sample of wings under load and then opening them up to
> determine whether they have the defect or not, it might be possible to
> draw up a non invasive procedure which can be used to determine if the
> defect exists in a particular aircraft, and if it does, to what extent.
>
> Anybody from DG reading this?
>
> Ian
>

Peter wrote:
> Are all DG300 certified "experimental" (in the U.S.) ?

Yes, but the operating limitations usually (always?) require that they
be maintained according to the published factory technical notes...

Marc