Duo Discus Tech note

Schempp-Hirth has issued a tech note 396-8 for Duo Discus serial numbers 165
through 389, and Duo Discus T serial numbers 1 through 78.

These Duo Discus must not be flown until the inspection and repair (if
necessary) is accomplished.

Further details of these tech notes can be found on their web site.

http://www.schempp-hirth.com

or, we can email you copies of the tech note.

Essentially, the bond between the spar and skin of the glider must be
inspected for voids.

The inspection will take 3 to 5 hours.

We are contacting USA repair shops to find out if they have the necessary
tools for the inspection and repair. Please call or email us with your
questions.

Tom Knauff
Knauff & Grove Soaring Supplies
(814) 355 2483
fax (814) 355 2633

"John Galloway" wrote in message
...
At 20:00 04 August 2003, Thomas Knauff wrote:

Essentially, the bond between the spar and skin of
the glider must be
inspected for voids.


Mr Knauff,

I believe this is not entirely accurate.

Splitting hairs over the wording is not going to change the fact that 300
odd Duo Discus are grounded until they have had holes drilled in their wings
and inspected.
Paul

Sorry for the error.
Doris and I just returned from a pleasant week at Oshkosh this morning and
faced this and nearly a thousand emails (almost half junk) to deal with.

It looks like we have things well in hand with the problem in the USA.

"John Galloway" wrote in message
...
At 20:00 04 August 2003, Thomas Knauff wrote:

Essentially, the bond between the spar and skin of
the glider must be
inspected for voids.


Mr Knauff,

I believe this is not entirely accurate. The Technical
Note says that the Duo involved in the incident had
'a failure in the bonding of the spar cap and the spar
web'. Furthermore the 'Actions' required by the technical
note include:

'1. The bonding between the upper spar cap and the
spar web are to be checked according to the instructions
in the appendix of this Technical Note.'

+

'2. Defects in the spar cap and spar web bonding are
to be repaired according to the instructions in the
appendix to this Technical Note.'

For those who are interested, the drawing at the bottom
of page 3 of the Appendix shows the spar construction
and the photograph on page 8 shows the defect between
an attachment flange of the spar web and the carbon
fibre spar cap quite clearly.

John Galloway

Changing the subject just a tad. It's obvious that if one can locate a
boroscope or similar device with a roughly 25 foot reach that it may be
possible to inspect the vast majority of the wing from a single well
placed hole. Those who have begun this process may be able to comment.

Furthermore, if anyone finds a solution which approaches the above
described level of elegance, please do NOT hesitate to post as much
information as possible so that the others may benefit. i.e. make and
model of the boroscope. Any particulars as to technique used for
reaching the necessary corners inside the wing. If there are any issues
with focal distance, etc.



Paul wrote:
"John Galloway" wrote in message
...

At 20:00 04 August 2003, Thomas Knauff wrote:

Essentially, the bond between the spar and skin of
the glider must be
inspected for voids.


Mr Knauff,

I believe this is not entirely accurate.


Splitting hairs over the wording is not going to change the fact that 300
odd Duo Discus are grounded until they have had holes drilled in their wings
and inspected.
Paul

"Mark Zivley" wrote in message
...
Changing the subject just a tad. It's obvious that if one can locate a
boroscope or similar device with a roughly 25 foot reach that it may be
possible to inspect the vast majority of the wing from a single well
placed hole. Those who have begun this process may be able to comment.

Not sure what the FAA would do but our New Zealand CAA would require an AMOC
to be completed and OK'd before the inspection could be changed from that of
the Techicnal Note or AD and a 25 ft long boroscope would not be lying
around most workshops. The Manufacturers has stated the inspection to be
carried out and that stands. The holes drilled can be taped up if they are
small enough . ( according to the TN note) Becomes academic if the web needs
repairing I guess.
Paul

Schempp-Hirth has issued a tech note 396-8 for Duo Discus serial numbers 165
through 389, and Duo Discus T serial numbers 1 through 78.

These Duo Discus must not be flown until the inspection and repair (if
necessary) is accomplished.

Tom Knauff

Neither the LBA nor the manufacturer has the authority to ground
gliders operating with
U.S. Standard Airwothiness Certificates. As of today, the FAA has not
issued an
AD requiring compliance with the Spar inspection technical note issued
by
Schempp-Hirth on the Duo Discus. There is every likelihood that the
FAA
will issue an AD regarding this.

However the factory's own web page states that,
"For security reasons a larger number of Duo Discus and Duo Discus T
have been grounded, as the exact serial numbers of potentially
affected gliders could not be determined in the short time given."

We may find that the FAA pushes the factory to determine the exact
serial numbers of potentially affected gliders, so that a more
accurate set of glider serial numbers can be included in any U.S. AD.

So for now at least, for U.S. owners, compliance with the inspection
is at their own discretion.

Interestingly, someone said to me the other day that if the potential
for faulty construction goes back at least 5 years with the DUO and it
includes CS DUOs manufactured in a different country, maybe the LBA
should consider requiring inspections on other Schempp-Hirth models as
well?

I would think that the factory would at least put up a page on their
Web site so that the DUO owners can see what the statistical results
of the inspections are as this debacle unfolds.

In the meantime, maybe the DUO owners can post to the news group with
the results of their gliders inspection and the degree of repairs
required. I'm sure the DUO owners would greatly appreciate the
information.

M Eiler

While it is correct that only the local Aviation Authority has the power
to ground aircraft it would be extremely unwise to ignore a safety
warning from the manufacturer.

The tech note and advice from Schemmp Hirth was correctly represented -
the factory say these aircraft must not be flown until inspected. If you
are affected by a factory defect, you might get some credit when it
comes to repair. If you (or your bereaved spouse) are the proud owner of
a pile of composite confetti, you may find the factory and your
insurance company less helpful.

Legally quite true, I guess.

However, if a manufacturer comes forward and says that serial no's x to y
are potentially not airworthy, common sense requires those aircrafts to be
grounded even if local authorities are not up to the news.

--
Bert Willing

ASW20 "TW"


"Caracole" a écrit dans le message de
om...
Schempp-Hirth has issued a tech note 396-8 for Duo Discus serial numbers
165
through 389, and Duo Discus T serial numbers 1 through 78.

These Duo Discus must not be flown until the inspection and repair (if
necessary) is accomplished.

Tom Knauff

Neither the LBA nor the manufacturer has the authority to ground
gliders operating with
U.S. Standard Airwothiness Certificates. As of today, the FAA has not
issued an
AD requiring compliance with the Spar inspection technical note issued
by
Schempp-Hirth on the Duo Discus. There is every likelihood that the
FAA
will issue an AD regarding this.

However the factory's own web page states that,
"For security reasons a larger number of Duo Discus and Duo Discus T
have been grounded, as the exact serial numbers of potentially
affected gliders could not be determined in the short time given."

We may find that the FAA pushes the factory to determine the exact
serial numbers of potentially affected gliders, so that a more
accurate set of glider serial numbers can be included in any U.S. AD.

So for now at least, for U.S. owners, compliance with the inspection
is at their own discretion.

Interestingly, someone said to me the other day that if the potential
for faulty construction goes back at least 5 years with the DUO and it
includes CS DUOs manufactured in a different country, maybe the LBA
should consider requiring inspections on other Schempp-Hirth models as
well?

I would think that the factory would at least put up a page on their
Web site so that the DUO owners can see what the statistical results
of the inspections are as this debacle unfolds.

In the meantime, maybe the DUO owners can post to the news group with
the results of their gliders inspection and the degree of repairs
required. I'm sure the DUO owners would greatly appreciate the
information.

M Eiler

And of course although quick, a posting on RAS or an
update on a manufacturers web site does not mean that
everyone affected will find out...


At 07:42 05 August 2003, Bert Willing wrote:
Legally quite true, I guess.

However, if a manufacturer comes forward and says that
serial no's x to y
are potentially not airworthy, common sense requires
those aircrafts to be
grounded even if local authorities are not up to the
news.

--
Bert Willing

ASW20 'TW'


'Caracole' a écrit dans le message de
. com...
Schempp-Hirth has issued a tech note 396-8 for Duo
Discus serial numbers
165
through 389, and Duo Discus T serial numbers 1 through
78.

These Duo Discus must not be flown until the inspection
and repair (if
necessary) is accomplished.

Tom Knauff

Neither the LBA nor the manufacturer has the authority
to ground
gliders operating with
U.S. Standard Airwothiness Certificates. As of today,
the FAA has not
issued an
AD requiring compliance with the Spar inspection technical
note issued
by
Schempp-Hirth on the Duo Discus. There is every likelihood
that the
FAA
will issue an AD regarding this.

However the factory's own web page states that,
'For security reasons a larger number of Duo Discus
and Duo Discus T
have been grounded, as the exact serial numbers of
potentially
affected gliders could not be determined in the short
time given.'

We may find that the FAA pushes the factory to determine
the exact
serial numbers of potentially affected gliders, so
that a more
accurate set of glider serial numbers can be included
in any U.S. AD.

So for now at least, for U.S. owners, compliance with
the inspection
is at their own discretion.

Interestingly, someone said to me the other day that
if the potential
for faulty construction goes back at least 5 years
with the DUO and it
includes CS DUOs manufactured in a different country,
maybe the LBA
should consider requiring inspections on other Schempp-Hirth
models as
well?

I would think that the factory would at least put
up a page on their
Web site so that the DUO owners can see what the statistical
results
of the inspections are as this debacle unfolds.

In the meantime, maybe the DUO owners can post to
the news group with
the results of their gliders inspection and the degree
of repairs
required. I'm sure the DUO owners would greatly appreciate
the
information.

M Eiler

That would be very unfortunate. It's pretty clear that SH has provided
suitable places to drill holes on the premise that whatever boroscope
used is fairly short. Clearly, the underlying objective is to make sure
that the entire length of the upper spar flange (aft side) is visually
inspected for any areas which didn't get enough resin and therefore
might not be adequately bonded. If you can do that with a 25-30' long
boroscope then you'd be complying with the intent of the tech note. If
you call around to some companies specializing in NDT or perhaps who do
boiler tube inspections, etc. you may find a suitable scope.

Paul wrote:
"Mark Zivley" wrote in message
...

Changing the subject just a tad. It's obvious that if one can locate a
boroscope or similar device with a roughly 25 foot reach that it may be
possible to inspect the vast majority of the wing from a single well
placed hole. Those who have begun this process may be able to comment.


Not sure what the FAA would do but our New Zealand CAA would require an AMOC
to be completed and OK'd before the inspection could be changed from that of
the Techicnal Note or AD and a 25 ft long boroscope would not be lying
around most workshops. The Manufacturers has stated the inspection to be
carried out and that stands. The holes drilled can be taped up if they are
small enough . ( according to the TN note) Becomes academic if the web needs
repairing I guess.
Paul