Blanik/Let questions

Noticed that all LET production has ceased including the L23 Blanik
and the L33 solo. Why?
Most reports have stated the cause of the L13 failure was fatigue, yet
all L13's are grounded. Most fatigue failures are the result of very
long life, yet they are not grounding L13's with over X number of
hours, they are grounding all L13's. There also seems to be something
about the percentage of dual over solo flight time.
Any new info on all of this?

On Jan 9, 8:38*pm, gldrgidr wrote:
Noticed that all LET production has ceased including the L23 Blanik
and the L33 solo. *Why?
Most reports have stated the cause of the L13 failure was fatigue, yet
all L13's are grounded. *Most fatigue failures are the result of very
long life, yet they are not grounding L13's with over X number of
hours, they are grounding all L13's. *There also seems to be something
about the percentage of dual over solo flight time.
Any new info on all of this?

And if the spar is the same on the L23 shouldn't they be grounded as
well...

On Jan 9, 11:11*pm, "
wrote:


And if the spar is the same on the L23 shouldn't they be grounded as
well...

Not if this is a fatigue problem. Fatigue would only show up after
many thousands of hours of service.
Remember that the L13 has been around for many years without any
problems until now.
The much newer L23 's might not suffer any failures for 20 more
years.
The FAA should be determining what a reasonable safe expected service
life for the L13 is, and then ground only the L13's that have
accumulated more than that number of hours service.
There should also be some kind of approved fix to bring these gliders
back into service.
Apparently sailplanes are a low priority with the FAA.
Has the SSA applied any pressure to get this resolved?

A small local club owns only a L13 and are left with no club glider
and I am sure there are other clubs in the same mess.

On Jan 10, 5:35*am, gldrgidr wrote:
On Jan 9, 11:11*pm, "
wrote:



And if the spar is the same on the L23 shouldn't they be grounded as
well...

Not if this is a fatigue problem. *Fatigue would only show up after
many thousands of hours of service.
Remember that the L13 has been around for many years without any
problems until now.
The much newer L23 's might not suffer any failures for 20 more
years.
The FAA should be determining what a reasonable safe expected service
life for the L13 is, and then ground only the L13's that have
accumulated more than that number of hours service.
There should also be some kind of approved fix to bring these gliders
back into service.
Apparently sailplanes are a low priority with the FAA.
Has the SSA applied any pressure to get this resolved?

There should be a tooth fairy and Santa Claus as well. What actually
needs to happen has been talked about here in detail - from both the
FAA and SSA perspectives and I believe pro-active owners are trying to
work on this. Just spouting off what the FAA should be doing is going
will get nothing done.

"Fatigue would only show up after many thousands of hours of service."
Well if only real world engineering was that simple. There was a fatal
crash in a not too old L13 that Austrian air saftey investigators
determined appeared to involve fatigue. Then EASA and the FAA followed
up with a slate of ADs to try to understand/manage the possible
fatigue issue, and I believe those agencies actually looked at this in
more than a cursory way. I kind of expect those folks know more about
fatigue than you. If you are a subject expert and think they are wrong
then do all the owners a favor and take up the issue with EASA and/or
the FAA.

A small local club owns only a L13 and are left with no club glider
and I am sure there are other clubs in the same mess.

The TC holder needs to drive the failure/fatigue analysis and
engineering fixes. Affected owners should be starting there. The FAA
and EASA was not tasked with engineering fixes for aircraft.

All this, including the SSA angle has been well discussed here in the
past. You can search the r.a.s. archives on Google groups (where the
original post was from).

Darryl

On Jan 10, 10:53*am, Darryl Ramm wrote:
On Jan 10, 5:35*am, gldrgidr wrote:





On Jan 9, 11:11*pm, "
wrote:

And if the spar is the same on the L23 shouldn't they be grounded as
well...

Not if this is a fatigue problem. *Fatigue would only show up after
many thousands of hours of service.
Remember that the L13 has been around for many years without any
problems until now.
The much newer L23 's might not suffer any failures for 20 more
years.
The FAA should be determining what a reasonable safe expected service
life for the L13 is, and then ground only the L13's that have
accumulated more than that number of hours service.
There should also be some kind of approved fix to bring these gliders
back into service.
Apparently sailplanes are a low priority with the FAA.
Has the SSA applied any pressure to get this resolved?

There should be a tooth fairy and Santa Claus as well. What actually
needs to happen has been talked about here in detail - from both the
FAA and SSA perspectives and I believe pro-active owners are trying to
work on this. Just spouting off what the FAA should be doing is going
will get nothing done.

"Fatigue would only show up after many thousands of hours of service."

Well if only real world engineering was that simple. There was a fatal
crash in a not too old L13 that Austrian air saftey investigators
determined appeared to involve fatigue. Then EASA and the FAA followed
up with a slate of ADs to try to understand/manage the possible
fatigue issue, and I believe those agencies actually looked at this in
more than a cursory way. I kind of expect those folks know more about
fatigue than you. If you are a subject expert and think they are wrong
then do all the owners a favor and take up the issue with EASA and/or
the FAA.

A small local club owns only a L13 and are left with no club glider
and I am sure there are other clubs in the same mess.

The TC holder needs to drive the failure/fatigue analysis and
engineering fixes. Affected owners should be starting there. The FAA
and EASA was not tasked with engineering fixes for aircraft.

All this, including the SSA angle has been well discussed here in the
past. You can search the r.a.s. archives on Google groups (where the
original post was from).

Darryl- Hide quoted text -

- Show quoted text -

Among those posts, LET has published a document setting out how they
intend to resolve the issue, and a time frame of early spring to get
it done.
After that, EASA and the FAA will have to agree to it.
The SSA has also published a detailed report from the FAA on the
problem.
That FAA report is very discouraging. Clearly, the piggyback rivets
used in that area of the wing structure are a big issue for the FAA,
and LET's document doesn't address that issue at all. LET'S planned
eddy current cract detection fix is also going to have to address the
issues already raised by the FAA about the effectiveness of such
tests.

I would not be surprised if there were somewhat more than 100 clubs in
the same situation as the one you are close to.
However, I'm afraid that given that Blanik L-13's were designed in the
50's, when repair labor costs were low, and they tend to be complex to
fix in some areas at the best of times, one shouldn't be surprised if
the fix that is eventually approved is complex and expensive to do.
And that, as you are obviously aware, is not going to be a good thing
for Soaring.

On Jan 10, 1:37*pm, Sandy Stevenson wrote:
On Jan 10, 10:53*am, Darryl Ramm wrote:



On Jan 10, 5:35*am, gldrgidr wrote:

On Jan 9, 11:11*pm, "
wrote:

And if the spar is the same on the L23 shouldn't they be grounded as
well...

Not if this is a fatigue problem. *Fatigue would only show up after
many thousands of hours of service.
Remember that the L13 has been around for many years without any
problems until now.
The much newer L23 's might not suffer any failures for 20 more
years.
The FAA should be determining what a reasonable safe expected service
life for the L13 is, and then ground only the L13's that have
accumulated more than that number of hours service.
There should also be some kind of approved fix to bring these gliders
back into service.
Apparently sailplanes are a low priority with the FAA.
Has the SSA applied any pressure to get this resolved?

There should be a tooth fairy and Santa Claus as well. What actually
needs to happen has been talked about here in detail - from both the
FAA and SSA perspectives and I believe pro-active owners are trying to
work on this. Just spouting off what the FAA should be doing is going
will get nothing done.

"Fatigue would only show up after many thousands of hours of service."

Well if only real world engineering was that simple. There was a fatal
crash in a not too old L13 that Austrian air saftey investigators
determined appeared to involve fatigue. Then EASA and the FAA followed
up with a slate of ADs to try to understand/manage the possible
fatigue issue, and I believe those agencies actually looked at this in
more than a cursory way. I kind of expect those folks know more about
fatigue than you. If you are a subject expert and think they are wrong
then do all the owners a favor and take up the issue with EASA and/or
the FAA.

A small local club owns only a L13 and are left with no club glider
and I am sure there are other clubs in the same mess.

The TC holder needs to drive the failure/fatigue analysis and
engineering fixes. Affected owners should be starting there. The FAA
and EASA was not tasked with engineering fixes for aircraft.

All this, including the SSA angle has been well discussed here in the
past. You can search the r.a.s. archives on Google groups (where the
original post was from).

Darryl- Hide quoted text -

- Show quoted text -

Among those posts, LET has published a document setting out how they
intend to resolve the issue, and a time frame of early spring to get
it done.
After that, EASA and the FAA will have to agree to it.
The SSA has also published a detailed report from the FAA on the
problem.
That FAA report is very discouraging. Clearly, the piggyback rivets
used in that area of the wing structure are a big issue for the FAA,
and LET's document doesn't address that issue at all. *LET'S planned
eddy current cract detection fix is also going to have to address the
issues already raised by the FAA about the effectiveness of such
tests.

I would not be surprised if there were somewhat more than 100 clubs in
the same situation as the one you are close to.
However, I'm afraid that given that Blanik L-13's were designed in the
50's, when repair labor costs were low, and they tend to be complex to
fix in some areas at the best of times, one shouldn't be surprised if
the fix that is eventually approved is complex and expensive to do.
And that, as you are obviously aware, is not going to be a good thing
for Soaring.

I heard second hand that eddy current testing will be over $10,000/
airframe. X-raying may be done for about $700/airframe, however,
someone will have to validate that as an AMOC. There are some recent
computer enhancements in xray methods, but not sure if they've been
fielded. Certainly DHS has pushed the xray envelope;^) To that end,
some owners have volunteered up to 11 wings that could be used to
validate an AMOC. Not all of the wings have logbooks.

The accident glider had 2200 hours. A wing departed an L-13 in
turbulence in Colorado in 1975. Happened again in Germany in 1976.
Not details on aircraft time in either case.

There are L-13's in the US with as few as 800 hours. It would seem
reasonable that low timers should be allowed to fly, perhaps under
some restrictions.

Frank Whiteley

On Jan 10, 1:37*pm, Sandy Stevenson wrote:
On Jan 10, 10:53*am, Darryl Ramm wrote:



On Jan 10, 5:35*am, gldrgidr wrote:

On Jan 9, 11:11*pm, "
wrote:

And if the spar is the same on the L23 shouldn't they be grounded as
well...

Not if this is a fatigue problem. *Fatigue would only show up after
many thousands of hours of service.
Remember that the L13 has been around for many years without any
problems until now.
The much newer L23 's might not suffer any failures for 20 more
years.
The FAA should be determining what a reasonable safe expected service
life for the L13 is, and then ground only the L13's that have
accumulated more than that number of hours service.
There should also be some kind of approved fix to bring these gliders
back into service.
Apparently sailplanes are a low priority with the FAA.
Has the SSA applied any pressure to get this resolved?

There should be a tooth fairy and Santa Claus as well. What actually
needs to happen has been talked about here in detail - from both the
FAA and SSA perspectives and I believe pro-active owners are trying to
work on this. Just spouting off what the FAA should be doing is going
will get nothing done.

"Fatigue would only show up after many thousands of hours of service."

Well if only real world engineering was that simple. There was a fatal
crash in a not too old L13 that Austrian air saftey investigators
determined appeared to involve fatigue. Then EASA and the FAA followed
up with a slate of ADs to try to understand/manage the possible
fatigue issue, and I believe those agencies actually looked at this in
more than a cursory way. I kind of expect those folks know more about
fatigue than you. If you are a subject expert and think they are wrong
then do all the owners a favor and take up the issue with EASA and/or
the FAA.

A small local club owns only a L13 and are left with no club glider
and I am sure there are other clubs in the same mess.

The TC holder needs to drive the failure/fatigue analysis and
engineering fixes. Affected owners should be starting there. The FAA
and EASA was not tasked with engineering fixes for aircraft.

All this, including the SSA angle has been well discussed here in the
past. You can search the r.a.s. archives on Google groups (where the
original post was from).

Darryl- Hide quoted text -

- Show quoted text -

Among those posts, LET has published a document setting out how they
intend to resolve the issue, and a time frame of early spring to get
it done.
After that, EASA and the FAA will have to agree to it.
The SSA has also published a detailed report from the FAA on the
problem.
That FAA report is very discouraging. Clearly, the piggyback rivets
used in that area of the wing structure are a big issue for the FAA,
and LET's document doesn't address that issue at all. *LET'S planned
eddy current cract detection fix is also going to have to address the
issues already raised by the FAA about the effectiveness of such
tests.

I would not be surprised if there were somewhat more than 100 clubs in
the same situation as the one you are close to.
However, I'm afraid that given that Blanik L-13's were designed in the
50's, when repair labor costs were low, and they tend to be complex to
fix in some areas at the best of times, one shouldn't be surprised if
the fix that is eventually approved is complex and expensive to do.
And that, as you are obviously aware, is not going to be a good thing
for Soaring.

100 US clubs affected is probably about right. I fear your analysis
is also right - L-13's will prove too expensive a fix. I sincerely
hope your are proved wrong for the sake of those 100 clubs.

On Jan 9, 10:11*pm, "
wrote:
On Jan 9, 8:38*pm, gldrgidr wrote:

And if the spar is the same on the L23 shouldn't they be grounded as
well...


Does anyone have specific information on the differences in the L-23
spar?

On Jan 10, 4:05*pm, Frank Whiteley wrote:
On Jan 10, 1:37*pm, Sandy Stevenson wrote:





On Jan 10, 10:53*am, Darryl Ramm wrote:

On Jan 10, 5:35*am, gldrgidr wrote:

On Jan 9, 11:11*pm, "
wrote:

And if the spar is the same on the L23 shouldn't they be grounded as
well...

Not if this is a fatigue problem. *Fatigue would only show up after
many thousands of hours of service.
Remember that the L13 has been around for many years without any
problems until now.
The much newer L23 's might not suffer any failures for 20 more
years.
The FAA should be determining what a reasonable safe expected service
life for the L13 is, and then ground only the L13's that have
accumulated more than that number of hours service.
There should also be some kind of approved fix to bring these gliders
back into service.
Apparently sailplanes are a low priority with the FAA.
Has the SSA applied any pressure to get this resolved?

There should be a tooth fairy and Santa Claus as well. What actually
needs to happen has been talked about here in detail - from both the
FAA and SSA perspectives and I believe pro-active owners are trying to
work on this. Just spouting off what the FAA should be doing is going
will get nothing done.

"Fatigue would only show up after many thousands of hours of service."

Well if only real world engineering was that simple. There was a fatal
crash in a not too old L13 that Austrian air saftey investigators
determined appeared to involve fatigue. Then EASA and the FAA followed
up with a slate of ADs to try to understand/manage the possible
fatigue issue, and I believe those agencies actually looked at this in
more than a cursory way. I kind of expect those folks know more about
fatigue than you. If you are a subject expert and think they are wrong
then do all the owners a favor and take up the issue with EASA and/or
the FAA.

A small local club owns only a L13 and are left with no club glider
and I am sure there are other clubs in the same mess.

The TC holder needs to drive the failure/fatigue analysis and
engineering fixes. Affected owners should be starting there. The FAA
and EASA was not tasked with engineering fixes for aircraft.

All this, including the SSA angle has been well discussed here in the
past. You can search the r.a.s. archives on Google groups (where the
original post was from).

Darryl- Hide quoted text -

- Show quoted text -

Among those posts, LET has published a document setting out how they
intend to resolve the issue, and a time frame of early spring to get
it done.
After that, EASA and the FAA will have to agree to it.
The SSA has also published a detailed report from the FAA on the
problem.
That FAA report is very discouraging. Clearly, the piggyback rivets
used in that area of the wing structure are a big issue for the FAA,
and LET's document doesn't address that issue at all. *LET'S planned
eddy current cract detection fix is also going to have to address the
issues already raised by the FAA about the effectiveness of such
tests.

I would not be surprised if there were somewhat more than 100 clubs in
the same situation as the one you are close to.
However, I'm afraid that given that Blanik L-13's were designed in the
50's, when repair labor costs were low, and they tend to be complex to
fix in some areas at the best of times, one shouldn't be surprised if
the fix that is eventually approved is complex and expensive to do.
And that, as you are obviously aware, is not going to be a good thing
for Soaring.

I heard second hand that eddy current testing will be over $10,000/
airframe. *X-raying may be done for about $700/airframe, however,
someone will have to validate that as an AMOC. *There are some recent
computer enhancements in xray methods, but not sure if they've been
fielded. *Certainly DHS has pushed the xray envelope;^) *To that end,
some owners have volunteered up to 11 wings that could be used to
validate an AMOC. *Not all of the wings have logbooks.

The accident glider had 2200 hours. *A wing departed an L-13 in
turbulence in Colorado in 1975. *Happened again in Germany in 1976.
Not details on aircraft time in either case.

There are L-13's in the US with as few as 800 hours. *It would seem
reasonable that low timers should be allowed to fly, perhaps under
some restrictions.

Frank Whiteley- Hide quoted text -

- Show quoted text -

I know you mean well, Frank, but I don't think the FAA or EASA will go
along with that idea.
It isn't just number of hours; it's also time. There isn't an L-13
newer than 30 years old.
I suspect they're going to want significant evidence that individual
machines
are demonstrably sound.
In that vein, the figure I've seen posted above of $10k for eddy
current
inspection I presume is for both wings including opening, repair if
necessry, and closing.
the eddy current inspection itself is already called for in one Blanik
AD, and my recollection is that
by itself it's only about $1500; possibly less.
However, LET is suggesting that they will be looking at a modified
form of eddy current in order
to address the issue of how much area around a rivet is actually
properly examined by a probe
inserted in the rivet hole.
It remains to be seen whether the inspection technique proposed will
be more expensive to perform
than the usual eddy current inspections.
If a way is found to assure the safety of the L-13 fleet at modest
cost I will be quite surprised, but
also greatly relieved.

On Jan 11, 8:56*pm, Sandy Stevenson wrote:
On Jan 10, 4:05*pm, Frank Whiteley wrote:



On Jan 10, 1:37*pm, Sandy Stevenson wrote:

On Jan 10, 10:53*am, Darryl Ramm wrote:

On Jan 10, 5:35*am, gldrgidr wrote:

On Jan 9, 11:11*pm, "
wrote:

And if the spar is the same on the L23 shouldn't they be grounded as
well...

Not if this is a fatigue problem. *Fatigue would only show up after
many thousands of hours of service.
Remember that the L13 has been around for many years without any
problems until now.
The much newer L23 's might not suffer any failures for 20 more
years.
The FAA should be determining what a reasonable safe expected service
life for the L13 is, and then ground only the L13's that have
accumulated more than that number of hours service.
There should also be some kind of approved fix to bring these gliders
back into service.
Apparently sailplanes are a low priority with the FAA.
Has the SSA applied any pressure to get this resolved?

There should be a tooth fairy and Santa Claus as well. What actually
needs to happen has been talked about here in detail - from both the
FAA and SSA perspectives and I believe pro-active owners are trying to
work on this. Just spouting off what the FAA should be doing is going
will get nothing done.

"Fatigue would only show up after many thousands of hours of service."

Well if only real world engineering was that simple. There was a fatal
crash in a not too old L13 that Austrian air saftey investigators
determined appeared to involve fatigue. Then EASA and the FAA followed
up with a slate of ADs to try to understand/manage the possible
fatigue issue, and I believe those agencies actually looked at this in
more than a cursory way. I kind of expect those folks know more about
fatigue than you. If you are a subject expert and think they are wrong
then do all the owners a favor and take up the issue with EASA and/or
the FAA.

A small local club owns only a L13 and are left with no club glider
and I am sure there are other clubs in the same mess.

The TC holder needs to drive the failure/fatigue analysis and
engineering fixes. Affected owners should be starting there. The FAA
and EASA was not tasked with engineering fixes for aircraft.

All this, including the SSA angle has been well discussed here in the
past. You can search the r.a.s. archives on Google groups (where the
original post was from).

Darryl- Hide quoted text -

- Show quoted text -

Among those posts, LET has published a document setting out how they
intend to resolve the issue, and a time frame of early spring to get
it done.
After that, EASA and the FAA will have to agree to it.
The SSA has also published a detailed report from the FAA on the
problem.
That FAA report is very discouraging. Clearly, the piggyback rivets
used in that area of the wing structure are a big issue for the FAA,
and LET's document doesn't address that issue at all. *LET'S planned
eddy current cract detection fix is also going to have to address the
issues already raised by the FAA about the effectiveness of such
tests.

I would not be surprised if there were somewhat more than 100 clubs in
the same situation as the one you are close to.
However, I'm afraid that given that Blanik L-13's were designed in the
50's, when repair labor costs were low, and they tend to be complex to
fix in some areas at the best of times, one shouldn't be surprised if
the fix that is eventually approved is complex and expensive to do.
And that, as you are obviously aware, is not going to be a good thing
for Soaring.

I heard second hand that eddy current testing will be over $10,000/
airframe. *X-raying may be done for about $700/airframe, however,
someone will have to validate that as an AMOC. *There are some recent
computer enhancements in xray methods, but not sure if they've been
fielded. *Certainly DHS has pushed the xray envelope;^) *To that end,
some owners have volunteered up to 11 wings that could be used to
validate an AMOC. *Not all of the wings have logbooks.

The accident glider had 2200 hours. *A wing departed an L-13 in
turbulence in Colorado in 1975. *Happened again in Germany in 1976.
Not details on aircraft time in either case.

There are L-13's in the US with as few as 800 hours. *It would seem
reasonable that low timers should be allowed to fly, perhaps under
some restrictions.

Frank Whiteley- Hide quoted text -

- Show quoted text -

I know you mean well, Frank, but I don't think the FAA or EASA will go
along with that idea.
It isn't just number of hours; it's also time. *There isn't an L-13
newer than 30 years old.
I suspect they're going to want significant evidence that individual
machines
are demonstrably sound.
In that vein, the figure I've seen posted above of $10k for eddy
current
inspection I presume is for both wings including opening, repair if
necessry, and closing.
the eddy current inspection itself is already called for in one Blanik
AD, and my recollection is that
by itself it's only about $1500; possibly less.
However, LET is suggesting that they will be looking at a modified
form of eddy current in order
to address the issue of how much area around a rivet is actually
properly examined by a probe
inserted in the rivet hole.
It remains to be seen whether the inspection technique proposed will
be more expensive to perform
than the usual eddy current inspections.
If a way is found to assure the safety of the L-13 fleet at modest
cost I will be quite surprised, but
also greatly relieved.

I think you are referring to the GFA document, which is over 20 years
old. This was a recent cost estimate. The long term problem is that
inspections will be recurrent at some maximum interval, like every 500
hours. If it's $1500/glider, might be doable. If it's the higher
estimate, maybe the Llewellyn mod would be better.

As of January 6th, the factory hopes to have some Eddy current testing
results by February.
See https://sites.google.com/site/blanikspar/home#BRUNO

Frank Whiteley