On Saturday, 6 May 2017 at 07:45:49 UTC-7, Frank Whiteley wrote:
> On Saturday, May 6, 2017 at 1:35:23 AM UTC-6, ifee...@hotmail.com wrote:
> > The latest update on the Blanik America site is October 2016 but it seems hopeful:
> >
> > http://home.nwi.net/~blanikam/ba/news.htm
> >
> > I live in Canada where the AD&C modification is already approved but the expense of the work coupled with the 5000 hour airframe limit seems to have resulted in few L-13's being made airworthy again. A really nice, very low time L-13 might be an economically viable project though. Personally if I had the time and money to do it I probably would, just as a labor of love.. I have a special place in my heart for the L-13, sorely miss flying them and it was a sad day when my club sold our last one. The L-23 we still have is a fine glider but it just doesn't have the same appeal for me.
> http://www.aircraftdc.de/images/produkte/blanik/ADxC%20Customerinfo%20Blanik%2002-Mar-12.pdf describes the increase to 5000hr life over the original 3750hr. It also appears to remove the 35% dual limit (which also exists for the L-23). So, amortizing the cost over the remaining life may make economic sense for L-13 with 2000hrs TTAF or less. Whether it makes financial sense is another question based on the user. The repair may be become much less attractive for those approaching 3000hrs TTAF. I've seen L-13's with three N-number shadows on the component parts, so I suspect there may be basic airframes with 2000hrs, but sporting a 4000hr wing. When first grounded I collected information on the L-13's in the US. There were about 190 on the FAA registry and possibly 90-100 that were being actively flown. At least a couple of sites had several hulks for spares, so there were several "composite" airframes out there. I'm not aware of any L-13A1's that may have been imported into the US. Those were the L-13's that LET had already modifed/replaced the root sections and extended the life to 5000hrs. Those were returned to service by EASA without the AD&C modification. I don't think the FAA considered this, but again, there may not be any in the US, so it would be moot. Unfortunately those couldn't be identified by serial number, but only buy inspecting the differential rivet pattern associated with the modification. I recall the RAFGSA did not pursue this as their L-13 fleet aged.
>
> Frank Whiteley

I have checked my wing according to AI MB No. L13/112a. and I have the exact rivet pattern like in the reinforced wing .They have steel rivets in the middle row and aluminium rivets in the rows beside.And they are spaced apart just a bit more .The splice extends past the but rib also. I compared it with the other L13 I also got last year and they indeed look like in the option 1 in the Ad .Rivets are closer together and all aluminum The reinforced version looks also exactly like in the L23. So I am hopeful I will get that L13 back in the air. The wings got built factory new in 1996 . EASA AD No.: 2011-0135R2. says under Required Action.
(2) After 20 July 2011 [the effective date of this AD at original issue], inspect the sailplane to determine whether the wing structure is in conformity to the L-13 A Blaník design specification, or in conformity to the L-13 Blaník ‘reinforced’ design specification, in accordance with the instructions of AI MB No. L13/112a.
and under (4) If, as a result of the inspection required by paragraph (2) of this AD, conformity is demonstrated, accomplish all the additional actions specified in paragraphs (4.1), (4.2) and (4.3) of this AD. Only after all actions have successfully been accomplished, flights can be resumed.
The remaining actions require just counting the hours for double seatet flying ,winch and aerobatics
from the log book
4.1
Table 1 - Maximum Limits
Type of Operations
aerobatic Flights 100 FH
Winch launches. 25 000 WL
Dual Flights. 2 500 FH

(4.2)
Inspect the areas of wing skin joints (ribs No. 7 and 13 of the wing) for cracks at ribs and stringers in accordance with the instructions of AI MB No L13/108a. In case a failed stringer or rib is detected, accomplish a repair in accordance with the instructions of AI Information Bulletin (IB) No L13/107b.
(4.3)
Amend the Aircraft Flight Manual (AFM) as follows: All aerobatics manoeuvres, e.g. Roll (Výkrut), Loop (přemet), Stalled turn (souvrat), Immelmann turn (překrut), Half roll (zvrat) and Inverted flight (let na zádech) are prohibited. This can be accomplished by inserting a copy of this AD into the AFM and invalidating the following “aerobatics” chapter of the AFM, as applicable:

On Tuesday, 17 May 2022 at 23:24:07 UTC-7, Walter Wissmann wrote:
> On Saturday, 6 May 2017 at 07:45:49 UTC-7, Frank Whiteley wrote:
> > On Saturday, May 6, 2017 at 1:35:23 AM UTC-6, ifee...@hotmail.com wrote:
> > > The latest update on the Blanik America site is October 2016 but it seems hopeful:
> > >
> > > http://home.nwi.net/~blanikam/ba/news.htm
> > >
> > > I live in Canada where the AD&C modification is already approved but the expense of the work coupled with the 5000 hour airframe limit seems to have resulted in few L-13's being made airworthy again. A really nice, very low time L-13 might be an economically viable project though. Personally if I had the time and money to do it I probably would, just as a labor of love. I have a special place in my heart for the L-13, sorely miss flying them and it was a sad day when my club sold our last one. The L-23 we still have is a fine glider but it just doesn't have the same appeal for me.
> > http://www.aircraftdc.de/images/produkte/blanik/ADxC%20Customerinfo%20Blanik%2002-Mar-12.pdf describes the increase to 5000hr life over the original 3750hr. It also appears to remove the 35% dual limit (which also exists for the L-23). So, amortizing the cost over the remaining life may make economic sense for L-13 with 2000hrs TTAF or less. Whether it makes financial sense is another question based on the user. The repair may be become much less attractive for those approaching 3000hrs TTAF. I've seen L-13's with three N-number shadows on the component parts, so I suspect there may be basic airframes with 2000hrs, but sporting a 4000hr wing. When first grounded I collected information on the L-13's in the US. There were about 190 on the FAA registry and possibly 90-100 that were being actively flown. At least a couple of sites had several hulks for spares, so there were several "composite" airframes out there. I'm not aware of any L-13A1's that may have been imported into the US. Those were the L-13's that LET had already modifed/replaced the root sections and extended the life to 5000hrs. Those were returned to service by EASA without the AD&C modification. I don't think the FAA considered this, but again, there may not be any in the US, so it would be moot. Unfortunately those couldn't be identified by serial number, but only buy inspecting the differential rivet pattern associated with the modification. I recall the RAFGSA did not pursue this as their L-13 fleet aged.
> >
> > Frank Whiteley