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At 10:10 23 November 2018, Nick Hill wrote:
On 22/11/2018 18:21, wrote:
I noticed the SZD-55 has a service life of only 3,000 hrs with a
possible
1,500 hr extension. Is this typical of other modern ships like the
Discus,
Ventus, LS, DG series etc??


Most new glider designs come to market with an initial service life,
which currenty seem to be 3000 or 6000Hrs. When some examples reach that
initial limit the manufacturer (assuming they still exist) then define
an inspection program to be undertaken which allows the life to be
extended be say 6000Hrs. The process repeats when one gets to 6000Hrs
etc.

If you look in the TN/ADs from the various maufactureres you will find
technical notes being issued defining extensions.

Example the LS4 originally had a service life of 3000Hrs. TN4027a for
the LS4 now details the inspection program as at 3000, 6000, 9000, 10000
and 11000 which allows a service life up to 12000Hrs.

DG and Schleicher still seem to start with 3000Hrs as did earlier
Schempp Hirth gliders. Later Schempp gliders have 6000Hrs as the initial
life.

The SZD-55 is probably an example that the life was initially 3000Hrs
after which SZD produced an extension up to 4500Hrs. The original SZD
manufacturer didn't really exist for a while so nothing further
happened. The newer Allstar PZL company which now owns the design and
manufactures the glider produced a TN to extend the life upto 12000 hrs
in 2012

Nick

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Nick Hill