What Bill said.

The L-23's around have a service life, nominally 6,000 hours, adjusted
by use; aerobatics, flying with extended tips, or winch launching.
That would put operational use at typically 15-25 years. Others have
periodic inspections to extend life. One glass glider has a 3000 hour
life limit in the US, so they will be sold into countries that have
life extensions as they time out here. Works the other way with some
gliders that have time limits in other countries, but no limit in the
US. Some have had a shelf life. The all metal IS28-B2 for example.
But that has been extended multiple times, including the number of
hours and landings. It currently doesn't appear there will be much,
if any, further metal production for a variety of reasons.

When composite gliders were first built, there were a lot of
unknowns. Design life for early designs was 18,000 hours, with 3,000
hours adopted as the initial service life. As they reached 3,000
hours, more information was gathered and extension schemes were
developed. Metal fatigue in the control systems resulted in some AD's
and periodic replacement of parts. Prior to JAR22 and EASA, OSTIV
provided some guidance. Those early glass sailplanes tended to be
overbuilt and some may well be flying in the 22nd century. Of the ten
original Phonix, at last check nine remained airworthy, now 50 years
old, but of course they are no longer daily drivers. Design,
materials and methods have moved along. Will modern builds prove to
be as robust? Time will tell.

Experimental racing/exhibition gliders generally have no component
life limits, see FAA Order 8130.2F. Doesn't mean you should ignore
bulletins and ADs in countries where the same airframe may be
certified. But these airworthiness certificates are based on a
condition inspection and are restricted by operating limitations.

Now, there are some gliders out there that are getting pretty long in
the tooth and may require work that may be less than economical to
perform, at least until supply and demand change that equation.

You must have a specific example in mind.

Frank Whiteley

On Nov 8, 8:51*pm, "BT" wrote:
Most "American" gliders do not have an airframe end-of-life.
Tube and fabric,... recover it and repair any rusting tubes.
Wood and fabric.. rebuild it, replace the wood if it has dried out, cracked,
weakened glue joints.

Most of the "plastics" have a life hour or calendar year maximum. Most if
they still have factory support, or at one time if the factory had provided
instructions on how to extend a life before closing down, have
instructions/inspections replacement parts etc to extend the life hours.
Those that do not.. are salvage.

I know of a BG-12 that was beyond reasonable salvage.. it met it's end in a
bonfire.
There is a plastic (fiberglass) glider out there now that has no factory
support on how to complete a "life extension inspection". It is grounded.

Most European fiberglass gliders have "life extension inspections" at 3000hr
intervals up to 9000 or 12000hrs, then 1000hr intervals. Most will not be
flyable beyond those years/hours.

BT

"Michael" wrote in message

...

Hi all,

Novice question here.....what happens when some of these vintage (or
even more modern) gliders reach their airframe end-of-life or number
of landing limits?

Is the aircraft now salvage or can things be done to refurbish it?
What things, if any, are typically done and about how many "additional
hours" does this give the glider?

--Michael
GHSA, Texas