Re: Older Aircraft

Date:         16 Sep 97 02:35:26 
From:         gfoley@freenet.columbus.oh.us (Gerard Foley)
Organization: The Greater Columbus FreeNet
References:   1 2
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Karl Swartz (kls@ohare.Chicago.COM) wrote:

: >I was wondering if anyone had statistics on the oldest aircraft
: >currently being flown by a U.S. carrier in regular service.

[snip]

: >How many cylces do most carriers (at least American ones) put their
: >planes through before they scrap them?

: >Do international airlines have different standards?

: There aren't really any standards -- except for Concorde and some
: early European types, most jetliners are not designed with a specific
: lifetime.  As long as you don't mind increasing amounts of mainteance
: you can keep flying them essentially forever.  Most often economics
: is what causes an airliner to be retired.

   There may be a materials problem.  Steel is unique among metals in
exhibiting an endurance limit, that is a cyclic stress below which
fatigue failure has never been observed.  Other metals have not shown
this behavior.  Lower cyclic stress simply means more cycles before
fracture.  On the other hand, a modest reduction in cyclic stress
level does give very large increase in life.

--
Gerry