My dad was an aeronautical stress analysis so I got some info regarding
these things, He worked for Grumman, Fairchild, Rockwell, Boeing, P & W
etc. I thought the various parts off the airframe had design lives which
they should meet and they could be extended or otherwise from
operational experience. I guess like many things these days you can't
test the product to its actual life cycle or it would be obsolete before
sale but you can try and predict its life. A single item such as
aluminium may not be to arduous but a composite structure I would expect
to be somewhat more difficult. Good thing for computers and hopefully
still people to make sure the answers make sense.

Too_Many_Tools wrote:

"I saw a program about that and they mentioned that a large part of the

problem was due to debonding of the adhesive so the rivets took all the

load which wasn't intended. It was mentioned that Boeing tightened
their procedures for the conditions under which the bonding took place
after those early planes were made and Aloha hadn't been carrying out
the checks properly to detect telltales signs of the problem.

Its something I consider when I see people querying about bonding car
panels and what conditions they are done under. Temperature, humidity,
surface prep can have a critical effect. "

Considering Boeing is now building planes that are made of carbon fiber
and LOTS of adhesive, it will be interesting to see what their long
time life span (and maintainance costs) will be.

TMT