Although the original writer is probably missing something, and although
large commercial airplanes seem to be going to composites, I have to say
I have also wondered about the effects of time and temperatures on
composites…particularly exposure to extreme temperatures. A colored
airplane could develop very high temperatures on the ground on a 90
degree day, then be way below freezing at altitude. Combined with our
relative lack of production controls, does this pose a long term risk?

And what about composite composites: The IV with the carbon fiber cabin
bonding to a fiberglass tail.

A long time ago, I remember someone in the fiberglass business telling
me that resins never finish drying, and that, over time, they just get
harder and harder. I don’t know if this means more brittle, but, if
true, it definitely means the nature of the composite changes (could be
good!).

I also have had a concern with static testing of composite wings, and
the lack of any testing of empennages. A new, composite wing, exposed to
a controlled, gradually increasing positive static load, may have very
little to do with an old wing, subjected to fluctuating, sudden,
positive and negative loads.

Finally, what was the report on the airliner that lost its vertical stab
leaving JFK a couple of years ago? I remember that the whole vertical
stab departed cleanly, and that it was composite. I have to assume that
companies like Boeing and Airbus are doing the rocket science on this
stuff. Are we benefiting from that? Is it similar technology? I wonder
what it tells them about inspections and when to retire an airframe?

Brian Barbata
IV-P Turbine (+100%)
Legacy (-100%)