As a Metallurgist who became a pilot I can concur with all above.
The bottom line is that although composites have been around for many years they are still relatively new. We simply do not have enough data on the "real" ageing properties of composites. I put that in quote marks because all age data so far is obtained by methods used to prematurely age a material (increasing operating temperature in aluminium being an example). I have a bad feeling that we may now be getting the real data. I hope to god I am wrong and this can be traced to a manufacturing flaw.
16 years ago a professor in this field stated that his opinion was that a composite would lose 50% of its structural integrity over 10 years. Just an opinion but a sobering one.
Another point was that a composite could be stressed repeatedly to 60% of it ultimate tensile strength before suffering fatigue cracking, a metal is typically 30-40% of UTS. In a composite panel a hole(eg a bullet hole) reduces the strengh to 60-70%, in a metal panel this reduces to 90%, a point to ponder in your carbon fibre winged AV8B/Harrier.
My personal feeling is that we are about to see a lot of ageing research carried out on genuinely aged composites.
[ 16 November 2001: Message edited by: whizzjet ]