The VC10 by the way, flew 3,000 hours at BOAC and nearly 6,000 hours at the RAF with an early composite rudder (1 section of the 3 rudders on VC10) over the course of 3 years. No problems were encountered and along with other trials (like the all composite HS125 wing) these 1970s experiments hastened the use of composites in aviation.
BUT no ageing tests across a decade of temp soak and chemical changes could have taken place in such short trials times. Which again takes me back to my early post- the fact of the ageing composite. Such phenomena is not as rapidly obvious as the Comet's meteal fatigue issues, but it exists.
I did some early work 25 years ago on trying to build an integral (not bolt in) sub-chassis from composite, within a composite skin structure - to create load/stress paths within the panel rather than just have the stuff 'creep' to its nearest weakness and shatter at random.
Yet to this day car makers and our european composite friends just mould a panel and glue or bolt in, composite and alloy reinforcements - which as you can see from the AA587 fin fracture history, does not maketh much sense.
Imagine a fiberglass car- much stronger/lighter than a steel one -but when it does break, it shatters at random and often where you least want it too.. Yachts are still the same.
Here endeth the lesson , but its all vital to the AA587 and subsequent failures - and to the forthcoming 787. I reckon there are lot of worried engineers out there on both sides of the pond...