Fuji
I would be interested to hear more about the DA42 landing gear repairs that went wrong, it was unlikely to have been due to mistakes at the factory who would have issued the drawings for such work, I would guess that it was a quality control issue by the people doing the work.
Unfortunatly a lot of the composite issues are not understood by the GA industry who are by and large metal centric, this metal influence could clearly be seen in the Boeing composite repair manual that Cirrus in the early days based their repair practices on. Cirrus have now moved on and are using techniques and practices that offer both a stronger and lighter repair than the Boeing system offered ( with the 787 Boeing must also have moved on !!)
You are correct about the quality control issues both in the lay up, cure and post cure stages. Also when the lay up is of a particularly critical component a test sample is made ( just as at original manufacture) and this is sent for the same destruction testing by the aircraft manufacturers that new components test samples receive.
Last edited by A and C; 6th Dec 2012 at 21:42.