Previous loss of a composite aircraft
I had the pleasure of driving the Lak test pilot in South Africa a decade ago.
He was partially crippled after a high speed, low level composite wing failure (flutter) which was due to fatigue.
He stated that they used Russian composites at the time but had based their structural calculations on the West's research figures.
The glider had passed all of the flight testing but the structure had failed iirc after two years of heavy use.