On Saturday, November 24, 2018 at 3:22:29 AM UTC-8, wrote:
There's a difference between what is technically possible and what is legally allowed. There's an interesting read in the "Schleicher-book": before the 18,000h lifetime extension on the ASK21 was approved, a wing was tested in a fatigue evaluation program. This program received public funding by the German government. The intention was to get approval for 24,000h, but the program was running out of funds before that was accomplished. So far, the ASK21 is the only German FRP-glider with 18,000h service life.

This is quite old now, but still good work

http://journals.sfu.ca/ts/index.php/...ewFile/708/666