A parachute is a simple device and rather easily tested for material degradation. A good rigger will do this on anything less than nearly new. On an older chute he will test canopy material to spec and shrouds to destruction. A car or glider, not so easily tested.

On Saturday, June 2, 2018 at 8:35:19 AM UTC-7, Jonathan St. Cloud wrote:
I think the acid wash took 5 years to show up on my softie. Not sure what might have reared it's head later, as at 20 years, I though I had sweated enough on the chute and purchased a new one. With all due respect, your logic jump, that a glider made of petroleum products isn't limited to a 20 year usable lifespan then a petroleum base chute should be either. This jump is not based in fact, logic, nor science. Hell, even petroleum has a very limited life. How would you like to drive your new car on petro that is 5 years old let alone 20? I have a feeling it would not drive. The "we" in "we fly 50+ plus year old Schweizers, is singular, as I don't fly 50 plus year old Schweizers, this has been covered on other threads about the state of soaring in America. Having said that, I do have a fair amount of time in 75 + year old WWII aircraft, that had been lovingly rebuilt. I flew those aircraft wearing a chute that was less than 20 years old.
Twenty years is a lot of wear an tear. You should have seen me twenty years ago.


On Saturday, June 2, 2018 at 3:42:33 AM UTC-7, wrote:
Acid mesh problem was a manufacturing error that took a lot less than 20 years to show up. Replacing parachutes every 20 years wouldn't have avoided anything. Do you throw out your glass gliders when they are 21 years old? Parachutes and glass gliders are both made out of petroleum if one can't be determined to be safe after 20 years neither can the other. It's funny we fly 50+ plus year old Schweizers that have spent their lives tied down outside yet some try to convince us that a parachute that spends most of its life in a bag stored in a closet is unairworthy at 21 years old.