OldAeroGuy wrote:kalvado wrote:OldAeroGuy wrote:
Ahh.. How soon we forget.
https://www.flightglobal.com/news/artic ... ad-204716/
Which is the more difficult problem to solve, wing structure or a cargo door latch/structure?
Let's see. A380 failed too early in an ultimate load test to destruction. Early failure is, of course, a problem, but it is a 2% error after all - and test artifact is a write-off either way
Is there any indication 777X was undergoing a destruction test to determine safety margin? I am pretty sure that would be explicitly mentioned a few times by now - but quazi-official "policy statement" above is pretty mum, and no official response from Boeing. Did they come to 2% within ultimate load during routine test, or this was a maximum load test - and that would mean whooping 50% error and no safety margin exists in the design?
This is a fatigue test frame; as far as I understand those are used for continuing test after the aircraft enters service - so destructive test is pretty doubtful to begin with.
Besides, are you sure this is a latch failure - and not a catastrophic structural failure of primary load-bearing structures? We all hope for the best....
Please read the referenced article.
ttps://simpleflying.com/boeing-777x-st ... l-testing/ quotes a Boeing spokesman:
"During final load testing on the 777X static test airplane, the team encountered an issue that required suspension of the test. The testing conditions were well beyond any load expected in commercial service. The event is under review and the team is working to understand the root cause. Final load testing is the last in a series of tests that Boeing has been conducting on this full-scale test airplane over the past several months."
- This was the static test airplane, not the fatigue airplane.
- Final load testing is to 150% of limit load, it doesn't need to be to destruction.
- The door failure could be due to a latching failure or structural failure. It's still easier to solve than a wing structural failure.
Glass half full or glass half empty?
We don't really know anything. Can be a latch failure at 149.95% of load limit, can be a structural failure at 102%. I am not actually aware of what the load limit could be; stuck outflow valve maybe? People throw around numbers that A is testing to 2x in-service maximum.
Overall, the issue can be resolved by analysis and a bit of reinforcement designed within a week, or it can require a dedication of another frame to testing due to structural damage to test article and still having to pass the test (which would be worse than A380 case). Neither you nor I are privileged to Boeing test data (and maybe it is still being processed). There are people who consider the best-case scenario only, I am looking at both ends of the spectrum. With Boeing recent history we can only pray things are closer to a mild problem.