And I’m supposed to fly on a 777-200 to Denver operated by United in just a few days. Yay!
One thing that does bug me, though is that we now have two events where the shroud was lost. Were these uncontained failures (problematic because of potential for wing damage) or contained faiLures followed by aerodynamic shedding of the damaged shroud (system functioning as designed). I'm also somewhat concerned about the fire remaining in the burner stage. Might have just been lubricants, but I'd want to make sure the fire handle had been pulled and investigate whether it worked correctly.
But in that type of failure, you can't control where the pieces go.
https://abc7ny.com/philadelphia-emergency-landing-southwest-...
It resulted in depressurization and partial ejection/death.
"Two small punctures were found in the right side fuselage just below the window belt with material transfer consistent with impact from pieces of an engine fan blade"
(From the link in parent to this thread https://avherald.com/h?article=4b4e8ca7&opt=0)
However, loss of the shroud doesn't necessarily imply there was a confinement failure. Damage to the shroud during the event can easily lead to the cowling shedding aerodynamically, which is also part of the design: the last thing you need is more drag on the dead engine side. We can't tell which that was in this case, but it's important that we do---the design criteria specifying that the aircraft can be safely recovered from a catastrophic single engine failure during any stage of flight would assume the failure is confined to the engine.
Some cheap airlines might ignore those rules, but none in the US. (Only the poorest, most corrup, countires in the world will ignore those limits)
https://en.wikipedia.org/wiki/Aircraft_maintenance_checks#D_...
A commercial aircraft does not just accumulate wear and tear for 25 years until something breaks. They can basically fly indefinitely, but in reality after two or three D checks they are usually retired because the cost of the D check is more than the value of the aircraft.
In this case, something obviously went awry and it's both engineering, planning, and a miracle no one died or was crushed from debris from above. Regardless, comments like yours leave me feeling far more confident in this sort of thing.
Yes, though even something going wrong doesn't necessarily mean that we'd need to change any procedures.
Sensible procedures bring risks down to acceptable levels at an acceptable price. That level of risk is generally still more than 0%.
But yeah, a D check is so expensive I've heard there's a habit of dumping the aircraft on less observing flying companies some thousand miles before it comes up...
How is that safe unless you've got a production line doing it? Seems impossible to re-assemble it in the same way as it was done in factory...
And in a similar incident in February 2018 on a 777 (referred to upthread), one of those checks was found to have failed: the NTSB determined that the root cause was a cracked engine fan blade that should have been detected on a previous inspection (and that would have resulted in the blade being replaced), but wasn't. If this incident turns out to have a similar root cause, that means there are issues with the preventive inspection and maintenance process.
Unlike some codebases, aircrafts actually have mandated maintenance. Which is why most accidents are due to human error and not massive technical failures.
(That's a feature, not a bug! The pervasive checklists and general professionalism mean that most 'normal' human errors are recovered from without enough consequences to make it into the news.
So only the really unlucky and incompetent are what we usually hear about.)
We don't know yet.
There are hundreds of flaws. Aircraft are not perfect. Any large airframe sees lots of little things break every year. That's what inspections and maintenance are for. But the system is designed so that such things never add up into something really bad. Be worried about the aircraft without flaws. To me, that means it either never gets used or isn't being inspected properly.
Enjoy your flight and enjoy Denver. Get a donut from Voodoo for me.