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This crash was really scary for me.

I feel like the DC10 is well past it's due date. It seems like that particular model has had so many fucked up problems that resulted in catastrophic outcomes, I am surprised they are still flying.
 
mercurial said:
I feel like the DC10 is well past it's due date. It seems like that particular model has had so many fucked up problems that resulted in catastrophic outcomes, I am surprised they are still flying.
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The aircraft that crashed was an MD-11. Similar, but different in many ways.
 
Climber said:
How hard would it be to detect the stress cracks? Is it something that would be apparent with inspection or not?
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Depends on what the material is, and where it’s at, as in, how hard it is to get to and actually do the inspection.
 
msethhunter said:
Depends on what the material is, and where it’s at, as in, how hard it is to get to and actually do the inspection.
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I can understand that.

But there needs to be a comprehensive maintenance plan to inspect all of the areas that can fail on a basis that takes worst case into account and assures that a part wouldn't have gone too long between inspections to fail. Any corner cutting in this kind of plan would put those parts at risk of failing.

Just for reference, I did most of the FDFI analysis for an entire air Force weapon system (Rail Garrison), so I've been through the whole anaysis and building maintenance plans for every component in the weapon system. It's an exhaustive process but straightforward because there was a lot of historical data on the parts and materials being used. The MTBF for individual components was known and equations for calculating composite MTBF was straightforward.
 
I think the FAA has requirements like that. IIRC they have periodic maintenance/inspection requirements with varying levels of detail that range from hundreds to thousands of labor hours.
 
This is interesting stuff and I'm hoping they can determine any human factors.

I spent more than a few years at Rolls Royce doing design and writing tech documents for engines. My job was created as a response to the Alaska Airlines 261 crash in 2000. The root cause of that crash was improper tool usage while swaging/measuring a nut, and new requirements were issued by the FAA and DOD to have everyone entirely redo their quality control and revamp their procedures.

Sometimes things just fail, usually things prone to failure are identified early, but sometimes not.

I do find it remarkable how safe the aviation industry really is, given how many things can go wrong, and how many people are involved. To me it's one if the most impressive demonstrations of human collaboration in the modern world.
 
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Interesting background Joe.

Appreciate your take. :thumbup
 
Enchanter said:
The aircraft that crashed was an MD-11. Similar, but different in many ways.
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It’s not very different at all. A couple of extra rings in the fuselage, a better avionics package and aerodynamic tweaks mostly. I think the DC10 and MD11 are a common type rating like the 757 and 767.
 
Lights_Guy3 said:
This is interesting stuff and I'm hoping they can determine any human factors.

I spent more than a few years at Rolls Royce doing design and writing tech documents for engines. My job was created as a response to the Alaska Airlines 261 crash in 2000. The root cause of that crash was improper tool usage while swaging/measuring a nut, and new requirements were issued by the FAA and DOD to have everyone entirely redo their quality control and revamp their procedures.

Sometimes things just fail, usually things prone to failure are identified early, but sometimes not.

I do find it remarkable how safe the aviation industry really is, given how many things can go wrong, and how many people are involved. To me it's one if the most impressive demonstrations of human collaboration in the modern world.
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261’s crash was from inadequate maintenance. They weren’t using enough grease noted was it frequent enough. Alaska had received approval for extended lube and play check intervals. The tube was clogged with dry grease, and the jack screw and acme nut were dry.
 
msethhunter said:
261’s crash was from inadequate maintenance. They weren’t using enough grease noted was it frequent enough. Alaska had received approval for extended lube and play check intervals. The tube was clogged with dry grease, and the jack screw and acme nut were dry.
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Yes but also the end play on the nut was checked with a shop made tool that was not part of the approved procedure.

That inspection yielded incorrect results that if done properly, should have triggered maintenance work.

As is often the case, multiple things need to go wrong at the same time for a disaster to happen.
 
Climber said:
I can understand that.

But there needs to be a comprehensive maintenance plan to inspect all of the areas that can fail on a basis that takes worst case into account and assures that a part wouldn't have gone too long between inspections to fail. Any corner cutting in this kind of plan would put those parts at risk of failing.

Just for reference, I did most of the FDFI analysis for an entire air Force weapon system (Rail Garrison), so I've been through the whole anaysis and building maintenance plans for every component in the weapon system. It's an exhaustive process but straightforward because there was a lot of historical data on the parts and materials being used. The MTBF for individual components was known and equations for calculating composite MTBF was straightforward.
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I don’t know the MX interval for inspecting the pylon mount but if it’s going to fail, it’s going to fail at rotation, like this one did. The gyroscopic forces in play are tremendous, and greatest at rotation. Guys who rip an airplane off the ground always make me nervous. Anyways, inspection of things that are buried in the wing like these pylon mounts are pretty infrequent. It’s usually only done during a big maintenance cycle or when the engine comes off. If memory serves correct, this airframe had over 100,000 hours on it and some 90k’ish cycles (take offs and landings). It was a high time airframe. When I get a new airplane, I NEVER look at its cycles or time, I don’t want to know.
 
Lights_Guy3 said:
Yes but also the end play on the nut was checked with a shop made tool that was not part of the approved procedure.

That inspection yielded incorrect results that if done properly, should have triggered maintenance work.
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I think it was also done in Mexico?
 
msethhunter said:
I think it was also done in Mexico?
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Maybe it was, I can't remember all the details.

I know the improper tooling aspect triggered lots of work for every company that worked with aircraft.

There were so soooooo many "shop made" tools at Rolls Royce. It was super common in the industry, and it was basically fine, until it wasn't. Most of those tools were actually quite clever, having been created by the mechanics/machinists doing the work. But they often didn't have the engineering background to account for misuse of the tool, or other factors that could affect measurements/outcomes.

Many of those tools were collected and destroyed, and some of the better ones got evaluated by engineers and incorporated into the official maintenance docs.

Heck, we even had to physically go around into the mechanics toolboxes and confiscate things. Even low level stuff like drifts and screwdrivers!
 
The bottom line is that there is risk in life. Whether it’s trying to break a speed record at a race track or walking down stairways at home. We all face dangers every day. And the folks here on this site risk more than most.

And we all try to minimize risk. But sometimes shit still happens. And if, one day, we determine that the risk isn’t worth it, we should stop our involvement in that risky behavior.

I am what many would call elderly. And I’ve done a number of risky things in my life. Riding a motorcycle is one of them. Now, when I get up from the sofa to take a piss, I always put my phone in my pocket so I can call someone if I should fall.

If one can’t minimize all the risk involved in a particular activity, perhaps it’s time to stop that activity. And sometimes you will decide the risk isn’t worth it. For instance, I was once hurt terribly by my first wife. I never wanted to feel those things again. Yet I made the decision to marry one more time. And though we had a rough time at the end (Alzheimer’s), I would do it all over again.

We all make decisions in life and we all have to deal with the results of those decisions. And no one gets out of life alive.
 
The part that really stood out to me was the reduced size of the horizontal stabilizer. Obviously enough of a change to require a stabilization system.


Not related to this crash, but I recently learned that fuel was pumped in and out of the horizontal tail for trim and balance during flight. Amazing.

More interesting info on the MD11:
boltflight.com

Unmasking the MD-11: The Shocking Truth Behind Its Extreme Landing Speed - Bolt Flight

The McDonnell Douglas MD-11 stands out not only for its elegant trijet layout and storied role in long-haul aviation but also for a trait that has captivated and confounded pilots for decades: its unusually high landing speed. Far beyond a minor quirk, this characteristic stems from deep...
boltflight.com boltflight.com
 
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Enchanter said:
The part that really stood out to me was the reduced size of the horizontal stabilizer. Obviously enough of a change to require a stabilization system.


Not related to this crash, but I recently learned that fuel was pumped in and out of the horizontal tail for trim and balance during flight. Amazing.

More interesting info on the MD11:
boltflight.com

Unmasking the MD-11: The Shocking Truth Behind Its Extreme Landing Speed - Bolt Flight

The McDonnell Douglas MD-11 stands out not only for its elegant trijet layout and storied role in long-haul aviation but also for a trait that has captivated and confounded pilots for decades: its unusually high landing speed. Far beyond a minor quirk, this characteristic stems from deep...
boltflight.com boltflight.com
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Yea here:


 
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