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Rockiedog2

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Captain Haynes had the biggest handful that I'm aware of...best I remember the tower told him he was cleared to land on Runway X and he said he was just gonna try to hit the airport. Or like that. Lotsa folks killed but lotsa folks lived too...outstanding job.

"Hero pilot" is such a creepy term...makes most pros' skin crawl mine included. The media does too.
 

wsimpso1

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Wonder why investigators jumped right in looking for metal fatigue?
Fan blade pieces were inside the fuselage. Fatigue IS the most likely way for that to happen. All of the other ways for that to happen also require the same precautions.

If you think that fatigue or some other mode is involved and you either want to prove it or disprove it, you have to preserve all of the fracture surfaces (and by that I mean prevent all fracture surfaces from touching any other thing or be contaminated with chemicals of any sort) so that they can all be microscopically examined, then examined under an electron microscopse. Find beach marks on surfaces, even microscopic ones, and you had fatigue going when the crack was proceeded through that area. Find initiation points, and you have the story. Find grain boundary separation or chemicals that shouldn't be there, and you start building a case for other failure sources. If you get ALL of the fracture surfaces, preserve them all, and do not find any evidence of cracks creeping across the parts, you might not have had fatigue. If you find evidence only of gross overload, and you have all the surfaces, you had something else happen... And if you are missing parts, well, your argument gets difficult to back up, because you do not know what happened to the parts you have no surfaces from...

So, the investigators are suspicious of fatigue. Good, they might be decent problem solvers. That won't prevent them from finding other things that were bad news too...

Billski
 

BBerson

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We were just talking about the engineering that goes into containment on this and other engines with someone that was on the team of engineers that actually have to figure all this out. This is not supposed to happen, ever, for any reason. Sad that this weird failure took a life. The woman was a Vermont native up through college before moving west. Many around here are a bit stunned. Terrible circumstances all around but it seems like there was a bunch of good stuff that happened at the same time. Happened to be an RN and a bunch of crew and passengers that contained the situation and gave life support. The captain definitely did a great job.

When you sit in a window seat comfy and climate controlled you don't think of the life threatening environment inches from you. 500+MPH and brutal cold not to mention the lack of oxygen content. This kinda puts that in perspective.

I'll be watching to see what the FAA does about this. I think GE and Pratt are going to have some verification work to do on the containment math and testing. This is a well regulated particular piece of procedural engineering. It was supposed to be fail safe.
I was looking at FAR 33. It appears they don't always actually test containment structures?

Fan testing article here:https://www.sciencedirect.com/science/article/pii/S100093611200009X
 
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Aerowerx

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We were just talking about the engineering that goes into containment on this and other engines with someone that was on the team of engineers that actually have to figure all this out. This is not supposed to happen, ever, for any reason. ....
The problem I have with statements like this is that, if you make something 100% failure proof, it would be way to heavy to ever get off the ground. Besides it being impossible to make something 100% failure proof.
 

BBerson

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The containment ring might be intact. Something could fly out the front and then the aircraft could hit it. A piece of loose foam took out the space shuttle.
 

Rockiedog2

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.

Maybe we can convince Rockiedog to contract with the news folks and provide a little common sense , technical experience, and southern charm to their aviation stories?

(hiding under the table as I hit "send", with Don Knotts eyes)[/QUOTE]

that was funny VB.
 

dcstrng

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If you think that fatigue or some other mode is involved and you either want to prove it or disprove it, you have to preserve all of the fracture surfaces (and by that I mean prevent all fracture surfaces from touching any other thing or be contaminated with chemicals of any sort) so that they can all be microscopically examined... So, the investigators are suspicious of fatigue. Good, they might be decent problem solvers. That won't prevent them from finding other things that were bad news too...


It’ll be interesting to see – fatigue, probably – but, as I recall one of the first TF-39s did that in the cell, the shaft-within-idler-bearing lost lube and the low-speed fan tried to accelerate to the compressor speed with predictable results, so when I saw the picture that was my first thought… of course that was about a half a century ago and everything was metal, so who knows how these modern critters behave…
 

TFF

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I have found doing ADs that many can be an annoyance. Once someone gets killed because of a defect, they drop the hammer.
 

Victor Bravo

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Counterfeit parts are apparently a big problem, because there is money in it. I suspect this may be a case of General Tso's Fan Blade with Spicy Paperwork.
 

Aerowerx

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Counterfeit parts are apparently a big problem, because there is money in it. I suspect this may be a case of General Tso's Fan Blade with Spicy Paperwork.
Reminds me of a (fictional) book I read where a (fictional) east asian airline was saving money by using counterfeit parts to repair their (fictional manufacturer) planes. Had something to do with a forward slat deploying at altitude.

Of course the media was out to burn at the stake the (fictional) airplane company that was building death traps. One of those killed in the incident was the pilot in command. So who was at the controls? The pilot's son, who was a wet-behind-the-ears pilot. The (fictional) airplane company demonstrated that if you just left the thing alone the autopilot could handle it, but the green pilot was fighting it causing things to go flying around the cabin, including a passenger's video camera which caught a shot of the pilot's son at the controls!
 

Turd Ferguson

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The story sounds more realistic than fictional, lol.



Reminds me of a (fictional) book I read where a (fictional) east asian airline was saving money by using counterfeit parts to repair their (fictional manufacturer) planes. Had something to do with a forward slat deploying at altitude.

Of course the media was out to burn at the stake the (fictional) airplane company that was building death traps. One of those killed in the incident was the pilot in command. So who was at the controls? The pilot's son, who was a wet-behind-the-ears pilot. The (fictional) airplane company demonstrated that if you just left the thing alone the autopilot could handle it, but the green pilot was fighting it causing things to go flying around the cabin, including a passenger's video camera which caught a shot of the pilot's son at the controls!
 

BBerson

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The fan blades should probably have a life limit, number of hours and cycles. Based on fatigue life like rotor blades.
 

TFF

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Those parts usually do have life limits. They are just not reaching them. A airline engine probably stays on wing 7000 hours; about four years from what I was use too.
 

BBerson

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I thought they did actual fatigue tests on blades to determine life. Then set the legal life at half, or something.
So they shouldn't fail in normal service.
 

Swampyankee

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I thought they did actual fatigue tests on blades to determine life. Then set the legal life at half, or something.
So they shouldn't fail in normal service.
I did ground test at an airframe company (I bounced around a few places in aerospace). At about the time AHS wanted to see how different companies, the major Western helicopter makers (iirc, Aerospatiale, Sikorsky, Boeing, McDonnell/Douglas, and Bell) evaluated a part with the same stress environment and fatigue test data results. The range was from a low of about 100 hours to a high of 25,000. The lesson is that 1/2 could be anywhere in the range of wildly optimistic to uneconomically pessimistic.

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A second issue, from when I worked in the engine business (my signature is one of several on some of the ALF-502 certification reports submitted by Lycoming) is that blade failures are supposed to be contained within the engine. I know from personal observation that this was a concern at both Lycoming and Pratt.

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Miles O'Brien, who is pilot, and owns a Cirrus, said one issue which he thinks may adversely affect airline safety in the future is that the number of military pilots available to the airlines is decreasing, and that the training that civilian pilots get tends to be less rigorous. He credits both Sullenberger's and Shults' ability to deal with emergencies to their military flight training.
 
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