Plane Crash - Jet Crash

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DejaMoo
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Re: Plane Crash - Jet Crash

#801

Post by DejaMoo » Thu Apr 19, 2018 12:48 pm

TollandRCR wrote:
Thu Apr 19, 2018 12:06 pm
Does Southwest give appropriate time and attention to routine maintenance?
The next question would be, where does that maintenance take place? A former coworker's hubby was an aircraft mechanic, and he had strong opinions about the trend of setting up maintenance facilities in second- and third-world countries and having the work done by locals there, instead of in the US. His concerns had to do with the ability of non-English speakers to fully grasp technical documentation written in English, oversight of the work, and a fear that the supply chains were more likely to end up with counterfeit parts, which are not built to spec and are thus more likely to fail.

The counterfeit parts bit resonated with me, because I have a brother whose career involved supplying industry, the military, and nuclear power plants with electrical hardware. He had lots of stories about corrupted supply chains and counterfeit parts. Sometimes the procurement persons for the organizations would bypass their established (and sometimes mandated) supply chains because the temptation to save all that money was just too great - and then learn the hard way why that was such a dangerously bad idea.

His best story that can be shared was about a prison that needed a replacement industrial capacitor (these are bigger than garbage cans) for their power plant. They requested bids and my brother, the official sales rep for the factory that built these, submitted his bid. To his shock and horror, the prison accepted a bid from the little local neighborhood hardware store in the small rural town near the prison. There was no way that business could've procured this part - they weren't authorized sellers and the factory confirmed they hadn't supplied them - but the prison ignored my brother's warning and purchased the suspicious capacitor. The cap soon blew up, damaging the power plant and causing a blackout at the prison. The prison had the chutzpah to submit an official warranty/damages claim for the bad cap through my brother to the ostensible manufacturer, who denied the claim, pointing out they'd already been told the factory hadn't built it.



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JohnPCapitalist
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Re: Plane Crash - Jet Crash

#802

Post by JohnPCapitalist » Thu Apr 19, 2018 12:53 pm

TollandRCR wrote:
Thu Apr 19, 2018 12:06 pm
Does Southwest give appropriate time and attention to routine maintenance?
I think their safety record is one of the best in the air. They have only had one single death in their nearly 50 year operating history prior to this incident, and only a relatively small number of major incidents. They're the biggest US airline in terms of annual passenger boardings, so those absolute numbers are even better when adjusted to a basis of per billion passenger miles or some other comparable number. I would have no problem flying SWA after this incident.



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Sam the Centipede
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Re: Plane Crash - Jet Crash

#803

Post by Sam the Centipede » Thu Apr 19, 2018 1:08 pm

TollandRCR wrote:
Thu Apr 19, 2018 12:06 pm
Does Southwest give appropriate time and attention to routine maintenance?
Jet turbine rotors are nasty beasts. They operate at high temperatures under immense loads, and metal fatigue is always going to be an issue. About ten years ago, I was at a short presentation about maintenance of these from a Rolls-Royce engineer (the Southwest Airline plane used SNECMA, now CFMI, engines). Health warning: what follows is based on distant memories, so might be wrong. Maintenance inspection identifies cracks, and when they are above a critical level, the blade is replaced. It's not realistic to simply replace every blade as soon as any sort of minor crack is found, cracking of some sort is normal in metals. The science of fracture mechanics aims to predict - with some degree of uncertainty - how quickly a crack will propagate under the expected loads. In simple terms, at the deep end of a crack, the "crack tip", there's a zone of metal that's placed under increased stress by the geometry of the crack changing the load paths through the component, and as the zone is stressed repeatedly, it absorbs energy which causes the crack to extend. For very small cracks, this isn't a problem, it's normal. But as the crack grows longer and longer, the stresses at the tip get higher and higher, and at some point the component fails as it can no longer absorb energy and fracture occurs.

But most metal fatigue and crack propagation calculations are probabilistic and sometimes "shit happens". Real cracks aren't as neat and tidy as the textbook diagrams; the cracks haven't studied the mathematics they're supposed to follow! As with most accidents, there are probably several causes to this one which came together in an episode of bad luck: possibly a crack that was missed, mis-measured or misrecorded for some reason (crack detection can be difficult) combined with a small fault in the engine, and the blade is just slightly over-stressed, and blam!, disaster.



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Azastan
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Re: Plane Crash - Jet Crash

#804

Post by Azastan » Thu Apr 19, 2018 1:12 pm

JohnPCapitalist wrote:
Thu Apr 19, 2018 12:53 pm
TollandRCR wrote:
Thu Apr 19, 2018 12:06 pm
Does Southwest give appropriate time and attention to routine maintenance?
I think their safety record is one of the best in the air. They have only had one single death in their nearly 50 year operating history prior to this incident, and only a relatively small number of major incidents. They're the biggest US airline in terms of annual passenger boardings, so those absolute numbers are even better when adjusted to a basis of per billion passenger miles or some other comparable number. I would have no problem flying SWA after this incident.
One of my horse clients started off as a mechanic for SWA, then became a pilot for them. Apparently he felt that the maintenance on the planes was good enough that he felt safe flying their planes!



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Sugar Magnolia
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Re: Plane Crash - Jet Crash

#805

Post by Sugar Magnolia » Fri Apr 20, 2018 5:06 am

My brother works for Eaton Aerospace, doing something or other with jet engines, and SW is his first choice.



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Re: Plane Crash - Jet Crash

#806

Post by RTH10260 » Fri Apr 20, 2018 12:47 pm

Sam the Centipede wrote:
Thu Apr 19, 2018 1:08 pm
TollandRCR wrote:
Thu Apr 19, 2018 12:06 pm
Does Southwest give appropriate time and attention to routine maintenance?
► Show Spoiler
But most metal fatigue and crack propagation calculations are probabilistic and sometimes "shit happens". Real cracks aren't as neat and tidy as the textbook diagrams; the cracks haven't studied the mathematics they're supposed to follow! As with most accidents, there are probably several causes to this one which came together in an episode of bad luck: possibly a crack that was missed, mis-measured or misrecorded for some reason (crack detection can be difficult) combined with a small fault in the engine, and the blade is just slightly over-stressed, and blam!, disaster.
The way I understand the aircratft industry they don't consider a stress failure of a turbine rotor blade a catstrophe. It's just a case of "shit happens" and for that the outside of the jet engine is constructed to absorb the metal parts. I understand that in this case too the stuff worked as designed and the blade was correctly sucked into the engine to cause destruction there. When this happen the whole axis of rotors gets out of sync and starts wobbling. The engine and its encasement is constructed in a way that no parts ought to leave the containment, or only shoot out thru the exhaust line. What happened here, and there are reports from a similar indcident in 2016, that the wobbeling destroyed the engine inlet, followed by parts of the cowling. These parts went flying, damaging the front of the left wing and one shrapnel hit a window. Interesting aspect: no glas of the window was found inside the airplane, all must have been sucked out by the decompression. Major parts of the cowling are being recovered along the flight path at and after the point of incident. Radar did detect dropping pieces and their final position was extrapolated.



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Sam the Centipede
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Re: Plane Crash - Jet Crash

#807

Post by Sam the Centipede » Fri Apr 20, 2018 4:23 pm

Yes, you're right, thanks. I shouldn't have said that fracture of a turbine blade is automatically a disaster in the sense of causing serious danger to the safety of the airplane and the people on it. It is a disaster in the sense that it will mess up the engine good and proper. But the engines should be - and are, I'm sure - designed to absorb the failure, but that didn't happen here. Whether that was a fault in design or a "shit happens" thing, I certainly don't know.

The Rolls-Royce guy talking to us was looking at the maintenance side, judging the appropriate service and inspection requirements, so he didn't talk to us about what happens if/when a blade fails, which is a whole different issue.

Good engineering design looks at many issues. Clearly the first intention is to design something that doesn't fail. But then, for many applications, one looks at what happens if components do fail, and you want it to fail safely. I mentioned in an old thread about how offshore oil platforms are designed so that can withstand boat impacts, but there's no way one could withstand an unpowered and out-of-control 300,000 ton tanker smashing into it, so they are usually designed so that the subsea valves won't fail and the wells won't leak if the platform does get knocked over. I know little or nothing of aircraft engine design but I'm sure it's all similar.

Incidentally, all modern airliner engines are mounted on pylons beneath the wings, which brings at least four advantages into play: (1) it means the aircraft can accept different manufacturer's engines and different models of engine (because they don't have to fit an arbitrarily sized nacelle); (2) problems with the engine are less likely to endanger critical structural components in the wing; (3) access for maintenance is easier; and (4) the engine is more likely to shear off safely in the event of a catastrophic landing. There's a lot more going on than meets the eye!



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Re: Plane Crash - Jet Crash

#808

Post by Judge Roy Bean » Fri Apr 20, 2018 5:14 pm

I had the "opportunity" (misfortune?) to arrange the temporary storage of a friend's vintage airplane that was scheduled to appear at an airshow some years ago. Needless to say, space was limited and we were pleased that one of the facilities at the airport could make some space for a couple of days before and after the show days. What I found myself in was a maintenance facility - not for any of the major airlines, but there were two DC-8s being worked on with livery I didn't recognize.

I borrowed a broom before we pushed the plane in - there were so many bits and pieces of metal on the floor that I was afraid it could have damaged a tire. The floor of the whole place was a mess. I talked with what appeared to be the boss, and he was very friendly and cooperative but we were often interrupted by "mechanics" who would come over to look at the plane and then ask him to look at something or read something in a binder and explain it. All of this communicating with the workers was in Spanish but all of the manuals were in English. :doh:


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Re: Plane Crash - Jet Crash

#809

Post by RTH10260 » Sat Apr 21, 2018 9:25 am

Another Juan Browne clip based on the Southwest incident




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TollandRCR
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Re: Plane Crash - Jet Crash

#810

Post by TollandRCR » Sat Apr 21, 2018 9:02 pm

Thanks for the interesting and educational replies to my naive question.


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Re: Plane Crash - Jet Crash

#811

Post by RTH10260 » Wed May 02, 2018 8:27 pm

At least 5 dead after military plane crash in Savannah, Georgia
By ELIZABETH MCLAUGHLIN RACHEL KATZ May 2, 2018, 6:44 PM ET

At least five people are dead and four remain missing after a C-130 "Hercules" plane belonging to the Puerto Rico National Guard crashed outside the Savannah/Hilton Head International Airport in Georgia at 11:28 a.m., according to Georgia Air National Guard Captain Jeffrey E. Bezore.

An Air Force spokesperson specified the plane was a WC-130 weather reconnaissance plane, belonging to the 156th Airlift Wing.

A Puerto Rico government official tells ABC News the plane manifest had 9 passengers on it.

"We don't expect any survivors," the official said.


https://abcnews.go.com/US/130-cargo-pla ... d=54882292



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Re: Plane Crash - Jet Crash

#812

Post by Kendra » Fri May 18, 2018 1:51 pm



Not much info yet.



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Re: Plane Crash - Jet Crash

#813

Post by Addie » Fri May 18, 2018 3:51 pm

Independent
Cubana airlines crashed after takeoff on domestic flight - over 100 dead ...

A passenger plane with 104 people on board has crashed shortly after take off from Havana's main airport.

State media reported that there were three survivors in a critical condition after the Boeing 737 jet, which was en route from Jose Marti International Airport to the eastern Cuban city of Holguin, came down.

Flight CU972 was scheduled to depart at 11am local time (4pm BST) and land an hour and 20 minutes later.

The jet came down close to the airport with photos shared on social media showing a large plume of thick, black smoke rising from near the terminal buildings.

Havana’s air hub is a short way southwest of the Cuban capital, and has pockets of population nearby as well as a major highway near one end of the runway.

There is concern that people on the ground may be among the casualties.


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Re: Plane Crash - Jet Crash

#814

Post by Addie » Thu May 24, 2018 7:02 am

The Guardian
MH17 downed by Russian military missile system, say investigators

Dutch investigators say they have uncovered hard evidence that a Russian army missile system fired the missile that shot down flight MH17 over eastern Ukraine in 2014.

The Malaysian Airlines Boeing 777 was travelling from Amsterdam to Kuala Lumpur when it was shot down over the conflict zone in eastern Ukraine on 17 July 2014. All 298 people onboard were killed.

In 2016, Dutch investigators announced they had evidence that the BUK system involved in the incident had crossed the border into eastern Ukraine from Russia and returned after the plane had been shot down.

At a press conference in The Hague on Thursday, Dutch police and prosecutors showed photo and video evidence they said proved that they had identified the specific BUK system responsible for shooting down the plane. They said they now had “legal and convincing evidence which will stand in a courtroom” that the BUK system involved came from the 53rd anti-aircraft missile brigade based in Kursk in western Russia.
Adding:
BBC News: MH17 missile owned by Russian brigade, investigators say


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Danraft
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Re: Plane Crash - Jet Crash

#815

Post by Danraft » Thu May 24, 2018 11:24 pm

I remember the captured radio transmissions. Didn't seem to be much doubt, although I'm still not sure it was intentional.
Wow.
Where would this go now? An international court?


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Re: Plane Crash - Jet Crash

#816

Post by vic » Fri May 25, 2018 12:09 am

Danraft wrote:
Thu May 24, 2018 11:24 pm
I remember the captured radio transmissions. Didn't seem to be much doubt, although I'm still not sure it was intentional.
Wow.
Where would this go now? An international court?
1) The NATO countries impose sanctions on Russia.
2) Putin agrees to let Trump build hotel in Moscow.
3) Trump rescinds sanctions; enters into agreement to buy fighter jets from Sukol and require US Government travel on Aeroflot where possible.



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Re: Plane Crash - Jet Crash

#817

Post by Volkonski » Fri May 25, 2018 9:57 am

MH17: Australia and Netherlands accuse Russia of complicity
Foreign minister says Australia will seek financial compensation from Moscow


https://www.theguardian.com/world/2018/ ... ression=tr
“Australia and the Netherlands have now informed the Russian Federation that we hold it responsible under international law for its role in the bringing down of MH17,” said Australia’s foreign minister, Julie Bishop, on Friday.

She called on Russia to “enter into negotiations to open up a dialogue about its conduct and to seek reparations”.

The call is likely to bring about a diplomatic standoff, with Russia continuing to deny complicity and refusing to cooperate with investigators.

On Thursday a team of international investigators that the missile system involved in shooting down the Malaysia Airlines plane came from a Russian military brigade.


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Re: Plane Crash - Jet Crash

#818

Post by Sterngard Friegen » Fri May 25, 2018 10:08 am

When responsible nations shoot down commercial aircraft, the agree to pay reparations. That's what the United States did after it shot down Iran Air FLight 655 in 1988.
In 1996, the United States and Iran reached a settlement at the International Court of Justice which included the statement "...the United States recognized the aerial incident of 3 July 1988 as a terrible human tragedy and expressed deep regret over the loss of lives caused by the incident...". As part of the settlement, even though the United States did not admit legal liability or formally apologize to Iran, they still agreed to pay US$61.8 million on an ex gratia basis, amounting to $213,103.45 per passenger, in compensation to the families of the Iranian victims.
https://en.wikipedia.org/wiki/Iran_Air_Flight_655

A country like Russia (in this case, the USSR) follows a different path. After it shoots down a commercial airliner it engages in bellicose accusations, blames others, and refuses to pay anyone anything. That's what happened in 1983 when the Soviets shot down Korean Airlines Flight 007.
https://en.wikipedia.org/wiki/Kal_007



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