Metrojet crash Eygpt
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I have seen many photos of plane crashes with the engines heavily damaged, but have I don't remember seeing any with a broken fwd fan shaft. Usually what is seen is the main fan disk still attached and heavy damage on all the fan blades.
So for me after loss of the tail, separation of the fan and the engines look plausible.
I can not think of any engine failure scenario that separates the fan but leaves the fan blades widely undamaged.
P.S. found a report link here :
http://www.oocities.org/capecanavera...3/comgalyp.htm
(b) Investigation by the de Havilland Engine Company Limited
80. The R.A.E. investigation did not deal with the engines. The history of their recovery and investigation is as follows.
81. The centre section of the wing of Yoke Peter was recovered from the sea on the 15th March. It was severely damaged by fire and by impact with the water. It contained the four Ghost engines substantially intact with the exception that the turbine disc of No. 2 engine (port inner) was missing. The shaft on which it had been mounted had broken near the hub to which it was bolted and it had escaped through a large gash in the exhaust cone. The disc has not been recovered.
82. The engines were removed and examined superficially by an engineer from de Havillands Engine Company Limited. They were then sent by air to that company's works where they arrived on the 21st March and were dismantled and examined in detail.
83. Dr. Moult, Chief Engineer of the de Havilland Engine Company Limited, said in evidence that there were no signs consistent with seizure of any engine, or of any excessive internal heat, or of any failure having occurred before the break-up of the aircraft. The extensive fire damage was all external to the engines. The four compressor impellers were intact on their shafts.
84. The turbine discs from Nos. 1, 3 and 4 engines showed no signs of failure. No blades were missing from them. In No. 2 engine, there was no evidence of penetration of the shroud ring surrounding the turbine, either by a blade or by the complete disc. There was no evidence of failure of any blade in any of the engines.
85. Examination of the hubs to which the turbine discs of Nos. 1, 3 and 4 engines were bolted showed that all were on the point of failing. Cracks were found in the same regions as those which had resulted in the fracture of No. 2 engine, which led to the loss of the disc.
86. The remarkable similarity of the damage to the turbine shafts of all four engines pointed to a common cause external to the engines, and further examination showed that the most probable cause was a sudden and very rapid rotation of the whole wing about a transverse axis, nose downwards, while the engines were still running normally. Such a rotation, being about an axis at right angles to the engine shafts, would produce gyroscopic couples tending to bend the shafts in a sideways direction, that is, in the plane of the wing. Since the clearances between the discs and the stationary parts surrounding them are small, signs of rubbing would be expected in definite regions. Examination showed such signs in each engine.
87. From this evidence the conclusion was reached that the engines had run, though only for a short time, possibly a few hundred revolutions after a sudden nose-down rotation of the wing and had not stopped suddenly. Further examination showed other evidence consistent with this, namely the absence of any deformation in the splines on the turbine shafts. This also suggested that by the time the whole of the centre section, including the engines, hit the surface of the sea, the engines were no lancer rotating.
88. The whole of the remaining extensive damage to the engines was considered to be due to impact with the surface of the sea. It was in the main confined to the upper parts of the engines, and was therefore consistent with the deductions from the examination of the centre section of the wing itself, which showed everywhere evidence of the wing having hit the sea upside down.
89. In order to investigate the conditions which were now thought to have caused the failure of the turbine hubs, tests were made on a Ghost engine supported in a framework which was pivoted about a horizontal axis some distance above the engine, so that it could swing in a vertical plane, like a pendulum. The engine was run at normal speed, and was pulled sideways, thus raising it from its lowest position. When released, it accelerated under the combined influence of its weight and the thrust from the jet. The rate of rotation round the transverse axis could be varied by releasing it from different heights. It was found that when this reached a value of nearly 180° a second (corresponding to the centre section of the wing turning upside down in about one second) the turbine disc hub broke and the engine slowed down and stopped without any further substantial damage. Examination showed the same type of failure and symptoms, as were found on the four engines of Yoke Peter.
80. The R.A.E. investigation did not deal with the engines. The history of their recovery and investigation is as follows.
81. The centre section of the wing of Yoke Peter was recovered from the sea on the 15th March. It was severely damaged by fire and by impact with the water. It contained the four Ghost engines substantially intact with the exception that the turbine disc of No. 2 engine (port inner) was missing. The shaft on which it had been mounted had broken near the hub to which it was bolted and it had escaped through a large gash in the exhaust cone. The disc has not been recovered.
82. The engines were removed and examined superficially by an engineer from de Havillands Engine Company Limited. They were then sent by air to that company's works where they arrived on the 21st March and were dismantled and examined in detail.
83. Dr. Moult, Chief Engineer of the de Havilland Engine Company Limited, said in evidence that there were no signs consistent with seizure of any engine, or of any excessive internal heat, or of any failure having occurred before the break-up of the aircraft. The extensive fire damage was all external to the engines. The four compressor impellers were intact on their shafts.
84. The turbine discs from Nos. 1, 3 and 4 engines showed no signs of failure. No blades were missing from them. In No. 2 engine, there was no evidence of penetration of the shroud ring surrounding the turbine, either by a blade or by the complete disc. There was no evidence of failure of any blade in any of the engines.
85. Examination of the hubs to which the turbine discs of Nos. 1, 3 and 4 engines were bolted showed that all were on the point of failing. Cracks were found in the same regions as those which had resulted in the fracture of No. 2 engine, which led to the loss of the disc.
86. The remarkable similarity of the damage to the turbine shafts of all four engines pointed to a common cause external to the engines, and further examination showed that the most probable cause was a sudden and very rapid rotation of the whole wing about a transverse axis, nose downwards, while the engines were still running normally. Such a rotation, being about an axis at right angles to the engine shafts, would produce gyroscopic couples tending to bend the shafts in a sideways direction, that is, in the plane of the wing. Since the clearances between the discs and the stationary parts surrounding them are small, signs of rubbing would be expected in definite regions. Examination showed such signs in each engine.
87. From this evidence the conclusion was reached that the engines had run, though only for a short time, possibly a few hundred revolutions after a sudden nose-down rotation of the wing and had not stopped suddenly. Further examination showed other evidence consistent with this, namely the absence of any deformation in the splines on the turbine shafts. This also suggested that by the time the whole of the centre section, including the engines, hit the surface of the sea, the engines were no lancer rotating.
88. The whole of the remaining extensive damage to the engines was considered to be due to impact with the surface of the sea. It was in the main confined to the upper parts of the engines, and was therefore consistent with the deductions from the examination of the centre section of the wing itself, which showed everywhere evidence of the wing having hit the sea upside down.
89. In order to investigate the conditions which were now thought to have caused the failure of the turbine hubs, tests were made on a Ghost engine supported in a framework which was pivoted about a horizontal axis some distance above the engine, so that it could swing in a vertical plane, like a pendulum. The engine was run at normal speed, and was pulled sideways, thus raising it from its lowest position. When released, it accelerated under the combined influence of its weight and the thrust from the jet. The rate of rotation round the transverse axis could be varied by releasing it from different heights. It was found that when this reached a value of nearly 180° a second (corresponding to the centre section of the wing turning upside down in about one second) the turbine disc hub broke and the engine slowed down and stopped without any further substantial damage. Examination showed the same type of failure and symptoms, as were found on the four engines of Yoke Peter.
Last edited by Volume; 27th Nov 2015 at 07:32. Reason: Link and quote added
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RE Volume and gyro loads
Volume said #183 (permalink)
That gyro loads can be very destructive ( reaction of a spinning disk at right angles to displacement ) was well documented in 1959-1960 re the Lockheed Electra crashes. In those cases, a weakened engine mount on the turboprop engine resulted in near total destruction of the wing and resultant crash(es)
Lessons Learned
IF the tail separated ( on the metrojet ) allowing a rapid pitch change then tearing of the pylons could be expected.
Check out the Comet crash investigation of G-ALYP. If I remember correctly, at least one turbine separated from the shaft. It was confirmed by testing that this can be atributed to gyroscopic loads if the wing pitching moment turns the engines quickly nose-down when the tail is no longer preventing this.
Lessons Learned
IF the tail separated ( on the metrojet ) allowing a rapid pitch change then tearing of the pylons could be expected.
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Metrojet versus JAL123 tail damage
I stumbled upon a drawing of the damage of the JAL123 tail. Damage was almost exactly like that of the Metrojet tail. So front of leading edge and tip missing, as well as wing box and rudder. And damage in same relative locations. Also same components still missing.
When you look at the english language report of JAL, the drawing appears to be a little different. But still a lot of similarities.
The structure size is of course quite different. And the location of the fin box versus the location of the pressure bulkhead also.
But still.
This could make a bomb in the cabin scenario a little less probable.
I wonder if anyone has a link to the Japanses language version of the report.. I hope the photos and drawings in that one are better than the ones that i have now.
When you look at the english language report of JAL, the drawing appears to be a little different. But still a lot of similarities.
The structure size is of course quite different. And the location of the fin box versus the location of the pressure bulkhead also.
But still.
This could make a bomb in the cabin scenario a little less probable.
I wonder if anyone has a link to the Japanses language version of the report.. I hope the photos and drawings in that one are better than the ones that i have now.
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JAL123 AAR by JTSB
A0283:
You may find JAL123 AAR by JTSB (parts you wanted) at:
http://www.mlit.go.jp/jtsb/aircraft/...2-2-JA8119.pdf
(Cover page)
http://www.mlit.go.jp/jtsb/aircraft/...-JA8119-05.pdf (illustrations)
http://www.mlit.go.jp/jtsb/aircraft/...-JA8119-06.pdf (photos 1)
http://www.mlit.go.jp/jtsb/aircraft/...-JA8119-07.pdf (photos 2)
http://www.mlit.go.jp/jtsb/aircraft/...-JA8119-08.pdf (photos 3)
You may find JAL123 AAR by JTSB (parts you wanted) at:
http://www.mlit.go.jp/jtsb/aircraft/...2-2-JA8119.pdf
(Cover page)
http://www.mlit.go.jp/jtsb/aircraft/...-JA8119-05.pdf (illustrations)
http://www.mlit.go.jp/jtsb/aircraft/...-JA8119-06.pdf (photos 1)
http://www.mlit.go.jp/jtsb/aircraft/...-JA8119-07.pdf (photos 2)
http://www.mlit.go.jp/jtsb/aircraft/...-JA8119-08.pdf (photos 3)
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AO283 post 177 concerning rudder doublet testing
Rudder doublets were not required nor were they tested/attempted during certification of Airbus A300 (AA587 aircraft) nor were doublets attempted/ required of Boeing 767 / 757 certification.
When asked about rudder doublets testing by Airbus while investigating the smoking wreckage of AA587, the Airbus safety/ pilot representative on site stated the "no they are not tested during certification, the vertical stabilizer would likely detach from the aircraft."
I doubt if other Airbus or Boeing commercial aircraft types are rudder doublet tested either.
Rudder doublets were not required nor were they tested/attempted during certification of Airbus A300 (AA587 aircraft) nor were doublets attempted/ required of Boeing 767 / 757 certification.
When asked about rudder doublets testing by Airbus while investigating the smoking wreckage of AA587, the Airbus safety/ pilot representative on site stated the "no they are not tested during certification, the vertical stabilizer would likely detach from the aircraft."
I doubt if other Airbus or Boeing commercial aircraft types are rudder doublet tested either.
Last edited by SKS777FLYER; 30th Nov 2015 at 19:27. Reason: AO283
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Reuters: Egypt has completed a preliminary report on the Russian plane crash in Sinai on Oct. 31 that killed all 224 people on board, the civil aviation ministry said on Monday.
"The technical investigative committee has so far not found anything indicating any illegal intervention or terrorist action," the ministry said in a statement.
"The technical investigative committee has so far not found anything indicating any illegal intervention or terrorist action," the ministry said in a statement.
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I'm sure that earlier in this thread, someone predicted the Egyptians would find nothing terrorist related. This crash has affected their tourism industry and they're very keen to get it back where it was.
How surprising that they'd find different to Western and Russian investigators, just like they have done before.
How surprising that they'd find different to Western and Russian investigators, just like they have done before.
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metrojet
Although I have followed the full thread I seem to have missed something.
Have we definitely seen the starboard tailplane?
Has anyone seen or got posession of SCREWJACK and end fittings?
If Egypts findings are sound it is wicked to cry " bomb" as an excuse for military politics.
Have we definitely seen the starboard tailplane?
Has anyone seen or got posession of SCREWJACK and end fittings?
If Egypts findings are sound it is wicked to cry " bomb" as an excuse for military politics.
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The Independent
Russian plane crash: Egypt report says 'no evidence' Sinai jet was brought down by Isis terrorists
Russian plane crash: Egypt report says 'no evidence' Sinai jet was brought down by Isis terrorists
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UPDATED: Egypt says preliminary investigation shows no evidence of terrorist attack in Russian plane crash
Ahram Online , Monday 14 Dec 2015
Egypt's civil aviation ministry said in a statement on Monday that results of a preliminary investigation into the downing of a Russian plane over Egypt's Central Sinai in October indicate that the crash was not the result of a terrorist act.
"The investigative committee completed on Sunday the preliminary report on the [Russian] plane crash," a statement sent to Ahram Online by Egypt's civil aviation ministry said.
"The technical investigative committee has so far not found any evidence indicating criminal or terrorist activity in the downing of the plane, chief investigator Ayman El-Muqqadam said.
The statement added that a copy of the report has been sent to authorised international experts taking part in the probe, including from Russia, Ireland, and France, and International Civil Aviation Organization (ICAO).
On 17 November, Russia asserted for the first time that a homemade bomb containing up to 1 kilogram of TNT blew apart the Airbus A321, which took off from the Egyptian resort of Sharm El-Sheikh en route to Russia's St Petersburg.
Since the 31 October crash, which claimed the lives of all 224 aboard, Egypt insisted that its full investigation must be completed to definitevely determine the cause of crash.
The Egyptian government has dismissed statements made by the US and Britain which back Russian assertion of a terrorist attack, saying that only an official probe can draw such a finding.
He added that the committee is "continuing its work," saying that the preliminary conclusion will be verified with more detailed information in later phases of the probe.
Quashing theories that the bomb was planted on the plane in Turkey, El-Muqqadam affirmed that black box recordings of the passenger jet indicated that the aircraft's route for five days prior to the crash remained confined to flights between Egyptian and Russian airports only,
Several countries have suspended flights to Sharm El-Sheikh or Egypt altogether over security fears, prompting concerns that the country's already-troubled tourism industry -- could face a huge drop.
Russia has also banned incoming flights by Egypt's state-owned airline EgyptAir over concerns of the company's implemented security measures on the back of the disaster.
Ahram Online , Monday 14 Dec 2015
Egypt's civil aviation ministry said in a statement on Monday that results of a preliminary investigation into the downing of a Russian plane over Egypt's Central Sinai in October indicate that the crash was not the result of a terrorist act.
"The investigative committee completed on Sunday the preliminary report on the [Russian] plane crash," a statement sent to Ahram Online by Egypt's civil aviation ministry said.
"The technical investigative committee has so far not found any evidence indicating criminal or terrorist activity in the downing of the plane, chief investigator Ayman El-Muqqadam said.
The statement added that a copy of the report has been sent to authorised international experts taking part in the probe, including from Russia, Ireland, and France, and International Civil Aviation Organization (ICAO).
On 17 November, Russia asserted for the first time that a homemade bomb containing up to 1 kilogram of TNT blew apart the Airbus A321, which took off from the Egyptian resort of Sharm El-Sheikh en route to Russia's St Petersburg.
Since the 31 October crash, which claimed the lives of all 224 aboard, Egypt insisted that its full investigation must be completed to definitevely determine the cause of crash.
The Egyptian government has dismissed statements made by the US and Britain which back Russian assertion of a terrorist attack, saying that only an official probe can draw such a finding.
He added that the committee is "continuing its work," saying that the preliminary conclusion will be verified with more detailed information in later phases of the probe.
Quashing theories that the bomb was planted on the plane in Turkey, El-Muqqadam affirmed that black box recordings of the passenger jet indicated that the aircraft's route for five days prior to the crash remained confined to flights between Egyptian and Russian airports only,
Several countries have suspended flights to Sharm El-Sheikh or Egypt altogether over security fears, prompting concerns that the country's already-troubled tourism industry -- could face a huge drop.
Russia has also banned incoming flights by Egypt's state-owned airline EgyptAir over concerns of the company's implemented security measures on the back of the disaster.
Last edited by Kulverstukas; 14th Dec 2015 at 12:06.
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No Suprises
No suprises then that the Egyptian Authorities have their heads firmly buried in the Sinai sand, hoping this cloud will pass over and the tourist dineros start to flow again. With this attitude, its difficult to believe that they can ever get Sharm security up to and maintained to International standards.If any of their airports.
I see EZY have pulled the route from September 2016, frankly can`t see anyone flying there anytime soon.
I see EZY have pulled the route from September 2016, frankly can`t see anyone flying there anytime soon.
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According to Wikipedia, Metrojet have suspended all operations from 5 December until next summer due to a severe reduction in passengers as a result of the accident and the security situation at its primary leisure destinations in Egypt.
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Kulverstukas says: "UPDATED: Egypt says preliminary investigation shows no evidence of terrorist attack in Russian plane crash"
The strange curving of the fuselage in this picture in #1206 needs explaining:
http://www.pprune.org/rumours-news/5...an-fir-61.html
Does a sudden decompression explain it?
The strange curving of the fuselage in this picture in #1206 needs explaining:
http://www.pprune.org/rumours-news/5...an-fir-61.html
Does a sudden decompression explain it?
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Egypt's civil aviation ministry said in a statement on Monday that results of a preliminary investigation into the downing of a Russian plane over Egypt's Central Sinai in October indicate that the crash was not the result of a terrorist act.
"The investigative committee completed on Sunday the preliminary report on the [Russian] plane crash," a statement sent to Ahram Online by Egypt's civil aviation ministry said.
"The technical investigative committee has so far not found any evidence indicating criminal or terrorist activity in the downing of the plane, chief investigator Ayman El-Muqqadam said.
"The investigative committee completed on Sunday the preliminary report on the [Russian] plane crash," a statement sent to Ahram Online by Egypt's civil aviation ministry said.
"The technical investigative committee has so far not found any evidence indicating criminal or terrorist activity in the downing of the plane, chief investigator Ayman El-Muqqadam said.
Sure, absence of evidence isn't quite the same thing as evidence of absence, but the absence of any evidence to support the 'conspiracy theory' that the aircraft was bombed out of the air deliberately is desperately thin.
No bomb. No missile. Quite reminiscent of TWA800 when the FBI tried to prove their conspiracy theory and the poor old NTSB was left with the conundrum of trying to claim that their own 'scientific' conclusions were wrong.
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What strange curving? It's a large section of skin & L3 door from the left mid-section just over the wing that's been torn from the structure just as the rest of the fuselage aft of the wings has been. The structure on the right is the aft section of the left-wing fairing.
Regarding "absence of evidence" & "evidence of absence", the Egyptians obviously need to fill in the gaping absence of explanations if the bomb theory is toast.
Similarly, I know the MAK is good, but the Russians need to provide the same quality of evidence for their bomb theory.
Either explanation needs to withstand independent scrutiny by people and organizations who do this kind of investigation work in their sleep.
Until then, all explanations are sadly just political posturing no matter what is said.
Regarding "absence of evidence" & "evidence of absence", the Egyptians obviously need to fill in the gaping absence of explanations if the bomb theory is toast.
Similarly, I know the MAK is good, but the Russians need to provide the same quality of evidence for their bomb theory.
Either explanation needs to withstand independent scrutiny by people and organizations who do this kind of investigation work in their sleep.
Until then, all explanations are sadly just political posturing no matter what is said.
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I know the MAK is good, but the Russians need to provide the same quality of evidence for their bomb theory.
Still waiting for any party involved to publish this report or at least confirm that they receive it.