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airhansa
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 8:28 am

Previously, I had ruled out an engine fire because there was no response indicating such from the pilot nor passengers, but media reports today have stated that the plane tried to turn back (albeit still did not communicate anything). I still find it odd that a passenger jet didn't mayday for help at all.

I can't think of a lone fire that would spread so quickly to create a "fireball" - especially an engine fire on a modern Boeing plane. The problem with a fire causing problems for the aircraft, is that such a fire would never spread so quickly to result in a situation where the pilot doesn't mayday for help. It could never spread quickly enough for utterly no-one to voice concern. And a fire would not lead to a situation where both an engine and communications were knocked-out yet the plane was able to turn around. Could it possibly be a cargo fire that got large enough without being noticed?

I agree that some sort of missile could provide a scenario where pilots reacted before calling mayday. Alternatively the only fireball situation I can think of is a cargo fire - an engine failure early on should result in something similar to the Concorde disaster and not a total fireball, with plenty of time for communications to be established.
 
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Carlos01
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 8:33 am

ragots wrote:

So basically, you could say it's all Iranians on board, plus the Ukranian crew.


If the passenger list posted here is correct, also a Swedish Lindberg -family was on board, mother, father and 2 young children.
 
artflyer
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 8:34 am

sevenair wrote:
I don't buy the 'engine parts needed to be replaced in Tehran, there are sanctions therefore a fake part was used, this led to the disasters and oh what a terrible man Trump is".

Since when did replacing an engine part only cause a one hour delay? By the time you open the things up, locate your part, remove it, replace it, close it all back up then sign off the paperwork, you're looking at a lot of time, even if we assume they started working on the engine the minute it reached the stand on arrival. I base this on it being a major part capable of complete and utter devastation of the engine, loss of control, inflight break up and a complete loss. This must have been some major engine part and not a simple oil filter change.

It's a good half hour just to get a top up of oil. It's an hour to check for bird ingestion.

UIA are a good operator from what I can tell. I can't imagine they'd be happy to fit their plane with suspected fake parts and would cancel a flight and replace the aircraft. Or they FedEx in a spare part which as a non Iranian airlines they will be permitted to do and won't be subject to sanctions.


Due to sanctions sending a spare part to Iran would take months. Pls see the case of DY, where it took more than two months. The plane being stranded for so long would also be a huge hit for UIA that is in serious financial difficulties, massively cutting routes while asking Ukrainian government for money to survive.

https://www.bloomberg.com/news/articles ... rives-home
 
iamtom
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 8:36 am

heyjoojoo wrote:
Personally, I believe that if there had been even the slightest possibility that Americans could have been blamed, Iran would have done so. The fact that they’re keeping this so close to the vest makes me think it was one of their ADA sites and someone screwed up.


In the same respect don't you think that if Iran had blown up a plane the US wouldn't have already announced that? The US (and others) have active satellites monitoring for missile launches across the globe. I imagine these eyes in the skies are tuned specifically to Iran right now, so if anything was fired they would know about it. It was also still dark and clear skies above Tehran so it's just not possible a missile launch (especially right now) could be missed.

Several European defence agencies have also announced they have no intelligence to suggest this was a missile attack, and they have absolutely no reason to protect Iran over this.
 
AeroplaneFreak
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 8:38 am

iamtom wrote:
The aircraft landed and had 3 hours on the ground before setting off and we know it was approximately 1 hour delayed leaving. Given there was very little traffic early morning, so unlikely delayed due to congestion, it would indicate a technical issue that needed attention. It's quite possible that the inbound crew flagged an engine overheating issue on their flight in and maintenance were called to investigate. That could easily have involved a support call to Boeing or the engine manufacturer and will absolutely have involved the airlines operations team. All parties involved will have everything logged.


I think what most people are having trouble with is the fact if it was an engine fire or engine failure how did it escalate so fast that essentially within 1 minute it falls from the sky? This would be a first in commercial aviation, of course just because somethings never happened doesn't mean it can't.
 
RickNRoll
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 8:38 am

This crash has instant classic written all over it. Political intrigue, fiery crash, threats of war, missiles being fired, black box data that won't ever be truly trusted.

My commiserations to the poor people who were caught up it.
 
Redd
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 8:38 am

airhansa wrote:
The problem with a fire causing problems for the aircraft, is that such a fire would never spread so quickly to result in a situation where the pilot doesn't mayday for help.


1. Aviate
2. Navigate
3. Communicate

Whether it was a missile or uncontained engine failure or another cause, the pilots first job is to fly the plane first, communicate last. If the pilots are dealing with a critical situation, there is no reasonable expectation that they would have communicated with ATC.
 
airhansa
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 8:40 am

iamtom wrote:
heyjoojoo wrote:
Personally, I believe that if there had been even the slightest possibility that Americans could have been blamed, Iran would have done so. The fact that they’re keeping this so close to the vest makes me think it was one of their ADA sites and someone screwed up.


In the same respect don't you think that if Iran had blown up a plane the US wouldn't have already announced that? The US (and others) have active satellites monitoring for missile launches across the globe. I imagine these eyes in the skies are tuned specifically to Iran right now, so if anything was fired they would know about it. It was also still dark and clear skies above Tehran so it's just not possible a missile launch (especially right now) could be missed.

Several European defence agencies have also announced they have no intelligence to suggest this was a missile attack, and they have absolutely no reason to protect Iran over this.


Even Malaysia refused to share military intelligence with the world on a good day, I doubt the US would share on a bad day.
 
sevenair
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 8:41 am

artflyer wrote:
sevenair wrote:
I don't buy the 'engine parts needed to be replaced in Tehran, there are sanctions therefore a fake part was used, this led to the disasters and oh what a terrible man Trump is".

Since when did replacing an engine part only cause a one hour delay? By the time you open the things up, locate your part, remove it, replace it, close it all back up then sign off the paperwork, you're looking at a lot of time, even if we assume they started working on the engine the minute it reached the stand on arrival. I base this on it being a major part capable of complete and utter devastation of the engine, loss of control, inflight break up and a complete loss. This must have been some major engine part and not a simple oil filter change.

It's a good half hour just to get a top up of oil. It's an hour to check for bird ingestion.

UIA are a good operator from what I can tell. I can't imagine they'd be happy to fit their plane with suspected fake parts and would cancel a flight and replace the aircraft. Or they FedEx in a spare part which as a non Iranian airlines they will be permitted to do and won't be subject to sanctions.


Due to sanctions sending a spare part to Iran would take months. Pls see the case of DY, where it took more than two months. The plane being stranded for so long would also be a huge hit for UIA that is in serious financial difficulties, massively cutting routes while asking Ukrainian government for money to survive.

https://www.bloomberg.com/news/articles ... rives-home


I get what you're saying but I just don't buy it that they'd fit a fake part. For it to seemingly tear the engine apart and render the craft unflyable then we are talking major component like an entire disc. You don't change an entire disc in a few hours.

If it was a single blade then I've known that be done in a few hours but a single blade failing on a wing mounted engine won't bring a plane down so suddenly and catastrophically.
 
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Jouhou
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 8:42 am

xmp125a wrote:
Pavlakakos wrote:
This is just a rumor and i just wanted to share with you. The mother of a flight attendant said she received a phone call from her daughter saying machine guns were being fired in the cabin and then the connection ended.
The stewardess was from the city of Nova Kakhovka and was my wife's classmate. Don't know if the rumor stands, however i guess we'll soon find out. If there was indeed gunfire, the Iranians will be quick to reveal that info, in order to clear themselves from the missile theory.


Since at this stage we all operate on very noisy and unreliable data, we should really talk in probabilities (and understand them as well -- unlike the media that blamed Nate Silver for assigning Trump "only" 30% probability to win).

So back to the topic.

I'd say that machine gun fire inside the cabin has about 0.1% probability to down the airliner in the manner we have seen (and on the data we can reasonably trust). First, the pilots would probably notify ATC or at least change the transponder code (hijacking). Second, I don't know about security in Tehran airport, but Tehran itself is not a war zone, it is not Baghdad, not even a typical US inner city overflown with guns. So someone bringing a machine gun onto an airplane is basically unbelievable.

Now, to divide the rest 99.9%, IMHO.

0.9% intentional downing by a state actor, either Iran or US (fully aware that it is passenger airplane)
19% intentional downing by a MANPADS, operated by some kind of guerilla or rogue force inside Iran
50% of iran making a tragic mistake with nervous and trigger-happy air defences which expected massive retaliation after hitting US bases with missiles
20% uncontained engine failure or other technical fault
20% some kind of unplanned accidental interference with US or Iran military operation (collision with the US drone, unfortunate collateral damage in legitimate Iran action to shoot down existing US aircraft or drone, etc).

I have assigned highest probability to iran's tragic mistake due to Iran being very tame about this incident and claiming basically immediately that it was not downed by a missile. Please note the usual fiery rhetoric from Iran about USA and the West in general (the great Satan etc.) Claiming that it wasn't a missile basically when aircraft barely touched the ground reveals that they know more than they are saying and the tame reaction basically means that they feel at least partly responsible for the downing - or they are sure there were no missiles in vicinity, therefore technical fault. MANPADS or any organized guerilla force in such close vicinity of Tehran airport and indeed urban city itself would be also a massive humiliation to Iran, so that would probably met with subdued silence as well.

Otherwise they would be screaming all over, after all there were two busloads of Iranians on that plane!

Note (0.9% still means that the outcome is possible... but very unlikely, lesson Nate Silver and Trump election).



Also it should be noted mechanical failures of equipment can create a variety of loud noises that may also happen in rapid succession. https://youtu.be/cR8Tr5T0CFQ?t=25s (example of loud scary noise happening repeatedly, not of machine gun like noise)

It's possible the rumor they are reporting is true, but based on misidentified scary loud noises.
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Interested
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 8:47 am

iamtom wrote:
heyjoojoo wrote:
Personally, I believe that if there had been even the slightest possibility that Americans could have been blamed, Iran would have done so. The fact that they’re keeping this so close to the vest makes me think it was one of their ADA sites and someone screwed up.


In the same respect don't you think that if Iran had blown up a plane the US wouldn't have already announced that? The US (and others) have active satellites monitoring for missile launches across the globe. I imagine these eyes in the skies are tuned specifically to Iran right now, so if anything was fired they would know about it. It was also still dark and clear skies above Tehran so it's just not possible a missile launch (especially right now) could be missed.

Several European defence agencies have also announced they have no intelligence to suggest this was a missile attack, and they have absolutely no reason to protect Iran over this.


And to date no eye witness claims of seeing or hearing any missiles launched and it's close to built up areas etc

Any missiles I've seen launched at night on video seem pretty hard to miss?
 
sevenair
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 8:51 am

Anyone familiar with B737 electrical system?

I'm wondering if anyone can explain the sudden stop of all data being transmitted from the machine.

On the A320 if say ENG1 goes, nothings driving the generator one and the system configures so that GEN2 feeds ACBUS1 AND ACBUS2 so a good majority of electrical systems are restored just with reduced redundancy. I'd imagine the B737 is similar.

I'm trying to work out why it simply went silent (from a data point of view) and what could cause that. If an engine is taken out, services supplied by that engine would be taken out but I'd imagine backup power would be supplied to the services that were lost.

Very queer indeed.
 
Interested
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 8:52 am

xmp125a wrote:
Pavlakakos wrote:
This is just a rumor and i just wanted to share with you. The mother of a flight attendant said she received a phone call from her daughter saying machine guns were being fired in the cabin and then the connection ended.
The stewardess was from the city of Nova Kakhovka and was my wife's classmate. Don't know if the rumor stands, however i guess we'll soon find out. If there was indeed gunfire, the Iranians will be quick to reveal that info, in order to clear themselves from the missile theory.


Since at this stage we all operate on very noisy and unreliable data, we should really talk in probabilities (and understand them as well -- unlike the media that blamed Nate Silver for assigning Trump "only" 30% probability to win).

So back to the topic.

I'd say that machine gun fire inside the cabin has about 0.1% probability to down the airliner in the manner we have seen (and on the data we can reasonably trust). First, the pilots would probably notify ATC or at least change the transponder code (hijacking). Second, I don't know about security in Tehran airport, but Tehran itself is not a war zone, it is not Baghdad, not even a typical US inner city overflown with guns. So someone bringing a machine gun onto an airplane is basically unbelievable.

Now, to divide the rest 99.9%, IMHO.

0.9% intentional downing by a state actor, either Iran or US (fully aware that it is passenger airplane)
19% intentional downing by a MANPADS, operated by some kind of guerilla or rogue force inside Iran
50% of iran making a tragic mistake with nervous and trigger-happy air defences which expected massive retaliation after hitting US bases with missiles
20% uncontained engine failure or other technical fault
20% some kind of unplanned accidental interference with US or Iran military operation (collision with the US drone, unfortunate collateral damage in legitimate Iran action to shoot down existing US aircraft or drone, etc).

I have assigned highest probability to iran's tragic mistake due to Iran being very tame about this incident and claiming basically immediately that it was not downed by a missile. Please note the usual fiery rhetoric from Iran about USA and the West in general (the great Satan etc.) Claiming that it wasn't a missile basically when aircraft barely touched the ground reveals that they know more than they are saying and the tame reaction basically means that they feel at least partly responsible for the downing - or they are sure there were no missiles in vicinity, therefore technical fault. MANPADS or any organized guerilla force in such close vicinity of Tehran airport and indeed urban city itself would be also a massive humiliation to Iran, so that would probably met with subdued silence as well.

Otherwise they would be screaming all over, after all there were two busloads of Iranians on that plane!

Note (0.9% still means that the outcome is possible... but very unlikely, lesson Nate Silver and Trump election).


It's a minor point

But you need to knock 10 per cent of one of those if you want 100 per cent!
 
timh4000
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 8:52 am

Well. I'm hardly an expert on aircraft major malfunctions and what they can do to a plane. So, I'll be more of in question mode. 1st, has there EVER been a case where an engine explodes for whatever reason and to have it cause this much damage?

I think back at all of the other major engine explosions and while not all of the planes made it down safely, none that I can think of just fell out of the sky in a fireball.

Another suspicion I have is how quickly the iranian government went to explaining this as mechanical failure. How would they know this literally from the moment of impact?

There apparently was a poster and a post that put down Iranians as worthy people or whatever, I didn't read the post just saw some of the aftermath of it. What I'm going to say shouldn't give you this reaction but if it does. I am stating now for the record that it is not my intent to do so.

A post, possibly more than one has made statements like Iran is shooting at iranians, that's unlikely or words to that effect... they have nothing to gain by doing so.

Iran has a history of not treating every group of citizens fairly or equally.

For example I worked with an Iranian born and raised but now an actual u.s. citizen. Unfortunately he was of the BA'HA' I' faith. (Btw, my writing the name is not 100%, accurate.) Although they wanted to stay in their home country, they had a choice between staying and facing horrible abuse and killing and leaving.
So my co-worker is among the many of the BAHA'I faith which left.

The thought that an iranian shooting down other Iranians is very much a real possibility. Iran today is known to be among the worst. And it's all done through government actions.

While there seems to be evidence against a shoot down from a missile, although we shouldn't put that one to bed yet. What about an internal bomb?

I'm deeply suspicious of the iranian government is saying it's a technical fault with the aircraft practically as it was hitting the ground. Secondly, there is very little to none of the times an engine has blown has caused the plane simply fall from the sky.
 
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Jouhou
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 8:59 am

sevenair wrote:
Anyone familiar with B737 electrical system?

I'm wondering if anyone can explain the sudden stop of all data being transmitted from the machine.

On the A320 if say ENG1 goes, nothings driving the generator one and the system configures so that GEN2 feeds ACBUS1 AND ACBUS2 so a good majority of electrical systems are restored just with reduced redundancy. I'd imagine the B737 is similar.

I'm trying to work out why it simply went silent (from a data point of view) and what could cause that. If an engine is taken out, services supplied by that engine would be taken out but I'd imagine backup power would be supplied to the services that were lost.

Very queer indeed.



I think we're all on the same page when it comes to concluding that the incident that caused the crash sealed the aircraft's fate long before it hit the ground. The fireball plummeting out of the sky did not look remotely recoverable.
Last edited by Jouhou on Thu Jan 09, 2020 9:00 am, edited 1 time in total.
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airhansa
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 8:59 am

Redd wrote:
airhansa wrote:
The problem with a fire causing problems for the aircraft, is that such a fire would never spread so quickly to result in a situation where the pilot doesn't mayday for help.


1. Aviate
2. Navigate
3. Communicate

Whether it was a missile or uncontained engine failure or another cause, the pilots first job is to fly the plane first, communicate last. If the pilots are dealing with a critical situation, there is no reasonable expectation that they would have communicated with ATC.


I agree with this generally, that when a small fire is discovered (maybe an engine goes down) then the pilot needs to steady the plane before contacting ATC. But surely there must have been enough time between steadying the plane and the fire spreading into a fireball for ATC to be contacted? E.g. how does such a large fire happen on a Boeing jet so quickly that there isn't enough time to Aviate/Navigate/Communicate? Especially an engine fire of all things.

Has this fire been brought up? http://en.wikipedia.org/wiki/China_Airlines_Flight_120 It was a fairly large fire caused by a punctured fuel tank in the aftermath of maintenance work - a fuel leak caught on fire after contacting areas heated by the engine. Image
 
rheinwaldner
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 8:59 am

zhetenyi1973 wrote:
And if you carefully watch the video from the car you will notice that it began with a faint light which

Forget the video. It shows nothing relevant. After ADSB data dropped, the plane flew 20km. The cause of the descend is not shown on any video.

The unanswered question for me is, how could the plane be knocked out electrically (no ADBS feed anymore) and still fly for several minutes on a rather shallow descend (~1:10)?

The missile theory is about as unprobable as the uncontained engine failure to explain that, imo.
Many things are difficult, all things are possible!
 
Interested
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:00 am

What about terrorist with machine gun and/or bomb somehow got on board and the pilots being taken out by the machine gun. I realise he has to get to the cockpit etc. Maybe one of the stewards??

But I'm just trying to expand on the machine gun rumour above. If you can get a machine gun on you can also get a bomb on same way and vice versa. Could a machine gun cause the fire after the pilots taken out?

That might explain the lack of communication and pilot intervention

And if it was some kind of rogue/extremist acting alone that would explain why nobody has claimed responsibility for bringing the plane down

I realise the above is also 1 in a trillion odds but so is uncontained engine failure this severe

The thing that puzzles me is Iran immediately saying a technical or mechanical issue though

If they hadn't said that and kept all options open then I would be more inclined to keep terrorism or bomb etc as an option myself

Are we sure Iran is saying mechanical or technical issue. Could something be lost in translation. I've not actually seen any links to statements from Iran themselves yet?

Just very very early reports on news of Iran saying "mechanical fault"

Have Iran officially made ANY statement yet about the cause of the crash?
Last edited by Interested on Thu Jan 09, 2020 9:11 am, edited 1 time in total.
 
aw70
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:01 am

iamtom wrote:
The US (and others) have active satellites monitoring for missile launches across the globe. I imagine these eyes in the skies are tuned specifically to Iran right now, so if anything was fired they would know about it.


These systems are intended to spot the launch of ICBM-sized missiles, though, not MANPADs or theatre AAMs. Essentially, these systems are super-sensitive thermal cameras, which have limits on their resolution and what can be picked up against the background signature of a busy suburban area.
 
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AirlineCritic
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:02 am

xmp125a wrote:
I'd say that machine gun fire inside the cabin has about 0.1% probability
...
0.9% intentional downing by a state actor, either Iran or US (fully aware that it is passenger airplane)
19% intentional downing by a MANPADS, operated by some kind of guerilla or rogue force inside Iran
50% of iran making a tragic mistake with nervous and trigger-happy air defences which expected massive retaliation after hitting US bases with missiles
20% uncontained engine failure or other technical fault
20% some kind of unplanned accidental interference with US or Iran military operation (collision with the US drone, unfortunate collateral damage in legitimate Iran action to shoot down existing US aircraft or drone, etc).


Not a bad analysis, although I'd probably increase the accidental interference a military drone or the interception thereof a bit. And going back to 100% from your 110% as someone noted :-)

I think the larger point is that we don't know, we don't have all the data, and people on this site are too quick to claim certainty. There are several possibilities, and unfortunately we have to wait to see better what happened here. We have no confirmation of the missile part picture, shrapnel hole pictures are not as common or clear as initially thought, people assign too much value to various statements that are quite typically coming out in the initial phases, etc.

But a horrible crash. Families with little children wiped out, etc. Sending my condolences to the relatives of the lost.
 
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AirlineCritic
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:04 am

And I should have added that a bomb should also still be listed as a possible cause. Maybe not a high likelihood (given no clear motive and the difficulty of getting one onboard). But it would definitely be able to cause the kind of catastrophic malfunction seen here.
 
airhansa
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:05 am

sevenair wrote:
Anyone familiar with B737 electrical system?

I'm wondering if anyone can explain the sudden stop of all data being transmitted from the machine.

On the A320 if say ENG1 goes, nothings driving the generator one and the system configures so that GEN2 feeds ACBUS1 AND ACBUS2 so a good majority of electrical systems are restored just with reduced redundancy. I'd imagine the B737 is similar.

I'm trying to work out why it simply went silent (from a data point of view) and what could cause that. If an engine is taken out, services supplied by that engine would be taken out but I'd imagine backup power would be supplied to the services that were lost.

Very queer indeed.


This was what I was trying to get at (I came to the same conclusion but it got reworded as "no communications with the pilot" by mistake)! There are two engines and a battery system (and possibly an auxiliary engine) on most aviation jets. I brought up the lack of radio (coupled with sudden loss of all communications) as suggesting that it wasn't an engine fire - such a fire would need to be located elsewhere to knockout communications (it is possible but again it would be elsewhere in the plane, but also it would be found before it became a major fire). I just can't understand how an engine fire could become so large that all communications were lost. A pilot should have ample time to gain control of a plane and make communications in any small fire.
 
airhansa
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:08 am

rheinwaldner wrote:
zhetenyi1973 wrote:
And if you carefully watch the video from the car you will notice that it began with a faint light which

Forget the video. It shows nothing relevant. After ADSB data dropped, the plane flew 20km. The cause of the descend is not shown on any video.

The unanswered question for me is, how could the plane be knocked out electrically (no ADBS feed anymore) and still fly for several minutes on a rather shallow descend (~1:10)?

The missile theory is about as unprobable as the uncontained engine failure to explain that, imo.


A small fire near the electrical/data cables could knock out communications - but at what stage does that fire turn into a fireball (and how?) and why doesn't anyone on board notice the small fire and inform someone - even a fight attendant could have done it!
 
Interested
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:09 am

timh4000 wrote:

I'm deeply suspicious of the iranian government is saying it's a technical fault with the aircraft practically as it was hitting the ground.


I think a lot of us are very influenced by that statement and feel very suspicious of it.

Which is why I've asked if we have any substance to prove that statement. I do know it was claimed virtually as news of the crash came out.

Who exactly in Iran has said this ?

Is there an official statement from Iran anywhere to actually back it up?

Could it be someone without authority who has been quoted?

Could something be lost in translation?

Apologies if it's already in the thread and I've missed it but is there any official statement from anyone high up in Iran at all that we can rely on?

Or is this potentially hearsay etc that people have taken at face value uptil now?
 
Jomar777
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:09 am

scbriml wrote:
Kadish wrote:
For those of u who may think that Iranian government took part in this sad crash, Can you tell me why they hit a plane from a foreign country with a lot of Iranian pax on ir, and a country with no issues against them?
It could be plausible If the plane were American,Saudi Arabian....


I don't think anyone is suggesting Iran deliberately shot down a passenger airliner, especially not with their history. But, until shown otherwise, in the circumstances an accidental shootdown is a distinct possibility.

See IR655
See MH17


Not really. As mentioned before, both the issues you highlight (MH17 and IR655) were know well on the outset to be the case of planes shot down (either accidentally or not).

On this case, so far, Western experts see little change of this having happened. The only chance for this to be terrorist related so far is a Bomb on the plane. Things may change but so far there's little evidence of this plane being shot down.

I still side with the current view that a catastrophic engine failure caused the issue.
 
sevenair
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:10 am

Interested wrote:
What about terrorist with machine gun and/or bomb somehow got on bad and the pilots being taken out by the machine gun. I realise he has to get to the cockpit.

But I'm just trying to expand on the machine gun rumour above. If you can get a machine gin on you can get a bomb on same way and vice versa.

That might explain the lack of communication and pilot intervention

And if it was some kind of rogue/extremist acting alone that would explain

I realise the above is 1 in a trillion but so is uncontained engine failure this severe

The thing that puzzles me is Iran immediately saying a technical or mechanical issue though

If they hadn't said that and kept all options open then I would be more inclined to keep terrorism or bomb etc as an option myself

Are we sure Iran is saying mechanical or technical issue. Could something be lost in translation. I've not actually seen any links to statements from Iran themselves yet?

Just very very early reports on news of Iran saying "mechanical fault"

Have Iran officially made ANY statement yet about the cause of the crash?


I'd be interested in knowing if the aircraft was left unattended during the layover? A turnaround of that length on a longish flight wouldn't work from an FDP perspective. I know UIA mentioned an augmented crew, but I'm not sure what their interpretation of that is. Does it mean the inbound crew flew into IKA and another crew flew the accident flight with the inbound crew flying back as passengers? If that was the case, then did they stay with the aircraft? Perhaps it could be tampered with.

You also have bars. Are they replaced or topped up? Are fresh options loaded for the return catering or do they have an all day bar in that they're loaded at IEV and stay with the aircraft all day? If they're replaced or topped up, then it's a risk that a device was loaded. We saw that with MetroJet. You also have baggage handlers.

Insider threats are a huge risk. Daalo Airlines had an insider on passenger security. MetroJet had an insider place the device onboard.
 
xmp125a
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:11 am

Interested wrote:
xmp125a wrote:
Pavlakakos wrote:
This is just a rumor and i just wanted to share with you. The mother of a flight attendant said she received a phone call from her daughter saying machine guns were being fired in the cabin and then the connection ended.
The stewardess was from the city of Nova Kakhovka and was my wife's classmate. Don't know if the rumor stands, however i guess we'll soon find out. If there was indeed gunfire, the Iranians will be quick to reveal that info, in order to clear themselves from the missile theory.


Since at this stage we all operate on very noisy and unreliable data, we should really talk in probabilities (and understand them as well -- unlike the media that blamed Nate Silver for assigning Trump "only" 30% probability to win).

So back to the topic.

I'd say that machine gun fire inside the cabin has about 0.1% probability to down the airliner in the manner we have seen (and on the data we can reasonably trust). First, the pilots would probably notify ATC or at least change the transponder code (hijacking). Second, I don't know about security in Tehran airport, but Tehran itself is not a war zone, it is not Baghdad, not even a typical US inner city overflown with guns. So someone bringing a machine gun onto an airplane is basically unbelievable.

Now, to divide the rest 99.9%, IMHO.

0.9% intentional downing by a state actor, either Iran or US (fully aware that it is passenger airplane)
19% intentional downing by a MANPADS, operated by some kind of guerilla or rogue force inside Iran
50% of iran making a tragic mistake with nervous and trigger-happy air defences which expected massive retaliation after hitting US bases with missiles
20% uncontained engine failure or other technical fault
20% some kind of unplanned accidental interference with US or Iran military operation (collision with the US drone, unfortunate collateral damage in legitimate Iran action to shoot down existing US aircraft or drone, etc).

I have assigned highest probability to iran's tragic mistake due to Iran being very tame about this incident and claiming basically immediately that it was not downed by a missile. Please note the usual fiery rhetoric from Iran about USA and the West in general (the great Satan etc.) Claiming that it wasn't a missile basically when aircraft barely touched the ground reveals that they know more than they are saying and the tame reaction basically means that they feel at least partly responsible for the downing - or they are sure there were no missiles in vicinity, therefore technical fault. MANPADS or any organized guerilla force in such close vicinity of Tehran airport and indeed urban city itself would be also a massive humiliation to Iran, so that would probably met with subdued silence as well.

Otherwise they would be screaming all over, after all there were two busloads of Iranians on that plane!

Note (0.9% still means that the outcome is possible... but very unlikely, lesson Nate Silver and Trump election).


It's a minor point

But you need to knock 10 per cent of one of those if you want 100 per cent!


Thanks :) Let's reduce MANPADS to 9% instead of 19.
 
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Jouhou
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:11 am

rheinwaldner wrote:
zhetenyi1973 wrote:
And if you carefully watch the video from the car you will notice that it began with a faint light which

Forget the video. It shows nothing relevant. After ADSB data dropped, the plane flew 20km. The cause of the descend is not shown on any video.

The unanswered question for me is, how could the plane be knocked out electrically (no ADBS feed anymore) and still fly for several minutes on a rather shallow descend (~1:10)?

The missile theory is about as unprobable as the uncontained engine failure to explain that, imo.


I'm going to take a wild guess and say as long as there are still wings creating lift the time until reaching ground will be prolonged even without thrust. So I guess maybe we can conclude the wings were still attached to the fuselage until soon before or at the time of impact? That really doesn't get us much closer to an answer.
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airhansa
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:14 am

Jouhou wrote:
rheinwaldner wrote:
zhetenyi1973 wrote:
And if you carefully watch the video from the car you will notice that it began with a faint light which

Forget the video. It shows nothing relevant. After ADSB data dropped, the plane flew 20km. The cause of the descend is not shown on any video.

The unanswered question for me is, how could the plane be knocked out electrically (no ADBS feed anymore) and still fly for several minutes on a rather shallow descend (~1:10)?

The missile theory is about as unprobable as the uncontained engine failure to explain that, imo.


I'm going to take a wild guess and say as long as there are still wings creating lift the time until reaching ground will be prolonged even without thrust. So I guess maybe we can conclude the wings were still attached to the fuselage until soon before or at the time of impact? That really doesn't get us much closer to an answer.


If a fire is near the subject wire, then it's entirely possible that the wires for communication could be knocked out by said fire, but for me it's the scale of the fire coupled with the lack of communication that makes me wonder - how does such a large fire happen on a plane without any time to steady the plane a mayday for help? Furthermore I believe that a fire near the wiring should be visible to cabin staff/passengers before it would get out of control - and it would not be near the engine.
 
sevenair
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:15 am

airhansa wrote:
sevenair wrote:
Anyone familiar with B737 electrical system?

I'm wondering if anyone can explain the sudden stop of all data being transmitted from the machine.

On the A320 if say ENG1 goes, nothings driving the generator one and the system configures so that GEN2 feeds ACBUS1 AND ACBUS2 so a good majority of electrical systems are restored just with reduced redundancy. I'd imagine the B737 is similar.

I'm trying to work out why it simply went silent (from a data point of view) and what could cause that. If an engine is taken out, services supplied by that engine would be taken out but I'd imagine backup power would be supplied to the services that were lost.

Very queer indeed.


This was what I was trying to get at (I came to the same conclusion but it got reworded as "no communications with the pilot" by mistake)! There are two engines and a battery system (and possibly an auxiliary engine) on most aviation jets. I brought up the lack of radio (coupled with sudden loss of all communications) as suggesting that it wasn't an engine fire - such a fire would need to be located elsewhere to knockout communications (it is possible but again it would be elsewhere in the plane, but also it would be found before it became a major fire). I just can't understand how an engine fire could become so large that all communications were lost. A pilot should have ample time to gain control of a plane and make communications in any small fire.


Indeed. There should be time to do something. If we think back to the Hudson, thanks to the emergency electrical configuration, it was still possible to transmit data and communicate with the ground and that's with two engines dead. I'm sure the B737 will have similar.

As we seemingly move away from the missile theory, I think this disaster is going to be a difficult one to figure out what happened and why.
 
Interested
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:19 am

Insider job would explain lack of communication whilst they were bringing the plane down.

Gun and bomb together would explain pilots not communicating if gun used on the pilots or one bomb used near the pilots

Maybe don't even need a bomb. Can the gun cause the fire

When it was pilot suicide I'm sure all the early discussion was there must have been a catastrophic event in cockpit to take the pilot out and the plane had just flew itself to the ground etc

Then insider job answered all the questions

Doesn't insider job potentially answer all the questions here?
 
Jomar777
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:24 am

airhansa wrote:
Redd wrote:
airhansa wrote:
The problem with a fire causing problems for the aircraft, is that such a fire would never spread so quickly to result in a situation where the pilot doesn't mayday for help.


1. Aviate
2. Navigate
3. Communicate

Whether it was a missile or uncontained engine failure or another cause, the pilots first job is to fly the plane first, communicate last. If the pilots are dealing with a critical situation, there is no reasonable expectation that they would have communicated with ATC.


I agree with this generally, that when a small fire is discovered (maybe an engine goes down) then the pilot needs to steady the plane before contacting ATC. But surely there must have been enough time between steadying the plane and the fire spreading into a fireball for ATC to be contacted? E.g. how does such a large fire happen on a Boeing jet so quickly that there isn't enough time to Aviate/Navigate/Communicate? Especially an engine fire of all things.

Has this fire been brought up? http://en.wikipedia.org/wiki/China_Airlines_Flight_120 It was a fairly large fire caused by a punctured fuel tank in the aftermath of maintenance work - a fuel leak caught on fire after contacting areas heated by the engine. Image


This is one of the examples that came to my mind when I felt that one of the likely probabilities would be electrical fault alliend to maybe a fuel leak or something. If the aircraft had an electrical fault, it might potentially justify the lack of comms as well as a spark cause, not only fire but the engine to explode (just as it did on Air China's case...).

Everyone here states that an issue with one of the engines cannot bring an aircraft down but consider that an engine explosion or catastrophic failure might, for example, impact on the hydraulics on that wing preventing a controlled flight. The aircraft was coming down on fire (at least we know that) and was uncontrolable. AFAIK, one of the engines found on the ground is completelly destroyed..

It is speculation, I know, but is based on what happened before. Engines nowadays are pretty safe and it was a new aircraft but we canot predict an 100% chance that engines would not blow up by any unknown issue.

The only thing that is unhelpful at present is that the Iranians do have the black boxes but that they will not surrender to Boeing (since it is an US company). I do hope they pass them on to experts which can correctly and impartially analyse the data since - not wanting to cause panic - who knows whether this issue that brought this plane down may not crop up elsewhere?
 
xmp125a
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:24 am

Jouhou wrote:
rheinwaldner wrote:
zhetenyi1973 wrote:
And if you carefully watch the video from the car you will notice that it began with a faint light which

Forget the video. It shows nothing relevant. After ADSB data dropped, the plane flew 20km. The cause of the descend is not shown on any video.

The unanswered question for me is, how could the plane be knocked out electrically (no ADBS feed anymore) and still fly for several minutes on a rather shallow descend (~1:10)?

The missile theory is about as unprobable as the uncontained engine failure to explain that, imo.


I'm going to take a wild guess and say as long as there are still wings creating lift the time until reaching ground will be prolonged even without thrust. So I guess maybe we can conclude the wings were still attached to the fuselage until soon before or at the time of impact? That really doesn't get us much closer to an answer.


Missile strike that sends shrapnel all around, kills the pilots (and perhaps many passengers), damages certain parts of the avionics, but not all, punctures the fuel tanks and possibly does not take out the engines? Plane would still fly as a massive fireball until structural integrity would be weakened to a degree where it would fall from the skies.

Just trying to explain that your logic fits with powerful SAM missile.
Last edited by xmp125a on Thu Jan 09, 2020 9:25 am, edited 1 time in total.
 
Interested
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:24 am

sevenair wrote:
airhansa wrote:
sevenair wrote:
Anyone familiar with B737 electrical system?

I'm wondering if anyone can explain the sudden stop of all data being transmitted from the machine.

On the A320 if say ENG1 goes, nothings driving the generator one and the system configures so that GEN2 feeds ACBUS1 AND ACBUS2 so a good majority of electrical systems are restored just with reduced redundancy. I'd imagine the B737 is similar.

I'm trying to work out why it simply went silent (from a data point of view) and what could cause that. If an engine is taken out, services supplied by that engine would be taken out but I'd imagine backup power would be supplied to the services that were lost.

Very queer indeed.


This was what I was trying to get at (I came to the same conclusion but it got reworded as "no communications with the pilot" by mistake)! There are two engines and a battery system (and possibly an auxiliary engine) on most aviation jets. I brought up the lack of radio (coupled with sudden loss of all communications) as suggesting that it wasn't an engine fire - such a fire would need to be located elsewhere to knockout communications (it is possible but again it would be elsewhere in the plane, but also it would be found before it became a major fire). I just can't understand how an engine fire could become so large that all communications were lost. A pilot should have ample time to gain control of a plane and make communications in any small fire.


Indeed. There should be time to do something. If we think back to the Hudson, thanks to the emergency electrical configuration, it was still possible to transmit data and communicate with the ground and that's with two engines dead. I'm sure the B737 will have similar.

As we seemingly move away from the missile theory, I think this disaster is going to be a difficult one to figure out what happened and why.


Bomb takes out pilots and causes fire same time?

Missile takes out pilots and causes fire at same time?

Insider (which could include a pilot or steward with access to the cabin) takes out pilots and causes fire with gun and/or bomb?

It's only an uncontained engine fire that leaves us having to explain why no communication isn't it?
 
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AirlineCritic
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:26 am

airhansa wrote:
I agree with this generally, that when a small fire is discovered (maybe an engine goes down) then the pilot needs to steady the plane before contacting ATC. But surely there must have been enough time between steadying the plane and the fire spreading into a fireball for ATC to be contacted? E.g. how does such a large fire happen on a Boeing jet so quickly that there isn't enough time to Aviate/Navigate/Communicate? Especially an engine fire of all things.


Well, the aviate-navigate-communicate isn't just the established process. Think of it this way: the pilots are fighting for their lives. They are doing everything they can to save the aircraft and its occupants. There's nothing that the ATC or other outsiders can do at this point, everything depends on what they can get out of the airplane, how they use the controls, how they use the systems. They will focus on that, not communication.

Also, there's no "open an a.net thread" button in the cockpit.
 
xmp125a
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:26 am

Interested wrote:
Insider job would explain lack of communication whilst they were bringing the plane down.

Gun and bomb together would explain pilots not communicating if gun used on the pilots or one bomb used near the pilots

Maybe don't even need a bomb. Can the gun cause the fire

When it was pilot suicide I'm sure all the early discussion was there must have been a catastrophic event in cockpit to take the pilot out and the plane had just flew itself to the ground etc

Then insider job answered all the questions

Doesn't insider job potentially answer all the questions here?


No, it does not explain the fireball, sorry.
 
CPHGuard
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:27 am

timh4000 wrote:
Well. I'm hardly an expert on aircraft major malfunctions and what they can do to a plane. So, I'll be more of in question mode. 1st, has there EVER been a case where an engine explodes for whatever reason and to have it cause this much damage?

I think back at all of the other major engine explosions and while not all of the planes made it down safely, none that I can think of just fell out of the sky in a fireball.


Air France AF 4590 comes to mind, and it was airborne for less than 90 seconds:

https://youtu.be/fjtsbAckbTg?t=74
 
uta999
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:30 am

airhansa wrote:
Redd wrote:
airhansa wrote:
The problem with a fire causing problems for the aircraft, is that such a fire would never spread so quickly to result in a situation where the pilot doesn't mayday for help.


1. Aviate
2. Navigate
3. Communicate

Whether it was a missile or uncontained engine failure or another cause, the pilots first job is to fly the plane first, communicate last. If the pilots are dealing with a critical situation, there is no reasonable expectation that they would have communicated with ATC.


I agree with this generally, that when a small fire is discovered (maybe an engine goes down) then the pilot needs to steady the plane before contacting ATC. But surely there must have been enough time between steadying the plane and the fire spreading into a fireball for ATC to be contacted? E.g. how does such a large fire happen on a Boeing jet so quickly that there isn't enough time to Aviate/Navigate/Communicate? Especially an engine fire of all things.

Has this fire been brought up? http://en.wikipedia.org/wiki/China_Airlines_Flight_120 It was a fairly large fire caused by a punctured fuel tank in the aftermath of maintenance work - a fuel leak caught on fire after contacting areas heated by the engine. Image


I recommend this video of the China Airlines 737 fire.

It is the worst case of firefighting I have ever seen. Like one of those old black & white Abbot & Costello movies.
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Jouhou
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:35 am

Well, as long as everyone is talking about rapidly progressing fires that disable the pilots and electrical systems fast, a fire originating near the oxygen system is one that hasn't been mentioned.
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majano
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:35 am

sevenair wrote:
airhansa wrote:
sevenair wrote:
Anyone familiar with B737 electrical system?

I'm wondering if anyone can explain the sudden stop of all data being transmitted from the machine.

On the A320 if say ENG1 goes, nothings driving the generator one and the system configures so that GEN2 feeds ACBUS1 AND ACBUS2 so a good majority of electrical systems are restored just with reduced redundancy. I'd imagine the B737 is similar.

I'm trying to work out why it simply went silent (from a data point of view) and what could cause that. If an engine is taken out, services supplied by that engine would be taken out but I'd imagine backup power would be supplied to the services that were lost.

Very queer indeed.


This was what I was trying to get at (I came to the same conclusion but it got reworded as "no communications with the pilot" by mistake)! There are two engines and a battery system (and possibly an auxiliary engine) on most aviation jets. I brought up the lack of radio (coupled with sudden loss of all communications) as suggesting that it wasn't an engine fire - such a fire would need to be located elsewhere to knockout communications (it is possible but again it would be elsewhere in the plane, but also it would be found before it became a major fire). I just can't understand how an engine fire could become so large that all communications were lost. A pilot should have ample time to gain control of a plane and make communications in any small fire.


Indeed. There should be time to do something. If we think back to the Hudson, thanks to the emergency electrical configuration, it was still possible to transmit data and communicate with the ground and that's with two engines dead. I'm sure the B737 will have similar.

As we seemingly move away from the missile theory, I think this disaster is going to be a difficult one to figure out what happened and why.

Problem with the missile theory is that it was based primarily on the circumstances in the region and mistrust of Iran. The physical evidence seen so far does not appear to support it. Mistrust of Iran could still be an issue if they do not allow parties external of Iran to support the investigation. Inviting Ukraine is a step in the right direction, but my feeling is that a party such as the French BEA or US NTSB (if possible) should be invited to bring further credibility to the investigation. This is not to say the Iranian authorities cannot do a good job. To the contrary, Zeke provided evidence of how thorough their investigations are. But with A-Net, however thorough they may be, some may still discredit the findings.
 
sgrow787
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:41 am

majano wrote:
I agree with view and wish to add that I cannot believe that there is someone still peddling the theory that the "holes" on the aircraft structures are some sort of evidence of shrapnel form a missile.
1. Some of the holes are on the top of the horizontal stabilizer, some are on the burnt side of the plane and other on the unburnt side.
2. Looking at the latest video from what is said to be a CCTV camera, one can seen a large quantity of debris from the ground being flung by the velocity just before ground impact.
3. Photographs of the ground itself show a lot of gravel stone around the crash site.
4. The direction of the rudder damage.
All of these factors seem to point to some of the holes being a result of the impact with the ground itself.


The area around the hole in the tail fin (which is metal; only the control surface on the NG is CFRP) shows no damage or indentation from rocks on the ground. I find it hard to believe a rock sitting on the ground could put a clean hole into the tail fin. The plane is traveling at a fraction of the speed at impact (400mph) vs that of fragments from an explosion (2000mph).
Just one sensor,
Oh just one se-en-sor,
Just one sensor,
Ooh ooh oo-ooh
Oo-oo-ooh.
 
sevenair
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:44 am

CPHGuard wrote:
timh4000 wrote:
Well. I'm hardly an expert on aircraft major malfunctions and what they can do to a plane. So, I'll be more of in question mode. 1st, has there EVER been a case where an engine explodes for whatever reason and to have it cause this much damage?

I think back at all of the other major engine explosions and while not all of the planes made it down safely, none that I can think of just fell out of the sky in a fireball.


Air France AF 4590 comes to mind, and it was airborne for less than 90 seconds:

https://youtu.be/fjtsbAckbTg?t=74


If it was a FOD like incident that could have caused this, I'd expect them ri say something. If there's a loud thud during takeoff or initial climbout, I'd expect to check all parameters and if normal, briefly mention the possibility of a birdstike before switching to departure. If it was a Concorde style event, I'd expect whatever caused it to make a heck of a bang and for their to be plenty time to at least say something.

I'm sure the CVRs will tell an interesting story. Even if the aircraft completely shuts down like it seems to here, hopefully in the minutes running up to that incident will paint a picture of what happened, including any bangs.
 
mxaxai
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:45 am

sevenair wrote:
Anyone familiar with B737 electrical system?

I'm wondering if anyone can explain the sudden stop of all data being transmitted from the machine.

On the A320 if say ENG1 goes, nothings driving the generator one and the system configures so that GEN2 feeds ACBUS1 AND ACBUS2 so a good majority of electrical systems are restored just with reduced redundancy. I'd imagine the B737 is similar.

I'm trying to work out why it simply went silent (from a data point of view) and what could cause that. If an engine is taken out, services supplied by that engine would be taken out but I'd imagine backup power would be supplied to the services that were lost.

Very queer indeed.

AA191 lost all electrical power on the captains side, as well as all communications, when the no. 1 engine detached. The FE could have switched the circuits but didn't do so for the 50 seconds between separation and impact.
Obviously a different airplane model, so you'd have to look at the 737NG systems architecture to check if something similar could happen.
 
artflyer
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:50 am

sevenair wrote:
Interested wrote:
What about terrorist with machine gun and/or bomb somehow got on bad and the pilots being taken out by the machine gun. I realise he has to get to the cockpit.

But I'm just trying to expand on the machine gun rumour above. If you can get a machine gin on you can get a bomb on same way and vice versa.

That might explain the lack of communication and pilot intervention

And if it was some kind of rogue/extremist acting alone that would explain

I realise the above is 1 in a trillion but so is uncontained engine failure this severe

The thing that puzzles me is Iran immediately saying a technical or mechanical issue though

If they hadn't said that and kept all options open then I would be more inclined to keep terrorism or bomb etc as an option myself

Are we sure Iran is saying mechanical or technical issue. Could something be lost in translation. I've not actually seen any links to statements from Iran themselves yet?

Just very very early reports on news of Iran saying "mechanical fault"

Have Iran officially made ANY statement yet about the cause of the crash?


I'd be interested in knowing if the aircraft was left unattended during the layover? A turnaround of that length on a longish flight wouldn't work from an FDP perspective. I know UIA mentioned an augmented crew, but I'm not sure what their interpretation of that is. Does it mean the inbound crew flew into IKA and another crew flew the accident flight with the inbound crew flying back as passengers? If that was the case, then did they stay with the aircraft? Perhaps it could be tampered with.

You also have bars. Are they replaced or topped up? Are fresh options loaded for the return catering or do they have an all day bar in that they're loaded at IEV and stay with the aircraft all day? If they're replaced or topped up, then it's a risk that a device was loaded. We saw that with MetroJet. You also have baggage handlers.

Insider threats are a huge risk. Daalo Airlines had an insider on passenger security. MetroJet had an insider place the device onboard.


By augmented crew they meant 3 pilots. I don't think inbound crew was flying back as pax as they had five weekly to IKA, so there would be little point in doing this.
 
sevenair
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:55 am

mxaxai wrote:
sevenair wrote:
Anyone familiar with B737 electrical system?

I'm wondering if anyone can explain the sudden stop of all data being transmitted from the machine.

On the A320 if say ENG1 goes, nothings driving the generator one and the system configures so that GEN2 feeds ACBUS1 AND ACBUS2 so a good majority of electrical systems are restored just with reduced redundancy. I'd imagine the B737 is similar.

I'm trying to work out why it simply went silent (from a data point of view) and what could cause that. If an engine is taken out, services supplied by that engine would be taken out but I'd imagine backup power would be supplied to the services that were lost.

Very queer indeed.

AA191 lost all electrical power on the captains side, as well as all communications, when the no. 1 engine detached. The FE could have switched the circuits but didn't do so for the 50 seconds between separation and impact.
Obviously a different airplane model, so you'd have to look at the 737NG systems architecture to check if something similar could happen.


That rings a bell actually. Wasnt the stall warning or stick pusher brought offline as a result of losing GEN1 on that flight?

I've had a look at the 737 elec schematics and as I expected it's easy to configure the system if a gen drops offline. You've also got the APU and battery providing 30 mins power should all busses fail. It seems that reconfiguring needs to be done ma usually though, so if whatever started this event took the pilots out, then power may never be restored. Autopilot will drop out, and can't be re-engaged until the opposite gen is manually brought online.
Last edited by sevenair on Thu Jan 09, 2020 9:59 am, edited 1 time in total.
 
CPHGuard
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Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:55 am

mxaxai wrote:
sevenair wrote:
Anyone familiar with B737 electrical system?

I'm wondering if anyone can explain the sudden stop of all data being transmitted from the machine.

On the A320 if say ENG1 goes, nothings driving the generator one and the system configures so that GEN2 feeds ACBUS1 AND ACBUS2 so a good majority of electrical systems are restored just with reduced redundancy. I'd imagine the B737 is similar.

I'm trying to work out why it simply went silent (from a data point of view) and what could cause that. If an engine is taken out, services supplied by that engine would be taken out but I'd imagine backup power would be supplied to the services that were lost.

Very queer indeed.

AA191 lost all electrical power on the captains side, as well as all communications, when the no. 1 engine detached. The FE could have switched the circuits but didn't do so for the 50 seconds between separation and impact.
Obviously a different airplane model, so you'd have to look at the 737NG systems architecture to check if something similar could happen.


As per Zeke this is correct, and could be the reason in this case.
 
mysfit
Posts: 60
Joined: Tue Dec 27, 2016 7:16 pm

Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:56 am

Based on the information so far, it would seem the aircraft suffered a rapid, explosive event resulting in a fireball on the way down

That leaves a number of blanks to fill in. We all are making assumptions trying to fill in those blanks. Without much in the way of hard facts. And statistics and probabilities don't always cut it. They are based on what we THINK we know.

A missile (intentional or not), an on board bomb, an onboard explosion, some kind of event that would be exceedingly rare. Lind of like a plane continually nosing down trying to kill you.

I think the only thing we can remotely agree on is it not being the result of pilot error. Given all that, it would be nice if we kept that in mind rather than smacking each other about the head over assumptions this early in the investigation.
Last edited by mysfit on Thu Jan 09, 2020 10:00 am, edited 1 time in total.
 
xmp125a
Posts: 292
Joined: Mon Mar 11, 2019 6:38 pm

Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 9:58 am

Jouhou wrote:
Well, as long as everyone is talking about rapidly progressing fires that disable the pilots and electrical systems fast, a fire originating near the oxygen system is one that hasn't been mentioned.


But fireball?
 
sevenair
Posts: 2959
Joined: Sun Feb 04, 2001 7:18 am

Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 10:02 am

mysfit wrote:
Based on the information so far, it would seem the aircraft suffered a rapid, explosive event resulting in a fireball on the way down

That leaves a number of blanks to fill in. We all are making assumptions trying to fill in those blanks. Without much in the way of hard facts. And statistics and probabilities don't always cut it. They are based on what we THINK we know.

A missile (intentional or not), an on board bomb, an onboard explosion, some kind of event that would be exceedingly rare. Lind of like a plane continually nosing down trying to kill you.

I think the only thing we can remotely agree on is it not being the result of pilot error. Given all that, it would be nice if we kept that in mind rather than smacking each other about the head over assumptions this early in the investigation.


We don't always get it right, but its impressive that they turned the plane into a fireball in the sky and into a billion pieces, especially with 30,000 hours of experience. I appreciate pilot error is still worrying common, but the f-ck up fairy has to be in a very bad mood to create this incident!
 
airhansa
Posts: 380
Joined: Wed Jan 08, 2020 3:18 pm

Re: Reports of Ukrainian 737 Crash in Tehran,Iran

Thu Jan 09, 2020 10:03 am

CPHGuard wrote:
timh4000 wrote:
Well. I'm hardly an expert on aircraft major malfunctions and what they can do to a plane. So, I'll be more of in question mode. 1st, has there EVER been a case where an engine explodes for whatever reason and to have it cause this much damage?

I think back at all of the other major engine explosions and while not all of the planes made it down safely, none that I can think of just fell out of the sky in a fireball.


Air France AF 4590 comes to mind, and it was airborne for less than 90 seconds:

https://youtu.be/fjtsbAckbTg?t=74


I actually use the concorde crash as a visual example of how a engine explosion [i]should[/i] look like at worst. An actually engine fire should be more contained as tools and protective design exists to help prevent such a fire from gaining out of control, I can't see how such a fire could a) bring down a plane to the point that all communications were lost (including no time for a mayday which is highly unusual) and b) engulf the plane in a fireball so quickly.

The Air Chine one posted above shows how a fuel leak + engine could create a massive fireball, far larger than the problems faced by Concorde, but there was a lot of time for the fire to spread and explode. It doesn't explain how the situation could collapse so quickly that the plane was both uncontrollable, engulfed in a large fireball and unable to communicate.

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