You may be right. Equally, given the volatility of the location at present, and the unpredictable nature of the leadership of the protagonists, more people stand to get hurt with any over reaction, by either side, for which speculation is a great fuel source. There is a non zero possibility of this being a Guns of August type moment in history, and if Tuchman's writings showed anything it was that the consequences of actions are poorly predicted by any side, whoever is involved. To that end, leaving this event to the AI and CI investigators is not a bad thing, they will be able to ascertain causation as a technical fault or criminal matter in their own deliberations, sticky pebbles or not.

Truth is written by the victors, if any remain to write it.

A bit more fact-free speculation.


As the problems appear to have occurred at about 5000' AGL if it were brought down by ground fire it would need to be a weapon effective at that distance from where it was fired, that rules out rifle fire, don't know the effective range of the Stinger and such like.


For that amount of disintegration before impact, if it was an on board bomb, I think it would have to have been a big one.

Good find!

The parts do seem to match up. There appears to have been some cutting of that fuselage part between the two images being recorded. See oval in yellow. Cut by recovery/rescue teams?

https://cimg0.ibsrv.net/gimg/pprune....e8030b3070.jpg

Lots of people speaking several languages. Likely he meant they added flight attendants who could speak Farsi.

With regards to the cutting, it looks like there may be a shadow on the low res TV image. It's likely any cutting would have dislodged the pebbles/dirt. Perhaps play with the brightness/contrast settings.

A bit more fact-free speculation.


As the problems appear to have occurred at about 5000' AGL if it were brought down by ground fire it would need to be a weapon effective at that distance from where it was fired, that rules out rifle fire, don't know the effective range of the Stinger and such like.


For that amount of disintegration before impact, if it was an on board bomb, I think it would have to have been a big one.

I see that not as a "cut out" on the picture on the left, but a further piece of the fuselage closer to the camera and bent up upwards - it's dark and unlit and blocking the view of the piece of the side behind it.

Indeed, it's a piece of fuselage that has torn and bent up. People are so bad at interpreting low res images, they shouldn't even try.

Apologies. Thanks for everyone that pointed out my poor interpretation. You are quite correct.

https://cimg1.ibsrv.net/gimg/pprune....585baa9c0f.jpg

High resolution at following link

https://inews.co.uk/images-i.jpimedi...ane-083866.jpg

I suspect that I know the answer but does the 737NG transfer maintenance data on ACARS?

Boeing doesn't typically read and evaluate data recorders after accident flights, so there's no reason it should receive this one. If anyone has information suggesting that Iran intends to withhold the FDR & CVR from appropriate investigators (BEA, perhaps), let us know.

It can if you opt for it. It's an expensive option. Not sure if UA have or have not.

U.S. Secretary of State statement on PS 752.

https://cimg3.ibsrv.net/gimg/pprune....77954fc4bd.png

The timing of the crash is around 6:18 am local time, which is a very reasonable timing for morning prayers. Might be someone on the way to or from a local mosque. There is not much happening around that time of the day, and airport being close I think it is pretty normal to film a fireball you spot in the sky with your phone and chase it to see what happens.

It's not a question of "withholding" access to the recorders.

Annex 13 requires that "the State conducting the investigation shall arrange for the read-out of the flight recorders without delay". It goes on to recommend that if the investigating state doesn't have that capability, it should use the facilities made available to it by other states, taking into account the capabilities and location of the facility in question and the likely timescale.

No third party has an automatic right to demand access to the FDR or CVR. In the unlikely event that the Iranians take up the US offer of assistance in this area, it would be the NTSB that reads the recorders. More likely, as alluded to above, it will be the BEA or BFU (or maybe even the AAIB).

Yes, absolutely. I didn't mean to suggest that Iran was under an obligation to share.

There are various sources reporting the Mehr news agency quoting the head of Iran’s Civil Aviation Authority (Ali Abedzadeh) as saying something to the effect that the black boxes would be examined in Iran under ICAO rules. However, I've not yet found a specific quote on the Mehr news agency site that sounds anything like that.

But if he did say that, then adding [words to the effect of] 'we won't send them to the manufacturer' would make a lot more sense.

Of course that makes for a far less juicy soundbite than "Iran will not provide Boeing with the black boxes", as if Boeing were somehow expecting to be given them.

It seems there is a lot being lost (and gained) in the translation and interpretation.

There was also the minor matter of Iran having just challenged a nuclear armed superpower, so people were out and about looking for incoming and outgoing missile/jet trails (and perhaps not wanting to risk being burned alive inside of their apartments.)

Another possibility for the accident to put out there is that the ground crew were nervous (and perhaps exhausted from the funeral/protest), the pilots wanted to get out while the getting was good, and the plane needed to be deiced. It would not be surprising if people were rushing and made a mistake somewhere.

The engine picture on AVHerald has outward bend wholes....
Uncontained engine failure with catastrophic result?

There also seems to be some sort of heat (whitened metal) discoloration visible.....

Any thoughts on that picture?

Can anyone recall an uncontainable engine failure on a 737 (or equivalent) that:

a) caused a significant inflight fire
b) brought the aircraft down
c) created a crew load such no contact with ATC occurred

- GY

Quite the debris field.

https://www.isna.ir/amp/98101813851/...mpression=true

And, d) left a debris field like the one we're seeing photos?

I don't know what happened to this aircraft, but it sure looks like there was a very, very big explosion in flight.

No disagreement. Common sense and Occam's Razor suggest missile, bomb, something powerful going boom. Whether it was deliberate or inadvertent and who may have "done it" are all just speculation at this point.

I am not drawing any conclusions. I do find it difficult though to believe a (simple) engine fire would require such aviation and navigation that a quick mayday to secure a free flight path would be too much.


And if you do return to a busy international airport, communication might be important to at least alert other aircraft and ATC of a deviation of the expected path.

Again, no conclusions, but if I were a betting man, I would not put any money on an engine fire as sole reason.

There was a large explosion, about 2 perhaps 3 seconds prior to impact as seen in the video.

A few months ago we'd have said the same about airplanes pointing themselves at the ground :uhoh:

I'd agree that the balance of probabilities points towards an explosive at this point, but something like SW1380 but worse is still a possibility.

The lack of crew contact is the most telling piece, with an engine failure I would think that at some point a mayday would be issued especially when carrying extra crew members. The fact Iran is refusing access to the flight recorders and a statement was made within an hour stating engine failure as the cause are all red flags. Tensions were extremely high just after the missed launch by Iran and it is not outside the realms of possibility that everyone would have been a bit trigger happy towards any perceived threats. I hope it is not the case but the evidence seems to be suggesting something more complicated that a poor
y controlled engine failure.

What do you think indicates that was the case?

In one of the photos published by the Iranian Students' News Agency either the CVR or FDR is visible in what appears to be electronic debris like notebook computers put in a pile. Hope it doesn't get lost or sold for scrap.

https://cimg6.ibsrv.net/gimg/pprune....563d548333.jpg

I have thousands or hours on 737s and have trained on all variants up to the -800.
This event looks totally unrelated to any normal or non-normal situation that has been seen before.
An engine fire does not bring down a plane. An engine failure same. Even double engine failure leaves a 737 flyable via manual reversion - the only type in the world that can still do that.
The icing scenario does not fit either. This plane seems to have exploded in mid air prior to impact looking at the vast debris field with burning parts over a large area. The video of what looks like a Concorde last moments is graphic , if true.
Sherlock Holmes said "eliminate the impossible and your are left with the probable"
So what is left?
It is going to be hard since the authorities in Iran are going to have all the evidence and can release what then wish people to think. I believe that even a regime like the one that exists there will have to apply ICAO protocols to the investigation but it will be like pulling teeth.
The one truth that I still believe in here is that the 737 is still one of the best and safest planes every built and this event alas adds fuel to the fire of the narrative that Boeing is bad for you.
Condolences to all aboard. Very sad indeed
Old Timer
Over.....

Uhh, as most notebooks has a built in camera, it's only logical to collect them as potential source of data for the investigation.

Don't know if notebook computer cameras would be used much on climbout but I do hope tablets and cellphones will be checked for video and images. Folks do tend to record takeoffs and landings these days even in the darkness.

What sort of mistake with deicing would cause the aircraft to erupt into a fireball?! Accidentally calling over the lighter fluid truck?!

Reuters article posted a few minutes ago...

Isn't it quite possible that if a portion (or all) of a wing failed at that point due to aerodynamic forces, that the rapid release of fuel in the slipstream would create a fireball which could be perceived as an explosion? Much like the fireball which erupted at the breakup of the Space Shuttle Challenger was caused by the failure of the main tank. In that case, It appeared to be an explosion, but in true defined terms, it was not.

I don't get the large debris field point. It seems that things spread to an area about 270 m long, and it seems the craft contacted a few brick / concrete walls and a concrete water canal along the route. Why do people think that it's unusual to have in pieces?

https://cimg3.ibsrv.net/gimg/pprune....7dc43d1981.jpg

Uncontained engine versus debris field
 

If there was some massive and unprecedented uncontained engine failure, it seems it would be evident in the debris field - i.e. the first parts to fall to earth, short of the primary debris field, would be engine or nacelle components. It was a relatively young airplane as well, so not getting near fatigue lives and such.

Indeed. Not only would Iran's SAM defences been on edge at the time, is it not highly likely that the US would have been overhead watching what was happening?

Perhaps the SAM was intended for a US military spy plane?

It might suit both sides to conceal the cause.

what picture ?????

Probably this one:
http://avherald.com/img/uia_b738_ur-..._200108_5a.jpg
https://cimg3.ibsrv.net/gimg/pprune....b0d14c44b1.jpg
And I would think no.

Image circulating on social media, Babak Taghvaee is an expat Irani aviation writer:

https://cimg1.ibsrv.net/gimg/pprune....9fda81b853.jpg

https://cimg7.ibsrv.net/gimg/pprune....44616b728f.jpg


https://cimg8.ibsrv.net/gimg/pprune....985ec94886.jpg

And:

https://cimg3.ibsrv.net/gimg/pprune....c8be6fa83b.jpg