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-   -   Sheremetyevo Superjet 100 in flames (https://www.pprune.org/rumours-news/621198-sheremetyevo-superjet-100-flames.html)

Anvaldra 5th May 2019 20:39

New figures - 41 fatalities

A Squared 5th May 2019 20:42


Originally Posted by Anvaldra (Post 10463856)
New figures - 41 fatalities

Ugh. Not good news, but not surprised. When I first saw the video and the reports of all surviving, I thought ... seems unlikely. No satisfaction in seeing that my initial reaction is correct.

tdracer 5th May 2019 20:43


Originally Posted by freshgasflow (Post 10463818)
I am not an aviation professional so grateful if someone could explain things to me:
If the theory of lightning strike are true, how does it lead to electrical failure ? I thought that an aircraft aluminium or metal mesh composite effectively created an Faraday cage ?
If there were local electrical transients, would this only trip circuit breakers. which presumably could be reset quickly ?
Thank you.

Aluminum does a good job of conducting the lightning current, however there can be significant 'induced' current on internal wiring (similar to the way a transformer works - current through the external windings induce a current to the internal windings). However, this should be designed for per 25.1316:


§25.1316 Electrical and electronic system lightning protection.

(a) Each electrical and electronic system that performs a function, for which failure would prevent the continued safe flight and landing of the airplane, must be designed and installed so that—(1) The function is not adversely affected during and after the time the airplane is exposed to lightning; and(2) The system automatically recovers normal operation of that function in a timely manner after the airplane is exposed to lightning.(b) Each electrical and electronic system that performs a function, for which failure would reduce the capability of the airplane or the ability of the flightcrew to respond to an adverse operating condition, must be designed and installed so that the function recovers normal operation in a timely manner after the airplane is exposed to lightning.
(note, the quote is the FAR, however the regulation has been harmonized so the EASA CS version should be identical - and to export the Superjet they'd have to show compliance with the FAR/CS)
There is a lengthy Advisory Circular that provides specifics on how to show compliance.
In short, critical systems can not be significantly affected by the lightning transient, essential systems can be affected but must self recover (with no resetting of circuit breakers). The allowable recovery time depends on the system, but 10 seconds was a good rule of thumb.

So the short answer is that a lightning strike should NOT have resulted in widespread system failures.

andrasz 5th May 2019 20:58


Originally Posted by tdracer (Post 10463861)
...a lightning strike should NOT have resulted in widespread system failures.

At the moment we do not really know if it was a lingthning strike, it is only speculation (though not unsubstantiated). From what is definitely known, aircraft first squawked 7600 about 7 minutes into the climbout, stopped the climb and returned to land, changing to 7700 about 6 minutes prior to touchdown. What happened next is on video... Closeup photos clearly show slats/flaps deployed (to about 25), aircraft was configured for a normal landing.

Hard to make any further judgment until we know what controlability issues the crew had to tackle. It could be a badly blotched landing with a perfectly controllable airplane, or an outstanding feat of airmanship in face of adverse circumstances.

BristolScout 5th May 2019 21:38

Looking at the images, hopefully the flight deck crew have survived which will help the investigation.

testpanel 5th May 2019 21:46


SanchesS80 5th May 2019 21:48


Originally Posted by BristolScout (Post 10463882)
Looking at the images, hopefully the flight deck crew have survived which will help the investigation.

Both Captain and FO are fine for sure (local media says they are being questioning by authorities now)

jantar99 5th May 2019 21:54

Cabin video after touchdown. Different from tlott's one.

JohnnyRocket 5th May 2019 21:55

Terrifying footage from inside the cabin here - https://www.youtube.com/watch?v=KwTpGLKPFXI&feature=youtu.be

andrasz 5th May 2019 21:57

Full uncut video of the first 5 minutes:

00:20 Aircraft comes to a stop
00:30 First slide deploys
01:51 First Fire truck arrives
02:13 Last evacuation on slide
02:50 RH cockpit crew evacuates using rope
03:30 Crew member climbs back to plane on slide
03:47 Smaller and larger dark objects slide down slide
03:55 Crew member slides down slide

yanrair 5th May 2019 22:19


Originally Posted by freshgasflow (Post 10463818)
I am not an aviation professional so grateful if someone could explain things to me:
If the theory of lightning strike are true, how does it lead to electrical failure ? I thought that an aircraft aluminium or metal mesh composite effectively created an Faraday cage ?
If there were local electrical transients, would this only trip circuit breakers. which presumably could be reset quickly ?
Thank you.

lightning strikes are usually harmless on properly constructed jets. I’ve had many over 35 years. Still here!

Traffic_Is_Er_Was 5th May 2019 22:32

It appears that after that last crew member slides back down at 03:55, there is still someone in the doorway who goes back inside. I don't see them come out, unless they use the slide on the other side. On watching again, it looks like that last crew member then runs around to check the slide on the other side, but no luck.

paperHanger 5th May 2019 22:51

From the cabin passenger video, there is an alert signal on the cabin intercom, so it would appear not *all* the electrical circuits are dead.

paperHanger 5th May 2019 22:55


Originally Posted by SanchesS80 (Post 10463887)
Both Captain and FO are fine for sure (local media says they are being questioning by authorities now)

It is Russia, someone has to pay for the bad publicity, they either have heroes, or someone goes to jail ... there seems to be no middle ground.



chafra 5th May 2019 23:02

Full investigation of all AC losses
 
This crash is too similar to the last one in 2018 with MLG collapse. And the first AC loss due to CFIT also had electrical failure, hadn't it? It's time for a full investigation of SSJ accidents. This AC is a menace to society. Poor families that lost their members. Rest in peace.

​​​​

jack11111 5th May 2019 23:51

I don't see flames until second bounce. Do others here agree?

Decision_Height 6th May 2019 00:00

If its in direct law then likely a handful, and we don't know exactly what systems that were down or why, so lets not rush to judgement on flying skills or otherwise.

What is truly sad is the mis-reporting, the video evidence clearly shows it wasn't on-fire on approach, and its a consequence of the bounce causing a puncture/rupture of the wing fuel tanks.

Reports here now that 41 fatalities.. sad indeed. :(

What-ho Squiffy! 6th May 2019 00:15

Much is up for debate wrt this accident. All except for the veritable AGE it took for ARFFS to get onsite.

2unlimited 6th May 2019 00:19

When I see the people running with their large luggage, it makes me furious. How many more could have been saved if it wasn't for some selfish morons, we will never know.

Apparently they had lost COMs, so I am guessing the reasons the fire services was so slow was that there had not been any communication from the aircraft as they came in for landing.

Does anybody know what the fire service rescue reaction time should be at an airport like this? Or what level of RFFS it is at this airport?
Someone should have spotted that burning aircraft on approach and raised some alarms you would have thought.

lomapaseo 6th May 2019 00:41

The landing may have been hard enough to break off the gear and the dislodged gear which rupture the fuel tanks. The videos so far posted show only the latter part of the landing slide out.

The first issue is why the hard landing and then to work the before and afters from that.


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