Rather alarming seeing this on flightradar24 at the moment. S75220 / SBI5220 S7 Airlines Airbus A321-271N VQ-BGU doing Magadan (GDX) - Novosibirsk (OVB) just now has just done some extreme manoeuvres. Seems to have had some kind of control issue forcing it into climbs in excess of 15000fpm and dives of -9000fpm including sharp turns. Currently off radar but looks like it may be diverting to Yakutsk (YKS).


https://imgur.com/a/MAQgW1F


https://imgur.com/ZxLye59


https://imgur.com/4C4Czz1

Will be keeping an eye on this, wonder what would cause such an upset?

Back up and showing on ADS-B again at FL290 indicating a diversion to Yakutsk however has just started climbing and making a turn to the south with some fluctuations.

Well this is interesting, curious to know what in the world is going on and why they didn't go back to GDX

ikolkyo wrote:

Well this is interesting, curious to know what in the world is going on and why they didn't go back to GDX

It is distantly possible they know exactly what caused the issue already —PIO or something like that— resolved, and that they want to continue.

Still, this looks like something that should require an immediate landing.


Edit: Looks like they are now diverting to Yakutsk (YKS).

ikolkyo wrote:

Well this is interesting, curious to know what in the world is going on and why they didn't go back to GDX

Interestingly it's not even going to Yakutsk anymore. Looks like it might even be heading straight to home base which is its destination, Novosibirsk (OVB). Seems like it may be being manually flown at the moment, not that it can be confirmed given how inaccurate this kind of data can be.

Maybe they were doing another Zero G music video for OK Go

https://youtu.be/LWGJA9i18Co

On our planes, private bizjets, I’ve seen some crazy graphs like these, turn out to be ADS-B anomalies

If Putin was near it may be gps jamming leading to the anomaly. Ive read in the past they jam gps signals around him when he is on travel.

https://foreignpolicy.com/2019/04/03/russia-is-tricking-gps-to-protect-putin/

This very much appears to be an ADS-B tracking anomaly, which is very common with civilian flight tracking software and is frequently noted on these forums. Therefore, the thread will be moved to Non Av as it isn't directly related to Civ Av. Should more concrete information become available, it will be moved accordingly.

✈️ atcsundevil

Appears to now be diverting to Irkutsk rather than doing the whole leg home to Novosibirsk. Just starting its descent now.

I disagree with it being dismissed as just an ADS-B glitch so prematurely, it's just far too precise rather than just erratic erroneous data which is what you'd expect from dodgy ADS-B; especially for an aircraft type this new with all other previous tracks being precise and normal.

Also, moved to non-av with title change based on one's own opinion? Interesting assessment but ok.
We shall learn more once it lands whether or not it was indeed a load of ADS-B whack or if a genuine issue did present itself. Until then I think an open mind would be good...

AllNippon767 wrote:

Appears to now be diverting to Irkutsk rather than doing the whole leg home to Novosibirsk.
I disagree with it being dismissed as just an ADS-B glitch so prematurely, it's just far too precise rather than just erratic erroneous data which is what you'd expect from dodgy ADS-B; especially for an aircraft type this new with all other previous tracks being precise and normal.
Also, moved to non-av with title change based on one's own opinion? Interesting assessment but ok.
We shall learn more once it lands whether or not it was indeed a load of ADS-B whack or if a genuine issue did present itself. Until then I think an open mind would be good...

These types of ADS-B anomaly threads come up on an almost weekly basis. There is no source to confirm the claim that something serious has occurred to this flight, only data from an app that is notoriously prone to glitches and anomalous readouts.

If/when an actual source becomes available to indicate that an incident actually occurred here, the thread title will be updated and the thread moved back to Civ Av. There is presently no information to suggest this is anything other than an anomaly.

On a side note, my experience as an air traffic controller tells me that the data indicating a 15000fpm climb in an A321 is absolutely erroneous and impossible — that's a climb rate exclusively reserved to high performance aircraft, particularly given that the A321 generally climbs like crap even compared to other similar types. That's why I changed the title and moved the thread.

✈️ atcsundevil

Very well we shall wait and see, hopefully it is just an ADS-B anomaly with absolutely no harm done. I too hope this thread and post was just complete nonsense on my part however the indications so far do raise questions despite no solid evidence.

To take up your point in regards to A321 performance, in normal conditions you would never expect to see an airliner of this class (or any for that matter) do such a thing, and I'm sure in your experience you wouldn't do. However to dismiss it as "impossible" is wrong and short-sighted. An A321 can absolutely do +15000fpm in a 30 degree climb at the speeds it was flying and the opposite is true, it can do -9000fpm in a 20 degree nose down descent at the speed it was doing. Those 2 nose up and nose down conditions and parameters are completely within the limits of the flight envelope of the A321 as the flight protection does not allow the aircraft to pitch beyond that range. The conditions are possible, it's just incredibly unlikely and rare for an event that would put it in such a condition like that to happen. An example of a rapid climb in an aircraft similar to the one in question was Air Asia 8501 which at a 24 degree nose-up pitch and achieved well over +10000fpm, of course not to say the circumstances presented are the same.

On a side note, the aircraft has landed safely in Irkutsk.

AllNippon767 wrote:

Very well we shall wait and see, hopefully it is just an ADS-B anomaly with absolutely no harm done. I too hope this thread and post was just complete nonsense on my part however the indications so far do raise questions despite no solid evidence.

To take up your point in regards to A321 performance, in normal conditions you would never expect to see an airliner of this class (or any for that matter) do such a thing, and I'm sure in your experience you wouldn't do. However to dismiss it as "impossible" is wrong and short-sighted. An A321 can absolutely do +15000fpm in a 30 degree climb at the speeds it was flying and the opposite is true, it can do -9000fpm in a 20 degree nose down descent at the speed it was doing. Those 2 nose up and nose down conditions and parameters are completely within the limits of the flight envelope of the A321 as the flight protection does not allow the aircraft to pitch beyond that range. The conditions are possible, it's just incredibly unlikely and rare for an event that would put it in such a condition like that to happen. An example of a rapid climb in an aircraft similar to the one in question was Air Asia 8501 which at a 24 degree nose-up pitch and achieved well over +10000fpm, of course not to say the circumstances presented are the same.

On a side note, the aircraft has landed safely in Irkutsk.

Since I fly the 321 often, I’ll just say if you were able to achieve a 15,000 fpm rate of climb it would be very temporary, and leave you in a very precarious situation. That would essentially be an upset recovery. I agree with those who took issue with the original thread title. It was drastic overstatement, based on very little information. The news media is often criticized on this forum for the same behavior.

Something did happen.

https://avherald.com/h?article=4f10cac3&opt=0

https://aviation-safety.net/wikibase/270140

https://www.mysafersky.com/news/2021/12 ... cal-issue/

Figured something was up when I saw they diverted to IKT. The incident highlights the remoteness and harshness of conditions in Siberia when you can't make an emergency landing at one Airport due to Icing and the chosen alternate was nearly 3 hours away. Fair chance IKT experiences plenty of Icing itself given it's located in the heart of Siberia.

It must have been a nervous wait for PAX and Crew to see if the Airplane was going to behave normally or erratically when they descended into IKT.

AllNippon767 wrote:

Something did happen.

https://avherald.com/h?article=4f10cac3&opt=0

https://aviation-safety.net/wikibase/270140

https://www.mysafersky.com/news/2021/12 ... cal-issue/

So what the articles are saying is that it was not a tracking software issue but a actual issue with the plane, very interesting to say the least.

Media starting to report the experience - https://www.dailymail.co.uk/news/articl ... beria.html

The avherald article has been updated today with Rosaviatsia report.

according to FDR the roll angles varied between 49.8 degrees and -91.1 degrees, pitch angles from 43.8 to -23.9 degrees.

It was pretty clear to me that it wasn't just an ADS-B glitch from the beginning, enough experience with that kind of data would tell you that. The FDR data has confirmed my suspicions into the steep climbs and sharp turns however, I am also surprised that the aircraft managed to venture that far beyond the limits of the FBW envelope protection.

Taking the latest updated reports into account the thread has been moved back into Civil Aviation forum.

Great job catching this near catastrophe as it unfolded AllNippon767 it's a truly remarkable event that could have ended very badly.

Skip through the drama in most of this and you will find suspicion of adulterated de-icer. Scary thought.

https://nypost.com/2021/12/03/hero-pilo ... r-5-hours/

Is this a record for the longest time a flight has had between declaration of emergency and landing?

Glad to see this, couldn’t believe it wasn’t posted sooner. Some of the ATC has been released, stall warning audible in the background on the RT. Pilots extremely agitated. Plane is completely out of control etc

Here's the video with ATC recording

https://www.youtube.com/watch?v=hzPm3Zcpt80

AllNippon767 wrote:

Here's the video with ATC recording

https://www.youtube.com/watch?v=hzPm3Zcpt80

Reported icing a number of times during the recording.
Towards the end of the recording, reported "very significant icing the plane is unable to climb"

-MIkhail

zkojq wrote:

Is this a record for the longest time a flight has had between declaration of emergency and landing?

No and according to other report on telegram (which I cannot link here) they cancelled the emergency. There is not requirement once an emergency is declared to land at the nearest airport, it depends on the emergency. In this case the nearest airport has severe icing and wind shear, so a safer decision it to get where the conditions are better.

“
⚡️According to the report of the Federal Air Transport Agency, on December 2, after take-off (at 3:42 Moscow time) from Magadan to Novosibirsk, the crew of the Airbus A321neo (VQ-BGU) S7 Airlines aircraft reported an uncontrollable flight speed (failure of the speed sensors), transmitted the signal "MEIDAY" , made a decision to return to the departure aerodrome.

After completing the landing approach due to severe icing and wind shear, the aircraft commander decided to proceed to the Yakutsk alternate airfield.

At 05:04 Moscow time, the crew reported a discrepancy in height and that it implies a landing with an excess of the landing weight, the board was in order, the distress signal was canceled.

At 5:37 Moscow time, the aircraft commander reported on the decision to proceed to the Irkutsk airfield.

The plane, performing flight S7 5220, landed safely at 8:16 Moscow time.

S7 Airlines official comment on the incident:

During flight S7 5220 Magadan - Novosibirsk, the plane got into a zone of severe icing, which led to the disconnection of the autopilot.

Before departure from Magadan, the board underwent de-icing treatment, the meteorological conditions for take-off corresponded to acceptable ones. All S7 Ailrines pilots practice manual piloting skills in training flights and simulator sessions.

The captain of the aircraft made a decision to land at an alternate aerodrome, because due to the effects of icing, the flight took place at a level below the calculated one and the fuel supply did not allow to fly to Novosibirsk. The plane landed safely at the Irkutsk airport.

The passengers were delivered to Novosibirsk by a reserve plane, it was also proposed to reissue for other flights, food and drinks were provided.”

In this thread on a Russian aviation website they claim to have photos of the ice on the aircraft after landing.

Сообщение в теме 'Инцидент с самолетом Airbus A321-271N S7 5220 02.12.2021'
https://aviaforum.ru/threads/incident-s ... st-3144686

Does -91 degrees of roll mean the wings were completely vertical?

cedarjet wrote:

Glad to see this, couldn’t believe it wasn’t posted sooner. Some of the ATC has been released, stall warning audible in the background on the RT. Pilots extremely agitated. Plane is completely out of control etc

It was actually posted as it was happening.. you want it even sooner then that?

AllNippon767 wrote:

Here's the video with ATC recording

https://www.youtube.com/watch?v=hzPm3Zcpt80

At 4:32, pilot saying we can't stabilize the aircraft while stall warnings going off.

Giving me chills

This reminds me of the E190 in Portugal a while back

Man, this crew was in big trouble. Kudos to them for getting out of that safely and if the reports are true about the deice fluid being counterfeit, people need to be in jail.

Spetsnaz55 wrote:

AllNippon767 wrote:

Here's the video with ATC recording

https://www.youtube.com/watch?v=hzPm3Zcpt80

At 4:32, pilot saying we can't stabilize the aircraft while stall warnings going off.

Giving me chills

I can't quite make out the first 2 words at 4:41

Starfuryt wrote:

Spetsnaz55 wrote:

AllNippon767 wrote:

Here's the video with ATC recording

https://www.youtube.com/watch?v=hzPm3Zcpt80

At 4:32, pilot saying we can't stabilize the aircraft while stall warnings going off.

Giving me chills

I can't quite make out the first 2 words at 4:41

horrible windshear ?

An-26 took off before them and reported MODERATE icing up till F100, that's the beginning of the ATC recording, this was passed on to the S7 crew.

However they didn't lose control or report any difficulties.

Ice ridges around the pitots after incorrect de-icing procedure (slush re-freezing again after sliding down the fuselage) causing unreliable airspeed indications.

http://avherald.com/h?article=4b572ccf&opt=0

Unreliable airspeed not enough to cause the control problems though right, unless the computer got in the way and kept doing stuff? So there was presumably significant ice left on control surfaces too? Am I right in assuming that the anti-icing capabilities of the plane itself is just enough to keep new ice forming rather than getting rid of anything that is there?

JohanTally wrote:

Does -91 degrees of roll mean the wings were completely vertical?

Yes. After seeing those numbers I can see why passengers were saying that they are luck to be alive.

JibberJim wrote:

Unreliable airspeed not enough to cause the control problems though right, unless the computer got in the way and kept doing stuff? So there was presumably significant ice left on control surfaces too? Am I right in assuming that the anti-icing capabilities of the plane itself is just enough to keep new ice forming rather than getting rid of anything that is there?

I’m assuming a thorough safety investigation will take place with Airbus. I wouldn’t be surprised to see some changes coming from this. I’m curious how the flight control computers responded to the unreliable airspeed values since there were problems with autopilot and auto thrust. There are checklists in place for unreliable airspeed which are supposed to guide the pilot to being able to maintain controlled flight, which does not appear to have happened in this flight. Avherald indicates severe turbulence and icing.

https://avherald.com/h?article=4f10cac3&opt=0


From Avherald:

On Dec 4th 2021 Rosaviatsia reported following takeoff the aircraft flew into clouds and into a zone of severe turbulence accompanied by strong icing. As result the aircraft got into a difficult spatial position, according to FDR the roll angles varied between 49.8 degrees and -91.1 degrees, pitch angles from 43.8 to -23.9 degrees. The crew declared Mayday.

Pilots are taught upset recovery, but in my opinion those pitch and roll values combined with severe turbulence, icing, unreliable airspeed and all the various alerts that go with it is not something where training truly can reflect reality to the point that all pilots would be expected to be able to recover.

Wow this reads like indeed everybody is lucky to be alive.

Any similarities to Air France 447?

‘902

TWA902fly wrote:

Wow this reads like indeed everybody is lucky to be alive.

Any similarities to Air France 447?

‘902

No, if the photos I've seen of ice on leading edges are genuine on this one the pilots apparently landed a very difficult to control airplane. On AF447, the pilots managed to crash an airplane that was perfectly flyable.

How did the pilots manage to land the plane with such pitch and banks? Normally, the end result would be a crash, and I wonder if what the pilots did, to land the plane safely, could be replicated in a simulator. Did the aircraft ever need to be flown under alternate law at any point?

N47 wrote:

If Putin was near it may be gps jamming leading to the anomaly. Ive read in the past they jam gps signals around him when he is on travel.

https://foreignpolicy.com/2019/04/03/russia-is-tricking-gps-to-protect-putin/

GPS jamming would have no effect on Airspeed Indications. The 787 and 777-9 have a backup Altitude source that uses GPS, but in general Air Data indications are unaffected by GPS. I expect this is true for Airbus airplanes also. So that would not likely have caused this event.

I thought de-icing pre-takeoff was to get an aircraft into the air, following which it's effectiveness wore off. The aircraft de-icing technology then took over.

So there should be no ice on landing, even if the original de-icer was not as effective as it should have been.

Is that right?

aemoreira1981 wrote:

How did the pilots manage to land the plane with such pitch and banks? Normally, the end result would be a crash, and I wonder if what the pilots did, to land the plane safely, could be replicated in a simulator. Did the aircraft ever need to be flown under alternate law at any point?

I assume the investigation will involve simulator sessions.

Can an A321 even get into a 90 degree bank during normal law? I thought it has bank angle protection

Weatherwatcher1 wrote:

aemoreira1981 wrote:

How did the pilots manage to land the plane with such pitch and banks? Normally, the end result would be a crash, and I wonder if what the pilots did, to land the plane safely, could be replicated in a simulator. Did the aircraft ever need to be flown under alternate law at any point?

I assume the investigation will involve simulator sessions.

Can an A321 even get into a 90 degree bank during normal law? I thought it has bank angle protection

according to leaked FDR data, about 1 minute after rotation roll went into DIRECT, and pitch into ALT, with a period of DIRECT during worst part of it - and never returned to normal. So they were hand flying till landing.
Hell broke loose some 8 minutes after the rotation, so they were flying manually more or less uneventfully - likely troubleshooting (and possibly descended into an icing cloud) for 7 min after first issue.
I don't quite understand change of control mode. Airspeed disagree is reported, but FDR shows little, if any, discrepancy between 2 channels.

Weatherwatcher1 wrote:

aemoreira1981 wrote:

How did the pilots manage to land the plane with such pitch and banks? Normally, the end result would be a crash, and I wonder if what the pilots did, to land the plane safely, could be replicated in a simulator. Did the aircraft ever need to be flown under alternate law at any point?

I assume the investigation will involve simulator sessions.

Can an A321 even get into a 90 degree bank during normal law? I thought it has bank angle protection

With the flight computers not getting reliable data, you'd get dropped to alternate law which loses the bank angle and pitch attitude protection.

JerseyFlyer wrote:

I thought de-icing pre-takeoff was to get an aircraft into the air, following which it's effectiveness wore off. The aircraft de-icing technology then took over.

So there should be no ice on landing, even if the original de-icer was not as effective as it should have been.

Is that right?

Deice on the ground blows off during takeoff. Aircraft deice and anti ice is done in the air, however no aircraft is certified for flight into severe icing.

Weatherwatcher1 wrote:

Can an A321 even get into a 90 degree bank during normal law? I thought it has bank angle protection

Sure, even inverted. Just not from within the normal flight envelope through pilot controls. I suspect what we see here is as the result of wing stall.

Astronage wrote:

With the flight computers not getting reliable data, you'd get dropped to alternate law which loses the bank angle and pitch attitude protection.

The protections will not stop a stall response, the protections are there to prevent adverse pilot inputs. In the case where an aircraft stalls and drops a wing in normal law the aircraft will change to unusual attitude law which has no protections.

Can you imagine the psychological impact this event had on the crew. Hopefully they get paid time off and counseling as necessary before they return. This being true for both flight deck and cabin crew.

Okcflyer wrote:

Can you imagine the psychological impact this event had on the crew. Hopefully they get paid time off and counseling as necessary before they return. This being true for both flight deck and cabin crew.

Or they may be appointed scapegoats, fired, criminally charged.
One count is on the surface - they signed out deice paperwork before the door was closed and deicing performed. Who cares that handing over those papers is too difficult when engines are running, snow falls, and air stairs are not there - and pilots cannot see much 9f a result anyway?

It seems they landed at IKT even though YKS was less than half as far and directly on the great circle route, IKT seems a very reasonable place to go but does anyone know why they wouldn't stop at YKS?