Aeroflot Superjet 100 fire and evacuation at UUEE

[Gabriel]

he report tells us (and shows us) the lightning damage- as determined over a matter of months at 0 knots and 0 feet AGL.

That is very important. What matters is not what we know now but what the pilots knew then.

Would you have blamed Sully for aiming for the river instead of returning to La Guardia if the engineering simulations and flight simulations showed that different crews were able to safely reach La Guardia with some margin and safely land, every single time that it was attempted? Of course not. In that case Sully would just (and rightfully) say "you should have given me this information when I was up there".

Sully said "the river was the only surface that was long enough, wide enough and smooth enough that I knew I could reach"

That said, I don't want to err on the opposite side either. I don't know what the pilots knew and how they judged the condition of the plane at the moment. It may very well be the case that there was no reason to judge that the plane was unsafe to fly and an immediate landing was required no matter what. The pilots decided to land instead of go around even when they had multiple reasons to go around before and after the touch down. But we don't know (at least yet) how was their thought process to say if it was good or bad judgement on their part. The fact that they didn't even discussed a go around at any point (for example, they didn't say "committed to land, no go around", but neither briefed a go around, and they didn't even said a word upon the 2.5 cycles (5 repetitions) of the "GO AROUND, WINDSHEAR AHEAD" warning (which REQUIRED a go around unless they used the PIC prerogative to deviate from any requirement in the name of safety) is indicative of a breakdown at least in CRM, if not in judgement too.

[Gabriel]

Yes, a bounce can happen after a stable approach, and a not_bounce greaser landing can happen after horribly unstable approach.

That said, there is a strong correlation between unstable approaches and bad things happening in the landing (including but not limited to bounces). There is a reason for the saying that a good landing is a culmination of a good approach.

And that said, there are bounces and bouNCes.

.I'd put more $ on what the pilots did after the bounce on being a primary cause...

That too. But the flare was quite horrible too. Not blaming the pilot, since it seems that a multitude of crews had similar issues.

By the way, what is your idea of what the pilots should have done after the bounce?

Because I have my ideas, but they seem to be incompatible with the pit's defense.

Go around? If they were committed to landing due to doubts of the condition of the plane to remain airborne safely to the point where they decided not to go around earlier when they were required too and when the pitch became out of control before touch down, we can't expect then to suddenly change their mindset and after bounce say "ok, now it the plane is safe to fly, let's go around as we should after a big bounce".

Manage the pitch during the bounce? If the reason for the bounce in the first place (or one of the main reasons) was the difficulty to control pitch in direct mode?

[3WE]

It was unstable. That's why planes bounce. Making it a no-bones-about-it requirement to abandon an unstable approach is the ONLY way to prevent these from happening.

"ONLY"

Wrong.

And not just because of the "absolute" rule.

Let's go rent a 172. I'm out of practice, but have a damn good idea I can fly a stable approach and bounce the $hit out of the plane.

Lots of things besides an unstable approach can cause a bounce.

I did read somewhere of an effective technique to manage a bounce after it occurs...and maybe these guys lacked that training and/or that skill and/or for whatever reason, they 'hiccuped' a bit too much or a bit too little a bit too soon or a bit too late....I'd put more $ on what the pilots did after the bounce on being a primary cause...well, that AND a lightning strike which is known to take out sensitive electrical systems like radios and who knows what else.

[3WE]

The report tells us (and shows us) the lightning damage- as determined over a matter of months at 0 knots and 0 feet AGL.

The lack of the bold font is again evidence of your strong, black and white bias to predominately blame the pilots.

Maybe you are "just quoting" someone else, but the omitted bold stuff is a big, obvious part of the equation.

[3WE]

1. ***The oversimplification of the week***
2. ***The report shows a very real and concrete contrast between the manual flight control inputs in normal law vs in direct law. [additional supporting stuff- with an emphasis on multiple crews]***

1. Thank you.

2. a. Thank you.
2. b. Such is the stuff bounces are made of.
2. c. And the spoilers didn't auto activate to suppress the desire of the (d.) really fast, (e.) lightly-flapped plane to maybe fly a bit more. (More stuff that bounces are made of.)

The prior sentences include a LOT of dots- including this one:.

And, what the heck, The accident was ultimately caused by the crews decision that it was safe to take off. (another little dot)

[Gabriel]

The crash occurred because they continued an unstable approach. (and you know what that little dot is)

The oversimplification of the week, close the investigation. In this case, the little dot is not a period (or a full stop). Is a "to be continued".

How many endings can you imagine for the sentence "the crash would not have happened if ______"?

The report also shows us the recorded manual flight control inputs, which were 'of an abrupt and intermittent character' and sweeping in nature. Those are not responses, those are pilot actions.

The report shows a very real and concrete contrast between the manual flight control inputs in normal law vs in direct law. For the accident crew and for another half dozen of other crews. The sample of control inputs in direct law are ALL of a much bigger amplitude and alternating both directions. For the accident crew and for the other half dozen or so.

[Evan]

I'm not sure how many times you admonish them for continuing to land a crippled airplane in spite of wind shear warnings (which in normal operations are followed mostly for an abundance of caution- not that a good safe landing isn't possible (as evidenced by tons upon tons of operations before Delta 191))...and then we see no real evidence of actual wind shear.

Once is enough. You don't do that. Unless there is some overriding reason not to, you go around, out of a minimum requirement of caution. (and you know what that little dot is)

The report does not establish any overriding reason not to go-around. (and you know what that little dot is)

The crash occurred because they continued an unstable approach. (and you know what that little dot is)

You still dismiss that they really didn't know what the lightning did or didn't fry...Is this really all that different from another crew dealing with engine anomaly's- should we land or should we not. There's parallels.

I don't; the report does. The report tells us (and shows us) the lightning damage. The report tells us the EIU's rebooted (probably due to loss of data or parameter threshold exceedance), causing the logic to degrade to DIRECT and remain there. If there were any other 'fried' avionics, I think they would be in the report.

The report also shows us the recorded manual flight control inputs, which were 'of an abrupt and intermittent character' and sweeping in nature. Those are not responses, those are pilot actions.

And yeah...they bounced the plane...it was faster than normal, configured differently from normal, and had slightly different control feel from normal (and remember, normal = a thousand or so prior landings)...that makes planes bouncy...and unfortunately, they blew it. Bobby and ATL probably would have greased it on, but I wouldn't put it past you or Gabriel (or me) to do what the crew did.

It was unstable. That's why planes bounce. Making it a no-bones-about-it requirement to abandon an unstable approach is the ONLY way to prevent these from happening.

Anyway- the pilots again suck, Evan can smile.

41 people died, including a cabin crew member. Evan can't smile.

But again, if there is a problem with pilot skills or safety culture, you have to call that out. You have to fix that.

[3WE]

***There is no confirmation of actual wind shear being present during the landing.***

***12) The crash was the result of PIO, but may be related to characteristics of the aircraft in DIRECT mode or (more likely) inadequate training for manual aircraft handling in this mode:***

***It appears that the crew set the parking brake before evacuating.***

I'm not sure how many times you admonish them for continuing to land a crippled airplane in spite of wind shear warnings (which in normal operations are followed mostly for an abundance of caution- not that a good safe landing isn't possible (as evidenced by tons upon tons of operations before Delta 191))...and then we see no real evidence of actual wind shear.

You still dismiss that they really didn't know what the lightning did or didn't fry...Is this really all that different from another crew dealing with engine anomaly's- should we land or should we not. There's parallels.

And yeah...they bounced the plane...it was faster than normal, configured differently from normal, and had slightly different control feel from normal (and remember, normal = a thousand or so prior landings)...that makes planes bouncy...and unfortunately, they blew it. Bobby and ATL probably would have greased it on, but I wouldn't put it past you or Gabriel (or me) to do what the crew did.

Given that they set the parking brake- it would appear that they had much training on procedures.

Anyway- the pilots again suck, Evan can smile.

[Evan]

Preliminary Report Out: PIC: "Nothing to worry about"

The report is in mostly intelligible English. It reveals a series of pilot errors, poor manual aircraft handling, poor judgement and PIO, but also reveals similar 'overamplitutude' commands from other pilots in DIRECT law.

Summary: Gross pilot error.

It appears that the aircraft was indeed controllable in DIRECT mode and that radio communications were functional. The crew disregarded the danger presented by the weather system they flew into. The crew disregarded multiple predictive windshear alerts. The PIC also disregarded a glideslope deviation alert. The crew failed to go around as required yet there were no apparent circumstances that required an immediate landing. The PIC seemed unskilled on manual aircraft handling in DIRECT mode and induced the PIO that resulted in the hard landing and gear collapse. The investigation revealed similar unskilled behavior in other Aeroflot pilots as well. The fuel breach was the result of multiple impacts, leading to a final impact with the main gear already dislocated, for which there is no design safety requirement.

(All quotes: Aviation Herald and the IAC report. Bracketing comments are mine.)

1) They deliberately flew into a dangerous weather system:

According to the Vnukovo doppler weather radar, the aircraft was flying through the active thunderstorm area (Fig. 3), that was moving from the southwest to north-east with the speed of 40-45 km/h. The transition to the selected heading mode caused the aircraft to initiate the right turn earlier than it is prescribed by SID KN 24E (Fig. 4). The crew did not requested the active thunderstorm area avoidance clearance.

During the period from 15:07:30 to 15:07:33, there is the following conversation in between the crew members was recorded: PIC: "We are going to get shaken", FO: "Damn it.", PIC: "Nothing to worry about"

2) A lightning strike damaged the external air data sensors on the right side of the fuselage (and possibly the VHF 1 radio antenna), which apparently resulted in a reboot of the EIU-100's (Electronic Interface Units) and a loss of NORMAL flight control mode (NORMAL mode cannot be restored in flight after a reboot). There is no mention of the electrical discharge penetrating the fuselage and damaging internal electrical systems.

Two single commands and , "EIU1 FAULT" and "EIU2 FAULT", were recorded simultaneously.

The MAK reported that examination of the fuselage revealed typical traces of "lightning impact" was found on the right hand angle of attack sensor, the right temperature probe and right ice detector.

3) The PIC (PF) exhibited poor manual flight control skills:

The PIC's first control input from was affecting the roll channel, the sidestick was declined to 11.7° to the left (which is for more than half of its travel range), after that the sidestick was advanced to 6.8° (which corresponds to the half of its pitch-down travel range). Further sidestick control movements both in the roll and in pitch channels was of an abrupt and intermittent character. At 15:08:22, the aircraft was turned to the right via multiple impulse deflections of the sidestick ranging from 30% to 65%. To set the roll of ≈20° the pilot performed more than 10 roll deflection movements of the sidestick during the period of 18 seconds. Moreover, at different moments of the further flight the PRIORITY / APOFF8 button was pressed momentarily (for approximately 1 second) on the left sidestick 6 times.

4) Radio communication was quickly restored on VHF2 and the tower vectored the approach:

At 15:09:35 radio-contact was restored at the emergency frequency (121.5 MHz) via VHFStation 2. After that, at 15:09:39, the FO reported the Approach controller: "Moscow-Approach, request return of 14-92, radio lost, aircraft in direct mode". The controller issued an instruction to descend to FL 80. Maximum altitude the aircraft gained was 10600 ft (3230 m) (QNE). The crew responded: "Aeroflot 14-92, heading 0-57, descending to FL 8-0". The controller confirmed the clearance for the descent with the maintained present heading. Further flight till the moment of the glideslope capture was performed by means of vectoring.

5) The aircraft was in DIRECT mode and the crew were aware of the specific requirements, particularly the need to extend the ground spoilers manually (yet they failed to do this):

After the permission confirmation, the FO started reading section QRH "F/CTL DIRECT MODE", inter alia: "… Auto throttle should not be used, fly smoothly. … Balance manually. … Speed brake no less than a half. … use Flaps 3. TAWS, landing gear, Flaps 3 on. V approach, V reference plus 10. Landing distance – increase by 1-34. … Speed brake set to full after touchdown. Go-around lever to NTO"

At 15:24:02, the crew armed the speedbrake system [despite having just read out that is was inoperative in DIRECT mode].

6) CRM was the next thing to go:

The crew performed neither the before-landing briefing nor the "APPROACH" checklist.

7) The crew disregarded the predictive windshear alert:

At 15:28:26, at 1600 ft (490 m) QNH (at the radio altitude of 1100 ft (335 m)) the "WINDSHEAR" warning was recorded, it is generated by the crew alerting system based on the wind shear forecast data of the weather radar, accompanied by the voice message "GO-AROUND, WINDSHEAR AHEAD". This warning informs the crew about the possible wind shear enroute. The alert lasted for 11 seconds and included 2.5 warning cycles (5 voice messages, each cycle consisting of 2 messages one after another, with the 1 second interval in-between). The crew had no discussion of this warning triggering.

8 ) The crew failed to subsequently go around as required in the QRH. The FCOM states that a go around is not required if the warning is deemed erroneous because there are "no other signs of wind shear", but the local weather conditions certainly don't provide for that excuse:

Note: In the QRH «W/S AHEAD» Section (1.18.8 ) states that the triggering of this warning during the approach indicates that the crew must initiate the go-around procedure. At the same time in the beginning of the section, there is the notice that if the crew is sure that there is no wind shear hazard and there are no other signs of wind shear, and the RWS is operative, this warning may require no responsive actions from the crew. The same provisions are incorporated into the Flight Operations Manual.

9) After intercepting the glideslope from below, the deviation was always between .5 and 1 dot low, with a couple dips approaching 1.5 dots low. The PIC disregarded a GLIDESLOPE warning as "advisory".

At 15:29:31, at 270 ft (82 m)...Starting from that moment, there was noted fast increase of the downward glideslope deviation (up to minus 1.4 dots), which caused the TAWS "GLIDESLOPE" alert triggering to indicate the glideslope deviation The alert was on for 4 seconds. The PIC confirmed hearing the alert by saying "Advisory". Over the RWY threshold, the glideslope deviation was minus 0.9 dot (i.e. below the glideslope).

10) The 'bounces' were the result of Pilot-Induced-Occillations and overcontrol (possibly due to aircraft-pilot coupling):

Almost simultaneously with the thrust levers positions changed to "IDLE", the PIC initiated the flare by pulling the sidestick by 8.8° (65% of its travel range). Further on, the PIC's everamplitude increasing pitch sidestick inputs were recorded up to the both maximum advanced and maximum retarded positions with a relatively long holding period in the both maximum positions. These inputs caused counter-reversal pitch change (+6…-2º). At 15:30:00, at a distance of ≈900 m from the RWY threshold at indicated air speed of 158 kt (293 km/h), first touchdown occurred. The touchdown occurred at the pitch angle close to zero ( 7 pitch up rate; at the moment of the touchdown, the sidestick was in the maximum retarded position; and during the landing within 0.4 seconds, its position was changed for the maximum advanced), for "threedots", with vertical g-force of no less than 2.55 g.

After the aircraft was bounced up, the sidestick continued to be held in the maximum advanced position...

Landing performed with the nose gear touching the ground first, with the high vertical speed and the fully retarded sidestick immediately before touchdown...

11) A late go-around was attempted after reversers had been commanded deployed. Therefore, the thrust did not respond:

During the second bouncing up, the aircraft reached the height of ≈ 15 - 18 ft (5-6 m). In 2-3 seconds after this repeated bouncing up, the thrust levers were set to "Takeoff" mode and the sidestick was pulled to the maximum retard position. This actions may be interpreted as an attempt to perform the go-around, as before that the thrust reverser system was engaged (the reverser doors were in the open position, though starting to close), the engine thrust did not increase.

12) The crash was the result of PIO, but may be related to characteristics of the aircraft in DIRECT mode or (more likely) inadequate training for manual aircraft handling in this mode:

The Commission carried out preliminary comparative analysis of the approaches performed by the PIC manually (with disengaged autopilot) in «NORMAL MODE», with the emergency flight (Fig. 42). The figure shows that the sidestick movements for the pitch in the emergency flight are characterized by significantly wider amplitude, and are oscillatory, which caused significant changes of longitudinal motion parameters. Similar "sweeping" movements were observed during landing performed in «DIRECT MODE» by other crews of the airline (Fig. 43). Reasons of these peculiarities are being analyzed.

13) The main gear is designed to break away above 3.75G without damaging critical wing structures, however, the landing gear shear pins actually failed after the second (5.85G) touchdown, causing the loosened main gear assembly to dislocate and thus compromise the wing structures and fuel containment upon the third 5G touchdown. The airworthiness requirements do not anticipate this scenario:

After the separation of the cylinder bracket of the right main landing gear there occurred a hole in the spar web, and the fuel spilled through it from the fuel tank of the right-side wing

The situation described above is not provided for in the current airworthiness standards.

There is nothing in the report about any delays or impediments to the subsequent evacuation procedure.

Work on analyzing the performance of rescue equipment continues.

There is no confirmation of actual wind shear being present during the landing.

Trivia:

It appears that the crew set the parking brake before evacuating. Checklist complete.

Attachment: Comparative plots btw NORMAL and DIRECT mode stick handling.

[Evan]

From avherald.com:

On Jun 5th 2019 the MAK reported the preliminary report of more than 100 pages has been drafted and is currently being proofread, it is estimated to be released in the coming days.

[ATLcrew]

Out of curiousity, under what conditions would you continue the approach despite the warning?

I can think of a couple scenarios. One might be when the warning is obviously false (clear and a million, not a cloud for miles and miles, wind is 0 gusting to 2, speed is spot-on etc). I've only had one instance in my whole career when the warning MIGHT have been false, so we went around anyway. Another one might be if the airplane is so dorked up that a go-around is likely to result in a crash somewhere off the airport (and away from the fire trucks). In that circumstance, I'll probably just barrel through and at least crash where help can get to me quickly. Obviously, if things got that far, it's been a pretty bad day.

[Evan]

QR must have different procedures then, for us any RED windshear is a W/S G/A, not a standard G/A.

Out of curiousity, under what conditions would you continue the approach despite the warning?

[ATLcrew]

I imagine that that is because they are preemptively going around for a windshear ahead, but they are not actually caught in a windshear.

QR must have different procedures then, for us any RED windshear is a W/S G/A, not a standard G/A.

[Gabriel]

What's interesting about that video is that it shows not a W/S G/A, but a standard G/A. There is a lot less workload in an actual W/S G/A.

I imagine that that is because they are preemptively going around for a windshear ahead, but they are not actually caught in a windshear.

[ATLcrew]

Nice video. It really shows the high workload involved.

What's interesting about that video is that it shows not a W/S G/A, but a standard G/A. There is a lot less workload in an actual W/S G/A.