Page 5 of 7 FirstFirst ... 34567 LastLast
Results 81 to 100 of 124

Thread: Aeroflot Superjet 100 fire and evacuation at UUEE

  1. #81
    Senior Member Gabriel's Avatar
    Join Date
    Jan 2008
    Location
    Buenos Aires - Argentina
    Posts
    6,972

    Default

    Quote Originally Posted by Evan View Post
    -No radio to get wind, altimeter setting, traffic
    Airworthy.
    Not so. Radio is required and probably there were several other things required that the combination of failures left inop and hence rendered the plane not airworthy.

    That doesn't mean that they should (or shouldn't) be committed to the landing despite the windshear alerts, the unstable approach in the last seconds, and the bounces.

    Airworthiness matters only before take-off. After take-off it is a matter of what is the safest course of action.

    --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
    --- Defend what you say with arguments, not by imposing your credentials ---

  2. #82
    Senior Member Evan's Avatar
    Join Date
    Jan 2008
    Posts
    6,694

    Default

    Quote Originally Posted by Gabriel View Post
    Not so. Radio is required and probably there were several other things required that the combination of failures left inop and hence rendered the plane not airworthy.

    That doesn't mean that they should (or shouldn't) be committed to the landing despite the windshear alerts, the unstable approach in the last seconds, and the bounces.

    Airworthiness matters only before take-off. After take-off it is a matter of what is the safest course of action.
    I think we are talking about 'airworthy' as in 'it will fly' rather than 'airworthy' an is regulations. If you lose coms after V1, would you reject?

    Thus far, the DFDR has been read out and nothing has been released that would rule out a go-around following repeated windshear alerts (let alone after losing speed and glidepath stability in the final 250' while landing an overweight plane at high-speed on a wet runway with a 45° crosswind gusting to 30kts). That's just all we know at this point.

  3. #83
    Senior Member Gabriel's Avatar
    Join Date
    Jan 2008
    Location
    Buenos Aires - Argentina
    Posts
    6,972

    Default

    Quote Originally Posted by Evan View Post
    I think we are talking about 'airworthy' as in 'it will fly' rather than 'airworthy' an is regulations. If you lose coms after V1, would you reject?
    The problem is that, unlike legal airworthiness, "flyability" is not binary. A plane is either airworthy or not airworthy. But there can be intermediate states between "will fly" and "will not fly".

    Your assertion implies that a "committed to land" condition would be justified if the plane will not fly, which is of course ridiculous. That would be committed to crash rather than to land.
    In the other extreme, if the plane is perfectly flyable with no detriment to safety, there is no excuse not to go around with repeated windshear ahead warning, unstabilized approach in the last seconds, significant pitch oscillations before touchdown, and severe bounces after touchdown.

    The problem is the grey area in between, where we don't feel comfortable flying the plane in this condition (which the pilots obviously didn't or they would have held and burned fuel instead of landing overweight) but the approach doesn't look nice (but still looks survivable although under normal circumstances we would go around). That requires a judgement call.

    It is a fact that we were in the grey area. I, as you, would like to have more information so we can make our own fact-based judgement call on whether it was reasonable for the pilots to continue with the approach and landing and not going around.

    --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
    --- Defend what you say with arguments, not by imposing your credentials ---

  4. #84
    Senior Member Evan's Avatar
    Join Date
    Jan 2008
    Posts
    6,694

    Default

    Quote Originally Posted by Gabriel View Post
    The problem is the grey area in between, where we don't feel comfortable flying the plane in this condition (which the pilots obviously didn't or they would have held and burned fuel instead of landing overweight) but the approach doesn't look nice (but still looks survivable although under normal circumstances we would go around). That requires a judgement call.
    Yes, my assertion is that, if the plane is considered flyable (i.e. there is nothing overwhelmingly wrong with thrust, flight control, structural integrity, fire or fuel and there are adequate back-up systems to accomodate any critical system failure), then not initiating a go-around would be gross pilot error. Thus far, nothing indicates that the plane was not 'flyable' by that definition. Direct Law on the SSJ is designed to be a very flyable (though not optimal) condition.

    There's an ocean of grey area here, as in, answers we don't have and things we can't determine. I'm just stating an initial conclusion based on what isn't grey, what has thus far come to light.

    So either, some further (as yet unknown) reason for ruling out a go-around or gross pilot error.

  5. #85
    Senior Member 3WE's Avatar
    Join Date
    Jan 2008
    Posts
    5,061

    Default

    Quote Originally Posted by Evan
    Airworthy...Airworthy...Airworthy....Airworthy
    These are decisions you made weeks after the crash at 0 knots, and 0 ft AGL, with all the time necessary to analyze the data in front of a computer that was not hit by lightning.

    While the plane was airworthy at the moment, what guarantee did they have that 5 minutes later the whole electrical system would die and disable the pink-purple-polka-dot hydraulic system?

    Does your's and ATL's manual you've been pouring over cover how the plane responds to a strange lightning strike, when 99.9999% of the time a lightning strike affects nothing, but this time it's affected a few things, and who knows exactly how many things (in the context of right then and there)?
    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

  6. #86
    Senior Member 3WE's Avatar
    Join Date
    Jan 2008
    Posts
    5,061

    Default

    -Faster than normal (BUT PRESCRIBED) approach speed.
    Causes bounciness- and when did they last get to practice landing in that configuration?

    -Significantly reduced (BUT PRESCIBED) flap settings
    Causes bounciness- and when did they last get to practice landing in that configuration?

    -No automatic spoilers
    Causes bounciness- and when did they last get to practice landing in that configuration?



    Additional suggestion:

    After the bike ride, spend about 10 hours shooting landings in a grossed out 172 using full flaps.

    Then, try it empty with 10 gallons of avgas and no flaps.

    Causes bounciness- and when did you last get to practice landing in that configuration?
    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

  7. #87
    Senior Member Evan's Avatar
    Join Date
    Jan 2008
    Posts
    6,694

    Default

    Quote Originally Posted by 3WE View Post
    Causes bounciness- and when did they last get to practice landing in that configuration?
    I did not know that. I thought bounciness was caused by unstable final approach, excessive vertical speed, g-forces and pilot error.

    Causes bounciness- and when did they last get to practice landing in that configuration?
    I did not know that. I thought bounciness was caused by unstable final approach, excessive vertical speed, g-forces and pilot error.

    Causes bounciness- and when did they last get to practice landing in that configuration?
    I did not know that. I thought bounciness was caused by unstable final approach, excessive vertical speed, g-forces and pilot error.

    3BS, this is about threat assessment and is a primary responsibility of the crew to protect the passengers. Wind shear is a grave threat on final and can be unrecoverable. Regardless of what other concerns you might be having with the aircraft, if it is in a flyable state (as this one appears to have been), it is hard to imagine what threat would be deemed higher than FIVE repeated wind shear alerts.

    So that is the question in my head. Was there something else happening to the aircraft that hasn't yet been reported, or was this egregious pilot error in unnecessarily taking the aircraft into a clear and present danger for which recovery might not be possible?

  8. #88
    Senior Member Gabriel's Avatar
    Join Date
    Jan 2008
    Location
    Buenos Aires - Argentina
    Posts
    6,972

    Default

    Quote Originally Posted by Evan View Post
    I did not know that. I thought bounciness was caused by unstable final approach, excessive vertical speed, g-forces and pilot error.
    Side hair-splitting comment, but despite what most people believe bounces (especially significant ones) are NOT caused by high vertical speed at touchdown and high landing g-forces. The shock absorvers have critically damped spring-damper combinations precisely to avoid that.

    Bounces are caused by either a) touching down nose gear first which causes the plane to pitch up and the AoA to increase during the touchdown sequence, or by b) the pilot pulling up too much during the flare, causing the plane to touch down with a wing load factor greater than 1 and hence with more lift than weights, so when the ground arrest the rest of the vertical speed the plane starts to accelerate up.

    a) is typically caused by 1) excessive speed which causes the plane to approach and land at a lower AoA than normal and hence a lower deck angle, which in turn would qualify as an unstable approach, or 2) (in some planes that have a nose-down attitude during approach) by insufficient flare, or 3) by pitch oscillations before touchdown, or 4) by the pilot trying to lower the nose after touching down on the mains despite of (or not realizing that) the plane bouncing on the mains because of b.
    b) is typically caused by 1) the pilot flaring too late and trying to compensate by pulling up header, or 2) by excessive sink rate which the pilot tries to arrest by pulling up more than normal when flaring from a normal altitude, or 3) by pitch oscillation before touchdown.

    From the videos, it looks to me that this case was a b3) followed by an a4)

    --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
    --- Defend what you say with arguments, not by imposing your credentials ---

  9. #89
    Senior Member 3WE's Avatar
    Join Date
    Jan 2008
    Posts
    5,061

    Default

    Quote Originally Posted by Gabriel View Post
    ***despite what most people believe bounces (especially significant ones) are NOT caused by high vertical speed at touchdown and high landing g-forces.***
    THANK YOU!

    While I have a few less hours than Bobby, my bounce experiences began with very OK touchdowns.

    Higher speed and fewer flaps very likely made the Russian plane bouncy.

    The pilots still may be deficient in the mysterious but "effective" bounce mitigation techniques, but conversely I wonder when they last practiced a fast, reduced flap landing? Plane might just behave differently than the prior 1000 landings they had done.
    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

  10. #90
    Senior Member 3WE's Avatar
    Join Date
    Jan 2008
    Posts
    5,061

    Default

    Quote Originally Posted by Evan View Post
    ***FIVE repeated wind shear alerts.***
    What is a wind shear alert?

    Last I knew, wind shear warnings happen a lot, and operations continue relatively uninterrupted. I have heard them on many clear, windy days- and even ridden a 172 through a PIREP'd one, and flown a 172 through unreported ones many times. I don't think the existence of five of them is necessarily significant.

    I assume there's something on the landing checklist FCOM where they add in a gust-factor to the final approach speed. (By the way, hadn't they already added a bad-ass 'gust-factor'...another good reason to continue to land their questionable aeroplanie?)

    Most wind shears are not Delta 191 70 knot-Delta-191 severe thunderstorm downbursts...

    "Be aware that your speed may fluctuate" vs. "Get the hell out before you get blown into the ground" are not the same scenario- nor is a fully functional airplane vs. a partially fired one the same scenario.
    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

  11. #91
    Senior Member Evan's Avatar
    Join Date
    Jan 2008
    Posts
    6,694

    Default

    Quote Originally Posted by 3WE View Post
    THANK YOU!

    While I have a few less hours than Bobby, my bounce experiences began with very OK touchdowns.

    Higher speed and fewer flaps very likely made the Russian plane bouncy.
    Oh, please. That's not what Gabriel said. There are plenty of high speed, even flapless landings that occur with no PIO or 'bounciness'.

    In this case, I think it was getting too fast in the final below 250', causing the pilot to command a series of pitch occillations to reduce speed in an attempt to save the landing (b3), the speed reduced somewhat, followed by an apparent three point touchdown (a1?) with little or no flare (or flared too high?) which resulted in a hard landing and then I think it was either (a4) or aircraft-pilot coupling due to the forces going on there.

    But it is not true that high-speed, low flaps = bounciness. Unstable = bounciness. Simple way to avoid ever bouncing like this: go-around if the approach becomes unstable in the final.

    What is a wind shear alert?
    Predictive Wind Shear Warning - the actual warning is:

    WIND SHEAR AHEAD - GO AROUND

  12. #92
    Senior Member Gabriel's Avatar
    Join Date
    Jan 2008
    Location
    Buenos Aires - Argentina
    Posts
    6,972

    Default

    Quote Originally Posted by Evan View Post
    Oh, please. That's not what Gabriel said. There are plenty of high speed, even flapless landings that occur with no PIO or 'bounciness'.

    In this case, I think it was getting too fast in the final below 250', causing the pilot to command a series of pitch occillations to reduce speed in an attempt to save the landing (b3), the speed reduced somewhat, followed by an apparent three point touchdown (a1?) with little or no flare (or flared too high?) which resulted in a hard landing and then I think it was either (a4) or aircraft-pilot coupling due to the forces going on there.

    But it is not true that high-speed, low flaps = bounciness. Unstable = bounciness. Simple way to avoid ever bouncing like this: go-around if the approach becomes unstable in the final.



    Predictive Wind Shear Warning - the actual warning is:

    WIND SHEAR AHEAD - GO AROUND
    Don't know if exactly the same system than in the Superjet, but... (there are 2 stages: advisory and warning)


    --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
    --- Defend what you say with arguments, not by imposing your credentials ---

  13. #93
    Senior Member Evan's Avatar
    Join Date
    Jan 2008
    Posts
    6,694

    Default

    Quote Originally Posted by Gabriel View Post
    Don't know if exactly the same system than in the Superjet, but... (there are 2 stages: advisory and warning)
    According to the report the Aeroflot crew received five cycles of wind shear warning (WIND SHEAR AHEAD - GO AROUND).

    Quote Originally Posted by avherald
    Winds during the approach came from 190 degrees at 30 knots, descending between 1100 and 900 feet the crew received 5 cycles of predictive windshear warnings "Wind Shear ahead, go around!".
    Nice video. It really shows the high workload involved.

  14. #94
    Senior Member 3WE's Avatar
    Join Date
    Jan 2008
    Posts
    5,061

    Default

    Quote Originally Posted by Evan View Post
    ***There are plenty of high speed, even flapless landings that occur with no PIO or 'bounciness'.***
    Plenty yes...always no. I believe we were a bit fast on this one with some wind shear in play..might have made it bouncy...The airplane was fine, but the pilots may have been fatigued.

    https://www.youtube.com/watch?v=VZvbPyt8n20

    The Moscow guys were dealing with a lot of schit and may not have been ready for a bounce.

    I'd love to hear the mysterious "effective" technique that some pilots are taught (or read in barely comprehensible manuals).
    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

  15. #95
    Member ATLcrew's Avatar
    Join Date
    Sep 2013
    Posts
    946

    Default

    Quote Originally Posted by Evan View Post

    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.

  16. #96
    Senior Member Gabriel's Avatar
    Join Date
    Jan 2008
    Location
    Buenos Aires - Argentina
    Posts
    6,972

    Default

    Quote Originally Posted by ATLcrew View Post
    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.

    --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
    --- Defend what you say with arguments, not by imposing your credentials ---

  17. #97
    Member ATLcrew's Avatar
    Join Date
    Sep 2013
    Posts
    946

    Default

    Quote Originally Posted by Gabriel View Post
    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.

  18. #98
    Senior Member Evan's Avatar
    Join Date
    Jan 2008
    Posts
    6,694

    Default

    Quote Originally Posted by ATLcrew View Post
    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?

  19. #99
    Member ATLcrew's Avatar
    Join Date
    Sep 2013
    Posts
    946

    Default

    Quote Originally Posted by Evan View Post
    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.

  20. #100
    Senior Member Evan's Avatar
    Join Date
    Jan 2008
    Posts
    6,694

    Default

    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.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •