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Plane with 71 on board goes missing after taking off from Moscow

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  • Evan
    replied
    Originally posted by Gabriel View Post
    I am not so sure... Probably the 800 kph (432 KIAS) of #1 just before the impact was accurate. There is no way for an airplane to accelerate from 100 kts to 430 kts in a few seconds, not even in free fall. There was an accident in Argentina in 1997 (the last pax jet fatal accident in Argentina) where the pilots thought they were too slow and about to stall. The maxed the thrust and started a descent but the IAS was still going down. They extended the slats and of course the oversped and overstressed them, because you know, Newton's opinion is that an airplane descending with max thrust and nose-down pitch is not going slow regardless of what the IAS indicates. Ok, the thing is that they totally lost control and started to fall almost vertically, the IAS still recorded low, until at some point it suddenly increased to almost Match 1. Of course that was not the plane accelerating faster than the gravity, but the ice in the pitot melting. I am thinking that something similar may have happened here (I am talking of the airspeed indication, not the slats). The magnitude of the impact seen in the video and the size of the debris seem to confirm a very very high energy impact, more like 400 kts than 100 kts.
    What about 432 KIAS in a dive with full thrust applied? We have seen how licensed and experienced pilots sometimes get themselves into a stall and then firewall the throttles without doing too much else.

    Stall warning, full thrust, pull-up, stall, Newton, uncommanded dive, overspeed, loss-of-control, fireball?

    Leave a comment:


  • Gabriel
    replied
    Originally posted by Evan View Post
    Two must be in agreement or the autopilot would have self-disengaged. That 108kts speed is probably reliable,
    I am not so sure... Probably the 800 kph (432 KIAS) of #1 just before the impact was accurate. There is no way for an airplane to accelerate from 100 kts to 430 kts in a few seconds, not even in free fall. There was an accident in Argentina in 1997 (the last pax jet fatal accident in Argentina) where the pilots thought they were too slow and about to stall. The maxed the thrust and started a descent but the IAS was still going down. They extended the slats and of course the oversped and overstressed them, because you know, Newton's opinion is that an airplane descending with max thrust and nose-down pitch is not going slow regardless of what the IAS indicates. Ok, the thing is that they totally lost control and started to fall almost vertically, the IAS still recorded low, until at some point it suddenly increased to almost Match 1. Of course that was not the plane accelerating faster than the gravity, but the ice in the pitot melting. I am thinking that something similar may have happened here (I am talking of the airspeed indication, not the slats). The magnitude of the impact seen in the video and the size of the debris seem to confirm a very very high energy impact, more like 400 kts than 100 kts.

    Leave a comment:


  • 3WE
    replied
    Originally posted by 3WE
    Familiar
    Familiar...like something they do multiple times during each flight...select power and attitudes to attain climbs, descents and level offs...multiple times each flight. Did I say every day, multiple times per flight...familiar???

    Originally posted by Evan
    ...memory items...memorized training...memory items...memory items....
    Please, encourage guys to memorize your numerous "items" (that's plural, you know)...I know, "familiar" just isn't sexy enough.

    However, I'd ask if memorizing that pitot heat should generally be turned on when flying in cold clouds, might be emphasized a bit more than memorizing the exact power setting and attitude one should use for UAS.

    Leave a comment:


  • Evan
    replied
    the #3 began to decrease reaching 200 kph (108 KIAS), the aircraft pitched down to about 30-35 degrees below horizon
    St_ll

    I'd like to buy a vowel...

    If this is accurate, the #2 and #3 pitots must have been unaffected. Two must be in agreement or the autopilot would have self-disengaged. That 108kts speed is probably reliable,

    But why is the pitot-heat not automatic? For instance, on the A320, you have a choice between AUTO and ON. Both are on in the air. There is no OFF in the air (unless a CB is pulled or the air/ground sensing system fails...)

    Leave a comment:


  • Gabriel
    replied
    We need more sticky notes pasted to the airspeed indicator of pilots learning to fly in IMC.

    Aviation Herald - News, Incidents and Accidents in Aviation

    In the afternoon of Feb 13th 2018 the MAK reported, that decoding of the FDR data has been completed. Preliminary analysis shows, that the pitot heatings for all three pitot probes were off while the pitot heatings had been turned on prior to departure on the previous 15 flights. About 2:30 minutes after becoming airborne a special situation developed at about 1300 meters of height and a speed of 465-470 kph (250 KIAS) when a disagreement between the speed readings #1 and #3 developed with the speed reading #2 not registering, #1 was showing about 30kph (15 knots) more than #3, an according message was issued. No significant altitude deviations between the pitot systems were noticed. At about 2000 meters height speed reading #1 began to reduce while #3 increased, another speed disagree message was issued. The crew disconnected the autopilot and continued in manual control. Speed readings from #3 reached 540-560 kph (290-300 KIAS), #1 speed readings continued to decrease. 50 seconds after the autopilot was disconnected the aircraft experienced vertical loads between 0.5 and 1.5G, the #1 speed reading reached 0, the #3 began to decrease reaching 200 kph (108 KIAS), the aircraft pitched down to about 30-35 degrees below horizont, the vertical load was 0G. Before collision with the ground #3 speed readings began to rapidly increase reaching 800 kph (432 KIAS) just before impact, #1 speed readings remained at 0. The pitch angle remained at 30 degrees below horizont until impact, 5 seconds prior to impact a right bank of 25 degrees developed. The MAK wrote: "A preliminary analysis of the recorded information, as well as an analysis of similar cases that occurred in the past, suggest that the development of a special situation in the flight could be caused by incorrect data on the flight speed on the pilots indicators, which in turn was apparently due to icing of the pitot probes when the heating systems are off."
    Strange no mention of any GPWS warning. While this comes from the FDR, not CVR, I believe that the GPWS status is being recorded in modern FDRs.

    Leave a comment:


  • vaztr
    replied
    WOW. amazing to see that the FDR data has been 'processed' so quickly

    Leave a comment:


  • Evan
    replied
    Originally posted by 3WE View Post
    Use familiar robust attitude and power settings after the confusion of the sudden loss of autoflght that, because you aren't practiced on memory items, led you to pull up into a stall for reasons you cannot explain, and die.

    (or do as Evan would like and consult your memorized training to look up one specific robust power and attitude setting once the situation is stabilized by memory items)...maybe use a setting you are familiar with from your memory items training while the PNF looks up the scientifically engineered figures...but only for as short of time as possible.
    Concur.

    Leave a comment:


  • 3WE
    replied
    Originally posted by Quench View Post
    ***Pitot icing in IMC***
    Use familiar robust attitude and power settings.

    (or do as Evan would like and consult FCOMQRHPOH to look up one specific robust power and attitude setting)...maybe use a setting you are familiar with while the PNF looks up the scientifically engineered figures...but only for as short of time as possible.

    Leave a comment:


  • Quench
    replied
    The crash of An-148 passenger plane in the Moscow Region may have been caused by incorrect flight speed data due to icing, the Interstate Aviation Committee (IAC) said after deciphering the flight data recorder.

    Investigators suspect that pitot icing may have been a factor. Looking at the CCTV video, looks like IMC.

    Pitot icing in IMC, makes me sad.

    Leave a comment:


  • orangehuggy
    replied
    About 1:25 into this video... they recovered that time
    Auf YouTube findest du die angesagtesten Videos und Tracks. Außerdem kannst du eigene Inhalte hochladen und mit Freunden oder gleich der ganzen Welt teilen.


    Aviation Herald - News, Incidents and Accidents in Aviation

    Leave a comment:


  • vaztr
    replied
    Or Germanwings 9525

    Leave a comment:


  • Evan
    replied
    Originally posted by Gabriel View Post
    Loss of control in IMC?
    Stall?
    Unreliable airspeed?
    AF-447?
    Colgan 3407?
    All of the above?
    Sudden loss of autopilot (or failure to engage it + assumption that it is engaged whilst aircraft is actually in an undetected descent) followed by up-pulling behavior leading to theoretic Gabriellian condition known as Vst = Vs * √n (or something)?

    Leave a comment:


  • obmot
    replied
    Not sure if this is of any value to anyone, but here's an image with the same flight track the day before (bluish green line), with the 'crash' flight track (hot pink) superimposed. They are identic (except for a touch of scaling error on my part I've not fixed exactly right).Click image for larger version

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  • Quench
    replied
    Originally posted by Gabriel View Post
    Loss of control in IMC?
    Stall?
    Unreliable airspeed?
    AF-447?
    Colgan 3407?
    All of the above?
    Or Icing ?

    Leave a comment:


  • 3WE
    replied
    Originally posted by Gabriel View Post
    Loss of control in IMC? Should not happen with working AI
    Stall? Generally requires slightly insidious speed loss or fear-induced relentless pull ups.
    Unreliable airspeed? Use AI and familiar, robust pitch and power (and heed stall warnings)
    AF-447? Independent joy sticks and a FBW system that destroys basic airmanship AND THEN GOES BEZERK OVER PITOT ICING are generally required.
    Colgan 3407? A mechanism to slow way down insidiously at a very low altitude during descent/approach is needed.
    All of the above? Doesn't fit all that great.
    '

    No strong statement here, you are aware of other possibilities, maybe a bit too speculative over some radar-indicated altitude changes..

    Better wait for the final report.

    Leave a comment:

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