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I'm curious the actual mechanics of this operation. The main primary-source I found is a Telegram post of an Aeroflot pilot memo [0], but this only discusses th

by bri3d 3y ago

I'm curious the actual mechanics of this operation. The main primary-source I found is a Telegram post of an Aeroflot pilot memo [0], but this only discusses the side-effects of reverser only braking, not the mechanics of "disabling the brakes." There is a possibility the brakes are still available and not worn through, and this is a preemptive measure to leave enough brake material to handle an emergency rejected takeoff while avoiding "unnecessary" braking on landing by using the reversers instead. It's still ridiculously dangerous and bad, of course, but a different situation from "they're running the aircraft with no brakes." [0]: https://t.me/aviatorshina/3679?comment=166821 https://t.me/aviatorshina/3679?comment=166821

thrway63245 3y ago
Thank you for that link. In case anyone else is wondering, this is a Telegram chat with actual pilots in it. There is currently a lot of cursing in that thread about stupid sensational news on the topic, along with an actual explanation. Aeroflot is disabling 1 out of 4 brakes, not all 4. Nobody is actually trying to stop a plane with just reverse thrusters.
- deleted 3y ago
  [deleted]
- Waterluvian 3y ago
  This feels like “it’s not as bad as it seems. Only three rooms are currently on fire, not twelve.” …They’re disabling brakes?
  - Dalewyn 3y ago
    I think the moral here is there is an unhealthy dash of sensationalism and propaganda that must be sifted away, if we actually want to take any worthwhile information out of this. As the saying goes, the first casualty in war is truth.
    - flangola7 3y ago
      But there's no sensationalism or propaganda here.
      - Dalewyn 3y ago
        There's a mile wide difference between "disabling some brakes according to manuals" and "disabling all brakes and relying on just the thrust reversers". I know it's cool to harp that Russia is doomed, but propaganda is bad regardless whether it's coming from the Russians or the west.
        flangola7 3y ago
        No one here is claiming Russia is doomed, I don't care about the west or Russia or whatever. Flying a plane without a full complement of brakes is foolhardy all by itself.
      - ithkuil 3y ago
        Propaganda has an interesting dynamics where it feeds off human instinctive behaviour. It would be hard to convince people about things they don't believe in already. Propaganda works by amplifying what people already want to believe and by giving tools for people who already want to believe in something but don't know how to back their beliefs with arguments. This leaves people who don't believe in the thing surrounded by people who wouldn't otherwise have strong rhetorical skills suddenly tooled with a barrage of pre-canned arguments and "facts" to disarm any fruitful conversation. A consequence of this dynamics is that often even pure factual presentations of an event gets spontaneously turned into "propaganda-like" discourse without necessarily any active involvement by state agends
    - mjan22640 3y ago
      I am curious what is the point of the omnipresent "Russia is doomed" propaganda in the first place? People are emotionally uninvested in Russia, and Russia itself is in practice irrelevant. What is to gain here by manipulating the public opinion in this way?
  - a1369209993 3y ago
    At the risk of confusing mixed metaphores, I'd say it's more like "It's not as bad as it seems. We only have one flat tire, not four.". I don't know if that claim is actually true, mind, but it sounds like a problem that has multiple levels of solutions still to go before it becomes catastrophic.
- antondd 3y ago
  I went and read through the last 3 days of chat history, including the part where the original article was mentioned. There are not really a lot of “cursing about stupid sensational news“ there. In fact, people were posting screenshots of news about Chemezov (the Head of Rostech) reporting to putin about the ongoing cannibalisation of the current fleet. Why use throwaway btw?
- jbergens 3y ago
  > Aeroflot is disabling 1 out of 4 brakes, not all 4 1 out of 4 brakes _so far_...
nvy 3y ago
So I used to work in aircraft maintenance (never in Russia though) and the policy is to change the brakes when there is $minimum_thickness of brake pad remaining. There's a little wire embedded in the pad and eventually as the pad wears thin the wire completes a circuit with the rotor, and lights up the aerospace version of the Check Engine Light. The brakes on these planes certainly have some remaining life but they're technically unserviceable as per the airworthiness policy that Boeing/whomever produced as part of the approved maintenance program for these aircraft. Whether the Russians follow that policy is another question. When I was in the Air Force we saw lots of Russian military Antonovs and they, uh, weren't in good shape.
- AndrewKemendo 3y ago
  How does the wire from the removable pad couple electronically with the permanent housing? Is it like a contact plate or is there an actual m-f style plug?
  - hatsunearu 3y ago
    some cars have this system and yes, there's a connector dangling out the back of a brake pad (more like the side, but you get the point)
  - sokoloff 3y ago
    On cars with the equivalent system, there’s a plug (single pin on most) and the wearing though of the sensor grounds that pin. On this page, the black cylinder is the sensor and white body is the connector: https://www.autozone.com/brakes-and-traction-control/brake-pad-wear-sensor-front/p/duralast-brake-pad-wear-sensor-wk06/296524_0_0 https://www.autozone.com/brakes-and-traction-control/brake-p...
  - nvy 3y ago
    I'm not sure I understand the question. When the techs install a new brake assembly, the wiring harness is connected at the same time as the hydraulic system. The pad itself is never changed on the flight line. It's quicker and easier to change the entire assembly and have the worn brakes rebuilt in a second line shop.
piskov 3y ago
The story looks like a penny dreadful of “Russia is doomed” series. 1. There’s no info on that Russian slide about actual planes flying without any breaks at all. There’s a manufacturer defined minimum equipment list that allows planes to have some breaks (actual number depends on the type of a plane) disabled for, let’s say, 10 days at the most. This is absolutely normal as planes cannot be serviced constantly (they fly back and forth, duh). As long as you don’t exceed the allowed number of breaks disabled, you’re fine. 2. The slide just warns about possible adversary effects (off-axis skid and longer landing distance) if some of the breaks are disabled. This is expected, somewhat corrected by algorithms, etc. https://youtu.be/DeEb_lbdlQs https://youtu.be/DeEb_lbdlQs 3. No one is telling planes to fly without any brakes. 4. There are different types of “breaks”: the ones used in a landing and the ones for an end-of-runway “stop” are not the same. 5. If the adhesion index is lower than required for the specific landing (weight, fuel leftover, etc.) even the brand-new “brakes” are to no avail. Again, another parameter out of many. tldr; it is absolutely safe to fly those nine Aeroflot planes that — at the moment of the slide — had some breaks disabled (not to mention another thousand of other Russian passenger planes). == More importantly, there is absolutely no shortage of airplane parts in Russia — they’re just delivered in a more “wink-wink” obscure way. I guess it’s just the same as there’s no problem there and in China to get modern GPUs that US “ordered” nvidia and amd not to sell :-) Or mastercard/visa/swift “blocking”: even kids in Russia now have foreign virtual cards that are topped-up via p2p crypto in a matter of minutes so that one could buy anything digital (and physical via mail forwarders) online and rendering that great — mostly pr/perception based —“exodus from Russia” obsolete.
- Johnny555 3y ago
  >More importantly, there is absolutely no shortage of airplane parts in Russia — they’re just delivered in a more “wink-wink” obscure way. That sounds like a hazard in itself, airlines being forced to buy parts outside of official supply lines makes it much easier for unscrupulous sellers to substitute counterfeit parts.
  - throwaway2037 3y ago
    You raise an interesting point. How does Iran, Cuba, and Syria get parts for any Boeing or Airbus civilian aeroplanes? Or are they all flying Russian aircraft now?
ramesh31 3y ago
>There is a possibility the brakes are still available and not worn through, and this is a preemptive measure to leave enough brake material to handle an emergency rejected takeoff while avoiding "unnecessary" braking on landing by using the reversers instead. The brake question is irrelevent. This will put unimaginable stress on the already taxed engines, which are orders of magnitude more expensive and complex to maintain. It's not something that is possibly sustainable at all. Typical magical thinking. "Well we can see the brake pads are running low, and we can't get any more. We can't see the fact that the engines are about to explode, so we'll just go with that."
- eesmith 3y ago
  > unimaginable stress It's quite imaginable. Already "most of the work of stopping a commercial aircraft is done through the use of thrust reversers", so it's not all that more than they do now. > We can't see the fact that the engines are about to explode, There's nothing magical about thrust reversers which make it impossible to inspect for increased engine wear and tear.
  - stef25 3y ago
    Is it kind of like shifting down gears in a car to slow down?
    - eesmith 3y ago
      No, it's not like engine breaking (see https://en.wikipedia.org/wiki/Engine_braking https://en.wikipedia.org/wiki/Engine_braking for a description of why that works). https://en.wikipedia.org/wiki/Thrust_reversal https://en.wikipedia.org/wiki/Thrust_reversal describes thrust reversal nicely: > On aircraft using jet engines, thrust reversal is accomplished by causing the jet blast to flow forward. The engine does not run or rotate in reverse; instead, thrust reversing devices are used to block the blast and redirect it forward. Take a look at the video of "A target-type thrust reverser being deployed" for an example.

by bri3d 3y ago

thrway63245 3y ago

Thank you for that link. In case anyone else is wondering, this is a Telegram chat with actual pilots in it. There is currently a lot of cursing in that thread about stupid sensational news on the topic, along with an actual explanation. Aeroflot is disabling 1 out of 4 brakes, not all 4. Nobody is actually trying to stop a plane with just reverse thrusters.

deleted 3y ago
[deleted]
Waterluvian 3y ago
This feels like “it’s not as bad as it seems. Only three rooms are currently on fire, not twelve.” …They’re disabling brakes?
- Dalewyn 3y ago
  I think the moral here is there is an unhealthy dash of sensationalism and propaganda that must be sifted away, if we actually want to take any worthwhile information out of this. As the saying goes, the first casualty in war is truth.
  - flangola7 3y ago
    But there's no sensationalism or propaganda here.
    - Dalewyn 3y ago
      There's a mile wide difference between "disabling some brakes according to manuals" and "disabling all brakes and relying on just the thrust reversers". I know it's cool to harp that Russia is doomed, but propaganda is bad regardless whether it's coming from the Russians or the west.
      - flangola7 3y ago
        No one here is claiming Russia is doomed, I don't care about the west or Russia or whatever. Flying a plane without a full complement of brakes is foolhardy all by itself.
    - ithkuil 3y ago
      Propaganda has an interesting dynamics where it feeds off human instinctive behaviour. It would be hard to convince people about things they don't believe in already. Propaganda works by amplifying what people already want to believe and by giving tools for people who already want to believe in something but don't know how to back their beliefs with arguments. This leaves people who don't believe in the thing surrounded by people who wouldn't otherwise have strong rhetorical skills suddenly tooled with a barrage of pre-canned arguments and "facts" to disarm any fruitful conversation. A consequence of this dynamics is that often even pure factual presentations of an event gets spontaneously turned into "propaganda-like" discourse without necessarily any active involvement by state agends
  - mjan22640 3y ago
    I am curious what is the point of the omnipresent "Russia is doomed" propaganda in the first place? People are emotionally uninvested in Russia, and Russia itself is in practice irrelevant. What is to gain here by manipulating the public opinion in this way?
- a1369209993 3y ago
  At the risk of confusing mixed metaphores, I'd say it's more like "It's not as bad as it seems. We only have one flat tire, not four.". I don't know if that claim is actually true, mind, but it sounds like a problem that has multiple levels of solutions still to go before it becomes catastrophic.
antondd 3y ago
I went and read through the last 3 days of chat history, including the part where the original article was mentioned. There are not really a lot of “cursing about stupid sensational news“ there. In fact, people were posting screenshots of news about Chemezov (the Head of Rostech) reporting to putin about the ongoing cannibalisation of the current fleet. Why use throwaway btw?
jbergens 3y ago
> Aeroflot is disabling 1 out of 4 brakes, not all 4 1 out of 4 brakes _so far_...

nvy 3y ago

So I used to work in aircraft maintenance (never in Russia though) and the policy is to change the brakes when there is $minimum_thickness of brake pad remaining. There's a little wire embedded in the pad and eventually as the pad wears thin the wire completes a circuit with the rotor, and lights up the aerospace version of the Check Engine Light. The brakes on these planes certainly have some remaining life but they're technically unserviceable as per the airworthiness policy that Boeing/whomever produced as part of the approved maintenance program for these aircraft. Whether the Russians follow that policy is another question. When I was in the Air Force we saw lots of Russian military Antonovs and they, uh, weren't in good shape.

AndrewKemendo 3y ago
How does the wire from the removable pad couple electronically with the permanent housing? Is it like a contact plate or is there an actual m-f style plug?
- hatsunearu 3y ago
  some cars have this system and yes, there's a connector dangling out the back of a brake pad (more like the side, but you get the point)
- sokoloff 3y ago
  On cars with the equivalent system, there’s a plug (single pin on most) and the wearing though of the sensor grounds that pin. On this page, the black cylinder is the sensor and white body is the connector: https://www.autozone.com/brakes-and-traction-control/brake-pad-wear-sensor-front/p/duralast-brake-pad-wear-sensor-wk06/296524_0_0 https://www.autozone.com/brakes-and-traction-control/brake-p...
- nvy 3y ago
  I'm not sure I understand the question. When the techs install a new brake assembly, the wiring harness is connected at the same time as the hydraulic system. The pad itself is never changed on the flight line. It's quicker and easier to change the entire assembly and have the worn brakes rebuilt in a second line shop.

piskov 3y ago

The story looks like a penny dreadful of “Russia is doomed” series. 1. There’s no info on that Russian slide about actual planes flying without any breaks at all. There’s a manufacturer defined minimum equipment list that allows planes to have some breaks (actual number depends on the type of a plane) disabled for, let’s say, 10 days at the most. This is absolutely normal as planes cannot be serviced constantly (they fly back and forth, duh). As long as you don’t exceed the allowed number of breaks disabled, you’re fine. 2. The slide just warns about possible adversary effects (off-axis skid and longer landing distance) if some of the breaks are disabled. This is expected, somewhat corrected by algorithms, etc. https://youtu.be/DeEb_lbdlQs https://youtu.be/DeEb_lbdlQs 3. No one is telling planes to fly without any brakes. 4. There are different types of “breaks”: the ones used in a landing and the ones for an end-of-runway “stop” are not the same. 5. If the adhesion index is lower than required for the specific landing (weight, fuel leftover, etc.) even the brand-new “brakes” are to no avail. Again, another parameter out of many. tldr; it is absolutely safe to fly those nine Aeroflot planes that — at the moment of the slide — had some breaks disabled (not to mention another thousand of other Russian passenger planes). == More importantly, there is absolutely no shortage of airplane parts in Russia — they’re just delivered in a more “wink-wink” obscure way. I guess it’s just the same as there’s no problem there and in China to get modern GPUs that US “ordered” nvidia and amd not to sell :-) Or mastercard/visa/swift “blocking”: even kids in Russia now have foreign virtual cards that are topped-up via p2p crypto in a matter of minutes so that one could buy anything digital (and physical via mail forwarders) online and rendering that great — mostly pr/perception based —“exodus from Russia” obsolete.

Johnny555 3y ago
>More importantly, there is absolutely no shortage of airplane parts in Russia — they’re just delivered in a more “wink-wink” obscure way. That sounds like a hazard in itself, airlines being forced to buy parts outside of official supply lines makes it much easier for unscrupulous sellers to substitute counterfeit parts.
- throwaway2037 3y ago
  You raise an interesting point. How does Iran, Cuba, and Syria get parts for any Boeing or Airbus civilian aeroplanes? Or are they all flying Russian aircraft now?

ramesh31 3y ago

>There is a possibility the brakes are still available and not worn through, and this is a preemptive measure to leave enough brake material to handle an emergency rejected takeoff while avoiding "unnecessary" braking on landing by using the reversers instead. The brake question is irrelevent. This will put unimaginable stress on the already taxed engines, which are orders of magnitude more expensive and complex to maintain. It's not something that is possibly sustainable at all. Typical magical thinking. "Well we can see the brake pads are running low, and we can't get any more. We can't see the fact that the engines are about to explode, so we'll just go with that."

eesmith 3y ago
> unimaginable stress It's quite imaginable. Already "most of the work of stopping a commercial aircraft is done through the use of thrust reversers", so it's not all that more than they do now. > We can't see the fact that the engines are about to explode, There's nothing magical about thrust reversers which make it impossible to inspect for increased engine wear and tear.
- stef25 3y ago
  Is it kind of like shifting down gears in a car to slow down?
  - eesmith 3y ago
    No, it's not like engine breaking (see https://en.wikipedia.org/wiki/Engine_braking https://en.wikipedia.org/wiki/Engine_braking for a description of why that works). https://en.wikipedia.org/wiki/Thrust_reversal https://en.wikipedia.org/wiki/Thrust_reversal describes thrust reversal nicely: > On aircraft using jet engines, thrust reversal is accomplished by causing the jet blast to flow forward. The engine does not run or rotate in reverse; instead, thrust reversing devices are used to block the blast and redirect it forward. Take a look at the video of "A target-type thrust reverser being deployed" for an example.