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Comment by woodruffw | Hacker News Reader

I think the more apples-to-apples comparison here would be a train without breaks, wouldn't it be? After all, people can sabotage airfields and airplanes as well.

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> I think the more apples-to-apples comparison here would be a train without breaks, wouldn't it be

No. Not really. Russia has the means to produce brakes for their trains. They do not have the means to do the same for these airplanes.

So the reality on the ground is that the trains have brakes while the airplanes don't (or they have breaks but with rapidly aging out of compliance parts.)

> No. Not really. Russia has the means to produce brakes for their trains. They do not have the means to do the same for these airplanes.

I meant in terms of riders' perceptions of safety, not industrial capacity. That being said, it astounds me that Russia can't fabricate replacement breaks here: we're talking about a country with some of the best metallurgists in the world and a domestic aerospace industry; what gives?

No one ever said that they can't. But going from zero to being able to buy replacement Boeing (or whoever the OEM was) brakes off the shelf is a process of many months (in the optimistic case) or years, not weeks.

After all, even the simplest analysis for an aviation supplier has to be "can we make enough money selling these replacement brakes to cover the cost of setting up a manufacturing, quality control, and distribution system?"

This would have made sense 12 months or even 9 months ago, but we're now 18 months into a war that Russia's government had otherwise been preparing domestically for. Again: what gives?

They hadn't been preparing for it to last 18 months, and part of their preparation had been oriented at influence operations to preemptivelt disrupt Western unity and political response when the war qas launched. While I won't say that categorically failed (it still has tangible effects), it has been far from a complete success.

It’s an incompetent oligarchy where competence is dangerous and gets you sidelined.

Rotten from the top down.

And here come 2 minutes hate people

Where's the hate?

Are you serious? It's an obvious slander bs.

Btw, it's a reference to Orwell.

Yes, obviously it's a reference to Orwell. However, I see no hate. Criticism of fascist invasions and their perpetrators is not hate.

Firstly, if you understood that this is a reference, why are you trying to interpret separate words literally?

And secondly, there was no constructive criticism or even any mention of "fascism" or "invasion".

Following your own logic, I could - just for the sake of example, mind you - claim that you come from hellish slave-hole where people eat babies and then justify it with actually literally the same slogan as you did. Would that be as fucking stupid? Yes, it would.

Now, should I expect you to accuse me of whataboutism for trying to build a consistent logical framework?

> 18 months into a war that Russia's government had otherwise been preparing domestically for

Eh, I think we all saw how "prepared" Russia was.

In any case, I think the following factors are definitive here:

- No one really considers the current situation as "permanent". The war will be over at some point and life will go on. So investing in manufacturing of those specific parts might prove a waste.

- This is specifically an issue with parts for foreign aircrafts. Is it even worth producing parts for foreign crafts?

- There are ways to evade sanctions and smuggle parts and right now, to some degree

- Russia passed a legislation allowing 3rd-party parts and signed a contract with Iran on airplane maintainance and parts supply - Iran already has an expertise and industrial capacity operating in somewhat similar conditions. Iran also has more experience smuggling.

Obviously, that work had started many months ago, not just now.

It's pretty clear that the war was planned under the assumption that they'd just march straight into Kiev, maybe shoot a few hardcases, scare the rest with how awesome they were, and basically be welcomed as liberators by most.

When that failed to work, they didn't seem to have any idea what to actually do next, besides claiming the attack on Kiev was always supposed to have been a feint and the real goal was always to grab a few chunks of eastern Ukraine.

Also, Russian manufacturing may have other urgent priorities right now. Wars (fought outside of the homeland) may be good for employment and industrialization broadly, but they often are the opposite for application of industry to civilian ends.

> I meant in terms of riders' perceptions of safety

But that is what I am saying. The apples-to-apples comparision is “airplane with questionable/no brakes” vs “train with brakes”. There the “apple” is “as the thing is right now when you want to travel”. The proposed comparision with “train with no break” is not apples-to-apples because there are no breakless trains servicing the route. It is not a hypothetical comparision with some hypothetical train service and hypothetical planes. It is the comparision between the realworld situation on trains and airplanes right now.

The discussion about industrial capacity just illustrates how this difference have happened.

where from you got idea about "best metallurgists" ? and domestic aerospace industry is a boutique shop (especially when we are talking about civilian planes) that mostly relies on foreign components. their production goals are like 10 planes a year

maybe they can make train brakes, but they can't make bearings.

Trains are more vulnerable because they will always have long unguarded sections of track.

A train without breaks isn't really comparable because the planes can break using thrusters. I don't believe that you can engine break on a train to a comparable degree.

> A train without breaks isn't really comparable because the planes can break using thrusters.

I'm pretty sure a plane at V1 can't break using thrusters.

I believe this to be true (the article definitely states "Brakes are also necessary for aborting takeoffs", and V1 is the speed at which takeoff ~~occurs~~ edit: must be committed to), but this is only one instant of the journey. At other times it is certainly feasible to brake (landings included) with just the use of the thrust reversers.

> At other times it is certainly feasible to brake (landings included) with just the use of the thrust reversers.

This could be true; it's also not particularly reassuring as a passenger :-)

(Not doubting you specifically, but it'd be nice to have one of the many pilots on HN opine here. My understanding as a passenger is that commercial airliners use breaks because the margins are very narrow, especially in the presence of a tailwind or busy runway designed with breaks in mind.)

There's definitely a difference between feasibility and what passengers should be guaranteed, yeah. Don't get me wrong, commercial airliners should have brakes.

There are two distances to calculate, called accelerate-stop and accelerate-go.

Accelerate-stop is the distance needed to accelerate to V1, lose an engine instants before that, take the first action to abort at V1, and the resulting accelerate-stop is the distance between the start and end of roll. On an uncontaminated runway, this is computed without thrust reversers. On a contaminated runway, you can compute it with thrust reverser on the assumed non-failed engine(s).

Accelerate-go is the distance needed to accelerate all engines to just below V1, lose and recognize the loss, continue to Vr, rotate, climb, accelerate to V2, and reach 35 feet above the ground at V2.

When the accelerate-stop and accelerate-go are the same for the chosen V1, we call that the balanced field length.

Brakes are critically needed to achieve anything close to the book accelerate-stop distance.

It's been a while, but isn't that V2? ISTR that V1 is the commit speed: above that point you have to take off since there isn't enough runway to abort.

V1 is the “takeoff decision speed” (roughly as you describe). Vr is the speed at which rotation occurs. Vmu is the “minimum unstick” speed (the lowest speed at which liftoff is possible). V2 is the takeoff safety speed, which is faster than liftoff speed, and the minimum target speed for initial climb.

I thought V1 was the decision speed, where you must takeoff unless the plane is literally incapable of leaving the ground.

Technically I think the takeoff speed is VRotate, where the plane is rotated and actually starts to leave the ground.

Isn’t the issue more specifically that not having brakes to abort lowers V1, which is the speed at which abort is no longer an option?

That's how train brakes work, actually. They short-circuit the electric motors through an array of resistors (with cooling fans to keep them from melting).. This is effectively engine braking on an electric motor. Electric cars do this too but they have batteries to absorb the energy instead of turning it all into heat.

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