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Aeroflot deactivates brakes on nine aircraft, relies solely on reverse thrust

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251–260 of 386 posts

Re: Aeroflot deactivates brakes on nine aircraft, relies solely on reverse thrust

#251

Earlier quoted context omitted.

> Technician busts out the ODB code-reader I assume you mean OBD (on board diagnostics), not Ol Dirty B*stard, who has a very different set of codes.

I have a bad habit of typing CVS when saving tabular data even if it's not the inventory of my local pharmacy

I went through a period of typing cvs instead of svn…

Re: Aeroflot deactivates brakes on nine aircraft, relies solely on reverse thrust

#252

How in the world would any common Russian trust an airplane in this current sanctioned state in Russia and fly in one?! Are people that brainwashed to trust their leader to get on a plane that doesn’t have brakes?!

Life matters not there. Not in war. Not in peace. Not in travel. Not in home. Most Western countries obsess about proventing deaths. The USA does as well, except among poor people and gun victims.

https://www.statista.com/statistics/1240400/maternal-mortali...

The US maternal death rate is sky high for a western country with reliable statistics.

Re: Aeroflot deactivates brakes on nine aircraft, relies solely on reverse thrust

#253

What’s going to be the effect of increased use of the engine? Airlines like to derate their engines for takeoffs that don’t require full performance in order to save wear and tear; how much quicker are the engines going to require overhaul due to extraordinary reverse thruster usage? I guess the brakes involve more rapidly consumable items, but this seems like a decidedly suboptimal solution when it knocks a good por…

I seriously doubt the thrust reversers significantly shorten the life of the engine for the few seconds they're on. All the reverser is is a couple of hydraulically operated clamshells that close over the exhaust stream forcing it to the side rather than back. Ironically, it doesn't actually "reverse" the thrust. The exhaust stream impinges on the clamshell, pushing the airplane backwards.

Ohhhh that makes so much sense than the halfbaked naive implementation in my head involving the turbine somehow reversing the direction of airflow entirely and sucking air from the back to the front.

Re: Aeroflot deactivates brakes on nine aircraft, relies solely on reverse thrust

#254
post #63
post #20

Earlier quoted context omitted.

I flew from Moscow to Vladivastok recently, and it's a choice between 8 hour flight and a week in a train. The planes might be missing some maintenance, but they are certainly not falling out of the skies, and it's not like the trains can't fail (especially considering occasional train tracks sabotages). There are always risks, it's not that big of a deal.

Isn't the in-between choice to drive or fly out of Russia towards Europe, then fly east on a non-Russian airline, and eventually take e.g. the Tokyo to Vladivostok direct flight?

This isn't _that_ relevant because China is there as an option but there are no flights direct from Japan to Russia, for the same reason there aren't EU to Russia flights right now either.

Re: Aeroflot deactivates brakes on nine aircraft, relies solely on reverse thrust

#255
post #182

Earlier quoted context omitted.

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…

>the aerospace version of the Check Engine Light. why does it use such a vague light. are they afraid one more specific light for "brake pad warning" lamp will just make the cockpit untenable?

There's a big light-- master caution, and then you can go and look at EICAS or whatever and see something like "R BRAKE FAIL" and wear data.

Re: Aeroflot deactivates brakes on nine aircraft, relies solely on reverse thrust

#256
post #211

Earlier quoted context omitted.

This literally happens everyday, everywhere and to every airline. Sometimes even between airlines. I’ve personally been responsible for a part getting pulled off another engine from another airline and swapped for one that got its electrical connector damaged so the engine would ship on time. There is a whole industry of buyers and sellers of 2nd hand aircraft parts.

Sure, but those types of things are stopgap measures that work in a normal, unsanctioned market. Like, they need a part now , but there's none available in the maintenance hangar (or whatever), and it would take a few days to order one, so they ask another airline at the same airport to float/sell them the part. Once the ordered part arrives, they're back to their usual number of parts. In this case, Aeroflot just ca…

> or unless someone local can manufacture them to the correct specs

This will likely happen except for the correct specs part. Sure, it will be manufactured to fit, but it likely won’t be able to be made to the same standard as the official Boeing part.

The impact of this could be absolutely nothing, or maybe Aeroflot planes just end up on runway excursions more often. It could also lead to catastrophic failure and separation of the landing gear bogie causing all sorts of additional trouble.

Re: Aeroflot deactivates brakes on nine aircraft, relies solely on reverse thrust

#257

Earlier quoted context omitted.

An aircraft operating nominally is designed and intended to be able to land safely relying on just the brakes. Thrust reversers are also used because they decelerate the aircraft quicker and with less wear on the brakes, aka thrust reversers are used out of convenience and benefits. Thrust reversers may be used solely in an emergency that renders the brakes inoperable, but such situations are so exceptional they aren…

> An aircraft that can't land safely with just brakes would not be certified to fly. Yes. That doesn't contradict what I wrote. The thrust reversers also greatly reduce the stress on the tires, another critical and expensive item. There's also the enormous heat generated, which stresses the rest of the landing gear and the bearings. One of the certification tests is the airliner is landed with flaps up, at max landin…

>The brakes are a backup system for the thrust reversers, not the other way around.

Absolutely *NO!*

Thrust reversers are always supplementary to the brakes, the brakes are always the primary means of bringing the aircraft to a stop on the ground. If the tires blow, the brakes burn out, and the landing gears are a goner in an emergency landing then so be it, that is all part of the design specifications.

Why is it like this? Well what happens when the aircraft loses all engines? This has happened many times, and far more frequently than failures concerning the brakes. If an aircraft is not designed and certified to land safely with just brakes, it means an aircraft with all engines out can't land safely. That is absolutely unacceptable.

Incidentally, plenty of flights land nominally without using thrust reversers depending on the situation. Using them is preferred because the brakes are worn out less and the aircraft spends less time on the runway, but if the pilot in command appropriately decides to land without thrust reversers that is still perfectly safe without any of the fireworks.

Thrust reversers are marvels of engineering, that is never in doubt, but they are never the primary means of stopping an aircraft.

Re: Aeroflot deactivates brakes on nine aircraft, relies solely on reverse thrust

#258
post #107

Earlier quoted context omitted.

If driving were 10 times more dangerous than it is now, we'd all still be doing it.

your lifetime risk of dying in a motor accident is about 1 in 100 (depending on where in the world you live) I suspect you'd see fewer people driving if it was 1 in 10

the coronavirus fatality was also similar no? yet we had lockdowns...

Re: Aeroflot deactivates brakes on nine aircraft, relies solely on reverse thrust

#259

While I agree that we should be sanctioning Russia, I think a carve-out should be made for things like commercial aviation parts. Eventually there will be an accident as a result of parts that can't be replaced, we don't need more lives lost to this war.

Russians could stop flying to take vacation in occupied Crimea beachfront instead

There are places in Russia proper which are only reachable by plane due to lack of roads.

Re: Aeroflot deactivates brakes on nine aircraft, relies solely on reverse thrust

#260
post #225

Earlier quoted context omitted.

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.

Ah I see, I had envisioned a pad that was replaceable like an individual brake pad on a car

I'm most familiar with the C-130 but I believe it's common on many types: the pad is replaceable but in order to do that you have to remove the entire brake assy, which means it's more efficient to just slap a new assy on and send the worn one to 2nd line to be rebuilt/overhauled.

Often that 2nd line is subcontracted out.

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