Russian Pilots told to brake less.
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Russian Pilots told to brake less.
From the DT:
Russian pilots have been told not to brake too much to reduce wear and tear amid a shortage of parts for plane repairs because of western sanctions.
According to internal memos from four Russian airline companies, pilots have been asked to be gentle when breaking and taxing.
S7 Airlines has told pilots to use engine reverse thrust and to avoid autobrake mode if the runaway is long enough, the Aviatorshina Telegram channel reported. Pilots were also told they shouldn’t go hard on brakes in order to get off the runaway quickly to make way for other planes.
Urals Airlines, Rossiya and Pobeda published similar memos instructing pilots to “pay close attention to a temporary policy of fuel efficiency and economising the aircraft’s resources”.
Traffic control were given separate instructions to offer aircraft longer slots for landing to give planes more time to taxi off the runway.
Russian pilots have been told not to brake too much to reduce wear and tear amid a shortage of parts for plane repairs because of western sanctions.
According to internal memos from four Russian airline companies, pilots have been asked to be gentle when breaking and taxing.
S7 Airlines has told pilots to use engine reverse thrust and to avoid autobrake mode if the runaway is long enough, the Aviatorshina Telegram channel reported. Pilots were also told they shouldn’t go hard on brakes in order to get off the runaway quickly to make way for other planes.
Urals Airlines, Rossiya and Pobeda published similar memos instructing pilots to “pay close attention to a temporary policy of fuel efficiency and economising the aircraft’s resources”.
Traffic control were given separate instructions to offer aircraft longer slots for landing to give planes more time to taxi off the runway.
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I thought the whole idea of Carbon Brakes was that one RTO used about as much as one gentle stop. Several light applications causes more wear than one dirty great big one. Treat 'em mean to keep 'em keen?
That was what we were taught when we upgraded the A300 brakes from steel to carbon.
What I was told was that using reversers saves around $100/landing in brake wear. If light use of carbon brakes causes just as much wear as heavy use (and carbon brakes were basic on the 777), that wouldn't be the case.
From, er, Boeing's Aero magazine:
"Because the wear mechanisms are different between carbon and steel brakes, different taxi braking techniques are recommended for carbon brakes in order to maximize brake life.
Steel brake wear is directly proportional to the kinetic energy absorbed by the brakes. Maximum steel brake life can be achieved during taxi by using a large number of small, light brake applications, allowing some time for brake cooling between applications. High airplane gross weights and high brake application speeds tend to reduce steel brake life because they require the brakes to absorb a large amount of kinetic energy.
Carbon brake wear is primarily dependent on the total number of brake applications — one firm brake application causes less wear than several light applications. Maximum carbon brake life can be achieved during taxi by using a small number of long, moderately firm brake applications instead of numerous light brake applications. This can be achieved by allowing taxi speed to increase from below target speed to above target speed, then using a single firm brake application to reduce speed below the target and repeating if required, rather than maintaining a constant taxi speed using numerous brake applications. Carbon brake wear is much less sensitive to airplane weight and speed than steel brake wear."
AERO: Operational Advantages of Carbon Brakes
"Because the wear mechanisms are different between carbon and steel brakes, different taxi braking techniques are recommended for carbon brakes in order to maximize brake life.
Steel brake wear is directly proportional to the kinetic energy absorbed by the brakes. Maximum steel brake life can be achieved during taxi by using a large number of small, light brake applications, allowing some time for brake cooling between applications. High airplane gross weights and high brake application speeds tend to reduce steel brake life because they require the brakes to absorb a large amount of kinetic energy.
Carbon brake wear is primarily dependent on the total number of brake applications — one firm brake application causes less wear than several light applications. Maximum carbon brake life can be achieved during taxi by using a small number of long, moderately firm brake applications instead of numerous light brake applications. This can be achieved by allowing taxi speed to increase from below target speed to above target speed, then using a single firm brake application to reduce speed below the target and repeating if required, rather than maintaining a constant taxi speed using numerous brake applications. Carbon brake wear is much less sensitive to airplane weight and speed than steel brake wear."
AERO: Operational Advantages of Carbon Brakes
I was told was that using reversers saves around $100/landing in brake wear
Salute!
Great thread and worth Tech Log forum, IMHO.
The wear of the brake rotors and disks and calipers needs to be compared with the ability of the brakes to absorb the energy - i.e. wear versus stopping ability. I used both the steel and the carbon brakes for many landings - a few thousands. And the carbon ones on the Viper were a surprise because they heated up easier than the steel ones. So the technique of one large application was about same as effect as many small, frequent ones as far as braking energy was concerned, but the heat build up was worse using the many applications.
I use the same technique on my auto brakes nowadays as I did in the Viper way back when we realized the new brakes were "different" than the old ones., with it's cosmic carbon brakes. One large application kept the heat down versus fequent taps. The rule of thumb is one third of speed reduction before braking results in one half of the brake energy requirement. A favorite number I use is that slowing 5 mph or so at highway speeds has about the same brake energy requirement /wear as braking from 30 mph to a full stop. It's the velocity change that is the driver - v1 squared minus v2 squared. Someone here can refine my numbers, but I am still going with that RoT and get super brake wear on my old truck.
Gums sends...
Great thread and worth Tech Log forum, IMHO.
The wear of the brake rotors and disks and calipers needs to be compared with the ability of the brakes to absorb the energy - i.e. wear versus stopping ability. I used both the steel and the carbon brakes for many landings - a few thousands. And the carbon ones on the Viper were a surprise because they heated up easier than the steel ones. So the technique of one large application was about same as effect as many small, frequent ones as far as braking energy was concerned, but the heat build up was worse using the many applications.
I use the same technique on my auto brakes nowadays as I did in the Viper way back when we realized the new brakes were "different" than the old ones., with it's cosmic carbon brakes. One large application kept the heat down versus fequent taps. The rule of thumb is one third of speed reduction before braking results in one half of the brake energy requirement. A favorite number I use is that slowing 5 mph or so at highway speeds has about the same brake energy requirement /wear as braking from 30 mph to a full stop. It's the velocity change that is the driver - v1 squared minus v2 squared. Someone here can refine my numbers, but I am still going with that RoT and get super brake wear on my old truck.
Gums sends...
Last edited by gums; 7th Aug 2022 at 05:09. Reason: grammar;clarification
It wasn't uncommon for Air Atlantique's DC6s to use aerodynamic braking back in the 80s/90s (landing roll and the yoke pulled back). Quite spectacular, cut down brake pad wear and saved a lot of scrabbling for the circuit breakers when the prop/s wouldn't come out of reverse.
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Get rid of reversers you say?
That's not consistent with what I've been told. Specifically, during the development of the 777 (and shortly after Lauda), I half serious asked why we just didn't get rid of the reversers. Thrust reversers are a whole lot of weight and complexity and are (relatively) high maintenance items. Just get rid of them and add a 'panic button' that releases a drogue chute if they need the extra braking.
What I was told was that using reversers saves around $100/landing in brake wear. If light use of carbon brakes causes just as much wear as heavy use (and carbon brakes were basic on the 777), that wouldn't be the case.
What I was told was that using reversers saves around $100/landing in brake wear. If light use of carbon brakes causes just as much wear as heavy use (and carbon brakes were basic on the 777), that wouldn't be the case.
Of all the "consumable" parts that they will have to somehow source to keep their fleets flying I don't think that break rotors, disks and calipers will be the hardest to source and/or to munufacture localy.
They may not be the hardest to manufacture. But someone still needs to do it. Factor in different aircraft types and proprietary manufacturing processes, never mind the cost and I think this is a good example of some of the difficulties Russia has following the sanctions. I heard a new set of brakes for a light business aircraft made in small numbers can be upwards of $100,000, which puts things in some perspective.
Intricate process:
https://www.meggitt.com/insights/how...carbon-brakes/
https://www.sglcarbon.com/en/markets...craft-brakes/#
The Russian can certainly learn to manufacture those. But is it worth for the relative small numbers?
https://cn.umatex.com/pdfs/About%20C...%20Rosatom.pdf
https://www.meggitt.com/insights/how...carbon-brakes/
https://www.sglcarbon.com/en/markets...craft-brakes/#
The Russian can certainly learn to manufacture those. But is it worth for the relative small numbers?
https://cn.umatex.com/pdfs/About%20C...%20Rosatom.pdf
