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The over use of autobrakes

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The over use of autobrakes

Old 7th Mar 2018, 12:31
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have seldom read such a load of rubbish. If this reflects current teaching about the design, function and use of automatic braking then everyone needs to go back to school and study how it works in reality
In the words of a well known Australian female politician, "Please explain."
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Old 7th Mar 2018, 21:36
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Blacksheep.
What is the point of saying "this is a load of rubbish?".What is your statement based upon.PLEASE EXPLAIN for the benefit of the rest of us.
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Old 8th Mar 2018, 08:10
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Originally Posted by vilas
But you do use idle reverse at least. In A320 even for that many airlines want you to move to full reverse position and back to idle.
Vilas, my A320 operator has this "full reverse then immediately idle" as a fairly common procedure, but not official SOP. I could never understand it myself, and personally will select idle reverse and listen out for a "reverse green" callout to confirm my selection.

Any chance you know where this habit comes from? Was it once recommended by Airbus?

Ta!
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Old 8th Mar 2018, 09:51
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Was it once recommended by Airbus?
Affirm.

See page 18.
https://www.cockpitseeker.com/wp-con...psWithALAR.pdf

"Adhering to the following operational guidelines
ensures an optimum braking during the landing roll:
Arming ground spoilers;
Arming autobrake with the most appropriate
mode for prevailing conditions (e.g., short
runway, low visibility, contaminated runway);
Selecting thrust reversers as soon as possible
with maximum reverse thrust (this increases
safety on dry and wet runway, and is mandatory
on runway contaminated with standing water,
slush, snow or ice);"
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Old 8th Mar 2018, 11:32
  #45 (permalink)  
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:

Was it once recommended by Airbus?
Affirm
Direct Quote from Airbus after selecting full reverse:
Monitoring airspeed indication and returning
reverse levers to the reverse idle position at the
published indicated airspeed or when airspeed
fluctuations occur, whichever come first;

Nothing about going to max reverse and then immediately going to idle reverse.
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Old 8th Mar 2018, 15:19
  #46 (permalink)  

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Originally Posted by Blacksheep
I have seldom read such a load of rubbish. If this reflects current teaching about the design, function and use of automatic braking then everyone needs to go back to school and study how it works in reality.
BS is correct.

Let's get onto the over-use of wings and elevators as well. Blatant, in my opinion.
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Old 8th Mar 2018, 18:51
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BS is correct.

Let's get onto the over-use of wings and elevators as well. Blatant, in my opinion.
Oh dear, someone else who doesn't understand the discussion!
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Old 8th Mar 2018, 21:55
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Personally I think a lot of this thread is a beat up about nothing.
As a professional I would expect that you would assess what is required on the day at a particular airfield, whether you use autobrakes or not, idle reverse or full reverse. On the assessment side of things your decision may come from having operated into an airfield you are very familiar with, or jump into the performance information and work out what you need for airfields you are not that familiar with.
If the airline sops are to use autobrakes then arm them, just after touch down and you feel no need for them, then cancel them!
To me that is airmanship or is it personship ....... but that is another topic!

Last edited by Offchocks; 8th Mar 2018 at 22:12.
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Old 8th Mar 2018, 22:29
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that is airmanship or is it personship
...or airperchildship...
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Old 8th Mar 2018, 23:25
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Originally Posted by Slippery_Pete
Said airline that put a 747 into the golf course now has an idle reverse policy!!! It beggars belief.
Not the same as back in the '90s. Then people were being marked down on sims for using anything other than idle reverse/flap 25. It was being aggressively pushed.

The current take up rate on my fleet is about half, with the bias heavily toward runways that have it in their own noise policy. I don't have the slightest problem with it on long, dry runways. The issue is thoughtless application of any policy, no matter what it relates to.
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Old 9th Mar 2018, 02:39
  #51 (permalink)  
 
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Originally Posted by Offchocks
Personally I think a lot of this thread is a beat up about nothing.
As a professional I would expect that you would assess what is required on the day at a particular airfield, whether you use autobrakes or not, idle reverse or full reverse. On the assessment side of things your decision may come from having operated into an airfield you are very familiar with, or jump into the performance information and work out what you need for airfields you are not that familiar with.
If the airline sops are to use autobrakes then arm them, just after touch down and you feel no need for them, then cancel them!
To me that is airmanship or is it personship ....... but that is another topic!
Spot on! Stop the monkey business. Unless your SOP has restrictions, the use of full reverser, autobrake or not should be at your discretion based on your experience and common sense.
In my home base, I almost never use autobrake as I need to vacate the runway at the far end, and with 3400M runway and with headwind, reverse idle only and no brakes application will bring down the aircraft to taxi speed just before the exit. Works like a charm.
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Old 11th Mar 2018, 15:58
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Discretion and common sense has long left the building in a lot of companies...
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Old 11th Mar 2018, 17:07
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Originally Posted by piratepete
Cent.
I really dont understand this quite common "idle reverse" policy...
I think that it comes down to money, but not in the way that most people would assume.

In many airlines engines are leased or on some form of guaranteed maintenance program. Brakes are simply purchased.

So the engine people want idle reverse [and aggressive derates, but that is another subject], and the brake people are very happy to sell brakes. Send a few "technical experts" to advise the airline customers, combined with a thinning out of engineering expertise in flight operations departments in the name of cost savings, and presto -- stupid and rigid SOPs.

And more overruns on wet/slippery runways.
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Old 11th Mar 2018, 18:51
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I really dont understand this quite common "idle reverse" policy...

There are many airports in EU where the noise lobby have influence, and the SOP is idle reverse unless you have a safety issue. Someone told them the auto brakes can do the same thing and TR's do not cause less stopping only more noise.
That, plus some airline SOP's/philosophy that brake maintenance is cheaper than engine maintenance, and don't forget fuel burn, is what causes some guys to stop thinking when it is required.
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Old 12th Mar 2018, 18:15
  #55 (permalink)  
 
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Blacksheep,..go easy on your flock!
But worth remembering,..autobrake is slave to reverse thrust,whilst manual braking has its own mind!......

Last edited by Yaw String; 12th Mar 2018 at 20:05.
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