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Autobrake System On A/C  
User currently offlineCmckeithen From United States of America, joined Jul 2003, 617 posts, RR: 1
Posted (10 years 5 months 3 weeks 1 day 11 hours ago) and read 3483 times:

Which is the best Autobreaking to use and what do each do?

Auto Break 1
Auto Break 2
Auto Break 3
Auto Break 4
Max Auto Break

32 replies: All unread, showing first 25:
 
User currently offlineCritter_592 From United States of America, joined Jun 2000, 279 posts, RR: 0
Reply 1, posted (10 years 5 months 3 weeks 1 day 11 hours ago) and read 3430 times:

1 is less aggressive than 4 or Max. Max is normally used in an emergency or extremely wet/icy conditions. I think the average is 2, maybe 3 depending on the runway length.

User currently offline3204ever From Denmark, joined Mar 2004, 21 posts, RR: 0
Reply 2, posted (10 years 5 months 3 weeks 1 day 9 hours ago) and read 3366 times:


Max breaking,short run way...


User currently offlineOPNLguy From , joined Dec 1969, posts, RR:
Reply 3, posted (10 years 5 months 3 weeks 1 day 9 hours ago) and read 3347 times:

I believe that's "autobraking"....

"Autobreaking" is when the aircraft keeps going out of service for successive technical faults...  Big grin


User currently offlineStarlionblue From Greenland, joined Feb 2004, 17017 posts, RR: 67
Reply 4, posted (10 years 5 months 3 weeks 1 day 9 hours ago) and read 3340 times:

... and hot brakes, and more wear, and scared passengers, which is why there are several levels. Normally, you would want to use as little as you need to get you to the right turnoff.

And may I say that spelling it "autobrEaking" cracks me up. "Press the autobreak, we'll roll halfway down the runway, then split in three large burning pieces."



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineOPNLguy From , joined Dec 1969, posts, RR:
Reply 5, posted (10 years 5 months 3 weeks 1 day 9 hours ago) and read 3322 times:

>>>And may I say that spelling it "autobrEaking" cracks me up

We commonly see the same thing each winter when we get "breaking action reports" from some stations. If the "breaking" action is reported, I guess it means that the "braking" action isn't very good, and there's one off the end somewhere in pieces...  Big grin


User currently offlineVC745D From United States of America, joined Feb 2004, 214 posts, RR: 1
Reply 6, posted (10 years 5 months 3 weeks 1 day 9 hours ago) and read 3286 times:

did the Spell Check button brake?

User currently offlineCmckeithen From United States of America, joined Jul 2003, 617 posts, RR: 1
Reply 7, posted (10 years 5 months 3 weeks 1 day 9 hours ago) and read 3273 times:

Yes the spell button broke. Sorry for not being perfect, but if it will make you happy, I will fix it.

User currently offlineOPNLguy From , joined Dec 1969, posts, RR:
Reply 8, posted (10 years 5 months 3 weeks 1 day 8 hours ago) and read 3225 times:

>>>Sorry for not being perfect,

Believe me, you're not the first person to confuse break/brake, and you certainly won't be the last. I don't think anyone was trying to imply that you weren't perfect (and NOBODY is), but were just trying to see that there is a difference. Were you to use "break" instead of "brake" during some point in an aviation career, someone higher up in the food chain might conclude that you were "unclear on the concept" or something. You'd rather know -now-, from freinds here on A.net, right?

Cheers...


User currently offlineCmckeithen From United States of America, joined Jul 2003, 617 posts, RR: 1
Reply 9, posted (10 years 5 months 3 weeks 1 day 6 hours ago) and read 3168 times:

Yes....thanks for the advice and correction. I was not trying to be harsh if I sounded like it. And if I was a smartass I am sorry for being that way.

Chris


User currently offlineOPNLguy From , joined Dec 1969, posts, RR:
Reply 10, posted (10 years 5 months 3 weeks 1 day 2 hours ago) and read 3128 times:

>>>Yes....thanks for the advice and correction.

No prob...  Big grin


User currently offlineB747skipper From , joined Dec 1969, posts, RR:
Reply 11, posted (10 years 5 months 3 weeks 21 hours ago) and read 3090 times:

Autobrake 1-2-3-4-MAX on modern airplanes, and...
Autobrake MIN-MED-MAX on my dinosaur 747-200s or 300s select a "rate" of deceleration by applying brakes. In both cases of MAX - 3,000 psi of hydraulic pressure is sent to the brakes for stopping the airplane, i.e. in emergency.
xxx
What is another fact is when selecting MIN (or A/B-1), with little deceleration required, if you use "full reversers" for that landing, chances are that the brakes will not even be applied, until... you get "out" of using reversers.
xxx
Happy contrails  Smile
(s) Skipper


User currently offlineAA717driver From United States of America, joined Feb 2002, 1566 posts, RR: 13
Reply 12, posted (10 years 5 months 3 weeks 16 hours ago) and read 3040 times:

It's ok to be a smartass on this board. It's not ok to be sensitive.  Big grin

On the 757, the only place I ever used autobrakes was SNA. Even then, it wasn't necessary. Usually, the natural tendency was to get on the brakes at 100 kts.(which disables autobraking) anyway.

I've been told that Max. gives the effect of an arrested landing! Then you have to wait to be dragged off the runway when the fuse plugs go off... Big grin TC



FL450, M.85
User currently offlineRick767 From United Kingdom, joined Jan 2000, 2662 posts, RR: 51
Reply 13, posted (10 years 5 months 3 weeks 16 hours ago) and read 3017 times:

Remember on several aircraft, like the 757/767, MAX autobrake provides less retardation than full manual braking.


I used to love the smell of Jet-A in the morning...
User currently offlineBMAbound From Sweden, joined Nov 2003, 660 posts, RR: 4
Reply 14, posted (10 years 5 months 3 weeks 15 hours ago) and read 2979 times:

Critter_592,

I was just wondering, is 4 or MAX really used for wet/icy conditions? To me, the chances of hydroplaning/skidding off the runway seem to increase if pilots are braking hard right after touchdown on a rainy day.

johan




Altitude is Insurance - Get Insured
User currently offline3204ever From Denmark, joined Mar 2004, 21 posts, RR: 0
Reply 15, posted (10 years 5 months 3 weeks 15 hours ago) and read 2965 times:



On the Airbus 320 there is 3 modes.

MAX mode is normally selected for take off.

MED or LO modes may be selected for landing.

When LO is selected,progressive pressure is sent to the brakes 8 seconds after the ground spoiler deployment order to provide a 1.7 m/s deceleration.

When MED is selected,progressive presure is sent to the brakes immediatly after the ground spoiler deployment order to provide a 3 m/s deceleration.


User currently offlineMr.BA From Singapore, joined Sep 2000, 3423 posts, RR: 22
Reply 16, posted (10 years 5 months 1 week 3 days ago) and read 2790 times:

Just a side note, MAX setting is not allowed to be used for landing. Should harder braking be needed than MED, pilots brake manually.


Boeing747 万岁!
User currently offlineRendezvous From New Zealand, joined May 2001, 516 posts, RR: 0
Reply 17, posted (10 years 5 months 1 week 2 days 11 hours ago) and read 2710 times:

Some planes also have the "RTO" setting don't they? I assume that means if you pull the power off during takeoff roll the planes stops real quick?

User currently offlineB747skipper From , joined Dec 1969, posts, RR:
Reply 18, posted (10 years 5 months 1 week 2 days 11 hours ago) and read 2708 times:

RTO position - Rejected Take-Off...
xxx
When armed, with RTO ON, if you slam your throttles closed, you get MAX brakes...
Spoilers deploy also at the same time... while you get busy getting these reversers...
xxx
Happy contrails  Smile
(s) Skipper


User currently offlineMr.BA From Singapore, joined Sep 2000, 3423 posts, RR: 22
Reply 19, posted (10 years 5 months 1 week 2 days 9 hours ago) and read 2669 times:

Hi Skipper,

I'm not sure about this but I think there is a certain 'speed limit' before the RTO brakes goes into action?

Let's say you abrt at 50 knots, would it come on? Or would it only come on above 70 knots? What about the spoilers?

Thanks!



Boeing747 万岁!
User currently offlineMr Spaceman From Canada, joined Mar 2001, 2787 posts, RR: 9
Reply 20, posted (10 years 5 months 1 week 2 days 9 hours ago) and read 2664 times:

Hi guys.

I've never seen any type of airliner rolling out after landing with smoke rising from some of the brakes, as can be seen in this photo, so I don't believe this BA 747's brakes are experiencing a normal situation.

What do you guys think would have caused these brakes to smoke like this? High pressure braking action or a mechanical problem?

Perhaps a set of brakes got locked up for some reason. Whatever the cause, I wonder if these brakes would cause a delayed turn-around so they had time to cool off?


View Large View Medium
Click here for bigger photo!

Photo © Joe Pries - A.T. TEAM



PS, I don't think this smoke is from the 747's initial touchdown ......... thus the questions. Big grin


Chris  Smile





"Just a minute while I re-invent myself"
User currently offlineAJ From Australia, joined Nov 1999, 2389 posts, RR: 24
Reply 21, posted (10 years 5 months 1 week 2 days 9 hours ago) and read 2661 times:

Alvin, on the 767 the RTO function of the autobrakes is activated passing 85kt groundspeed.

Chris, recently serviced brakes can smoke like that if excess grease/dust similar remains in the brake area.

Carbon brakes thrive in the heat, so the high temperatures can cause foreign materials to burn off after application. This is generally a short lived phenomenon. There is a limit of course, get the brakes too hot and you can wind up blowing the fuse plugs on your tires...embarassing and dangerous! It also increases the downtime of the aircraft having hot brakes, as they must have cooled sufficiently to allow the RTO function to effectively operate on the next takeoff. Fans are sometimes used during short turnarounds to help cool hot brakes.

Cheers.


User currently offlineMr.BA From Singapore, joined Sep 2000, 3423 posts, RR: 22
Reply 22, posted (10 years 5 months 1 week 2 days 8 hours ago) and read 2644 times:

Thanks AJ. Just wondering, what is the minimum brake temperature before the RTO is being allowed to function on the next takeoff? Or do the B767s read the brake temperature in units?


Boeing747 万岁!
User currently offlineAJ From Australia, joined Nov 1999, 2389 posts, RR: 24
Reply 23, posted (10 years 5 months 1 week 2 days 7 hours ago) and read 2639 times:

Yes, the brake temperatures are displayed in values from 0 to 9. A Brake Temp light illuminates for values of 5 or above. Releasing the parking brake (on chocks of course) can help reduce brake temperatures.

If the Brake Temp light comes on for the next takeoff a table entitled 'Max Quick Turnaround Limits' is consulted. A minimum turnaround time of 75 minutes must be applied (would cause chaos on a Cityfler!).

The table limits the takeoff weight for the next flight. For example after a Flap 30 landing at Sydney on a 20 degree day the next takeoff weight with hot brakes is limited to 149,000kg.


User currently offlineMr.BA From Singapore, joined Sep 2000, 3423 posts, RR: 22
Reply 24, posted (10 years 5 months 1 week 2 days 4 hours ago) and read 2614 times:

Thanks AJ for the imput. I don't know if many airlines do this... would it be viable to use more reversers (definately more than idle) during hot days and fast turnaround time? I guess that would ease a lot of pressure on the brakes upon rollout?

I note that cost-saving carriers like Swiss always use full reversers for landings. I don't think it saves more money than using more brakes?

Cheers!



Boeing747 万岁!
25 Post contains images B747skipper : The RTO gets automatically armed at 80 Kts during takeoff for a 747. xxx As far as brake temperature gages... we have gages with green, yellow and red
26 Cx flyboy : On the 777, we use Autobrake 2, 3 and sometimes 4 for a short runway like Fukuoka or Nagoya when wet. For long runways we used to use Autobrake 1, but
27 Post contains links and images Mr spaceman : Hi guys. > AJ & B747skipper, Thanks for explaining that seeing smoke from the brakes is normal after maintenance has serviced the brakes or installed
28 3204ever : ECAM=Electronic Centralized Aircraft Monitoring..
29 Post contains images Mr Spaceman : Hello 3204ever. Thanks for your answer about what ECAM stands for. I guess the in-flight test is pretty simple. The Captain probably just looks at som
30 Post contains links and images Liamksa : Gday Mr Spaceman Don't know the specifics of the A300, but i'd imagine it would be similar to other modern aircraft. In the case of the B767, the norm
31 3204ever : On the Aibus 320 series,there are 4 braking modes available depending on: -The hydraulic system in use. -The position of the A/SKID NOSE WHEEL switch
32 Post contains links and images Mr Spaceman : Hi guys. >> Liamksa, Thanks for your information and for providing that 767 photo. Here's the best shot I could find of an A300's cockpit that shows w
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