Changing auto brake setting during roll out

[stilton]

I’ve not seen any specific guidance against this or done it personally


If I’m not getting the required deceleration
i’ll disconnect the AB and manually brake


But I’ve seen it done and curious as to
thoughts on this technique

[BluSdUp]

Madness...

[Tee Emm]

Technically possible but what's the point? It's a gimmick and lacks class

[InSoMnIaC]

It seems like a good/acceptable idea until you accidentally hit MAX

[N1EPR]

I often changed the auto brake settings on the B757. It was a smooth operation. I never used the technique to increase braking.

[pineteam]

It seems like a good/acceptable idea until you accidentally hit MAX

Exactly my thought too. I often use Autobrake low and disconnect it if I need more or less braking. I always try to brake as smooth as possible and take the last high speed exit for the sake of confort and brakes life. If a pilot relies so much on automation on the ground, I would be concerned.

[FlyingStone]

Seen it being done, never really understood the point, especially when people would change it mutiple times during rollout (i.e. 3 to 2, then 2 to 1).

Isn’t it much easier just to press the pedals to disconnect the autobrake and brake manually?

[AmarokGTI]

If you are not getting the required deceleration changing the setting might not work if the reason is a fault with the system. Once you work that out you have even less time for the manual option.

[172_driver]

I often changed the auto brake settings on the B757. It was a smooth operation. I never used the technique to increase braking.

Same here.

It's in the 737 FCOM that autobrakes can be selected and changed during landing roll out. No warning or caution.

[73qanda]

It seems like a good/acceptable idea until you accidentally hit MAX
Exactly my thought too.
I can’t imagine anyone ever ‘accidentally ‘ selecting MAX. Would you accidentally lift the knob up and over ? It’s not that easy to do.
I don’t use the above technique and prefer to select a slightly lower setting than required and override to disengage.

[CaptainProp]

It seems like a good/acceptable idea until you accidentally hit MAX

Exactly THAT! What a load of BS! Taking your eyes of the runway on rollout to “locate” switches and stuff is simply unprofessional. As far as I’m concerned you touch nothing until clear of runway and spoilers are being disarmed.

CP

[InSoMnIaC]

Not all aircraft use knobs to set autobrake.

[ACMS]

Ummmmmm..........:8

[Skyjob]

If you are not getting the required deceleration changing the setting might not work if the reason is a fault with the system. Once you work that out you have even less time for the manual option.
I'd only use it the other way around:

Say you've prepared performance rollout data for a WET runway but during landing its damp at best if anything.
Having checked DRY and WET performance prior to landing, you know that a lower AB setting would make the desired exit in DRY conditions.
Lowering the AB eating to the desired lower one is good airmanship in this case, alternatively, manual braking to disconnect the higher auto brake selected the other option.

[FlightDetent]

Skyjob: AB usually provides a controlled deceleration rate.

The Boeing RTO OFF-1-2-3-MAX is far superior to AB's LO-MED MAX in the interface, given the task suggested above.

AB: no, unless you really want to do the inevitable.
B: to reduce decel rate? Worked nicely, I seem to remember (steel brakes at the time).

[vilas]

Routinely in normal conditions doesn't make any sense. But in rain and crosswind etc. if one wants to increase braking effect not a bad idea to change to medium from low. You are assured of even braking.

[FullWings]

It’s the poor man’s Brake To Vacate...!

[Tee Emm]

Lowering the AB eating to the desired lower one is good airmanship in this case, alternatively, manual braking to disconnect the higher auto brake selected the other option.
All very complicated and unnecessary fiddling about. If you land with autobrake MEL'd u/s, should you declare Mayday or simply PAN? Or just land and use normal manual braking like ordinary pilots have done so in the past 50 years. Much ado about nothing, IMHO

[stilton]

Not necessarily against it, particularly in
adverse conditions with gusty winds and
a wet / short runway


But If you do, I think it should be the PNF
that adjusts the setting, it’s an awkward reach to where the selector is usually
located and an unnecessary distraction to the PF



I was in the jump seat of a 747 Classic a
few years ago however that had the AB selector mounted on the left side of the overhead panel in easy reach of the CA

[Old Fella]

Not all aircraft use knobs to set autobrake.
No, but some other knobs might change the setting during roll out.

[Paulm1949]

How about moving the flaps up at the same time?

[Uplinker]

Exactly THAT! What a load of BS! Taking your eyes of the runway on rollout to “locate” switches and stuff is simply unprofessional. As far as I’m concerned you touch nothing until clear of runway and spoilers are being disarmed.

CP




I generally agree but just playing devil’s advocate........ In your car, have you never looked down to change the radio or heating controls while driving at 70 mph on a motorway only a few feet away from lots of other vehicles and heavy trucks, and do you wait to adjust any control that is out of your eyeline until you have turned off the motorway and reduced to a very low speed?

What I am aluding to is that no proper professional pilot will take their eyes off the situation outside unless the aircraft is fully under control and the conditions are benign. When it is fully under control, looking down (or up) for a second to change a switch.......is it such a big risk?

If it is, just ask the other pilot for what you want.

Hard hat on to deflect incoming...................

[DooblerChina]

This happens all the time in my airline, the 75/76 auto brakes are very smooth so modifying the decel rate is almost standard practice. Regarding taking your eyes off the runway well no probs as the auto brake selector is in PM’s area of responsibility.

I love the ‘madness’ shouts, they make me laugh and just show cultural differences between airlines.

[Nightstop]

I was a passenger in a FR 738 some time back when the crew inadvertently selected what I believe to be RTO during the landing roll out. The sudden decelaration was enough to propel me into the seatback in front, I sustained a minor injury to my right hand while trying to save myself. Very unpleasant and no explanation from the flightdeck. Senior Cabin Crew was in the flightdeck during disembarkation asking WTF was going on..

[Fursty Ferret]

I don't do it - unpleasant jolt on the 787 if you go twiddling the autobrake knob, which isn't conveniently located to begin with. Especially when you have the deceleration scale in the HUD, why would you want to? Do the performance calculation properly, land it in the right place, and leave the autobrake in until taxi speed.

[Derfred]

I just heard a theory that the PNG crew increased their autobrake setting at 50’ in heavy rain at Truk.

It seemed like a good idea at the time.

[PEI_3721]

Why are aircraft fitted with autobrake ?
Why do pilots use autobrake ?
Why change settings ?

After any serious incident, the press release will always state that “safety is our first priority”.

[de facto]

Just read your damn bulletins

[beamer]

Never a problem on 75/76 in my experience.

[Beakor]

B757 FCOM Systems:

”Autobrake application occurs slightly after main gear touchdown. Deceleration is
limited until the pitch angle is less than one degree, then deceleration increases to
the selected level. The deceleration level can be changed (without disarming the
system) by rotating the selector.”

[Intrance]

I don't mean to step on toes, and I understand autobrakes are a tool to be used and probably nice to have, especially the bigger and heavier the type gets. But I agree with the notion of why go through the trouble of fiddling with selector knobs or buttons when there's two big pedals at your feet you can use? It might not be as accurate as the computers can do it, but I think I managed about 10 years of flying so far without giving the passengers any injuries or bruises from their seatbelts (my type does not have autobrakes).

Taken to extremes, next up we will have accidents because pilots don't know how to brake with care anymore ;).

[misd-agin]

Wait a minute, you have your feet on the rudder pedals and you’re fiddling with a switch down FO’s knee to modulate the braking?!? We’re doomed.

The car radio analogy? Anyone think fiddling with a speed control setting on the dash screen is a great idea when you have your foot of the accelerator?? Can you do it? Sure. Great idea? Debatable.

[PEI_3721]

‘It’ (radio or AB) can be changed; should it be, is it necessary.
Is there less distracting alternative - aircraft, yes, manual braking.

Re bulletins:
Who writes / authorises the bulletins ?
What do they say, why, to what purpose ?
Who holds the final safety responsibility for the bulletin ?
… for the aircraft … You ?

[Check Airman]

I've seen somebody disengage the AB via the pushbutton on the panel (A320) during rollout. What if he'd selected max instead? Would anyone die? Probably not, but there's some risk of injury with max AB, I assume.

There's nothing expressly prohibiting it, but it just seems like way more work than using the pedals. Not worth me getting worked up over it though.

[CaptainMongo]

We are to disconnect autobrakes via manual braking, not using the switch. I believe that is still required across all fleets at our company. I can understand directing the PM to change the auto brake setting during the approach because of unanticipated conditions.

I can not understand doing that on the runway. So the Captain is landing and now decides to: take his eyes off the runway, look over to the autobrake panel, take his right hand off the TL’s and reach across the cockpit to deselect, select, or increase the AB setting. Or one may say, well no, he directs his FO to do the action. So now that FO is presented with a command from the Captain he most likely has never encountered nor anticipated and is to complete during a critical phase.

I can easily imagine a hundred things which could go wrong. Isn’t our job to manage the threats inherent in our occupation not add to them?

[BluSdUp]

It was either " Madness" or " Moronic", so I say figured the former was less insulting.
On a technical level , there is no advantages ( on the 737, anyway) and only a heap of hurt if getting it wrong.
The fact that a bunch of test pilots with zero line experience has gotten away with using it , and does not see the potential for a disaster in our hands , repeating it a few million times a year , instead of proper conservative breaking , means nothing. In my book!

Another little thing on the 737 the autobrake some times does not arm. All you do then is go to zero for a few seconds, then back to desired selection , and voila, it arms. Doing that midfield at 100kts eats rwy!?
Anyway
I recall doing a thing or two some times back, when the "culture" was somewhat more relaxed. Sure we had fun , and we were good, but most of the time lucky.
Buzzing my Brothers farm on empty trips at 100 feet comes to mind,,,

You all have fun now
Cpt B

[DooblerChina]

I disagree but can’t be bothered arguing, different types, different airline cultures. All the best.

[172_driver]

On a technical level , there is no advantages ( on the 737, anyway) and only a heap of hurt if getting it wrong.

I have been taught that particularly the carbon brake's (which we have, 737) lifetime is favoured by the auto brakes rather precise application.

[flash8]

Nowhere in the 737CL FCTM does it imply fiddling about with the autobrakes after landing, this action surely is a "kludge" at best!

[172_driver]

Nowhere in the 737CL FCTM does it imply fiddling about with the autobrakes after landing, this action surely is a "kludge" at best!

Read the FCOM then, at least the NG's. There it "implies" the autobrake switch may be used after landing to change decceleration rate.

[Chesty Morgan]

I did it yesterday. 3 would have required a large backtrack due to WIP at one of the exits and max would have meant stopping too soon. So I went from max to 3. It worked, we kept the advantage of auto brakes and if you hadn't guessed by now I am still alive.

[Chesty Morgan]

Of course.

[Cloudtopper]

I was a passenger in a FR 738 some time back when the crew inadvertently selected what I believe to be RTO during the landing roll out. The sudden decelaration was enough to propel me into the seatback in front, I sustained a minor injury to my right hand while trying to save myself. Very unpleasant and no explanation from the flightdeck. Senior Cabin Crew was in the flightdeck during disembarkation asking WTF was going on..
No . Your wrong. Its not possible to arm RTO while in the air.

[misd-agin]

I did it yesterday. 3 would have required a large backtrack due to WIP at one of the exits and max would have meant stopping too soon. So I went from max to 3. It worked, we kept the advantage of auto brakes and if you hadn't guessed by now I am still alive.

So you think using MAX right after landing, and later reducing to 3, was better for the aircraft than using 3 and then increasing brake pressure after your speed had decreased??

[Chesty Morgan]

I used the aircraft the way it was designed to be used.

Are you implying that using MAX is bad for an aeroplane?

[Nightstop]

No . Your wrong. Its not possible to arm RTO while in the air.

I didn’t say “in the air”, the event was during the roll out after landing.

[Intrance]

I used the aircraft the way it was designed to be used.

Are you implying that using MAX is bad for an aeroplane?


By your logic in the second line, aren't you now implying manual braking is not how the plane is designed to be used and bad for the airplane? I'm sure you managed fine and are still alive. Personally I'd still prefer to keep my attention outside and hand and feet in standard positions instead of going for knobs/buttons during rollout. To each their own.

[Chesty Morgan]

By your logic in the second line, aren't you now implying manual braking is not how the plane is designed to be used and bad for the airplane?

The use of autobrake reduces brake wear and minimises brake temperatures whilst still achieving what you want to achieve. Brakes are obviously designed to be used without autobrake or brake pedals wouldn’t be fitted and whilst manual braking is not necessarily bad for the aeroplane it is, categorically, not as efficient as using autobrakes.

[Intruder]

The use of autobrake reduces brake wear and minimises brake temperatures whilst still achieving what you want to achieve. Brakes are obviously designed to be used without autobrake or brake pedals wouldn’t be fitted and whilst manual braking is not necessarily bad for the aeroplane it is, categorically, not as efficient as using autobrakes.Apparently you are not familiar with the concepts behind your first statement, but are only trying to justify a practice that is not supported anywhere that I have seen.

First, using MAX autobrakes when they are not needed will NOT minimize brake temperature or brake wear. To minimize temperature, you use as little braking as possible while the airplane is at high speed. As others have pointed out, in your case you should have started with Autobrakes 3, then increased pressure after the airplane had slowed down.

Second, the practice of changing the Autobrake setting during the landing roll is not supported in any Boeing document that I have seen, and was actively discouraged - effectively prohibited - at my airline. Trying to move a switch, that is unnecessary and which may not remain in the newly selected position, during the landing roll is a major distraction at best and a dangerous risk if the switch solenoid happens to release or fail during the attempt. Use of the brake pedals to manually modulate brake pressure is the proper way to override the Autobrakes setting.

From the Boeing 747-400 Flight Crew Training Manual:Use an appropriate autobrake setting or manually apply wheel brakes smoothly with steadily increasing pedal pressure as required for runway condition and runway length available. Maintain deceleration rate with constant or increasing brake pressure as required until stopped or desired taxi speed is reached.
. . .

For normal landing conditions, autobrakes 2 or 3 optimizes brake wear, passenger comfort, and stopping performance.
. . .

To minimize brake temperature build-up, use the following landing techniques:
. . .
use an autobrake setting, consistent with reported runway conditions, that will result in the use of all available runway length. A stopping distance safety margin should be used in accordance with airline policy. Although the autobrakes initially increase brake temperature, the brake contribution is minimized after reverser deployment

[Chesty Morgan]

Well my dear MAX was the minimum needed to ensure we made the exit. But thanks for your input on a flight you have no knowledge of.

And, FYI, autobrake will minimise brake wear when compared to manual braking. A concept I assume you are aware of.

[Too Few Stripes]

B737 bulletin CEX-5 certainly hints at not changing the autobtake setting during the landing roll as the RTO mode CAN be inadvertently activated (a service bulletin provides a fix to the RTO logic that allows this).

[Intrance]

Still not quite sure why you would prefer fiddling with knobs when your focus could be outside, all limbs on the necessary controls and ready to react to anything non-standard. Again, to each their own.

Pretty sure in the near future, we'll have pilots who have no idea what it feels like to slow a plane down with manual braking.

[flyburg]

This discussion is such BS. The airplane has the ability to change AB setting during roll out. No, it is not described in the FCOM. Neither is the use of the lights!! Airmanship comes into play!! When transitioning from AB to manual braking often times you have to increase pressure on the pedals beyond the braking pressure being applied by the AB system giving an uncomfortable jolt in braking when transitioning!! I find it much more comfortable to apply brake pressure just before the point where the AB system kicks off and then asking the PM to select AB off, this gives a much smoother transition to manual braking!! I have on occasion asked the PM to increase the brake setting to a higher setting to make an exit. Again this is usually a smoother transition than applying manual brake.!!

the notion that you could inadvertently select RTO is absolute nonsense!! The RTO mode won’t arm unless speed is less than 60kts and then will only engage with speed above 90kts! How is this going to happen during landing!!

Yes, I have spent the first half of my career flying airplanes without AB and I do now how to brake without AB. However, the system is there, use it! And NO, I don’t change it myself!! I simply ask the PM to change it “set autobrake off” while looking outside!! DUH!!

And yes, I have used AB max as well! granted, probably 3 or for times, but flying a heavy 900 sometimes that’s what needed! Shortest runways I fly to are ABZ and AMS rwy22 under stormy conditions. AB 3 won’t be enough with the 15% increase( it is there for a reason!). Simple PA to the PAX, ” due to WX conditions/ short runway we will be landing on today we will use a higher braking setting, please make sure that your seatbelts are securely fastened, please don’t be alarmed, it is normal under the circumstances to guarantee maximum safety”, done!!!!

some of the comments I read here, really, are you that insecure about your flying skills that you have to constantly propagate about manual skills versus using the automatics the manufacturer build into the airplane?

[Escape Path]

Refreshing my SOPs during this pandemic I found something of interest that caught my eye, and couldn’t find a reference for. In the landing section of my A320 SOPs it says:

WARNING: Never change the A/BRK selection during roll out.

I already knew we weren’t supposed to switch selection during landing roll; but not “Note”, not “Caution”, “Warning”. And well, it is specifically prohibited. Yes, I know FCOMs are tailored.

Warning implies “risk of personal injury or loss of life”... Any inputs on this?

Regards

[FlightDetent]

Inadvertent MAX selection through action slip or worse. Just a guess.

IIRC the original FCOM wording of MAX changed not so long ago from use for landing is not recommended to simply imply that MAX is not a landing setting at all.

[vilas]

Inadvertent MAX selection through action slip or worse. Just a guess.

IIRC the original FCOM wording of MAX changed not so long ago from use for landing is not recommended to simply imply that MAX is not a landing setting at all.
Airbus FCOM is silent about selection change during roll out. On new MSNs it is simply not possible to select MAX for landing. So Airbus has ended the discussion.

[macdo]

This is an old thread, but I still found it disturbing that the subject even came up for discussion. Unnecessarily twiddling knobs or pushing buttons during the landing roll seems a distinctively unprofessional during a critical phase of flight.
If you don't like what the automatics are doing, disconnect and revert to manual.

[Escape Path]

Airbus FCOM is silent about selection change during roll out. On new MSNs it is simply not possible to select MAX for landing. So Airbus has ended the discussion.

My quote is straight out of my A320s FCOM.

Macdo: I concur with your opinion (and I apply that myself). I just found it curious that it’s labeled as a warning. Then again, I think FD’s right on the money.

[vilas]

My quote is straight out of my A320s FCOM.

Macdo: I concur with your opinion (and I apply that myself). I just found it curious that it’s labeled as a warning. Then again, I think FD’s right on the money.
I am referring to manufacturer's FCOM. Yours is company FCOM as you said.

[Vessbot]

I have yet to fly a plane with auto brakes so no first hand experience, but all this talk gives me the feel of watching when someone's flying by twiddling the heading and VS knobs like an Etch-a-sketch and making a harder job for themselves, than simply using the yoke.

[vilas]

I checked two different airline's FCOM as well as manufacturer's FCOM and they are silent on changing AB selection during roll out. AB definitely reduces the brake wear as it is a single application also it is even braking. Now the question of setting change, if company forbids then you must not but it remains company specific. System wise there is no problem. The objections that are valid are PF shouldn't do it, also even if PM did it it's a push button and may not engage so he has to ensure that it does and that cannot be monitored by PF who should be looking ahead. Besides selecting a higher rate is opting for more braking whether it will suffice is a guesswork. So taking over manually is a single action solution. However if someone wants to change AB selection during rollout it is not forbidden by every airline.

[Check Airman]

I checked two different airline's FCOM as well as manufacturer's FCOM and they are silent on changing AB selection during roll out. AB definitely reduces the brake wear as it is a single application also it is even braking. Now the question of setting change, if company forbids then you must not but it remains company specific. System wise there is no problem. The objections that are valid are PF shouldn't do it, also even if PM did it it's a push button and may not engage so he has to ensure that it does and that cannot be monitored by PF who should be looking ahead. Besides selecting a higher rate is opting for more braking whether it will suffice is a guesswork. So taking over manually is a single action solution. However if someone wants to change AB selection during rollout it is not forbidden by every airline.
My airline doesn't say I can't use my inboard arm to use the sidestick and my outboard arm to control the thrust levers either.

[Chesty Morgan]

My airline doesn't say I can't use my inboard arm to use the sidestick and my outboard arm to control the thrust levers either.
But you would if you could?

[vilas]

My airline doesn't say I can't use my inboard arm to use the sidestick and my outboard arm to control the thrust levers either.
Are you sure? Before you strap up in simulator for your first FFS in your type rating something is elaborately explained on how to adjust the outboard arm rest for the outboard arm. May be long time ago you forgot.

[Uplinker]

I have yet to fly a plane with auto brakes so no first hand experience, but all this talk gives me the feel of watching when someone's flying by twiddling the heading and VS knobs like an Etch-a-sketch and making a harder job for themselves, than simply using the yoke.

Nothing wrong with flying an aircraft by "twiddling" heading and V/S while on autopilot - most airliners are designed to do exactly that to make short term changes to flight path using the FCU ('glare-shield') controls, without having to disconnect the AP.

95% of the time, this is how we fly radar vectors and vertical profile to intercept an ILS, for example. It makes the job easier, not harder - especially when you are in busy airspace such as the London TMA, when it is not helpful if PF is hand-flying.

However, unlike the FCU controls, I don't think the auto-brake selector is designed or intended to be manually modulated (changed) during its operation.



PS, there is an argument that not hand-flying causes our manual skills to become rusty, but that is for another thread.

[FullWings]

I occasionally use this technique when the planned exit point falls between two autobrake settings but only if the PM has been briefed to change it on request. I find it smoother (and better for passenger experience) to land with a higher setting and reduce it rather than the other way round.

When I’m positioning and someone takes out the autobrake then applies jerky heavy braking, from the reactions of those around me they appear to think that the chances of going off the end have dramatically increased. A firm landing followed by a gentle rollout is preferable to a smooth touchdown followed by increasing retardation, it seems...

[Uplinker]

+1

I think that a sudden increase in heavy braking (to make an exit) is more uncomfortable and frightens the passengers more - they think we are about to go off the end - than an initial medium retardation after touchdown that then reduces or ceases.

Unless we have been told to vacate at the end, or at a very distant exit, I like to use medium autobrake (A320 family), and as soon as I can feel and assess the retardation rate, I can either leave medium auto-brake in or drop it out by applying gentle manual braking if it is too much.

[Escape Path]

Thank you vilas for your clarification on OEM FCOM vs company FCOM.

I do think we are not supposed to be pushing buttons in the middle of a landing roll. Takeover manually if your setting isn’t doing what you wanted

[Check Airman]

But you would if you could?
Assuming I’m still employed when I’m due for my next sim session, maybe I’ll give it a shot ;)

[Check Airman]

Are you sure? Before you strap up in simulator for your first FFS in your type rating something is elaborately explained on how to adjust the outboard arm rest for the outboard arm. May be long time ago you forgot.

Ha! Good point. You’re probably right.

[vilas]

Thank you vilas for your clarification on OEM FCOM vs company FCOM.

I do think we are not supposed to be pushing buttons in the middle of a landing roll. Takeover manually if your setting isn’t doing what you wanted I was just saying that most airlines suggest that if not satisfied with deceleration then take to manual braking without expressly forbidding setting change in mid roll like your airline does. As I pointed out in AB setting change midstream there are too many variables. I would myself prefer to change to manual braking.

[Kirks gusset]

The Autobrake settings equate to pressures:
• Autobrake setting 1 - 1250 PSI equates to 4 ft per second squared.
• Autobrake setting 2 - 1500 PSI equates to 5 ft per second squared.
• Autobrake setting 3 - 2000 PSI equates to 7.2 ft per second squared.
• Autobrake setting MAX and RTO - 3000 PSI equates to 14 ft per second (above 80 knots) and 12 ft per second squared (below 80 knots).

If the autobrake is stopping you too quickly, then it's easy to as the PM to select a lower setting, or simply gently apply brakes until the disarm like comes on, at this point you will have the same pressure as the system, conversely if more stopping is required either select a higher setting or apply brakes gently and increase the pressure. The common mistakes are jolts from over ambitious disarming via the switch or stamping on the brakes.
Remember some landing conditions dictate the use of autobrakes so its not a personal choice
Its much safer usually to manually brake to make the required adjustments rather than have heads down in the cockpit,

[Winemaker]

There is of course a thread on PPrune Technical about brake application and wear:

https://www.pprune.org/tech-log/514065-logic-illogic-use-hard-braking-carbon-brakes-long-dry-runways.html#post7830359

[Kirks gusset]

Carbon brake wear is primarily dependent on the total number of brake applications — one firm brake application causes less wear than several light applications. Safety and passenger comfort should remain the primary considerations.

Boeing article quote

[Vessbot]

Nothing wrong with flying an aircraft by "twiddling" heading and V/S while on autopilot - most airliners are designed to do exactly that to make short term changes to flight path using the FCU ('glare-shield') controls, without having to disconnect the AP.

95% of the time, this is how we fly radar vectors and vertical profile to intercept an ILS, for example. It makes the job easier, not harder - especially when you are in busy airspace such as the London TMA, when it is not helpful if PF is hand-flying.
We’re talking about different things. You’re talking about normal usage of heading mode, which is setting headings for discrete lengths of time during which you intend to fly that heading (most often because of a vector). What I’m talking about comes up pretty rarely so maybe you haven’t seen it, in which case you should count yourself lucky.

But when you do, it’s eye-watering. Like there’s the LGA 31 expressway visual, an approach in the US where for a large segment of it you’re supposed to follow a road. Every once in a while I’ll fly with someone who isn’t comfortable flying and wants to “reduce the workload” and use the autopilot, and they’ll be virtually unable to take their hands off the heading knob having to make constant corrections for the initial overshoot, later overshoots from that overshoot (as inevitably the slow roll rate and overall response of the AP does not match up with the ground track he thought was gonna happen) wind changes, slight turns in the road, etc., all the meanwhile he’s trying to manage the VS as well.

There’s another control for that! And this is not what the autopilot was meant for.

[Check Airman]

We’re talking about different things. You’re talking about normal usage of heading mode, which is setting headings for discrete lengths of time during which you intend to fly that heading (most often because of a vector). What I’m talking about comes up pretty rarely so maybe you haven’t seen it, in which case you should count yourself lucky.

But when you do, it’s eye-watering. Like there’s the LGA 31 expressway visual, an approach in the US where for a large segment of it you’re supposed to follow a road. Every once in a while I’ll fly with someone who isn’t comfortable flying and wants to “reduce the workload” and use the autopilot, and they’ll be virtually unable to take their hands off the heading knob having to make constant corrections for the initial overshoot, later overshoots from that overshoot (as inevitably the slow roll rate and overall response of the AP does not match up with the ground track he thought was gonna happen) wind changes, slight turns in the road, etc., all the meanwhile he’s trying to manage the VS as well.

There’s another control for that! And this is not what the autopilot was meant for.

Flying the expressway visual (https://aeronav.faa.gov/d-tpp/2008/00289EXPRESSWAY_VIS31.PDF) in heading mode should be illegal. I've also flown with somebody who's insisted on doing the river visual (https://aeronav.faa.gov/d-tpp/2008/00443RIVER_VIS19.PDF) with the AP (albeit in NAV mode). What's the point?

[Fursty Ferret]

Not that I want to weigh in, but I loathe the practice of changing autobrake settings on the landing roll. If PF does it, I think it's an example of extremely poor judgement and if they ask PM to do it they're forcing the non-handling pilot to look inside and move something unmonitored at a critical moment. On top of that it's not good for passenger comfort because there's a jerk from the brakes whether they're increasing or decreasing the force. 787 even has a deceleration indicator in the HUD to help you judge the braking.

If you're not capable of smoothly disconnecting the autobrake and modulating the brakes to an appropriate level manually then IMHO you shouldn't be flying a passenger aircraft. Or driving a car, frankly...

[Uplinker]

@ Vessbot and Check Airman, Ah OK.

However, if someone is not able to lay off drift to track something, and/or is overshooting a track, then how would making them hand-fly as well help the situation? Wouldn't that add even more inaccuracies?

[Check Airman]

I think you’re talking about the parkway (https://aeronav.faa.gov/d-tpp/2008/00610PARKWAY_VIS13LR.PDF) visual (aka Canarsie visual) to jfk. I’ve never seen anyone use the AP for that approach. Did you find it easier? What vertical mode did you use?

I think what Vessbot is talking about re HDG mode is the fact that the AP reacts way too slowly for the fine correction that’s needed to fly those approaches, so it actually increases workload.

[Uplinker]

Actually sorry, no I was briefed on it very comprehensively but never actually flew it - my bad :ugh:

I'll get my coat.........

[Check Airman]

Actually sorry, no I was briefed on it very comprehensively but never actually flew it - my bad :ugh:

I'll get my coat.........

No worries. It’s dirt simple and heaps of fun. Keep the road to your left, then follow the lights in. Have an eye on the PAPI (which is offset so you can see it in the turn).

[Chesty Morgan]

If you're not capable of smoothly disconnecting the autobrake and modulating the brakes to an appropriate level manually then IMHO you shouldn't be flying a passenger aircraft. Or driving a car, frankly...
To deride fellow professionals based on the assumption that they cannot do something because they choose one way of doing that something as and when it's suitable is laughable.

[student88]

I did it once or twice on the Airbus and found it mildly satisfying but I would advise against routinely using it as your go-to auto brake deselection method.

[giggitygiggity]

The Autobrake settings equate to pressures:
• Autobrake setting 1 - 1250 PSI equates to 4 ft per second squared.
• Autobrake setting 2 - 1500 PSI equates to 5 ft per second squared.
• Autobrake setting 3 - 2000 PSI equates to 7.2 ft per second squared.
• Autobrake setting MAX and RTO - 3000 PSI equates to 14 ft per second (above 80 knots) and 12 ft per second squared (below 80 knots).

If the autobrake is stopping you too quickly, then it's easy to as the PM to select a lower setting, or simply gently apply brakes until the disarm like comes on, at this point you will have the same pressure as the system, conversely if more stopping is required either select a higher setting or apply brakes gently and increase the pressure. The common mistakes are jolts from over ambitious disarming via the switch or stamping on the brakes.
Remember some landing conditions dictate the use of autobrakes so its not a personal choice
Its much safer usually to manually brake to make the required adjustments rather than have heads down in the cockpit,
Forgive me, but how can a brake pressure in PSI possibly equate to a specific deceleration rate? Wind, weight, touchdown speed... They're all going to affect that MASSIVELY. Surely the autobrake setting modulates brake pressure to give the desired deceleration rate upto the max brake pressure? I'm not saying it doesn't apply that specific pressure in PSI but there is no way that a pressure can remotely guarantee a deceleration rate - even on the worlds most perfect and dry runway.