The post's subject terminology may be Boeing-specific. If I'm not mistaken, Airbus has LO, MED, and MAX. Feel free to correct me if I'm wrong! Three questions for the front-office folks:

1) Do MAX and RTO apply the same amount of braking force? Does RTO brake harder?

My understanding is that when MAX is set for landing for whatever reason (RWY contamination, etc.), autobrake disengages upon manual braking input.

2) When you've had to engage MAX on landing , after touchdown, has that powerful braking been engaged for more than several seconds before you manually disengaged the autobrake? (a) If so, what did the deceleration feel like? Did you make a PA announcement afterwards? Beforehand? If so, what did you tell your pax?

3) For those of you whom have rejected a takeoff at >80/100kts and <V1: What mechanism automatically engages RTO/MAX braking? ..and of course, the (a) part of question 2 is something about which I'm also curious.

Only speaking for Boeing and specifically for the 757 / 767 although I believe this is the same across all of them


RTO brakes harder, it is maximum available braking, all the system can give you, if you pull the throttles to idle above 80 knots during take off (initiating a reject) the Autobrakes immediately apply this maximum braking with the anti skid as always preventing wheel lock



The RTO braking will remain engaged until the aircraft has come to a stop unless you disengage it, you can do this by applying manual brake pressure, turning off the Autobrake switch or moving the speedbrake lever forward



Max is a landing setting and it’s different in that it’s the maximum deceleration preprogrammed rate that can be selected, the Autobrakes attempt to give you this rate but it’s not maximum available braking like RTO



It can be turned off the same way, we were told not to use Max Autobrakes on a dry runway normally as the deceleration is impressive, however we did so once in a no slat landing in a 767 with an approach speed of 180 knots, they worked very well

Can't contribute to the Boeing side but MAX for Airbus is a takeoff only setting, so your questions are mostly Boeing related I gather.

On the A320, MAX braking in an RTO will slow you down pretty quick. Under 72kts the spoilers won't go up and the autobrakes won't engage, but manual braking in the 320 is fine for low speed rejects. Above that the spoilers come up and the brakes feel very aggressive. I've only rejected in the simulator in the 320 type. I've heard the brakes get quite hot, which makes sense because the A320 already has toasty brakes.
MAX, if it were a valid landing setting, would probably send stuff flying and a jumpseater into the windscreen, and then catch the brakes on fire. It's supposed to be MAX lol

On the B777 the aircraft aims for a specific deceleration, depending on the autobrake selector position.
Autobrake 1 is 4.0ft/sec² with a maximum brake pressure of 1385psi.
2 is 5.0 ft/sec² at max 1600psi
3 is 6.0ft/sec² at max 1850psi
4 is 7.5ft/sec² at max 2150psi
MAX AUTO is 11.0 at max 3100psi
RTO is all you can get at a maximum command pressure of 3100psi.
All settings except RTO have a 0.1sec delay after the ground signal is received.

The MD11 has 5 settings, OFF, T.O., MIN, MED and MAX.
MIN aims for 6.5ft/sec²
MED aims for 9.0ft/sec²
MAX and T.O. gives you all it can get at 3000psi

On the A320 the autobrake system kicks in as soon as the ground spoilers deploy. In LOW mode the brake pressure then gradually ramps up over the span of 3sec until it reaches 1.7m/sec² (5.6ft/sec²). MED mode aims for a deceleration of 2m/sec² (6.6ft/sec²) without delay when the ground spoilers deploy which is then increased to 3m/sec² (9.8ft/sec²) when the aircraft pitch is less than 1° or after 4 seconds.
MAX mode aims for 10m/sec² (32.8ft/sec²). This is more than the maximum possible deceleration of the aircraft so the system applies full pressure.

rjsampson wrote:

The post's subject terminology may be Boeing-specific. If I'm not mistaken, Airbus has LO, MED, and MAX. Feel free to correct me if I'm wrong! Three questions for the front-office folks:

1) Do MAX and RTO apply the same amount of braking force? Does RTO brake harder?

My understanding is that when MAX is set for landing for whatever reason (RWY contamination, etc.), autobrake disengages upon manual braking input.

2) When you've had to engage MAX on landing , after touchdown, has that powerful braking been engaged for more than several seconds before you manually disengaged the autobrake? (a) If so, what did the deceleration feel like? Did you make a PA announcement afterwards? Beforehand? If so, what did you tell your pax?

3) For those of you whom have rejected a takeoff at >80/100kts and <V1: What mechanism automatically engages RTO/MAX braking? ..and of course, the (a) part of question 2 is something about which I'm also curious.

Airbus follows:

1. There is no RTO setting on Airbus. MAX is used for takeoff only, never for landing. To emphasize this, the LO and MED buttons are adjacent, and there's a small gap to the MAX button. The A380 and A350 have BTV, MED and MAX instead of LO, MED, and MAX.

2. As mentioned, MAX is never used on landing. MED is rarely used in our case. It's quite "sharp".

3. Rejected takeoff: If wheel speed is higher than 72kt, ground spoilers extend automatically if thrust levers are set to idle. Extension of ground spoilers triggers automatic braking if MAX is armed (given nose gear compressed and wheel speed over 40kt).

(If ground spoilers are not armed, they will automatically extend if wheel speed is higher than 72kt, one reverse is selected on at least one engine.)

Note: 72kt for A330 and A350. This may vary for other Airbus types.

Starlionblue wrote:

rjsampson wrote:

The post's subject terminology may be Boeing-specific. If I'm not mistaken, Airbus has LO, MED, and MAX. Feel free to correct me if I'm wrong! Three questions for the front-office folks:

1) Do MAX and RTO apply the same amount of braking force? Does RTO brake harder?

My understanding is that when MAX is set for landing for whatever reason (RWY contamination, etc.), autobrake disengages upon manual braking input.

2) When you've had to engage MAX on landing , after touchdown, has that powerful braking been engaged for more than several seconds before you manually disengaged the autobrake? (a) If so, what did the deceleration feel like? Did you make a PA announcement afterwards? Beforehand? If so, what did you tell your pax?

3) For those of you whom have rejected a takeoff at >80/100kts and <V1: What mechanism automatically engages RTO/MAX braking? ..and of course, the (a) part of question 2 is something about which I'm also curious.

Airbus follows:

1. There is no RTO setting on Airbus. MAX is used for takeoff only, never for landing. To emphasize this, the LO and MED buttons are adjacent, and there's a small gap to the MAX button. The A380 and A350 have BTV, MED and MAX instead of LO, MED, and MAX.

2. As mentioned, MAX is never used on landing. MED is rarely used in our case. It's quite "sharp".

3. Rejected takeoff: If wheel speed is higher than 72kt, ground spoilers extend automatically if thrust levers are set to idle. Extension of ground spoilers triggers automatic braking if MAX is armed (given nose gear compressed and wheel speed over 40kt).

(If ground spoilers are not armed, they will automatically extend if wheel speed is higher than 72kt, one reverse is selected on at least one engine.)

Note: 72kt for A330 and A350. This may vary for other Airbus types.

The newer Airbus aircraft have an ''RTO' setting, too.
A350 via the 'A/BRK' button or A380 via the 'T.O.' button.

ReverseFlow wrote:

Starlionblue wrote:

rjsampson wrote:

The post's subject terminology may be Boeing-specific. If I'm not mistaken, Airbus has LO, MED, and MAX. Feel free to correct me if I'm wrong! Three questions for the front-office folks:

1) Do MAX and RTO apply the same amount of braking force? Does RTO brake harder?

My understanding is that when MAX is set for landing for whatever reason (RWY contamination, etc.), autobrake disengages upon manual braking input.

2) When you've had to engage MAX on landing , after touchdown, has that powerful braking been engaged for more than several seconds before you manually disengaged the autobrake? (a) If so, what did the deceleration feel like? Did you make a PA announcement afterwards? Beforehand? If so, what did you tell your pax?

3) For those of you whom have rejected a takeoff at >80/100kts and <V1: What mechanism automatically engages RTO/MAX braking? ..and of course, the (a) part of question 2 is something about which I'm also curious.

Airbus follows:

1. There is no RTO setting on Airbus. MAX is used for takeoff only, never for landing. To emphasize this, the LO and MED buttons are adjacent, and there's a small gap to the MAX button. The A380 and A350 have BTV, MED and MAX instead of LO, MED, and MAX.

2. As mentioned, MAX is never used on landing. MED is rarely used in our case. It's quite "sharp".

3. Rejected takeoff: If wheel speed is higher than 72kt, ground spoilers extend automatically if thrust levers are set to idle. Extension of ground spoilers triggers automatic braking if MAX is armed (given nose gear compressed and wheel speed over 40kt).

(If ground spoilers are not armed, they will automatically extend if wheel speed is higher than 72kt, one reverse is selected on at least one engine.)

Note: 72kt for A330 and A350. This may vary for other Airbus types.

The newer Airbus aircraft have an ''RTO' setting, too.
A350 via the 'A/BRK' button or A380 via the 'T.O.' button.

Oops. You're correct. The A350 and A380 have RTO instead of MAX.

Starlionblue wrote:

ReverseFlow wrote:

Starlionblue wrote:

Airbus follows:

1. There is no RTO setting on Airbus. MAX is used for takeoff only, never for landing. To emphasize this, the LO and MED buttons are adjacent, and there's a small gap to the MAX button. The A380 and A350 have BTV, MED and MAX instead of LO, MED, and MAX.

2. As mentioned, MAX is never used on landing. MED is rarely used in our case. It's quite "sharp".

3. Rejected takeoff: If wheel speed is higher than 72kt, ground spoilers extend automatically if thrust levers are set to idle. Extension of ground spoilers triggers automatic braking if MAX is armed (given nose gear compressed and wheel speed over 40kt).

(If ground spoilers are not armed, they will automatically extend if wheel speed is higher than 72kt, one reverse is selected on at least one engine.)

Note: 72kt for A330 and A350. This may vary for other Airbus types.

The newer Airbus aircraft have an ''RTO' setting, too.
A350 via the 'A/BRK' button or A380 via the 'T.O.' button.

Oops. You're correct. The A350 and A380 have RTO instead of MAX.

The A380 has got Disarm, BTV, LO, 2, 3 and HI on the mode selector and the RTO button is seperate.
A350 just the autobrake pushbutton with a knob selector for runway condition/braking action. This gives BTV, BTV contam and basic autobrake (med) and one RTO mode.

Starlionblue wrote:

2. As mentioned, MAX is never used on landing. MED is rarely used in our case. It's quite "sharp".

Dear SB,
I can confirm the "sharp" braking of MED autobrake on the A320. I once flew as a passenger on an OS A320, returning to Vienna RWY 29 on a late evening. The gate was on the north-east end of terminal T3, therefore the crew decided to reduce the landing roll (I got this info from the FO in a chat after the landing). We touched down, spoilers came up and almost simultaneously the brakes kicked in violently, reaching a level of deceleration rather uncommon in a normal pax flight. I read that MED yields 2,94m/s² on the A320. This feels quite thrilling, the seat belt restraining my body and my feet firmly on the cabin floor.

FO jokingly said that they sometimes need to peel Business Class pax off the flight deck door after such a landing...

Happy landings!
Hendric

Our A320 airline uses MED autobrake settings regularly landing on certain runways, like LGA, MSY, BUR, SNA. For BUR/SNA once the aircraft touches down, we override the auto brakes and apply manual braking along with max reverse. Since the auto brake targets a specific deceleration rate, any application of other deceleration aids (like reversers) means that the auto brake applies less braking.

So I can’t really say how “sharp” the decel rate is for MED, I can say that in BUR, the aircraft will come to a complete stop within 3000ft with manual braking and max reverse. Even though the landing distance calculations say that the landing distance is 4600-4800ft with MED autobrake.

One thing that is coming on our new delivery A320s is ROPS. It is one of the A350 safety enhancements that Airbus is backporting to the A320s/A330s. It alerts pilots that the landing runway is too short based on current environmental conditions and after touchdown continuously monitors the remaining runway distance available and warns that additional deceleration actions are required if the current deceleration is insufficient to stop on the remaining runway.

https://youtu.be/F5nw2Mt3I1I

A separate enhancement is Takeoff Surveillance, that will warn the flight crew that the runway selected for takeoff is too short at 3 separate points of the takeoff, (1) after engine start, (2) when TO CONFIG is checked, and (3) after application of takeoff thrust, based on current aircraft position and takeoff runway distance remaining.

That 3000’ stop sounds reasonable and correct with the 4600-4800’ landing distance. “Landing distance” is calculated crossing the threshold at 50’, touchdown at 6fps and prompt application of stopping devices. A flare distance of 1400-2000’ is in the ballpark—widebodies being on longer side.

A friend of mine did the RTO testing on the G7500, even on the overload test (5% over MGTOW) it was against the shoulder harnesses until stopped

I do warn the pax before landing in BUR/SNA that it’s not going to be a “smooth/greaser” landing.

It’s definitely get the wheels down firmly, FO says “SPOILERS”, I respond “MANUAL BRAKES” and override the MED auto brakes immediately by applying the brakes with the rudder pedals while simultaneously manipulating the thrust levers and sidestick to apply MAX reverse and derotate the nose so that the nosegear doesn’t slam onto the runway, FO responds “REVERSER GREEN, AUTOBRAKE OFF, DECEL” During the rollout, monitor the remaining runway and adjust the brake pressure off whether I’m happy with deceleration.

It’s not abrupt, I don’t think the pax are thrown against their seat belts or planting their faces in the seat back in front of them. It’s a smooth rapid deceleration in 3000ft with a turnoff the runway.

Woodreau wrote:

Our A320 airline uses MED autobrake settings regularly landing on certain runways, like LGA, MSY, BUR, SNA. For BUR/SNA once the aircraft touches down, we override the auto brakes and apply manual braking along with max reverse. Since the auto brake targets a specific deceleration rate, any application of other deceleration aids (like reversers) means that the auto brake applies less braking.

So I can’t really say how “sharp” the decel rate is for MED, I can say that in BUR, the aircraft will come to a complete stop within 3000ft with manual braking and max reverse. Even though the landing distance calculations say that the landing distance is 4600-4800ft with MED autobrake.

One thing that is coming on our new delivery A320s is ROPS. It is one of the A350 safety enhancements that Airbus is backporting to the A320s/A330s. It alerts pilots that the landing runway is too short based on current environmental conditions and after touchdown continuously monitors the remaining runway distance available and warns that additional deceleration actions are required if the current deceleration is insufficient to stop on the remaining runway.

https://youtu.be/F5nw2Mt3I1I

A separate enhancement is Takeoff Surveillance, that will warn the flight crew that the runway selected for takeoff is too short at 3 separate points of the takeoff, (1) after engine start, (2) when TO CONFIG is checked, and (3) after application of takeoff thrust, based on current aircraft position and takeoff runway distance remaining.

You'll love the ROW/ROP voice. It sounds like a very snooty British man with a monocle is standing behind you screaming. "RUNWAY TOO SHORT! MAX REVERSE!"

Good times.

@starlionblue. Does the brit voice sign off with, “And quite right too”?

DFW17L wrote:

@starlionblue. Does the brit voice sign off with, “And quite right too”?

Sadly not.

To be fair, he does get your attention.

Woodreau wrote:

I do warn the pax before landing in BUR/SNA that it’s not going to be a “smooth/greaser” landing.

It’s definitely get the wheels down firmly, FO says “SPOILERS”, I respond “MANUAL BRAKES” and override the MED auto brakes immediately by applying the brakes with the rudder pedals while simultaneously manipulating the thrust levers and sidestick to apply MAX reverse and derotate the nose so that the nosegear doesn’t slam onto the runway, FO responds “REVERSER GREEN, AUTOBRAKE OFF, DECEL” During the rollout, monitor the remaining runway and adjust the brake pressure off whether I’m happy with deceleration.

It’s not abrupt, I don’t think the pax are thrown against their seat belts or planting their faces in the seat back in front of them. It’s a smooth rapid deceleration in 3000ft with a turnoff the runway.

Out of interest why do you not just leave MED engaged until reverse is cancelled? It would make for less workload?

AndrewJM70 wrote:

Woodreau wrote:

I do warn the pax before landing in BUR/SNA that it’s not going to be a “smooth/greaser” landing.

It’s definitely get the wheels down firmly, FO says “SPOILERS”, I respond “MANUAL BRAKES” and override the MED auto brakes immediately by applying the brakes with the rudder pedals while simultaneously manipulating the thrust levers and sidestick to apply MAX reverse and derotate the nose so that the nosegear doesn’t slam onto the runway, FO responds “REVERSER GREEN, AUTOBRAKE OFF, DECEL” During the rollout, monitor the remaining runway and adjust the brake pressure off whether I’m happy with deceleration.

It’s not abrupt, I don’t think the pax are thrown against their seat belts or planting their faces in the seat back in front of them. It’s a smooth rapid deceleration in 3000ft with a turnoff the runway.

Out of interest why do you not just leave MED engaged until reverse is cancelled? It would make for less workload?

Runways at the aforementioned airports are short. I'm not sure if he's applying more brake pressure than what medium calls for.

It’s perfectly valid to do “nothing” and let MED autobrake do everything.

When we run the performance numbers for landing we get the runway landing distance for the various autobrake settings.

At the airports where we use MED autobrake normally, the performance numbers typically come back with the rough ballpark numbers: LOW - Not Authorized, MED - 4800ft and OFF - 3700ft. The landing distance calculation is based on no thrust reverser usage. You get a shorter landing distance applying manual braking than you do with MED autobrake.

I imagine the workload could be higher, I haven’t noticed the higher workload applying manual braking at touchdown.

So I guess it’s a control thing.

AndrewJM70 wrote:

Woodreau wrote:

I do warn the pax before landing in BUR/SNA that it’s not going to be a “smooth/greaser” landing.

It’s definitely get the wheels down firmly, FO says “SPOILERS”, I respond “MANUAL BRAKES” and override the MED auto brakes immediately by applying the brakes with the rudder pedals while simultaneously manipulating the thrust levers and sidestick to apply MAX reverse and derotate the nose so that the nosegear doesn’t slam onto the runway, FO responds “REVERSER GREEN, AUTOBRAKE OFF, DECEL” During the rollout, monitor the remaining runway and adjust the brake pressure off whether I’m happy with deceleration.

It’s not abrupt, I don’t think the pax are thrown against their seat belts or planting their faces in the seat back in front of them. It’s a smooth rapid deceleration in 3000ft with a turnoff the runway.

Out of interest why do you not just leave MED engaged until reverse is cancelled? It would make for less workload?

The autobrake doesn't know how far the turnoff you're aiming for is, or where exactly you touched down. It just gives you a set deceleration. Once you've slowed down a bit, you'll modulate the brakes manually to make your desired turnoff. This may mean braking harder or softer, or even releasing the brakes to coast.

BTV changes all that, of course.

Thanks very much for the answers. From my experience of flying in the Airbus as a passenger it is very good at stopping!

AndrewJM70 wrote:

Thanks very much for the answers. From my experience of flying in the Airbus as a passenger it is very good at stopping!

Most airliners are extremely good at stopping. We very rarely use anything even near the full braking capability.

I think the only thing that stops better would be an arrested landing using arresting gear.

Although bringing a 10000ton ship from 31kts to a stop in 1500ft/450m comes close.

Starlionblue wrote:

AndrewJM70 wrote:

Woodreau wrote:

I do warn the pax before landing in BUR/SNA that it’s not going to be a “smooth/greaser” landing.

It’s definitely get the wheels down firmly, FO says “SPOILERS”, I respond “MANUAL BRAKES” and override the MED auto brakes immediately by applying the brakes with the rudder pedals while simultaneously manipulating the thrust levers and sidestick to apply MAX reverse and derotate the nose so that the nosegear doesn’t slam onto the runway, FO responds “REVERSER GREEN, AUTOBRAKE OFF, DECEL” During the rollout, monitor the remaining runway and adjust the brake pressure off whether I’m happy with deceleration.

It’s not abrupt, I don’t think the pax are thrown against their seat belts or planting their faces in the seat back in front of them. It’s a smooth rapid deceleration in 3000ft with a turnoff the runway.

Out of interest why do you not just leave MED engaged until reverse is cancelled? It would make for less workload?

The autobrake doesn't know how far the turnoff you're aiming for is, or where exactly you touched down. It just gives you a set deceleration. Once you've slowed down a bit, you'll modulate the brakes manually to make your desired turnoff. This may mean braking harder or softer, or even releasing the brakes to coast.

BTV changes all that, of course.

The 777-9 has that same feature also that will brake to get to your selected turnoff. It’s called BTE - Brake to Exit. Just change one word from what Airbus calls it.

Interesting thread. How long is the landing roll distance of an A320/737 at max landing weight if you apply full autobrake and full thrust reversers? Not talking about the certification margins but the real distance?

Full auto brakes aren’t no maximum braking capacity, so you would need to look at using manual braking. Then, dry runways landing distances do not use full reverse. Performance engineering might have the charts or computer app that calculates stopping distance from touchdown. Crews have landing distance beginning at 50’ over the threshold, flare and stopping using full manual braking,

GalaxyFlyer wrote:

Full auto brakes aren’t no maximum braking capacity, so you would need to look at using manual braking. Then, dry runways landing distances do not use full reverse. Performance engineering might have the charts or computer app that calculates stopping distance from touchdown. Crews have landing distance beginning at 50’ over the threshold, flare and stopping using full manual braking,

Good information. So with that said, let's apply it to what TheSonntag said above --

How long is the landing roll distance of an A320/737 at max landing weight if you apply full MANUAL BREAKING and full thrust reversers? Not talking about the certification margins but the real distance?

*Distance beginning at 50' above the threshold.

Thanks!

AAPilot48Heavy wrote:

GalaxyFlyer wrote:

Full auto brakes aren’t no maximum braking capacity, so you would need to look at using manual braking. Then, dry runways landing distances do not use full reverse. Performance engineering might have the charts or computer app that calculates stopping distance from touchdown. Crews have landing distance beginning at 50’ over the threshold, flare and stopping using full manual braking,

Good information. So with that said, let's apply it to what TheSonntag said above --

How long is the landing roll distance of an A320/737 at max landing weight if you apply full MANUAL BREAKING and full thrust reversers? Not talking about the certification margins but the real distance?

*Distance beginning at 50' above the threshold.

Thanks!

For an A320 at MLW, dry runway, ISA conditions and sea level, with manual braking and reverse full, I get a landing distance of 3510ft. Actual, not factored.

Note that I don't know if the software calculates manual braking as "press as hard as you can" or some more modulated approach.

I assume reverse is calculated as full down to 70kt, then idle, as per SOP.

Starlionblue wrote:

AAPilot48Heavy wrote:

GalaxyFlyer wrote:

Full auto brakes aren’t no maximum braking capacity, so you would need to look at using manual braking. Then, dry runways landing distances do not use full reverse. Performance engineering might have the charts or computer app that calculates stopping distance from touchdown. Crews have landing distance beginning at 50’ over the threshold, flare and stopping using full manual braking,

Good information. So with that said, let's apply it to what TheSonntag said above --

How long is the landing roll distance of an A320/737 at max landing weight if you apply full MANUAL BREAKING and full thrust reversers? Not talking about the certification margins but the real distance?

*Distance beginning at 50' above the threshold.

Thanks!

For an A320 at MLW, dry runway, ISA conditions and sea level, with manual braking and reverse full, I get a landing distance of 3510ft. Actual, not factored.

Note that I don't know if the software calculates manual braking as "press as hard as you can" or some more modulated approach.

I assume reverse is calculated as full down to 70kt, then idle, as per SOP.

Thank you for the information. They can stop pretty quickly!

AAPilot48Heavy wrote:

Starlionblue wrote:

AAPilot48Heavy wrote:

Good information. So with that said, let's apply it to what TheSonntag said above --

How long is the landing roll distance of an A320/737 at max landing weight if you apply full MANUAL BREAKING and full thrust reversers? Not talking about the certification margins but the real distance?

*Distance beginning at 50' above the threshold.

Thanks!

For an A320 at MLW, dry runway, ISA conditions and sea level, with manual braking and reverse full, I get a landing distance of 3510ft. Actual, not factored.

Note that I don't know if the software calculates manual braking as "press as hard as you can" or some more modulated approach.

I assume reverse is calculated as full down to 70kt, then idle, as per SOP.

Thank you for the information. They can stop pretty quickly!

Indeed. As the great SlamClick once said, "Compared with a Seneca, the 737 is a STOL airplane."

For context, the same calculation as above for an A330-300 spits out 4199ft.



I saved the full post. Worth a read.

SlamClick From United States of America, joined Nov 2003, 9998 posts, RR: 78
Reply 15, posted Fri Feb 11 2005 10 11 2005 10:57:56 your local time (5 years 6 months 2 weeks 1 day 2 hours ago) and read 8235 times: Support Airliners.net - become a First Class Member!

One thing I remember from my early days as a light plane pilot was how much wrong information I had about airliners.

Partly it grew out of light plane experience, because light planes are terrible performers when compared with airliners.

Takeoff distance:

A 2000 lb. airplane might take 2000 feet of runway. So a 130,000 lb 737 should take 130,000' right? (almost 25 miles) No way. Landing is similar. So airliners have runway requirements that are only maybe five times that of a light single, but carry a hundred, two hundred, three hundred times the weight.

Compared with a Seneca, the 737 is a STOL airplane.

The brakes on light planes are weak, compared with airliners.

Now as to the original question (disregaring the "THOUSAND TONS" of fuel which is more than a 747 would hold if the filler cap was on top the tail) I think I can put some realistic numbers to it. Using actual weight and balance documents from the last time/place I flew the 737:

72000 lbs BOW of the heaviest 737-300 in the fleet sample I have.
10380 winter weight of 60 passengers
1410 bags of 60 pax at the 23.5 lbs per in use at the time
6400 lbs landing fuel includes alternate at 100 nm away and :45 IFR reserve fuel
90190 landing gross weight of my sample Boeing

For 90K landing weight at Flaps 40 I get VREF of 116 knots. That means stall speed of 89.2 knots. So if I want to do a STOL landing I think I can do the last 200' or so at 1.1 VSO or 98 knots approach speed.

Add to that, automatic ground spoilers that are going to kill the lift upon wheel spin-up, thrust reversers that no one has said I cannot use, and the mind-boggling multi-disc, multi-puck, anti-skid protected brakes and I'm beginning to think that the last thing I'd see before sliding to stop in a cloud of tire and brake smoke is my own paint job sliding off the nose of the airplane.

I have a brake energy chart at hand. It is a "web of death" grid chart with skewed lines and I don't want to blow my whole day staring at that but I believe that I could start at the end with ultimate energy absorbtion (roll the fire trucks) and at the beginning with my weight and solve to the middle to find my runway length required. That is not what these charts are for, but I think I could do it and give the actual feet of runway that would be used up. I just don't want to take the time but I'm pretty sure it will support my claim.

Also, as stated in reply #2, second line, it would require a precise approach and landing and would absolutely not be "normal." but I'd bet my life that I could get it stopped between the first brick and the last brick of a 2400' runway.

I landed a reasonably heavy C-5 (600,000 pounds, IIRC) at Ramstein (ETAR) and turned off at mid-field about 4,300’ from the threshold. We had a gear problem that precluded doing a 180 at the end, so it was mid-field or cause a large F-16 divert. Brakes on large planes are simply amazing.

The unfactored distance includes as far as I know also a firm touchdown which will also take quite some energy (more than one would think). Recently I did a bit of a firm touchdown (around 1.4 or 1.5g when I checked it later on) at my home base and at the point where we usually have around 70kts we were already down to taxi speed...but when those airplanes are light its really amazing. I once brought an empty A320 to Toulouse-Francazal for a some scheduled maintenance (landing gear replacement). The runway is around 1800m long but with Autobrake Medium we easily stopped before the half way point (i.e. less than 900m).

6 feet per second is the certification standard sink rate at touchdown

AAPilot48Heavy wrote:

...How long is the landing roll distance of an A320/737 at max landing weight if you apply full MANUAL BREAKING and full thrust reversers? Not talking about the certification margins but the real distance?

*Distance beginning at 50' above the threshold.

Thanks!

The answer depends on the weight and model and even elevation (i.e. true airspeed) to some degree, of course.

During 737 IOE, we were required to demonstrate a flaps 40 degree landing, a max auto-brake landing and an auto-land. Just as well do all three in the same landing.

I always warned the flight attendants about the high deceleration rate when landing with max auto-brakes. I'd then make a statement to the passengers, too, so that they wouldn't worry about the sharp breaking.

As for 737 RTO braking, it's surprising strong. Once, as a passenger, we experienced a rejected take off from about 100-110 knots (my best guess); some passengers screamed.

Velocirapture wrote:

AAPilot48Heavy wrote:

...How long is the landing roll distance of an A320/737 at max landing weight if you apply full MANUAL BREAKING and full thrust reversers? Not talking about the certification margins but the real distance?

*Distance beginning at 50' above the threshold.

Thanks!

The answer depends on the weight and model and even elevation (i.e. true airspeed) to some degree, of course.

During 737 IOE, we were required to demonstrate a flaps 40 degree landing, a max auto-brake landing and an auto-land. Just as well do all three in the same landing.

I always warned the flight attendants about the high deceleration rate when landing with max auto-brakes. I'd then make a statement to the passengers, too, so that they wouldn't worry about the sharp breaking.

As for 737 RTO braking, it's surprising strong. Once, as a passenger, we experienced a rejected take off from about 100-110 knots (my best guess); some passengers screamed.

RTO breaking on all Boeing models is incredibly strong. It’s an emergency stop. It’s a maximum 3000 lbs psi Hydraulic brake application. Except 787, which has electric brakes. I assume Airbus is the same.

Max Auto for landing is strong, but not as strong as maximum manual braking, nor RTO.

Starlionblue wrote:

AAPilot48Heavy wrote:

GalaxyFlyer wrote:

Full auto brakes aren’t no maximum braking capacity, so you would need to look at using manual braking. Then, dry runways landing distances do not use full reverse. Performance engineering might have the charts or computer app that calculates stopping distance from touchdown. Crews have landing distance beginning at 50’ over the threshold, flare and stopping using full manual braking,

Good information. So with that said, let's apply it to what TheSonntag said above --

How long is the landing roll distance of an A320/737 at max landing weight if you apply full MANUAL BREAKING and full thrust reversers? Not talking about the certification margins but the real distance?

*Distance beginning at 50' above the threshold.

Thanks!

For an A320 at MLW, dry runway, ISA conditions and sea level, with manual braking and reverse full, I get a landing distance of 3510ft. Actual, not factored.

Note that I don't know if the software calculates manual braking as "press as hard as you can" or some more modulated approach.

I assume reverse is calculated as full down to 70kt, then idle, as per SOP.

Does that landing distance start at the threshold (with the airplane at 50 ft)? If so, how much of that distance is after touchdown?

I've been on plenty of A320 flights that had a landing ground roll of under 4000 feet, and the braking didn't feel particularly sporty (granted, they likely weren't at MLW).

The most notable was a landing at LGB on runway 26R, which is very unusual (we got there very late at night, and I assume runway 30 was closed for some reason). Landed, and came to almost a complete stop, because we did a u-turn at the far displaced threshold. Somewhere around 3000 feet roll, if I remember correctly.

vikkyvik wrote:

Starlionblue wrote:

AAPilot48Heavy wrote:

Good information. So with that said, let's apply it to what TheSonntag said above --

How long is the landing roll distance of an A320/737 at max landing weight if you apply full MANUAL BREAKING and full thrust reversers? Not talking about the certification margins but the real distance?

*Distance beginning at 50' above the threshold.

Thanks!

For an A320 at MLW, dry runway, ISA conditions and sea level, with manual braking and reverse full, I get a landing distance of 3510ft. Actual, not factored.

Note that I don't know if the software calculates manual braking as "press as hard as you can" or some more modulated approach.

I assume reverse is calculated as full down to 70kt, then idle, as per SOP.

Does that landing distance start at the threshold (with the airplane at 50 ft)? If so, how much of that distance is after touchdown?

I've been on plenty of A320 flights that had a landing ground roll of under 4000 feet, and the braking didn't feel particularly sporty (granted, they likely weren't at MLW).

The most notable was a landing at LGB on runway 26R, which is very unusual (we got there very late at night, and I assume runway 30 was closed for some reason). Landed, and came to almost a complete stop, because we did a u-turn at the far displaced threshold. Somewhere around 3000 feet roll, if I remember correctly.

The landing distance is indeed calculated from the threshold. And since you're nominally at 50 feet at the threshold, the ground roll is shorter than the landing distance.

The nominal aimpoint is at 1000 feet, and your actual touchdown point is a couple of hundred feet beyond that since you flare. So in this example, you could, if you nail it, stop 3510 feet from the threshold, but the actual ground roll is probably something like 2300 feet.

vikkyvik wrote:

The most notable was a landing at LGB on runway 26R, which is very unusual (we got there very late at night, and I assume runway 30 was closed for some reason). Landed, and came to almost a complete stop, because we did a u-turn at the far displaced threshold. Somewhere around 3000 feet roll, if I remember correctly.

My guess is that RWY 30 was just fine. The fact that you were landing very late at night indicates to me that this was more about noise abatement. LGB inarguably has the strictest policies in the nation. Fines are just the beginning. LGB noise-abatement policy allows for, and they have been known to, engage in criminal prosecution of violators! (including 121 operators)

My guess you were flying a certain airline that has repeat violations, and may have been willing to cook the brakes rather than risk another.

Starlionblue wrote:

The landing distance is indeed calculated from the threshold. And since you're nominally at 50 feet at the threshold, the ground roll is shorter than the landing distance.

The nominal aimpoint is at 1000 feet, and your actual touchdown point is a couple of hundred feet beyond that since you flare. So in this example, you could, if you nail it, stop 3510 feet from the threshold, but the actual ground roll is probably something like 2300 feet.

Thanks, that makes a bit more sense to me. I'm not surprised that it can stop in that distance.

What is the approach speed used for that calculation?

rjsampson wrote:

My guess is that RWY 30 was just fine. The fact that you were landing very late at night indicates to me that this was more about noise abatement. LGB inarguably has the strictest policies in the nation.

I'm aware, but I thought the noise abatement and curfew policies were for the airport in general, rather than any specific runway. Final approach to 26R is over residential areas, same as 30.

And yes, your guess on airline is correct.

vikkyvik wrote:

rjsampson wrote:

My guess is that RWY 30 was just fine. The fact that you were landing very late at night indicates to me that this was more about noise abatement. LGB inarguably has the strictest policies in the nation.

I'm aware, but I thought the noise abatement and curfew policies were for the airport in general, rather than any specific runway. Final approach to 26R is over residential areas, same as 30.

And yes, your guess on airline is correct.

Indeed noise abatement/curfew does apply to the entire airport. I've heard from pilots of said airline that there are FAR fewer noise monitors (microphones) on the other approaches that'll rat them out. While technically 12/30 is the only "active runway" after hours -- probably to catch violators -- I've heard that ATC will accommodate requests for other runways.

EDIT: I verified that those pilots were correct regarding the number of monitors: A total of 12 microphones on 12/30, and only 3 for the other runways.

https://www.longbeach.gov/lgb/resources/noise-abatement/. So I guess cooking the brakes > potential prosecution.

vikkyvik wrote:

Starlionblue wrote:

The landing distance is indeed calculated from the threshold. And since you're nominally at 50 feet at the threshold, the ground roll is shorter than the landing distance.

The nominal aimpoint is at 1000 feet, and your actual touchdown point is a couple of hundred feet beyond that since you flare. So in this example, you could, if you nail it, stop 3510 feet from the threshold, but the actual ground roll is probably something like 2300 feet.

Thanks, that makes a bit more sense to me. I'm not surprised that it can stop in that distance.

What is the approach speed used for that calculation?

To be clear, the VAPP isn't an input. It's an output that the app spits out.

For the A320, VAPP is 141kt and landing distance is 3510 feet.

For the A330-300, VAPP is 143kt and landing distance is 4199 feet.

To recap, this is sea level, nil wind, ISA conditions, max landing weight, manual breaking and reverse full, with distances calculated from the threshold which you pass at 50 feet.

I used to be a max reverse minimum brakes kind of guy. A few times I could land and taxi to the gate without the brake temps exceeding 50c.

the pilots got an operations bulletin saying brake temps after landing were not high enough causing excessive brake wear and early brake replacements.

So now I’m a idle reverse and let the brakes do all of the work to get them nice and toasty after landing. It’s quieter that way anyways.

rjsampson wrote:

Indeed noise abatement/curfew does apply to the entire airport. I've heard from pilots of said airline that there are FAR fewer noise monitors (microphones) on the other approaches that'll rat them out. While technically 12/30 is the only "active runway" after hours -- probably to catch violators -- I've heard that ATC will accommodate requests for other runways.

EDIT: I verified that those pilots were correct regarding the number of monitors: A total of 12 microphones on 12/30, and only 3 for the other runways.

Interesting, thanks.

Starlionblue wrote:

To be clear, the VAPP isn't an input. It's an output that the app spits out.

I know, that's what I meant. What Vapp is calculated.

141 kts and 143 kts seem quite reasonable for a MLW landing. Surprised they are so low!

Presumably these are Flaps Full (or Config Full or whatever it's called) as well.

Not to go too far off topic, but since we had discussed LGB's draconian noise abatement policy, something didn't make sense. I took another look at it on the link I posted:

Departure
Attain as much altitude as possible before reaching residential areas. Use full length of runway when able.

I don't understand. Why would a pilot "use full length of runway when able" [that's one heck of a derate!] if trying to "attain as much altitude as possible before reaching residential areas."

Wouldn't a crew want to get off the runway quickly? I would think this would be a better practice to attain a much higher altitude over residential areas.

Am I missing something?

rjsampson wrote:

Not to go too far off topic, but since we had discussed LGB's draconian noise abatement policy, something didn't make sense. I took another look at it on the link I posted:

Departure
Attain as much altitude as possible before reaching residential areas. Use full length of runway when able.

I don't understand. Why would a pilot "use full length of runway when able" [that's one heck of a derate!] if trying to "attain as much altitude as possible before reaching residential areas."

Wouldn't a crew want to get off the runway quickly? I would think this would be a better practice to attain a much higher altitude over residential areas.

Am I missing something?

It comes down to your complete climb profile.

- More flap gives shorter ground roll and lower initial climb speed, but higher initial climb gradient.
- Less flap gives longer ground roll and higher initial climb speed, with lower initial climb gradient BUT higher second segment climb gradient.

If the residential areas are not quite at the end of the runway, but a few miles away, the second option works best as you'll be higher when you reach them.

NADP2 would presumably also be used.

vikkyvik wrote:

rjsampson wrote:

Indeed noise abatement/curfew does apply to the entire airport. I've heard from pilots of said airline that there are FAR fewer noise monitors (microphones) on the other approaches that'll rat them out. While technically 12/30 is the only "active runway" after hours -- probably to catch violators -- I've heard that ATC will accommodate requests for other runways.

EDIT: I verified that those pilots were correct regarding the number of monitors: A total of 12 microphones on 12/30, and only 3 for the other runways.

Interesting, thanks.

Starlionblue wrote:

To be clear, the VAPP isn't an input. It's an output that the app spits out.

I know, that's what I meant. What Vapp is calculated.

141 kts and 143 kts seem quite reasonable for a MLW landing. Surprised they are so low!

Presumably these are Flaps Full (or Config Full or whatever it's called) as well.

Config full indeed.

If you are very overweight you might end up needing Config 3 due to go-around gradient requirements, but otherwise config fill is standard.

rjsampson wrote:

Departure
Attain as much altitude as possible before reaching residential areas. Use full length of runway when able.

rjsampson, the interpretation I get from the specified procedure is twofold:

First, "use full length of runway when able," implies a reduced thrust (flex) takeoff thrust setting to minimize the noise footprint around the airport (i.e., lowest possible thrust setting allowed to satisfy all takeoff performance criteria), and

Second, "attain as much altitude as possible . . ." i.e., climb using the NADP1 (Close-in community noise abatement departure procedure). At my operator, this would be to reduce thrust from FLEX/MCT to CLB (Airbus A-320 series) at 1,000 feet above field elevation; maintain V2 + 10 until reaching 3,000 feet AFE; then lower the nose, accelerate, and retract the flaps on schedule. In conjunction with the first parameter--using reduced thrust for takeoff and maintaining that thrust during the climb--this seems to be a logical solution to reducing noise around the airport and it would comply with all aircraft and company operating procedures.

I agree at first glance the procedure recommended by the Long Beach airport authority seems unusual and perhaps contradictory. But if you think about it, it is perhaps their best, or most optimum, attempt to peacefully co-exist with residential areas in a noise sensitive environment.

I think it makes sense.

e38

rjsampson wrote:

Departure
Attain as much altitude as possible before reaching residential areas. Use full length of runway when able.

I don't understand. Why would a pilot "use full length of runway when able" [that's one heck of a derate!] if trying to "attain as much altitude as possible before reaching residential areas."

Wouldn't a crew want to get off the runway quickly? I would think this would be a better practice to attain a much higher altitude over residential areas.

Am I missing something?

In addition to what others posted, "full length" also refers to starting at the very ending of the runway, as opposed to an intersection departure. If their goal is to have people as high up as possible, you want to start your ground roll as far back as possible. If they have long runways where people would normally do intersection departures to save time, they might want to discourage that.

LH707330 wrote:

rjsampson wrote:

Departure
Attain as much altitude as possible before reaching residential areas. Use full length of runway when able.

I don't understand. Why would a pilot "use full length of runway when able" [that's one heck of a derate!] if trying to "attain as much altitude as possible before reaching residential areas."

Wouldn't a crew want to get off the runway quickly? I would think this would be a better practice to attain a much higher altitude over residential areas.

Am I missing something?

In addition to what others posted, "full length" also refers to starting at the very ending of the runway, as opposed to an intersection departure. If their goal is to have people as high up as possible, you want to start your ground roll as far back as possible. If they have long runways where people would normally do intersection departures to save time, they might want to discourage that.

That is my interpretation of that clause. Don't do intersection departures.

I don't think I've ever seen one done at LGB anyway, at least not by an airliner.

Starlionblue wrote:

It comes down to your complete climb profile.

- More flap gives shorter ground roll and lower initial climb speed, but higher initial climb gradient.
- Less flap gives longer ground roll and higher initial climb speed, with lower initial climb gradient BUT higher second segment climb gradient.

If the residential areas are not quite at the end of the runway, but a few miles away, the second option works best as you'll be higher when you reach them.

NADP2 would presumably also be used.

Makes perfect sense Arch, and thank you (as always) for an outstanding explanation/visualization. I did a screen grab of LGB and its proximity to residential areas [extremely close], so based on the image below, it strikes me that NADP1 would the right profile and with either 8,000' or 8,650' of useable RWY available. Even with FLEX thrust at MTOW, this is enough for narrow bodies (right?). I do wonder when that noise abatement document was written. Given that modern turbofans have negligible noise difference on the ground between FLEX/derate and higher thrust settings, perhaps it was developed back when Maddogs and the like were ubiquitous?

e38 wrote:

I agree at first glance the procedure recommended by the Long Beach airport authority seems unusual and perhaps contradictory. But if you think about it, it is perhaps their best, or most optimum, attempt to peacefully co-exist with residential areas in a noise sensitive environment.

I think it makes sense.
e38

Indeed it does, e38.

LH707330 wrote:

In addition to what others posted, "full length" also refers to starting at the very ending of the runway, as opposed to an intersection departure. If their goal is to have people as high up as possible, you want to start your ground roll as far back as possible. If they have long runways where people would normally do intersection departures to save time, they might want to discourage that.

Yeah LH, I hadn't thought of that. I think you hit the nail on the head as LGB's primary runway is 10,000' with 1,350 and 2,000 displaced thresholds. I'm guessing this would almost always be NADP1. Here's what it looks like:



Of course, these are my assumptions. If anyone wants to chime in, please do!

Just looking at that, NADP1 would probably be used.

Typically something like thrust reduction 1500ft, acceleration (and flap retraction) 3000ft.

So far the only Boeing I've flown is the 737, so I'll be speaking from that perspective. The 737 has 4 autobrake settings for landing (1, 2, 3 and MAX), plus RTO. The landing settings all aim for a fixed rate of deceleration and the amount of braking will be affected by the use of speedbrakes and reverse thrust in order to maintain the chosen deceleration rate. On a dry runway MAX autobrake will provide slightly less effort than what is possible with max manual braking, but on wet or slippery runways the anti-skid system renders this small difference moot. All modes will bring the airplane to a full stop unless disengaged by the pilot.

RTO mode is different: If a takeoff is rejected above 90 kts and the autobrake is armed (in RTO mode), max available braking will be applied without regard to speedbrake or thrust reverser usage. Like the landing modes, RTO mode will bring the airplane to a full stop unless disengaged by the pilot and at my company it is standard procedure to allow the autobrake to stop the airplane during an RTO.

MAX landing mode is quite abrupt and we generally use it only for slippery runways during the winter. The selector switch even has a detent which requires you to pull out the switch before rotating it all the way to MAX, presumably to help prevent crews from selecting MAX inadvertently.