Questions tagged [braking]

Questions about usage of mechanical brakes on the wheels for slowing down.

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Why is it necessary to set the parking brake on for the walkaround on an A320?

Our Airbus A320 FCOM prescribes that the PM sets the PARK BRK ON before the walkaround. Simple question: why?
Ulu83's user avatar
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13 votes
5 answers
6k views

For large commercial jets is it possible to land and slow sufficiently to leave the runway without using reverse thrust or brakes

I have long wondered whether its possible (in theory at least) for jetliners under typical loading scenarios (pax and cargo), landing at a normal airport such as LHR to come to a slow enough speed to ...
robbie70's user avatar
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1 vote
1 answer
21 views

What do "NAC Dynamic" and "ASFT" mean according to the image in the LTAF AIP document?

What do "NAC Dynamic" and "ASFT" mean according to the image in the LTAF AIP document? I found out that ASFT stands for "Airport Surface Friction Tester" but I don't know ...
pilot162's user avatar
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20 votes
3 answers
7k views

Is Aeroflot flying airliners without brakes?

I have just read the news that the Russian flag carrier Aeroflot has deactivated the brakes on nine of its aircraft. Not to dismiss the journalistic talent behind these reports, but could it be that ...
Quora Feans's user avatar
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5 votes
2 answers
686 views

If a jetliner is giving TOGA thrust but never releases the (parking) brake, will the brakes heat up?

From my - admittedly - limited knowledge of physics, the energy generated from the engines needs to go somewhere; will it go into the brakes or does it just dissipate into the air?
Nico's user avatar
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2 votes
1 answer
441 views

How many master cylinders are there in a typical dual brakes Cessna 172?

After searching in the AFMs of the several C172 my flight school operates, all of them describe the system very basically with no diagrams, as exemplified in the following picture: Is there one ...
rosaqq's user avatar
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6 votes
1 answer
721 views

Why are the brake temperatures so high during the cruise?

While monitoring the A320 aircraft systems during cruise I noticed that brake temperatures are relatively high compared to the OAT. I have seen brake temperature indications range between 20°C and 120°...
user38116's user avatar
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9 votes
2 answers
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How much momentum is lost through the wheels when landing?

I am idly curious whether any significant proportion of a landing plane's momentum is lost through wheel braking vs. everything else like thrust reversers, aero drag, etc? If I have to pick a plane, ...
Azor Ahai -him-'s user avatar
0 votes
1 answer
257 views

Which speed should we look for recommended brake cooling in case of rejected takeoff?

Which speed should we look for recommended brake cooling in case of rejected takeoff? (Airspeed or groundspeed)
Arcil Tralleis's user avatar
19 votes
4 answers
3k views

What ground speed reference is used for anti skid control?

I was reading about slip ratio controlled anti skid system and had this one particular question in my mind. In addition to the wheel speed data, slip ratio controlled systems need a ground speed ...
ASV's user avatar
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26 votes
6 answers
6k views

Do airplanes really expose their internal wires and electronics like this on the wings when braking?

While watching a video today about airplanes and how they have little thingies on their wings to make them come to a stop much quicker than otherwise, I noticed something very odd: Are those cables ...
C. Oesterle's user avatar
17 votes
4 answers
6k views

What causes a Cessna 172 and its gear to shake violently after landing and braking?

I am sure this was due to my own ignorance on proper technique, but immediately after landing in a Cessna 172, I applied brakes and some moderate aerodynamic braking and experienced an awful and ...
Ryan Griffith's user avatar
23 votes
2 answers
6k views

Is this aerodynamic braking procedure normal in a 747?

I found this instagram video via YouTube: The description in the YouTube video states that: This aerodynamic baking procedure is applied to reduce wheel brake and engine wear I have two questions: ...
nodapic's user avatar
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4 votes
1 answer
277 views

Is there a name for the fast decline + pull to climb pattern?

I'm a hobby photographer and I've noticed some patterns in the bird flights, so I tried to poke a bit into the aviation terminology for it. Phalacrocorax carbo does this movement similar to the ...
Peter Badida's user avatar
7 votes
2 answers
2k views

How does an inoperative Anti-Skid affect V speeds?

I am trying to figure out why is it that when you have an inoperative anti-skid system, the calculated V Speeds are lower? I'm trying to see this from a performance perspective, could this be due to ...
shogunnyan's user avatar
2 votes
3 answers
718 views

Are there any GA trainer aircraft without toe brakes?

I'm a student pilot, and I've built about 20 hours on a Cessna 172. I also have an old ankle injury that makes it hard to bend my left ankle, and I'll probably be getting an ankle fusion later this ...
Chris's user avatar
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8 votes
1 answer
2k views

What's the difference between multiple disc brake and segmented rotor brakes?

Going through FAA's aircraft maintenance manual I came across a topic under braking systems, which had two different types of brakes: multiple discs and segmented rotor disc brakes Looking at the ...
Salmonbeing00's user avatar
9 votes
2 answers
2k views

Could an airliner abort a landing after using the brakes system while landing?

Everyone knows that doing a go-around is a normal procedure, although the go-around happens usually before applying the brakes system (spoilers, ground/air brakes, and/or thrust reversers), but, could ...
JuanP. Zuniga's user avatar
1 vote
3 answers
252 views

Can water-cooled brakes be used for takeoff aborts?

Airliner engines are sized to continue the takeoff if one engine fails after it has become too late to brake. This means that the oversized engine has to be lugged around the whole flight, increasing ...
Abdullah is not an Amalekite's user avatar
1 vote
1 answer
547 views

Why does the DC-9's antiskid system have to be manually disarmed during landing rollout following a ground-shift-mechanism malfunction on takeoff?

An aircraft's ground-shift mechanism (usually a sensor wired to the nosegear strut that looks to see whether the strut is compressed or not) tells the aircraft whether it's on the ground or in the air....
Vikki's user avatar
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5 votes
1 answer
248 views

Why use thrust reversers? [duplicate]

I see a lot of planes using thrust reversers and stopping in the middle of the runway in plane spotting videos, but I don't understand why they do it when they can obviously not use the reversers and ...
Air Canada 001's user avatar
2 votes
1 answer
448 views

How does keeping the parking brake applied when brake temperatures are high contribute to the dragging brake phenomenon?

While going through a presentation on the Airbus WIN application with regard to cost saving practises. It was told with regard to brake life. If the parking brake was applied when the brake ...
Jai's user avatar
  • 1,492
0 votes
2 answers
4k views

Why does the A320 have an anti skid system and how does it work? [duplicate]

Can somebody explain why do A320 aircraft have an anti skid system? What is its purpose? And a brief explanation on how it works.
Johnson's user avatar
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2 votes
3 answers
461 views

If the pilots used the brakes upon landing, would the force essentially slam the front wheel down?

So if the pilots braked immediately, with only the back wheels down, and nose wheel still up, would the force from braking cause the front wheel to come slamming down?
George Clooney In a Mooney's user avatar
15 votes
4 answers
6k views

Why does the Eurofighter Typhoon pitch up on brake release?

In the video here of an airshow take-off, it's noticeable that when the brakes are released there's a brief but pronounced fluctuation in pitch as the aircraft accelerates. This is something you see ...
Party Ark's user avatar
  • 13k
17 votes
2 answers
3k views

What is the "Brake to Exit" feature on the Boeing 777X?

I have come across a new feature called BTE (Brake to Exit) on the 777X, but I am unable to find any documentation related to that. There are vendors who are working on this technology for the 777X.
NitinG's user avatar
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8 votes
2 answers
3k views

What powers the air required for pneumatic brakes in aircraft?

What powers the air required for pneumatic brakes in large airliner aircraft? Is it bled from the engines, or do they have a separate motor and pump?
securitydude5's user avatar
10 votes
2 answers
2k views

How far would a landing Airbus A380 go until it stops with no brakes?

If an Airbus A380 lands with all brakes disbled, including reverse thrust, wheel brakes and any other measures it has to stop or slow down. Then how long would it take it to reach a complete stop.
Faros Lamiani's user avatar
4 votes
1 answer
439 views

How should ground crews act to safely extinguish an airliner's brake unit fire?

When the brake unit was overheated and had just begun to catch fire due to excessive braking because of long taxi distance upon arrival, the ground personnel (not firefighters) made the first ...
GolfCharlie's user avatar
28 votes
4 answers
8k views

Why are thrust reversers not used to slow down to taxi speeds?

In reading this question (Would more throttle when using reverse thrust reduce stopping distance?), it prompted me to remember that on many of my flights (typically on 737s or CRJ type aircraft), it ...
Milwrdfan's user avatar
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-1 votes
2 answers
971 views

How are aircraft brakes applied? [duplicate]

I read somewhere that when both rudder paddles are pushed simultaneously it produces a braking effect. Is this true? If yes, please provide a detailed description of the above mentioned system.
Het's user avatar
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6 votes
2 answers
10k views

What's the difference between setting auto brakes to MAX vs. RTO in Boeing Aircraft?

On Airbus aircraft, before taxiing and before take off, pilots turn auto brakes to MAX. But on Boeing aircraft, they will set auto brakes to RTO. Why does Boeing not use auto brakes MAX instead of ...
user avatar
9 votes
1 answer
2k views

Why does the flight controls check come before arming the autobrake on the A320?

As per SOP on the A320 we first perform the flight controls check and then arm the autobrake to max. What is the reason behind this?
Jai's user avatar
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1 vote
1 answer
209 views

What are the three sources that are relayed to the brakes and steering control unit of an A320?

There is the sentence: Electrical signals from the three sources are relayed to the brakes and steering control unit (BSCU) and are computed into the nose steering angle. The question: What are ...
Victor Chernobay's user avatar
5 votes
2 answers
2k views

Why don't nose landing gears have brakes?

Nose brakes can help the aircraft in braking and it can also help in reducing the travel on the runway length. So why don't we use brakes in the nose landing gear?
Sakshi Shrivastava's user avatar
1 vote
1 answer
373 views

Do any aircraft have liquid-cooled brakes?

Aircraft wheelbrakes, especially those on heavy aircraft, get really, really hot during landings and rejected takeoffs, and cool down very, very slowly without active cooling. This imposes limits on ...
Vikki's user avatar
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2 votes
2 answers
760 views

Why don't commercial aircraft have drag chutes for aborted takeoffs? [duplicate]

We were watching the program Air Crash Investigation and there was an episode where it was too late to abort the take-off and the pilots had to attempt to climb still but since an abort was not ...
Hanky Panky's user avatar
  • 6,011
1 vote
2 answers
208 views

What is the 'fuel cost' of a pneumatic braking system vs. a hydraulic one, in terms of weight?

A pneumatic braking system has indisputable advantages over a hydraulic braking system for large and heavy aircraft in terms of braking force and secondary perhaps in terms of weight (pipes and ...
securitydude5's user avatar
12 votes
1 answer
877 views

Why is braking action (with Anti-Skid) best when the wheel rotates at ~85% of the actual speed?

During my ATPL training the subject of tires and braking was discussed. I understand the principle of the anti-skid and also the differences between aircraft and similar systems in cars. Physics also ...
Julian Bernhuber's user avatar
2 votes
2 answers
2k views

What happens if an A320 goes to full throttle with the parking brake set? [duplicate]

The question is simple: what happens? Is the aircraft going to stay stationary, or will the engine power overcome the brakes? I'm assuming everything is fully functional. I know the FCOM says not ...
Maverick283's user avatar
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12 votes
2 answers
3k views

Is aerodynamic braking really effective?

(YouTube) In the frame above the pilot is pulling back, as evident by the stabilator's position, and this technique is usually cited as a means of slowing down. But wouldn't the brakes have better ...
user avatar
2 votes
1 answer
213 views

How can I reduce the responsivness of my homebrew brake system?

I have a hydraulically actuated aircraft brake system. Each main landing gear are equipped with brake disk hydraulically operated. The actuation is realized independently for each wheels by means of ...
Rahmat Ali Akbar's user avatar
5 votes
3 answers
684 views

Do large Airliners use full thrust when reversers are deployed?

Do large and heavy Airliners, Jumbos and Super Jumbos wide bodies included use full thrust for braking when reversers are deployed? What is the thrust setting?
securitydude5's user avatar
4 votes
2 answers
609 views

Engines more powerful than the brakes?

This might be more of an anecdotal question, but are there any aircraft where under full throttle (with afterburner in worst-case) where the wheels wouldn't provide enough friction against the runway ...
Milwrdfan's user avatar
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3 votes
2 answers
884 views

Why is V1 based only on using brakes?

V1 is the speed that an aircraft may abort a takeoff so long as the airspeed is below it, or is committed to flight if it is over that speed. V1 calculations are based only on the brakes (not sure ...
jwzumwalt's user avatar
  • 11.5k
11 votes
3 answers
5k views

Why are parking brakes not used for parking jetliners?

From the question 'Do I Set the Parking Brake On the Ramp?' it is concluded that you do not set the parking brake when parking the aircraft. The question concerns small aircraft which can be parked ...
Brilsmurfffje's user avatar
3 votes
1 answer
323 views

What guidance is there for pilots when reporting braking action?

I was listening to "[REAL ATC] Eastern B737 (candidate Mike Pence) OFF RUNWAY at LaGuardia!"(1) and the LGA Tower asks for and receives reports of braking action from several landing pilots. I assume ...
CGCampbell's user avatar
  • 11.1k
24 votes
6 answers
5k views

Would increasing the number of wheels of a Jumbo reduce the braking distance?

If weight was not an issue, would increasing the number of main gear wheels on a jumbo such as the Airbus A380 from 20 to 40 wheels, each equipped with braking disks and braking equipment, considering ...
securitydude5's user avatar
13 votes
3 answers
3k views

Why aren't there brake lights on aircraft?

Why don't aircraft have brake lights so you can see when an aircraft in front is slowing down? I know there are air traffic controllers to control aircraft but they cannot do much about an aircraft's ...
Harry Cameron's user avatar
8 votes
1 answer
2k views

Does the 747-8 / A380 nose-wheel encounter more weight during braking?

Given that the nose wheels of both the Boeing 747-8 and Airbus A380, as is true for almost all aircraft, are not equipped with brakes, do they encounter more weight during braking? If so, how much ...
securitydude5's user avatar