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  • 43

Airplane Tires Don’t Explode on Landing Because They Are Pumped!

Soumis
 
ONE THING YOU almost never see when an airplane lands is a blowout. Think about that: Again and again, the tires hit tarmac at 170 miles per hour and bear the weight of a modest office building. And they nail it. Every time. (www.wired.com) Plus d'info...

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awsauerman
Albert Sauerman 10
As a Former Aircraft Mechanic on the C5A/B, C-130 & B-52 I find Mr Hartmann Esq. opening inquiry as to why a gentleman is a former pilot to be inappropriate and not in line with the thread. I am curious as to the type of aircraft he owns since he is asking such "personal" questions. I for one do not own or fly any aircraft and am not a pilot. But as an aircraft mechanic I always found interest in this site and try to insert my opinion on something that I am sure I know and understand.
AABABY
AABABY 4
Albert-- Mr. Hartmann Esq. is a Lawyer. Don't try to argue with a lawyer. It's pointless.
akayemm
Er.A.K. Mittal 2
Dear Mr. AABABY, please don't brush every lawyer in the same colour.
Like other sections of society every group has its own share of variety of people, and lawyers are no exception.
Regards
davidrbarnes
David Barnes 3
Mr. Mittal:
I straddle the fence on this one (and I say this as the son and grandson of a lawyer). Don't try to argue with a lawyer. It's pointless...BECAUSE THEY ENJOY IT TOO MUCH.
Most take it in good humour and enjoy the resultant intellectual sparring. Some, however, take any "arguing" as a personal affront.
Just my opinion.
akayemm
Er.A.K. Mittal 2
Mr. Barnes , in ur last sentence U hit the nail on the head , like sledge hammer ..
So ur opinion almost overlaps the international kind
;-p

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AABABY
AABABY 5
Mr Hartmann.Esq: I red the article and have seen your critical posts to several other members of FlightAware. You impress me as a frustrated litigator that has no pressing work at your office. So why don't you just sit back, relax and go someplace else?
AABABY
AABABY 4
That should read as READ the article. Keyboard hang up.
Nonetheless, Go away!
akayemm
Er.A.K. Mittal 2
Dear friend Mr. Sauerman , every one knows engineers make aircrafts and lay down guide lines for flying as compatible with machine. The authorities make rules and regulations as compatible with society.
And pilots fly them within these two sets of parameters.
Hence IMHO , this portal is as much relevant for engineers as for pilots.
Each one gains from the other.
Regards

[This poster has been suspended.]

wingbolt
wingbolt 6
So a bus half full of attorneys go off a cliff.....
akayemm
Er.A.K. Mittal 5
or may be full of attorneys ! :-p
he ... he ...
lynx318
lynx318 2
Don't forget to load some on the baggage roof rack!
akayemm
Er.A.K. Mittal 3
Dear friend lynx318 , inspite of being a lawyer currently, I enjoy these jokes immensely!
ha .. ha ...
lynx318
lynx318 2
Something I observed in my youth in High School, no matter what class you're in there is always one clown to spoil it. Mr Hartmann has a big red nose & long floppy shoes.
wingbolt
wingbolt 2
Thanks for your sense oh humor...I don't want you to think it was directed towards you.
awsauerman
I don't need to be forgiven for anything. Yes I am military, served 20 years for my country, and you? The last 5 was with the 101st as a Flight Operations Chief covering 18 helicopters, 36 aviators etc. I was a Federally Certified Aircraft Mechanic which is the same in the mechanics circle as a pilots license. Got my certification by completing 800 hours at A&M. We insured the planes that flew were safe. Now to the item at hand. Several FAA items were issued regarding tire usage and pressures. Part 25 of the Federal Aviation Regulations (FAR) (14 CFR Part 25 as changed reads For an airplane with a maximum certificated takeoff weight of more than 75,000 pounds, tires mounted on braked wheels must be inflated with dry nitrogen or other gases shown to be inert so that the gas mixture in the tire does not contain oxygen in excess of 5 percent by volume, unless it can be shown that the tire liner material will not produce a volatile gas when heated or that means are provided to prevent tire temperatures from reaching unsafe levels.
If you read the FAA rulings generally about the aircraft you are flying/servicing you normally won't go wrong. The internet is a great place to find the answers.
joelwiley
joel wiley 6
I doubt I am alone here in saying "thank you for your service" Mr. Sauerman.
sandylns
Brian Lager 5
The original reason for nitrogen in aircraft tires was to preclude a source of oxygen/air in the case of a wheel well fire.

In the mid sixties, early seventies there were a number of aircraft losses due to the aforementioned fires in the wheel well. Nitrogen was chosen because it doesn't support combustion. There are other advantages as well. Nitrogen is essentially dry with no water content. The same cannot be said for air. Even using a dryer attached to a compressor, there will always be some moisture present. Nitrogen also doesn't interact with rubber compounds and doesn't promote corrosion in the metal components of a wheel. It can also support the high temperatures developed on landing. Although in my experience blowouts do occur on landing but fairly rarely.

In commercial aviation each tire is checked daily for wear and inflation. Usually on the overnight stop but can also be done on a through flight or turnaround. Airlines, especially in North America, don't skimp on this.

Wherever compressed air is required invariably airlines will use nitrogen rather than compressed air.

In my 45 years in the industry I have seen and replaced blown tires on landing. Usually the aircraft will clear the runway and taxi to a spot out of everyone's way. Because of the fire issue from burning rubber, maintenance will change the tires before the aircraft proceeds to the terminal.
akayemm
Er.A.K. Mittal 4
FA team,
thanX for bringing this thread to normalcy and sanity.
Now I can continue learning peacefully and purposefully.
Regards
wingbolt
wingbolt 2
BIG thumbs up.
ToddBaldwin3
Todd Baldwin 1
Er. Mittal. Thank you for explaining the Er. in front of your name, I always wondered what it meant. As you are probably aware, that is not a title typically used here in the the US. Now that sanity has returned, I'd like to inquire ask what your particular engineering disclipine is? It is out of curiousity not malice that I ask.
akayemm
Er.A.K. Mittal 2
Dear Mr Baldwin , my disciplines are/have been these are electrical engineering(1970) added by MBA(1980) then changed to lawyering (1996).
Therefore I have the misfortune of developing interest in too many subjects !
As I have admitted that use of Er. has no legal sanctity , only a matter show of recognition , just like a medical doctor without a PhD happily being addressed as Dr. ....
Regards
GaAubie
Ken Hardy 3
The most critical part is the bead seat of the wheel, if it develops a crack around the seat area, the wheel can explode at any time even inside the wheel well causing damage to the wing or fuselage, I used to sell equipment to test the wheel for cracks
dondasa
don dasa 3
Tire companies tried pre-spinning in the 40's and 50's -- or before. Gain was zilch. 98% of aircraft tire wear comes from the long taxis. Do the math and see the THOUSANDS of miles on the ground for each recap. Landing wear is just a "smidgen". Aircraft tires are so over deflected that compared to your car tires the aircraft's are essentially "flat". That over deflection is what causes the wear.

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wingbolt
wingbolt 4
Aircraft tires are normally deflected around 35 to 38 percent...cars around 18. Defect your car tire to 35 percent and give it a good speedy drive, the faster the better. At that point I'm sure it will become clear. Might want to buckel up and hang on though.

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wingbolt
wingbolt 5
My experience is in the business aircraft area. Certainly not the biggest but big enough to fly execs doing business in over 40 states with over 70,000 employees with over 600 locations. Not the biggest company but respectable in its own right. And I don't have to wear a tie, so it works for me.

As to the tires it's basically the ratio of the squat of the tire when it's under a load as opposed to no load. In short terms the amount of flex in the sidewall. Makes them look flat even in the 35 percent range. It is measured at the recommended tire pressure and even though an under inflated tire causes more deflection the term itself has nothing to do with the amount of air in the tire.

The Michelin man says so.

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wingbolt
wingbolt 3
I wish there were words to describe how wrong you are on this issue, but unfortunately they don't exist.

Only thing I can closely compare you to is a crazy old man standing on the roof in his underwear screaming at imaginary children to get off his lawn. Please consider asking the FAA to grant you a moving TFR with a 50 mile radius every time you fly. That is if you are even involved in aircraft operations and actually own an aircraft. Maybe you should see if you can have your medication dosage adjusted.

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bentwing60
bentwing60 6
Mr. Hartmann, since Preacher1, the former unofficial moderator of this site is no longer able to squawk or post on this particular site, I'm acting as his intermediary. For those who might be interested, you have contributed exactly Zero squawks on this site in your inglorious 7 years of participation. Your insatiable desire to denigrate the other participants on this site with your comments however lead to an ever greater number of squawks doing the "dead mans spiral" into the "esquire bash". What's the point? Were it up to me, you would be banished to the legal forum where you might, or might not excel. Alas, it is not to be. Perhaps your response will be the catalyst for sanity.
davidrbarnes
David Barnes 3
Well said, Bentwing!
akayemm
Er.A.K. Mittal 2
Hats off to you, Mr.bentwing60
Keep up the good work.
wingbolt
wingbolt 3
Wrong again.

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joelwiley
joel wiley 7
Mr. Hartmann, what does your post have to do with the technical questions raised by this "thread"?

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joelwiley
joel wiley 4
In short, while you frequently challenge board posters with off-topic questions, you decline to respond directly to a question about the relevance of your post.
I think your comments are irrelevant and immaterial for the most part.

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lynx318
lynx318 1
Well stop standing in front of it!
wingbolt
wingbolt 1
💩
wingbolt
wingbolt 7
Can we just stipulate that your an idiot? That way you won't have to prove it over and over again.
jeroberts88
jeroberts88 3
Don't get hard little Peter, their just a playing with ya.

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lynx318
lynx318 4
I take his name as being J.E. Roberts not Mr. Jero. Are you being racist? Cause that sounds defamatory and referring to a pet goat also sounds like stereotyping. As a lawyer, I'd think you would want to avoid that!
akayemm
Er.A.K. Mittal 2
Dear friend lynx318 as experience has shown, Hartmann is an arrogant conceited narcissist , all in addition to adjectives used by U .
Regards and happy blogging .
augerin
Dave Mathes 4
...I take a vacation and come back to this dribble?....man, what a waste
I'm outta here....
jzaeske
john zaeske 2
Most airlines use Nitrogen in their tires thus fewer flats/blow outs
This was introduced I believe in the 70's
akayemm
Er.A.K. Mittal 2
Dear FA Team ,
I'm an insignificant and junior member of this august forum.
But in my humble opinion the magnificence of this forum is in peril.
Some member has chosen to use language utterly unbecoming of a gentleman, language full of absolute filth and profanity.
He wrote ...
" .... For an example of why I think your post should be deleted...... You mention my xxxxxxx xxxxxx AND your favorite pet goat.... "
I'm sure there are men and women browsing this portal who'll feel uncomfortable reading such a foul language.
No freedom is absolute, boundaries are always inbuilt, since the times immemorial.
U R the best judge how to run this portal.
Regards
Banditz71
Richard Haire 2
The fact that the term "tarmac" is used proves they don't know what they're talking about.....it's either asphalt or concrete.....as usual, the ignorant media doesn't have a CLUE!!

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AABABY
AABABY 4
What the heck is Tarmac anyway?
I always thought is was a term used in old pulp fiction novels involving flying by the seat of your pants and fending off nasty spies.
lynx318
lynx318 3
Tarmac is a road surface using asphalt bitumen or tar mixed with stone aggregate.Any person who can't look it up, same as I did, I'd regard as ignorant!
jzaeske
john zaeske 2
I believe the tires are filled with nitrogen, this has been done since the 1970's
Prevents blow outs at high speed high temp landings
akayemm
Er.A.K. Mittal 2
My half cent ....
It's amusing to notice a highly engineering based topic being thrown open for discussion among not-so-technical people.
I'm an engineer but not specialised in tyre technology. Therefore , I will make a limited observation.
Every pilot worth her/his salt is expected to make a "featherlight" touch-down.
Right ?
And they all do it to 95-99.9% perfection.
Practically and technically it means that the weight of the entire aircraft comes on the undercarriage "slowly" and "gradually". And tyres are very much a part of the undercarriage.
The tyre pressure again is a matter of material of tyre and the 'total' surface area of the tyre vis-a-vis the load to be borne !
After all while at rest, the weight of the entire aircraft is being borne by these 'poor babies' !

joelwiley
joel wiley 7
I see you have become acquainted with Mr. Hartmann, a self-appointed gate-keeper and arbiter as to who should or should not be posting to FA. He has expressed in the past that only those who hold a pilot's license should be allowed to participate, and gets 'testy' if others violate his canons.
akayemm
Er.A.K. Mittal 4
May I add .... currently valid pilot's licence ....
:-p
talktalatka
F A 4
An-124 land on the last two tires. They fail often when landings are firm. An-124 crews carry extras.
Bratfalken
As far as I've learnt, the optimal way to land is when you reach stallspeed on touchdown, and that transfers the weight from the wings to the gear pretty fast, of course this should be done so that the springs on the gear woun't compress to the bottom, then you get bounced up again, but within it's range of travel. By landing that way, you can start braking as fast as possible and runwaylength can be shorter. Of course, if you have an indefinit long runway you can ease the plane down extermly slowly, but most of the time that is not the reality, look at carrierlandings, those planes have extremly sturdy gears that they use to slam the plane down on the deck. Of course, landing prop Cessna on an international airport, makes it easy to make a smooth landing as you have a very long airstrip to use, but on a short grass strip you don't want to float around for any long time just to make it smooth. :)

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akayemm
Er.A.K. Mittal 1
Dear friend , please read my comment fully and carefully. U'll learn about my background.
May I know what is flare while landing and why is it done ? What's its effect?
Why is nose landing a "crime" ?
U need not answer it , I know it to the extent a non flier need to know.
It's to help you re visit and jog your memory about flying.
Happy flying .

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akayemm
Er.A.K. Mittal 1
For Hartmann
Again go back to my original comment and read like a good lawyer.
I wrote " U need not answer it , I know it to the extent a non flier need to know."
I know about pits and falls of nose landing to the extant necessary for a lay man. There are many well meaning pilots on this portal who are ready and willing to teach ignorant but enthusiastic learners like me.
And I try to keep learning from them.
God bless these teaching pilots !

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akayemm
Er.A.K. Mittal 7
You use a suffix Esq. to your name.
I use a prefix 'Er.'to my name.
Both indicate certain qualifications or status.
And there are certain guidelines of using it (Esq.) , by who and how to , kindly check link below

https://lawschooli.com/what-does-esquire-mean/

My humble suggestion, better be careful for future comments about any one , me included.

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akayemm
Er.A.K. Mittal 7
It's Er. Mittal , and not Mr. Mittal.
Now this is from one attorney to another ... yes I am a lawyer too , just like you claim .
It's a public forum.
And being an engineer by qualification and experience I am entitled to share my views on technical matters.
And my comment is fully engineering based.
It's for your information.
And
Stop trolling me .

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wingbolt
wingbolt 7
I must admit I have become obsessed with down voting you...I guess it's how I spend my time between the ever increasing commercials. I did cancel my Facebook account so I guess I have some extra time on my hands. I just wished they had a little hand with the middle finger sticking up, that would be grand!
AABABY
AABABY 2
What would Preacher say?

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wingbolt
wingbolt 10
Nah...I'm just gonna keep down voting you. If there ever was a case for censorship you make it. Besides if anyone does make a contribution you just question their credentials. I'm not hostile, just think your a tool. What I do consider hostile is calling someone fishy just because he is a former pilot. Your an embarrassment to the profession.

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wingbolt
wingbolt 6
I know several formal pilots...they just didn't convert their military flight time to civilian. They just went on to something different. Nothing diabolical or even suspect except with you. As long as you don't mind being wrong stay the course. With that in mind I enjoy exchanging ideas and knowledge, just not with you. It's obvious you live by the phrase " I reject your reality and substitute my own". Nonetheless, thanks for giving me something to down vote, I got my fix.

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wingbolt
wingbolt 4
easy or not I know several ex military that had no desire to fly civilian. To each their own...that's what makes the world go around.

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wingbolt
wingbolt 4
You have got to be the most paronoid person walking the face of he earth. They come in here for the same reason you do....because they can. There is this thing that you should be very familiar with...it's called "presumption of innocence". If you forgot about it wipe the dust off some of your old law books and check it out. As the self appointed spokesperson on the "American way" it should always be fresh on your mind. Not everybody has sinister thoughts except apparently you.
akayemm
Er.A.K. Mittal 2
well said buddy.
AABABY
AABABY 2
I repeat my earlier remark on the subject for you Peter F. Hartmann Esq.

AABABY 2 days ago

Only problem is that any tire spinning without a load on it or controlled speed could throw off the tread.
AABABY
AABABY 4
As for my knowledge of Preacher, may he rest in peace. He was a very sensible contributor who didn't persist in criticizing others.
I asked you to go away. You are becoming a nuisance to others as well as myself.
sparkie624
sparkie624 2
It is very RARE! but a/c tires do and can blow up doing millions in damage. Most of the time this is caused by a Brake or Anti-Skid issue. I remember one many years ago on a 737 a tire exploded and the damaged it caused ultimately caused a fire and the plane burnt to the ground... No one was on board, but the plane was a total loss.
Viperguy46
Jesse Carroll 2
The C%-A spend them up prior to touch down. Think the Shuttle did also!
Bratfalken
First I got to say that I'm no more than a desktop jockey but, what if.... there was centrifugal regulated small turbinewings sticking out just enough to get the tires to start spinning while in the air before landing? As they reach normal landingspeed the wings retract, no electronics that can fail, just simple mechanic. How would this affect the landings? The runways would be less filled with rubber that needs to be removed, the tires would have less initial heat when the braking starts and less proune to get flat spots. Would this idea be possible or am I thinking totally wrong, like if you need that initial friction as they touch the runway and start spinning? The system wouldn't have to be especially large in size as there often is plenty of time before touchdown for the wheels to start spinning and there could be some sort of spring retraction that would allow the wings to be pushed in when the gear retracts in the bays. I have had this idea for 20 years, but have too little knowledge of how flying works in detail to get around to do something about it. Give me your some info, I haven't patent anything, and if someone would go ahead with the idea and make something out of it, I'm glad to have contributed to some diminished risks or costs for passengers and airlines. Of course, this could be pure crap, but someone would know? :)
Dougie11
Robin Douglas 3
Very interesting! As a former pilot, this exact same idea came up in 1989 and it stuck with me ever since. Why not spin up the wheels to equalize or at least approach ground speed and see a huge reduction in tire cost? Electronically, mechanically or by combination thereof? I proposed this to a colleague-captain once, and I think the answer was that there is just too little room in the wheelbays of commercial jets to accomodate the necessary equipment. Though I still doubt that answer...
AABABY
AABABY 2
Only problem is that any tire spinning without a load on it or controlled speed could throw off the tread.
Bratfalken
That is the reason I thought of a centrifugal assisted withdrawal of the small wings, as the wheel reaches the normal landing speed the wings retract and the wheel stay at that speed. (I was once too tempted with putting a powerwasher too close to a bicycle pedal with the result you know, the pedal pieces continued in the straight line, ie. "exploded" ;) You need some way to make the wings retract so that the speed of the wheel doesn't get too fast, why not use centrifugalpower to retract them, like the way a CVT gearbox works?

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Bratfalken
You only need the brakes wich can produce the same amount of friction that the tire can produce against the ground, otherwise you'll lock up the tires. (Unless you have some sort of ABS-system) I don't know if you're familiar with the swedish fighterjet SAAB JAS39 Gripen, it's most powerful brakes are on the nosegear, it uses it's canards to get more pressure on the nosegear while braking and also has a type of ABS-system so that it woun't get out of controle. That is handy when using roadstrips in the presens of wartime. It's predesseser (sp?)37 Viggen had reverse thrust with doors closing the exhaust and forcing all power forward (it uses that to back up during airshows)But 39 Gripen is one of a few planes with brakes on the nose gear as far as I've learn't?
talktalatka
F A 2
My Airborne Outback LSA WSC...nose wheel brake.
Bratfalken
I understand that a light trike would gain from as little extra weight as possible, having the brakes on the nosegear close to your feets must fill that demand! :)

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Bratfalken
As I stated in my very first line, I'm no more than a desktop pilot, my knowledge comes from interest and curiosity about mechanics in general and flying especially. I have a two year education in mechanical construction and know how to weld almost all the ways possible,I fix most of the things on my own cars but let specialist take care of the things I don't have the tolls and knowledge about, like aligning wheels. I work as a pulpdryer operator at a large paper and pulp plant with machinery that we sometimes have to fix ASAP. My flying interest has been filled with the most accurate sims available for the last 20 years, I'm NOT saying these are like real life, they only give you a hum about how things work and are wrong on so many items. This hasn't stopped me from being interested i flying, and nore will you, how rude you ever become among all these flight interested people and pilots!You're behaviour is more like a well spoken troll!

On the subject of brakes, I don't think that manufactorers is driven by greed, they want to sell you the best plane they can build as that sells more planes. Of course they want to make money, but not at any known risk for safety!
ysfsim
Ant Miraa 2
Im not too sure but i heard that spinning tires method is used on the 747
delravi
zx zczc 2
Jan Stromback - Like you, I too am an armchair enthusiast but the concept shared by you has been in my mind for a long time. Basically, on-board computers could set the tires spinning, before touch-down, to exactly the same speed when contact is made with the tarmac. This would 1. cause lesser wear and tear of the tires, 2. reduce element of debris being generated due to impact and 3. reduce impact force on the tarmac at point of contact.
Admittedly, this might be rather simplistically put since there could be other more graver factors to be considered on the subject.
hatch
ian hatch 2
In the 1970's working in Iran on an air defense system at Sharoki Air base (Hamadan), an F4 landed, apparently with his brakes on, as both main gear tires exploded on touchdown. it remained on the runway fortunately.
yr2012
matt jensen 3
Partially true. But it's really a nitrogen fill that keeps them from exploding. That and a regulator. Due to the complex nature of construction and the severe operating conditions of aircraft tires, Michelin and other leading tire manufacturers recommend the use of Nitrogen as does the FAA.

Nitrogen is a totally inert gas that will not support corrosion or oxidation within aircraft wheels and tires.

Compressed Nitrogen has a larger gas molecule than compressed air, so low tire pressure due to allowable leakage is minimized. Gentec Nitrogen aircraft tire inflation systems are available in two versions.

http://www.boeing.com/commercial/aeromagazine/aero_05/textonly/m03txt.html
davidrbarnes
David Barnes 6
Matt:

It's not just a recommendation in the FAA's eyes: 14 CFR 25.733 requires the use of nitrogen. No options here in the US (for aircraft MTOW over 75000 lbs.)
sparkie624
sparkie624 3
Very true.
ToddBaldwin3
Todd Baldwin 8
It's not so much that nitrogen is "totally inert." It's not, nitrogen is not one of the noble elements found in the last column of the periodic table. What makes nitrogen the gas of choice for aviation tires is that it will not support combustion. In terms of molecular sizes, bear in mind that air is 78% nitrogen with a Van der Waals radius of 1.55 Angstroms (I know, old school measurement, but I'm and old school chemist), and 21% oxygen, with a Van der Waals radius of 1.52 Angstroms). Ideally, helium, neon, argon, or xenon would be the best gasses, but those gasses are far more expensive.
sparkie624
sparkie624 3
you are correct. Keep in mind that the Nitrogen keeps it pressure very close (with about 20 to 25 lbs), thus is why we have temperature tables to make sure that we get the proper inflation... But do keep in mind that when they get Super Heated (and I am not talking about every day landings) they can blow. One thing to keep in mind is if you do more than 2 aborted take off's within a very short period of time, brakes need time too cool. That is what caused the plane that I listed with the Brake/Anti Skid issue to be a total loss was a VERY VERY HOT brake and thus increased the tire pressure. N2 is a great help, but not a fix all.
30west
30west 2
Sparkie, Very true. Then there is the "Brake Cooling Schedule" chart for use after an RTO to determine cooling time required before a subsequent takeoff attempt and the likelihood of the fuse plugs melting.

The x-axis on our charts show "normal" range with no special procedure required, "cooling time required" range with times, "fuse plugs may melt" range with delay takeoff one hour and "fuse plugs melt" range with wait one hour before taxiing or approaching tires.
ColinSeftel
Colin Seftel 2
It's rare, but it has happened with disastrous consequences. A burst tire at take off caused the crash of an Air France Concorde in 2000 and the loss of all 109 souls on board, after the tire was punctured by debris on the runway.
joelwiley
joel wiley 3
I think the tire burst when running over debris on the runway. Said debris also punctured a fuel tank. I don't believe the tire was the culprit, and the plane was on takeoff rather than landing.
davidrbarnes
David Barnes 7
The BEA concluded that the titanium strip caused the tire burst. Shredded tire debris then impacted the wing, sending a pressure wave through the fuel in the tank, which then in turn caused the fuel leak. (See https://www.bea.aero/docspa/2000/f-sc000725a/pdf/f-sc000725a.pdf for details, page 115)

That said, and on topic with this thread, the tire burst was directly caused by FOD on the runway.
musephoto
Geoff Rowe 8
So ordinarily I don't comment on these threads as I am just a consumer of the service and I do love reading all the expert pilot comment but I have to interject something here as 1) I am a Brit and rather proud of the Concorde and 2) I am rather sad that I never got to fly it and 3) I did a lot of research on what happened.

The FOD story was heavily pushed by the French as a way to divert attention and blame. They do love the blame Americans for just about everything but it isn't the whole story by far.

Many things went wrong with that takeoff starting with the runway selected. Please feel free to correct me if I am wrong but I believe that Concorde required a much higher take off speed than a normal jet so needs the longest runway possible. At the time there were a number of surface roughness issues with the runway chosen for takeoff and the tower should have been aware of that and directed the takeoff to occur on another runway.

Next problem, the undercarriage had been serviced the night before and when reassembled a vital spacer was missed from one of the main gear axles. This piece is deduced to have been missed out as it was never recovered from the crash scene. This would have caused the front two wheels on the left main gear to "wobble" as they accelerated down the runway (I think it was the left gear from memory).

It was the stress of the wobble and the potholes in the runway that overheated and overstressed the tire which finally let go.

There was one final incident that doomed the plane. A 747 carrying the French President no less, encroached on the takeoff runway and caused the Concorde pilot to rotate too early resulting in them not having the speed to climb out to a safe altitude and go-around.

All tragic mistakes which, had they not happened, might have saved the plane....
30west
30west 5
Geoff, Concorde was a special airplane and I understand your pride. I, too, missed the opportunity to fly in Concorde waiting for a convenient time, a time that unfortunately never came. Many of my fellow pilots at my airline did take advantage of that opportunity and had great memories that they enjoyed sharing. It was more than just another airplane ride, attested to when seasoned professional pilots relish talking about it time and time again!

Also, I understand your reluctance to "buy into" the official accident report. I saw that same reluctance from fellow pilots and flight attendants when the official accident reports were published for TWA800 (a 1996 accident) and AA587 (a 2001 accident), after each flight departed JFK. The alternative theories about the causes, including conspiracy to cover-up an act of terror, for those accidents are still held by some. I could find no alternative theory that could outweigh the official reports in my mind, no matter how much I wanted that to be the case.

In addition to the French members of the investigative team; British reps, Bae reps, RR reps, FAA reps and NTSB (given accredited representative status for this investigation) reps, and others conducted the investigation and issued the final report. It is difficult for me to believe a conspiracy of all those players existed, allowing an intentionally fraudulent report to be published with their signatures attesting to its veracity and all remaining silent to this day.

Just my thoughts.
musephoto
Geoff Rowe 3
This is not the sum total of the research I did but this article does seem to sum up all the major points!

http://www.askthepilot.com/untold-concorde-story/
lynx318
lynx318 3
Not sure when or where but I've certainly heard at LEAST twice the front tyres on Concorde were just barely meeting the specifications to do the job with little safety margin. Subsequently any damage however minor could potentially burst them was the fear.
davidrbarnes
David Barnes 2
Geoff: Thanks for the insight. I based my post on the official BEA report which, as you note, could be shaded by cultural/societal opinions. If there's any doubt of that possibility, one can easily note EgyptAir 990's conflicting investigation reports.
rmchambers
rmchambers 2
Wasn't there also an aspect of British versus French best practices. I thought the British birds had kevlar based shields over the tanks where the wheels would hit if the tires let go. The British suggested that Air France install the same things and they elected not to do so.

It was a tragic day for both airlines and it will be a long time before consumer mach 1+ travel happens on a scheduled airline I suspect.
joelwiley
joel wiley 1
sparkie624
sparkie624 3
Joel, it has been proven beyond the shadow of a doubt that Air france Concorde crash was the direct result of Debrie that was determined to have come off a United 747 from a Previous Departure. It caused the tire to blow on departure at high speed. When the tire blew a fragment of fire punched the fuel tank access panel causing a massive fuel leak and with Afterburners on at the time the rest is history.
williambaker08
william baker 2
I'm sorry the debrie came off of a continental dc-10. It was a engine strip if I'm not mistaken and the found the plane missing the part in Houston Texas.
sparkie624
sparkie624 3
You may be correct from that... Not sure why united came to mind or the 747... Still was a strip of metal that fell of another a/c.
Viperguy46
Jesse Carroll 1
OOP's....C5-A's
Bratfalken
Figured that out by looking at my keyboard, no worrie! :)
Viperguy46
Jesse Carroll 1
LOL...plus my fat fingers!
akayemm
Er.A.K. Mittal 1
Business Aircraft ! !
ACJ and BBJ
Are these two from different genre or same !
It's not a question.
It's for information of some of those who think they "know all" .

[This poster has been suspended.]

akayemm
Er.A.K. Mittal 4
Hartmann ,
My title is Er. , granted by a University. Not like one adopted by convention like Esquire !
Long ago I gave U the link for this. But like any arrogant hollow and shallow person U haven't cared to check it.
If U R really knowledgeable as you boast, why have U evaded BBJ and ACJ example.
ThanX to many good teacher pilots, I know a vee bit about aviation from a layman'n perspective.
Clearly all ur claims about ur possessions and knowledge are fake.
U R far from being a qualified engineer so it'll be good if U stay away from engineering based topics even if they are manageable by some technical common sense and clearly U don't and can't have that either.
Now before U venture to take cudgels about my technical credentials, bear in mind that aircrafts are made by engineers and not by pilots or aircraft owners.
U continue to troll inspite of a reprimand by a senior and competent person like Mr.bentwing60.
I wonder what kind of a human U R ?
davidrbarnes
David Barnes 2
I'm honestly not familiar with the honorific "Er." What does it denote, and would you be kind enough to share a bit of information for my own edification and enlightenment?
akayemm
Er.A.K. Mittal 4
Dear Mr. David Barnes , these are all to be used as prefixes to names, Dr. for doctors, Er. for engineers, in Germany Ing. for Ingeneur (engineer). In many places Arch. is for architects and so on.
I admit that I have not come across any law or official directive calling for their use .
Even the practice of a PhD qualified person using Dr. as prefix find no mention in any University gazette or the like.
Even use of Esquire after the name is not mandated any where . Yes by convention the manner of use has evolved, differently in UK and USA. But one thing is clear , like one never introduces himself like ' I'm MR. ... ' similarly one is not expected to use Esquire at the end f one's own name. Yes for others it can be used.
But prefixes like Dr., Er., Arch., Ing., etc can be used for own name .
It'll not be inappropriate for me introduce myself as Er. Mittal , but definitely not as Mr. Mittal
That's all I know.
davidrbarnes
David Barnes 3
Interesting. I'd never seen the prefix Er. associated as an honorific for Engineers. In fact, in most (if not all) US states, the "typical" honorific for a licensed engineer is a suffix of "PE" (Professional Engineer), and this a title bestowed by a state licensing board, not by a university. In my case, I have a Bachelor's degree in Mechanical Engineering from a university, but have not yet passed the licensing exams for the PE title.

As you mention, the manner of use has evolved differently in the USA and elsewhere, so your post piqued my curiosity. Thanks for the information.
akayemm
Er.A.K. Mittal 2
u r welcome Mr. Barnes.
We in India do have system of licensed engineers BUT not the practice of addressing them as such .
Different places different practices and rules !

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akayemm
Er.A.K. Mittal 3
Hartmann, for heaven's sake stop acting like a possessed idiot and start behaving like a lawyer if U R really one .
Are U at all familiar with principles and practices of international law ? Clearly U R not.
N do U know what Mr. Barnes and I were blogging about ? No, U don't know that either.
So shut up.

[This poster has been suspended.]

akayemm
Er.A.K. Mittal 2
hartmann ,
Clearly U R a Nazi.
Period.
wktaylor
Wilfred Taylor 1
Dry Nitrogen should be the only compressed gas for use on any aircraft... tires, hydraulic accumulators, landing gear shock-struts, etc.... for same reasons cited by matt Jensen. Eliminate internal corrosion potential [metal parts], reduce oxidation potential [non-metal parts] and eliminating compressed oxygen [IE: high pressure air] mixing with aircraft system fluids that can be an initiation source for internal detonations [at high system temperatures, and/or in failed components that experience massive friction forces]. Regardless, the importance of pressure relief [blowout] plugs in wheels and certain system elements cannot be overstated as a prime safety measure... especially for dragging brake effects on wheels. NOTE. Keeping high quality dry nitrogen for use on all aeronautical equipment, including support equipment and vehicles, keeps mechanics and other crew-members from accidentally servicing aircraft with compressed air meant strictly for non-aero equipment.

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lynx318
lynx318 1
Doesn't nitrogen have less pressure change with temperature change than oxygen or for that matter straight air?
ToddBaldwin3
Todd Baldwin 4
Since air is 78% nitrogen, there is very little difference in the change in pressure vs temperature for Clean Dry Air (CDA) as compared to Clean Dry Nitrogen. Where you usually see the difference is when someone has filled up a tire with air straight from the compressor (not run through a dryer and oil separator) due to the expansion of water vapour.
lynx318
lynx318 2
What worries is they filled the tyres from a tank of pure oxygen (not stated) instead of the nitrogen.
akayemm
Er.A.K. Mittal 2
Result - fire hazard at slightest of provocation (excessive heat or minor spark) !
;-p
akayemm
Er.A.K. Mittal 1
I'll make a limited observation.
Change in volume in ALL gases follows Boyle's + Charle's Laws (or the combined Gas law) where change in volume is SAME due to same change in pressure or temperature.
Regards
akayemm
Er.A.K. Mittal 1
Typo
It is Charles's not Charle's
My apologies.
babyrne
Barry Byrne 1
A million years ago, 1973, when I was a student pilot one of the rich guys in El Paso was given a Saberliner by his Grandmother. It was one of the first Corporate Jets in town.

So one evening the rich guy was going to show off his new toy to some of the other rich folks. I was taxiing my Cherokee 140 back in on a parallel taxiway as they took off, and right as they rotated both main tires exploded.

Seems the FBO had serviced the tires with oxygen instead of nitrogen. Made a heck of a mess of the trailing edge of the flaps.

Anyway, they took off, flew for a while to burn off fuel, and made a successful landing on what bit of rubber remain on the rims.

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sparkie624
sparkie624 18
What are you saying: "If the information here is correct, they've "skimped" dangerously on their tire and brake capacity."

In the airline industry we monitor tire pressures and serviceability of tires daily. Every Day Ever Tire in our system is looked at for serviceability.

The airline that I work for we have an automatic box that the Nitrogen tank is connected to. It checks the temperature of the tire and inflates the tire to the proper level and every tire will be at its exact pressure per the AMM every time.

From a maintenance stand point of being a mechanic and be one of the people to decide which planes gets checked at which station on a daily basis I have to take offense to your statement. Things will happen and there will be blow outs... That does not mean that skimpy maintenance was to blame. We recently has an antiskid problem on one particular a/c that took several days to troubleshoot and repair that was causing damaged tires that had to be removed from service. This does not mean that improper maintenance was done... that means something in the system had to troubleshoot and fixed. Some problems are easier to fix than others.

Our Airline flies over 1000 Flight Hours PER DAY, and things happen... Things break... and we have to fix them. Some are deferral, others are grounding items

Noting your comment: ""skimped" on brake and tire design to the point where we have to worry about..even have "heat tables" " Again... You have blown it here... For one thing most general aviation has 2 disk and 2 brake pads, and rotates at approx 60 knots... We have Multi Disk Rotor brakes that are housed inside the brake assembly. When you abort take off, you rotate at a much lower speed and your brakes can cool fairly quickly, not to mention you are stopping less than 3000 lobs. A 737 for example rotates at over 100 knots. When a 737 has to RTO (or abort in laymen's terms) I think you would agree that airlines will build a lot more heat than the average GA aircraft.

and you say: "Makes you wonder". " have they cut corners?" - the answer is NO! with emphasis... I can tell you if you are on one of my planes and I am not happy with a maintenance item, you AINT (AINT WITH EMPHASIS) going. We got published guide lines from the manufacture of what we can and cannot do. If they say we cannot do it, we do not do it.

Aircraft Mechanics as a whole are very professional in our work and make sure it is done correctly. Mistakes do happen, and when they are found that plane is grounded where ever it is at and I don''t care if it is 100 miles north of Siberia, it is not going to move until it is completely taken care of... PERIOD...

Mr Hartman, please do not push off on maintenance. We have a lot of work to do and we do it safely and we never cut corners!
akayemm
Er.A.K. Mittal 4
Bravo !
Though late ...
davidrbarnes
David Barnes 5
Sparkie and Mr Mittal:

I, too, share your frustration with Mr. Hartmann's antics. He adds nothing to the discussion, berates anyone with whom he finds nits to pick, plays the alarmist/extremist/sensationalist card on any posts which require the slightest bit of technical understanding, and generally makes the experience unpleasant.

I've sworn off directly replying to him, but have to fight the urge time and again to respond to his technical ignorance, arrogance, and pomposity. I say technical ignorance because, by his own admission, he is not familiar with the design, construction, maintenance, or operation of large commercial aircraft. His arrogance and pomposity are self-evident, in my estimation.

Unfortunately, FA lacks a user-by-user "block" or "hide" feature by which those of us who tire of his behaviour could clear his clutter out. Unfortunately, such a feature would reduce our ability to vote his comments according to their merits. (And I believe his scores reflect those merits accurately.)

Regards,

David
akayemm
Er.A.K. Mittal 4
Well said .
wingbolt
wingbolt 5
Good show David.

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davidrbarnes
David Barnes 5
Mr. Hartmann:

Your behaviour is out of line, and I will not tolerate continued personal attacks from you. I've discussed my experience and knowledge previously with you (http://flightaware.com/squawks/view/1/y_days/popular/56335/Avoiding_air_turbulence_may_soon_get_easier#175884) and were you to to have any recollection or respect, you'd recall this. Of course, this is clearly asking too much from such a boor as yourself.

I'm NOT one of your so called "flyer friends", but instead work in a Part 121 operation and have designed components, modifications, and maintenance programs for Part 121 aircraft. My most recent program includes landing gear hydraulic system modifications which are set to begin installation later this year. Were you to come by my office, I'd be tempted to wrap one of them around your neck as a permanent reminder that many, if not most, people in here do, indeed, know what they're talking about.

I'd recommend you offer a modicum of respect towards other posters. I come in here because I have a knowledge of aircraft, a bit of experience to share, enjoy aviation, and love talking about it with people. In the last month, I've flown in everything from single engine toys up to the big boys. (And before you get defensive about your small aircraft, I was going for a rhyme between toys and boys.)

Second, given that about a quarter million people are employed by the three largest airlines in the US (AA, DL, and UA each have about 80k on payroll), I think it's safe to say that the number of who are "involved in Part 121 operations" far exceeds the number of general aviation pilots. (170,718 is the number Mr. Wiley quotes below, and when one includes smaller operators like WN, B6, and others, the involvement in 121 operations is easily well above that count.)

You, sir, have not clearly inquired what you would like to know about aircraft tires, but instead berated anyone and everyone with your rants, demeaning them and their contributions to the forum while instead contributing nothing yourself.

You, sir, can go fly a kite, as far as I'm concerned.

[This poster has been suspended.]

davidrbarnes
David Barnes 3
Alas, I don't think that sitting in the pointy end of a flying machine makes you a god. But I'll leave a discussion regarding your delusions of grandeur to another forum.

Again, I point out, in case you missed it in two different conversations: I am "involved in Part 121 operations" far more intimately than you are and likely ever will be. I just double checked my bank account and yes, indeed, my paycheck came just this morning from a Part 121 carrier. I also just checked my business card, and yes, indeed, that says I'm an engineer for a Part 121 carrier.

As to tires, what clearly articulable questions do you have that I can answer for you?

If you have an actual question, I'd be more than happy to try and answer it. I don't claim to be all knowing, but I'm like a dog with a bone when it comes to learning more about how those beautiful machines parked not 50 feet from my desk operate. Else, I'll leave you to your incessant blabbering and emotional drama.

[This poster has been suspended.]

davidrbarnes
David Barnes 3
1. Considering that I inquired of you "what clearly articulable questions do you have that I can answer for you?" at 12:22p EDT on Wednesday and you didn't articulate your question to me until 9:01p Thursday, how would I have answered your question?
2. Unfortunately, I can't find the phrase "panic stop" in any of my aircraft manuals. Can you provide a manual reference in which that term is used or defined?
3. That said, the most severe braking experience is assumed to be a rejected takeoff at MTOW. In this case, kinetic energy, which has to be absorbed by the brakes, increases with velocity squared (a doubling of velocity results in a quadrupling of kinetic energy) and increases linearly with weight. Because of the sheer amount of energy required to stop a fully loaded aircraft in an RTO, this gets absorbed as heat. The heat takes time to dissipate, and larger aircraft are equipped with a number of mechanisms by which to deal with this energy. Brake temperature gauges to monitor the current temperature, and brake fans are installed on some aircraft to aid in cooling. Additionally, fuse plugs, which melt open at higher temperatures are installed in the tire to prevent the tire from over-pressurizing (a blowout) in the presence of elevated temperatures. Recall the ideal gas law states that pressure increases with absolute temperature. These fuse plugs aren't designed to prevent movement of the aircraft, but to provide controlled depressurization of the tire, which can cause personnel injury to those on the ramp working near the landing gear.
4. While it's not an aviation application, surely you're familiar with brake overheating on long mountain descents.
5. The amount of brake mass to distribute that kinetic energy on a large aircraft would be impractical, and frankly, unnecessary. Procedures are in place to prevent dispatch of an aircraft with high brake temperatures, but no safety margins are being sacrificed. In this case, a procedural change (brake cooling) is used to mitigate the heating of the brakes. Manufacturers (and by extension airlines who pay the bills) have elected this, and resultant possible delays, over the increased weight and associated fuel burn. The aircraft is, at all times, able to perform an RTO at MTOW safely, ergo the safety margin is not compromised.
joelwiley
joel wiley 4
According to the FAA Statistics available on Table 1 at:
https://www.faa.gov/data_research/aviation_data_statistics/civil_airmen_statistics/
as of 12/31/2015 there were some 590,039 active airmen certificates held. Of these, 122,729 were student, 170,718 private, 101,164 commercial, 154,730 Airline Transport certificates. There are also 190 recreational (only) 5,482, 15,566 rotocraft (only)and 19,460 glider (only). Which ones that one includes under general aviation is left to the reader.
wingbolt
wingbolt 4
There is really only 170,717 private certificate holders. One doesn't count because he is a complete nut job.

[This poster has been suspended.]

wingbolt
wingbolt 4
Thanks for confirming you don't count. If nothing else with this thread at least we got that out of the way. I might even consider up voting you on this one but it makes me break out in a cold sweat.
wingbolt
wingbolt 3
Nope, couldn't do it with a twitching finger...like all the rest of your posts down you go.

[This poster has been suspended.]

joelwiley
joel wiley 3
I was not responding to the original topic, ie pressurizing aircraft tires, I was responding to your statement "What you folks have to deal with - is the fact that the number of general aviation aircraft and pilots far exceeds those who are involved in Part 121 operations", which likewise is off the topic of pressurizing aircraft tires. I find your assertion of the preponderance of GA licensees does not seem to be supported by FAA data, and thus should be taken with a grain of salt.
ToddBaldwin3
Todd Baldwin 15
You have once again reminded me of the old adage "It is better to be silent and be thought a fool, than to speak and remove all doubt." (attribution to Abraham Lincoln).

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ToddBaldwin3
Todd Baldwin 12
First, I'm going to refer you to Sparkie's comments above. Second, before making a comment like you made, perhaps you should do a little research into aircraft operations, especially large aircraft and high performance aircraft. By your own admission, in many of your posts, you are not a commercial operator, neither am I. My heavy aircraft experience was all military. I have some interest, and experience in the dynamics of a rubber tire hitting the ground, then accelerating from near standstill to 160 knots in a very short time, then supporting it's share of well over 100,000 pounds. That is why I commented and clarified on the use of nitrogen as a filler for high performance tires. Everything about an airplane, be it your little amphibian, my little bug smasher, or an A380 is a balance between safety and practicality. Even the military has to balance those factors. One reason the SR71 had to refuel shortly after take off was that when fully fueled, taxiing put a tremendous strain on the tires and the brakes. There's a lot more to aircraft design than you seem to think.

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joelwiley
joel wiley 4
Mr. Hartmann, the term 'but smasher' appears to be a sensitive trigger for you. Why is that?

[This poster has been suspended.]

wingbolt
wingbolt 3
There is no way you have friends, something sounds "fishy" here.
joelwiley
joel wiley 11
Looking back at your original post and reply, I have to wonder if we were reading the same article as the Squawk headline.

You express concerns regarding non-GA braking systems: brakes were not mentioned in the article. You mentioned 'scary stuff' and airlines have '"skimped" dangerously on their tire and brake capacity.'. After rereading the article, I still don't see 'scary stuff' in it.

You stated "We in general aviation .... and "Our general aviation aircraft have sufficient excess reserves...". Are you presenting yourself as an authoritative expert on General Aviation as a whole, or just expressing an opinion limited by your own personal experience?

I infer from your comments that you may feel Mr. Baldwin was calling you a fool. He remarked that your OP reminded him of an adage. Your comments of your unease and concerns about general design topics far beyond the squawk subject may have elicited that reminder.

[This poster has been suspended.]

wingbolt
wingbolt 4
The Lear 55/60 shoots your theory down. Brakes and tires both too small and far from a "heavy".

[This poster has been suspended.]

wingbolt
wingbolt 4
The design criteria for the brakes of transport category aircraft is a set criteria and based on 100% wore out brakes. The airline has no say as to the size of the brakes and tires. So with that in mind your statement about the airlines skimping on the size of their brakes and tires is completely false. The certification standards of your part 23 aircraft has very little to do with part 25, commuter, or transport category aircraft so your analogy is ludicrous.. Since the Lear 55/60 operates at the lower end of the criteria they sometimes take a big hit on their balanced field length with respect to brake energy limitation. Not a big deal if the available runway is long enough.

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wingbolt
wingbolt 4
To skimp on brakes would throw off the BFL which is a performance criteria not required to be calculated in Part 23 aircraft unless they are guaranteeing part 25 performance. It would be silly for them to throw that calculation so far out of whack that it makes the airplane unsuitable for most runways. Also the formula as it pertains to the size of brakes is set by the controlling authority, eg. The FAA or EASA.

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wingbolt
wingbolt 2
That sound you keep hearing is the subject matter as it sails by well above your head.
joelwiley
joel wiley 2
"I remain concerned that the airliners do not operate under the safety margins we do in general aviation. I hope I am wrong - but it sounds like the design engineers of large aircraft correctly recognize that the larger and heavier of the body-in-motion, the greater the force is needed to stop it. BUT were told to reduce the safety margins ! If that is a reasonable assumption, then we get back to the question of why they don't have adequate tires and brakes for the size, speed, and load they are trying to stop ?"

Thank you for clarifying your question. May I suggest you pose the question over in the discussion forums, perhaps in general or airlines categories. That might open the question to a wider audience that would have a wider set of perspectives.
joelwiley
joel wiley 11
Re 'Flyers'
https://www.fecundity.com/pmagnus/humpty.html (attribution to Charles Dodgeson)

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