I flicked the annunciator test switch to show you all the pretty lights associated with the autobrake system.
Them’s the Brakes…
This post is for you! I commented in my previous post I received your letter and your book was sent Friday. Enjoy the read!
Yes, aircraft implement anti-skid and the idea spilled over to cars which you well know as ABS (anti-lock brake system). This topic got me into the books. Well I had to do something on the six hour flight to San Francisco. J
One thing I didn’t realize it did not activate below 20 knots so if I brake and skid a little on some ice, I may leave some rubber behind.
The anti-skid system compares the speed of each main gear wheel (tachometer) with the speed of the aircraft (reference speed). When the speed drops below .87 times the reference speed, the system orders brake release. The Airbus is like an onion, it has many layers of complexity. Maybe I should call it the Airbus Onion. (I also know a few people who have multiple layers)
The Airbus autobrake system has four simple settings: off, low, medium and maximum. It does not arm below 72 knots so in a reject we must be cognizant of this limitation and apply manual braking. We take off with the system in “max.” So with max reverse and max braking... “weez a stopping in a hurry.” Lol
“Lo” setting activates in 4 seconds after the main’s touch and the ground spoilers deploy. This “lag” is a little too slow if we are landing at airports with a “get on, get off” operation. Myself, I land using “low” and with idle reverse, but if need be, I will apply manual braking. I also use the system in crosswind landings. Again, it takes patience to wait for the autobrake to kick in and to determine if you will make the the appropriate turn off.
We tend to maximze brake use over reverse because our brakes are leased and it saves wear and tear on the engines. The glitch is... the brakes warm up in a hurry and carbon brakes work better with one or two smooth applications instead of multiple inputs.
"Medium" kicks in 2 seconds with a deceleration rate of 9.8 ft/sec squared versus 5.6 for low. We tend to use medium in places like USS La Guardia (USS because water stares at us on three of the four runways). J Also if the runways are contaminated (i.e slippery) or landing in low visibility we employ medium.
"Maximum" is NOT recommended for landing because anything not strapped down would end up in the front of the airplane. And that’s where we are!
The Decel (deceleration) lights activate when at 80 % of the selected rate.
The nose wheel steering disengages above 70 knots. The nosewheel rudder pedals disengage above 130 knots…after that you are steering with only rudder.
So what happens when we reject around 70 knots due to an engine failure? The autobrake is not armed, max reverse is less effective at low speeds and the nosewheel rudder pedals only allows a deflection of +/- 6 degrees. Translation, if you don’t get onto the nosewheel steering (hand wheel) and brakes…it’s off into the tulips you go. Yes, sometimes a low speed reject is much slippery than a high speed.
And how many rejects have I had after accumulating thousands of take offs?
Zero! Okay... I had a couple of very low speed rejects due to NON mechanical issues but that’s it!
The end of February will see Captains Doug in the simulator and rest assured I will be yelling “reject” as part of the ride.
It's Valentines Day and I hope all of your significant others don't say to you..."Them's the Breaks" in the romance department. :)
Maximum breaking sounds fun! Haha, kidding.
In the sim, on the Express Way 31 richard had told me to slam on the breaks because of the short runway. Did that and instantly forward I go - ( thank god for the seatbelts LOL! ) My dad, who had been sitting in the seat behind Richard, who was in the F/O seat almost wen't flying ( I had a little laugh at that ).
Lets just say when the did landings at YHZ on 23/05 I didn't use full breaks but rather 3/4 reverse.
The breaks seem pretty strong though, which is good in certain situations.
Daniel. Sounds like Richard put you through your paces. Captain Doug
Capt. Doug: I am honored and thanks. You super response needs another read to be sure that I understand it all, but first-class stuff and Thank You! Back to you soon. Did I say thanks?
Cedarglen (Craig) I'm glad you liked it. Captain Doug
This blog is shaping up to be a fine example of a new kind of 21st century novel...
Written day by day, with rich digital photos...and immediate feedback from readers.
And, like WAR AND PEACE, it covers a lot of ground.
When I look at how many posts this blog has, I tend to agree....it is getting up there.
Now I wish I could figure out how to copy my blog onto a file. :)
And you're spot on...it does cover lots of ground.
I admit it is time consuming (my wife says TOO much) and it has taken away time to write a weather book.
I keep telling myself to settle down, but I think I need to check into "blog rehab."
Captain Doug :)
THe weather here in St. John's is living up to the standards of the land of the four seasons in one day snow, ice pellets, freezing rain, rain, and freezing over and starting all over again. Oh well that what you get when you live in a area that stick out have ways across the atlantic. Anyways goodflying and take care, Chris.
Doug, Thanks again. I've had a chance to study your remarks on braking and I think I understsand *most* of it. If I error in a my quick recap, please correct me. Perhaps in reverse order...
I understand the MAX setting and why it is used at TO: If one must abort, you owant to stop, NOW. The arming speeds were interesting and I can appreciate the need to keep the (Auto)braking action in mind with a low speed abort. Hmm. This sort of leads to a (dumb?) question, but... If I read you correctly, the auto brake function on landing (Low or Med) really IS automatic and is triggered by the mains hitting a certain RPM - NOT the PF touching the top of the rudder pedals. (Interesting and I had thought otherwise.)
I'm guessing here, but it sounds like the Auto Brake system will continue to apply max brake pressure until the main's RPM drops below the arming threshold. Am I doing OK so far? I'm also reading that the Anti-skid is the function similar to automobiles ABS, in that it applies max brake pressure, but quickly backs off when the RPM approaches what might be a lock up and/or skid. Again, unless I've missed something, even with auto Brake off, you can use the anti-skid and max pedal pressure for maximum stopping power - sort of like the pusling that we feel when using max pedal in the car. If I'm still on track, that leads to the last question: In a normal landing with Auto Brake set MED, reverse and spoilers deployed, what happens if you push the brakes? Does it disable Auto Brake or perhaps do nothing? Most drivers in winter climates are familiar with studded snow tires. (Tyres for some.) DO aircraft tires still have those fine wires protruding from the contact surface to enhance runway gripping power? (Be careful, those suckers are sharp!) Thanks Doug, for addressing my question in such detail. I've been wondering about parts of it for ages. You have explained it well and I'm sure that others learned a lot as well. Yup! I can understand why the MAX button is offset just a bit and not used for routine landings. Ias much as I'd love to visit your flight deck, I don't want to make an involuntary visit during braking. Stopping on a dime anyone. So why was this techno business important? Amateur physics, I guess. Airplanes stop with far greater efficiency than do large road trucks. An 80k pound truck typicall has 18 wheeles on the ground, 16 of which are making ax braking effort. The square inches of contact surface (tire to road)are much greater, yet the much heavier airplane (as Max Landing Weight) manages to curb its inertial energy far better. Thanks again! I think I understand it a lot better now. Did I mention that I enjoy your blog . Good stuff, friend and Thank you.
P.S. I never did find the reply about receipt of my letter and the book business, but I have no concerns. When it arrives, I will enjoy the reading. Glad that you had a nice lay over in SF. I made that bike ride x-the GG Bridge some 10-15 years ago and had a wonderful time. It was a but windy, but that goes with the territory. Best wishes.
Doug: As you and others have noted, you do cover a lot of ground in the blog. Your readers understand the significant amount of time that you devote to it and we are grateful. The hit counts, let alone the (mostly) on topic comments suggest that you have a Very Substantial and Very Loyal following. From this reader's perspective, it is fun to see very frequent posts and posts that are on-spot responsive to our questions. I just enjoyed the Rolls Ride, but many other readers have enjoyed a similar response and, boldly speaking for all, Thanks!
Thanks again for the time you do spend on your blog, the frequent posts and amount of time you spend on your responses to your Comments is what makes your blog so popular and unique compared to the other blogs I read on a regular basis.
I hope you'll be able to spend a little more time working on your weather book, I for one look forward to reading it and hope it will become the 'go to' book about Canadian Meteorology! We live in one of the more fascinating countries in the world when it comes to the variety of weather we face.
I'm more worried about my significant other saying "reject" than "them's the brakes" ;)
Blake. Love it! Let's hope it's not a speed reject because things can get heated up pretty fast...brake wise I mean. :)
YYC Dispatcher. Thanks for your comments. I will be in YYC next week on the 22nd (long layover).
Maybe our paths will finally cross?
I posted a response about your book on my post, Day Two of Four. (Sorry I should have sent you an email)
.....Thanks for the suggestion of a post on auto brake. Will do!Sounds like you have a pretty good understanding already!
You posted some other great comments as well. People taking breaks, J class mentality, and a rendition of the good ole days. :)
It's all good stuff. I guess many out there are kind of shy to post. :)
I received your letter yesterday. Again, you are a man of kind words!
I sent your signed book today.
Enjoy the read and again thanks for all the thought provoking comments!......
Looks like you have a great handle on autobrake! And it looks like I forgot to mention how we disarm it. :) There are two ways but my company wants
us to disarm it by applying brake pressure. That sometimes takes finesse because we may apply TOO much pressure. Remember smoothness counts. :)
The other way is to disarm the switch but in the "heat" of things MAX braking may be armed. Not so good. :)
Just readying for an LAX trip.
Doug: Thanks for the update. Of course, I was primarily thinking about getting Big Bird (or Little Bus?) Stopped. You, the expierienced captain, were also considering PAX comfort and avoiding 100 unexpected visitors during the landing roll . That's why the company pays you - and not me. And you answered the supplemental questions as well. (You 'da man!) I can appreciate why AC prefers thee pedal for disarming as a poorly aimed finger, well you explained it just fine. I hope that the L.A. trips goes well. If you approach from the East, have your FO waive to my brother, near SMO's (Santa Monica) departure end.
I hope all of your significant others don't say to you..."Them's the Breaks" in the romance department. :)... reheated lasagne leftovers and a nice bottle of red kept the breaks off for me :-)
Thanks for an interseting post. Just a few further questions (1) is reverse thrust also automatically activated to a set value? (2) when landing in snow do you use max reverse thrust in preference to braking to avoid slippage? (3) in the event of a quick turn around (Ryan-air style) is there a limit as to how much the brakes can be 'cooked', for example is it a risk to fold landing gear with red-hot brakes?
Carlton (looking forward to some sunny weather!!)
Thanks Craig. I will delicate the task to the F/O in finding your brother's place.
Although, he may tell me to go pound sand. :)
I like that phrase..."poorly aimed finger."
Yes, it can get you into trouble. :)
Doug: I looked backward and found your post. The very best part was the hockey game. Uno what I mean. And I understand how I missed it (Sorry). I read or at least scan comments, but only for a couple of days. As popular as your blog is, even older posts generate fresh comments and I guess I miss some of those. Obviously, Capt, Doug sees/scans all. My error, Sir. Why am I NOT surprised that AC has asked you to handle the Pilot Questions for their Face Book page. Congratulations. My only concern is that the volume might explode on you, affecting both the blog and Mrs. Captain Doug - and the hockey team. Perhaps some compensation is in order. Of course, you are a natural for the duty. Months ago, as I read through your entire archive, your objectivity, honesty and polite avoidance of extreme or sensitive issues was obvious. In the end, you have the skill set and experience to represent both your line and the industry, but without clogging up the airwaves with controversy. That, Sir, is called talent. I'm sure that some of the PR folks at AC follow your blog, but take a handful of stats with you, including a reasonable estimate of the hours devoted to your 72nd hobby.
Blog Rehab [perhaps there's one online?]
Some might say that daily entries does not a novel make...but, I disagree. E.g. Bram Stoker's 5th
And, of course, aviation has figured prominently in a few famous novels, like Arthur Hailey's AIRPORT...
Send me an email re: 22nd layover, my schedule is open. I've got a book to get signed, and I've promised you a beer!
Interesting read yet again, thanks Doug! Also sounds like you're getting a lot of flying in this month.
As for the valentines brakes in the romance department, I think I put them on myself by accidentally forgetting to leave a gift for my wife while overseas for a few weeks:( No excuses I know, but expecting an especially warm welcome home would be like putting on that park brake in the flight deck and expecting the aircraft to move forwards:)
Wishing you safe flights wherever you are at. I'll likely be flying over your head on flight 002 when you're on that layover in YYC the 22nd, so I'll have a drink in your honor.
Doug, I forgot to include this in my last comment, but I have a question about night flights. It isn't related to brakes, but thought I'd shoot anyway.
In your book, you mention a benefit of night flights is smoother air. A specifically remember a flight I had from YYZ-LHR on an A330, fin 937 (not that it's significant), where the seat belt sign was on for almost the complete duration of the flight. I were rocked back and forth the whole way across the Atlantic, and at times it felt like we were thrown. After a few hours it got old! I looked out the window several times, but didn't notice any cloud, at least not anywhere near our flight level. It was early September, so I'm guessing it had something to do with an unusual jetstream? It was by far not the norm for a night flight in my experience, but what's your professional opinion on why the ride was so rough for so long?
I too want to thank you for taking the time to write this blog and respond to all of us aviation junkies! It's much appreciated, and it's actually like reading "From the Flight Deck 2", only customized:) Hat's off to you!
AC leases its brakes? I knew airframes and engines could be leased, but not brakes. Better make sure the lease payment is made, having them repoed in the middle of a flight would make for an exciting landing!
On an unrelated note, interesting news about the pilot retirement age issue being kicked back to the human rights board as they didn't take into account all of AC's data submissions. Maybe Capt. Doug will make 767 a little sooner if the ruling is reversed...
Cedarglen (Craig). You made some excellent points. I think the word "balance" comes to mind. Balance in taking on too much and balance with
content on my blog. I can guarantee you my blog is watched and scrutinized. In fact, I met a "stratospheric level flight manager" in flight planning yesterday. He oversees my enRoute and my blog. He said "hi" and smiled. I hope that translated into a further green light.
I just queried AC again about the Facebook gig.
And speaking of compensation...I just received a request to give a one hour talk to a elementary science teacher convention in Alberta.
They are offering $100. Would you go? :)
Good one regarding consulting a "blog rehab" on line. I like it! :) :) :)
Sitting here in LAX on a long layover, although the weather here is looking awful Maritimish (new word). :)
Edwin from Sweden has sent me my blog's HTMLs so now I have to figure out how to put it into a word file.
Who knows, this blog may become a virtual book? :)
Captain Doug in wet LAX.
YYC Dispatcher. Will do! Captain Doug in wet LAX
Christer. I'm certain you can work your charm when you get back. According to Carlton and myself...red wine works. :)
Yes, have a toast and let's hope it's a "J" class toast.
I see Air Canada is distinguishing you frequent flyers by a new ACMM acronym. (Air Canada Million Mile) member. I had one on my flight to LAX yesterday.
Captain Doug waiting for the "red eye" back to YYZ.
Christer. Sounds like your flight was flirting with a jet stream the entire time. When I mentioned about smoothness and night time, I meant with conditions near the ground i.e. no "day time heating" (convection).
I should go back and check what I wrote. :)
A good weatherman must always qualify things.
Thanks Doug, I likely misunderstood what I read re: night time flying. That makes sense though. I've also encountered some pretty nasty bumps eastbound over the Pacific at night.
Yes, the AC Million Mile thing seems to have gained more exposure recently. Not sure if it's a new policy to recognize the uber-top-tier members or if it's always been in place in a more discreet way. I believe it comes with lifetime Elite status, regardless of how much you fly. Currently, I'm only a quarter of the way there with AC, and my other ~400 000 miles are with other carriers. Guess I need to start sticking to the good guys more often here, but living outside of Canada often makes it impossible:)
Hope your red eye flight is enjoyable (then again, do the words red eye and enjoyable even mix?!). Are there any special rest quotas for you guys and gals up front before operating one of those flights?
Doug: You ask even tougher questions than I can pose . At least that senior manager smiled - and did not look down over his reading glasses, saying, "Young man, we neet to have a talk..." Sort of like the Carpet Dance. I think you are on the right path. As for the $100 convention talk, ouch. If you can stimulate some science teachers, it is worth it. Maybe AC can support this a bit. Honestly, if I could get there and back with less than $100 of OOP expense, I would go. The video will get to the kids sooner or later and jazzing them about the joys of science is always a good thing. So what is flying? Last I heard, it was at the high-end of Applied Science. If it can be done without serious pocket penalty, please do!
Christer. Nothing special to do regarding "red eyes." I'm not one for sleeping in the hotel in the afternoon.
But it's funny, as soon as I put my uniform on...I get tired. LOL
Lucky we have the option of "controlled naps" and yes I capitalized. It's all that is needed to charge my batteries. Captain Doug greased it on at 5:00 a.m this morning on the noise abatement runway 15 left.
P.S Yes, more flying with the "good guys" is a must. :)
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