The Pilots Who Had No Options Left | LTE International JY-JAR
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- čas přidán 2. 02. 2022
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On the 18th of may 2005 a chartered A320 tail number JY-JAR was flying from fuerteventura in spain to Leeds bradford international airport in spain. The plane departed the spanish city at 7:35 am and the first officer was the one who flew the plane into leeds. The four hour flight was as boring as could be. I suspect that the passengers onboard were dreading going into work the next day , you know how you get at the end of a good holiday? But for now that was the biggest problem that they had. The A320 was radar vectored to land on runway 14 and theyd be using the ILS system. Before they lined up the pilots went through the approach. They talked about speeds and things like that, they decided to keep the autobrake on low as the runway at leeds was almost 7400 feet long and the weather was good. Today wasn't the day for aggressive braking.
As the plane was on final the captain took over from the first officer as neither pilot had flown into this airport before. So it made sense to have the more experienced pilot in control. Just in case something went wrong.as they landed Their speed was right where it should have been, they touched down smoothly,but they landed 700 meters or 2200 feet away from the end of the touchdown zone. But with plenty of runway left this shouldn't be an issue.
The pilots verified that reverse thrust was indeed engaged and that the spoilers were out the captain even added a bit of manual braking after touchdown. But as the a320 hurtled down runway 14 at Leeds the captain felt that something was wrong. His plane wasnt slowing down as he expected it to. So he applied max breaking and selected max reverse thrust. But the plane didn't slow down. The first officer also was braking as hard as he could trying to get the plane to slow down. The runway at leeds isnt flat there's a depression in the middle and so the pilots hadn't seen the end of the runway. But as they came out of that dip they saw that the end of the runway was fast approaching. The captain knew that the odds of them stopping before the end of the runway was slim so he thought of using the alternate braking system but using that would mean that he would lose his nose wheel steering and he definitely needed that as there were houses just 2000 feet from the end of the runway adding to his problems there was a shallow decline after the runway so if the plane over ran it would slide down a hill. Faced with the very real prospect of overrunning the runway the captain knew that his best option was to take the plane off the runway onto the grassy sides of the runway.
As he decided to do that the plane ran through the end of runway 14 and now they were in the runway overrun area and. The captain put the plane into a right turn and it skidded to a stop. It basically did one of those handbrake turns. With the nose wheel in the grass the plane was safe . They had just narrowly avoided disaster as there was only 35 meters or about a 100 feet of paved surface remaining. To put that in context there was just the length of one a320 standing between them and the start of the downward decline. All 178 people were fine not one person was injured. - Věda a technologie
No blood was spilled, the plane remained almost on the runway, so yes, I think the captain made a sound decision.
Not to mention, the aircraft completely intact without a scratch!
Given his circumstances and lack of knowledge of what was happening, I wholeheartedly agree.
As the saying goes, "Any landing everybody can walk away from is a good landing."
Exactly, and they had an intact plane for examination and to find the reason.
Hats off to the Captain...
Considering everyone survived with out injury, cant argue with that outcome so yeah it was the right call
Agreed!
100% he did the right thing based on the information he had at the time. A data conflict warning would have helped. Anytime a computer has a conflict it should be relayed to the flight crew. In the end they are in control.
The pilot did what he was supposed to do with the information he had, or in this case didn't have. All passengers walked off the plane and the aircraft was not damaged any further.
Nice work by the crew!
If the plane is gone and all the passengers survive, it's a good landing.
IT AMAZES ME HOW THIS GUY CAN TURN OUT SO MUCH GOOD STUFF.
It's the power of a proper paycheck!
@@hariman7727 NOPE. HE HAS A PASSION
@@ronniewall1481 that helps a lot too.
BUT HE CAN'T TURN UP HIS VOLUME IT SEEMS, IS THIS A VIDEO FOR WHISPERERS?
@@supermaster2012 ?
Many of these accidents and near misses will never be spoken about again if not for you. Thank you. Happy lunar new year!
Brother
Every safe flight is a near miss in my understanding.
They fool us that flying is the safest mod for travel
There are many variables otherwise if used to calculate then every safe flight is a miracle actually.
which they won't tell ever
And they lied about the concord crash cause as well.
They said that the Tyre burst and chunk of it hit fuel tank from outside which caused fire....... Come on is this believable....... Not at all. Yes it's possible but very less likely. Because tyres did burst in all the planes many times in past. But never ever this caused a fuel tank fire . And here is why it's a lie m
If this all was true the simple fix would had been to reinforce the fuel tank so nothing same happens again a simple do able fix.
Actually
The big chunk of Tyre entered the engine which caused the accident.
And this is the reason they grounded the concord for ever because this could not had been fixed. Fixing this would had ment complete change of landing gear design and positioning which was not possible.
So if you are scratching your head after reading this all hit a like
@@5thgen418 I’m scratching my head because I can’t imagine what kind of tinfoil hat you are wearing or what kind of stuff are you smoking. Yes, flying is the safest mode of travel of all. Everyday you hear about car crash everywhere, while you only hear about a fatal accident involve a passenger jet at most twice in any given year. And that’s a rare occurence (unless you let Boeing runs amok). And there is statistic given to proof that. I’ll give you a dislike instead mate, a big one at that. If you have ever seen an aviation tire, you’ll realize how massive it is to the human scale. And yes, that piece of debris did cause the massive tire to blown up. The tire wall may be thick, but at high speed, the impact force can be enough to pierce the tire. The chunk of tire on concord wheels not only contain synthetic plastic (a very dense material) in it but also metal wire to strenghthen it. The pressure and heat inside is enough to make it explode. The design flaw of the concord made the electrical wire accessible to maintainance also make it easy to be damage if the piece of wire is cut, creating arc flash. The fuel tank when get puntured releasing the jet A-1 fuel inside the tank, and the fuel is ignited by the arc flash. That’s what cause the fire. Even if the engine is damaged, the pilot can turn if of and cut the fuel like any other jet on the sky. As well as melted aluminium on the scene indicated that the plane was burn through on the wing. And if you don’t know this, the air intakes for the engines of the concord are positioned a bit ahead of the landing gear, ie, it is nearly impossible that any debris from the wheels can fly into the air intakes at take off speed. Just google an image of concord and look. The design of the concord did change after the accident, but by then, 2 airline British Airway and Air France have seen difficulties making sells of seat to the public. Due to financial reason, they decided to retire the type from service. Not everything is a damn coverup, so stop with these stupid conspiracy ffs.
@@NoName-sb9tp oooo please don't give me that more die in cars
Yess more die in cars but millions and millions more travel by cars then planes. So both can't be compared
It's Apple and orange comparison
That's what I'm saying it depends on the variables you take to prove how much safe it is.
Planes had accidents for as small as a nut failing. Cars don't do that
And yess you give dislike doesn't bother me. Neither a like makes me happy
@@5thgen418 are you looking at what you wrote mate? They are comparable as both are modes of transportation. And I am not using the raw number to compare, I talk about the percentage of fatalities compared to total number of users. You don’t think I know that? Beside, plane do get into accidents, yes, but most of the time, they will be scrutinized from the most minor to the major detail and figure out way to stop the accident, with some will have their cause to be undetermined because of missing wreckage and/black boxes. Unlike some people who got off scot free and continue to drive after traffic violation/accident, pilots who cause an accident/incident that has a potential to harm people on board and survived will have their wings clipped. Those who are not at fault will have to retrain after the recovery period to be able to fly again. Airline industry takes safety as a very serious matter, unlike some people on the road.
And yeah, I don’t give a damn if you’re sad or not. I’ve wandered the field of damnation, and it’s barren.
I've had a car where the anti lock brake sensor was broken, it put a warning light on right away. It's amazing that something as complex as an A320 didn't have the same thing.
Car is not plane sensors is old technology and it must change in future than we find better technology . If planes would have same sensors warning as car it would be insane pilots would get errors every 20% of flights it would demage planes and kill people ...
I had the same thought. The thing about abs systems is that when they fail, which is often, they revert to working as a normal braking system. In other words, the computer doesn't release the pressure on the brakes, rather the braking is simply proportional to the amount of pressure applied to the pedal.
The ABS uses asymmetrical signals to detect when a specific sensor is malfunctioning. Don't quote me on this but I think some modules use a threshold to determine whether a signal is good or corrupted. The wheel speed sensors use a hall effect sensor and if you graphed the voltage going back to the module you would see a square wave. I think the computer expects this square wave and if it doesn't see it, it triggers a code for an "implausible signal".
If it was as simple as "no signal from sensor 2" for example, it probably would have failed the sensor and gone into a reversionary mode - whether that would be ignoring that sensor or displaying "antiskid failed" or whatever and giving the pilots manual braking only. The key here is that it was still giving data, it was just too high, and having 2 sensors wrong but in agreement.
I've experienced a number of ABS failures where corrosion on the tone wheel lead to the signal still being accurate at speed, but dropping to 0 slightly before it should. The most common result is antilock triggering and releasing brakes on that wheel.
I even had one car where the sensors appeared to be working as far as the ABS was concerned, but there was just enough of a discrepancy that when I tried to do a relearn on the electronic power steering, it would fail to initialize, without any kind of error message. Had to figure it out by looking at the datastream and picking out the slightly different sensor value.
@@bigdogbandal But the system didn't know that it had failed.
He absolutely made the right call, by the time alternate braking was mentioned, they were far too close to the end of the runway to stop. Listening to all the problems these safety systems can cause almost makes me feel safer on older planes....almost. Then again, we don't hear about the incidents and accidents they prevent, do we?
Well, this system is equivalent to the ABS on a car. The pilot made the right decision, cos just like in a car, when your brakes fail, you swerve away from the obstacle. The crew decided to steer the plane off the runway, protecting the plane and pax from the hill. Also, modern planes are quite safer compared to older ones, since in the 1970s, many planes did not have TCAS or terrain systems. :) 10/10 piloting skills.
@@thatguyalex2835 That's a good comparison, unfortunately my car doesn't have ABS, so I just accept that if I'm a Muppet I'll skid. That's not something that you can do with 179 passengers. A+ pilot diagnosing and reacting to a problem on the runway.
@@thoralexander9387 Amen to that. Those pilots deserve recognition by the ICAO, their airline and local governments, and a big fat bonus in their paycheck. By the way, I don't drive, even though I am in my 20s, cos I have a lot of ADHD. A bad combination of that disability and an unfamiliar situation would lead to a crash. :) I do know how ABS works somewhat though. What model of car do you have? Most cars made in the 2000s-today have ABS. Newer ones also have autonomous electronic braking (AEB), such as Volvo.
@@thoralexander9387 "so I just accept that if I'm a Muppet I'll skid" FYI what the antiskid system does is try to keep the tires rolling at about 10-15% less the the speed of the vehicle, i.e. a slip ratio of 10-15%. Depending on the surface, that's optimum for achieving maximum deceleration. But even without an A/S, you can practice (somewhere safe) modulating the brake such that it just hangs on the edge of a skid vs letting the tires lock up. Won't be nearly as good as ABS, which makes the adjustments more like 100 times a second than 2 times a second, but it might still be enough to make the difference sometime.
@@thatguyalex2835 1987 Pontiac Fiero
Not only is he a great pilot, but a phenomenal driver too! He absolutely made the right call. I don’t think he had enough runway to make a go-around.
Did I hear right, there were 19 other incidents like this before, and Airbus hadn't addressed the problem?
Yes you did. That is reprehensible. But wait: It took 2 crashes for Boeing to take a look at the heretofore secret MCAS!
@@milantrcka121 Yes because every soul on board those 2 flights were lost. Unlike the 19 airbus incidents 😅
@@matisbabau6825 no souls would have been lost if Boeing had disclosed the MCAS software and pilots were required to train for it. As Boeing saw fit (reprehensibly), there was no difference between the 737 Max and previous versions of the plane so no training required - resulting in the loss of 346 lives.
@@michaelwatt1718 I don't care about their shoes, I care about their _lives!_
@@Milesco typed in haste - I edited the comment to prevent further confusion as this was an obvious tragic series of events
Absolutely he made the right decision. Everyone walked away safe and I assume the aircraft was repaired and put back into service. Great informative video.
When all known regular means of stopping fail, ground loop it. This maneuver saved me once in Papua New Guinea. Long story.
What's that mean?
Honestly, these sorts of 'near miss' saves are just as interesting as when things end badly. It reveals a lot of skill and fast thinking of the pilots.
loss of braking memory item calls for turning off the nose wheel steering which will also turn off the anti skid and in turn stop the aircraft. directional control can be maintained by differential braking. Would've it resulted to a better outcome, perhaps yes, but it is easy to say at the comfort of our chair. Its a different world when sitting on the cockpit
Pilots would loose license doing it second time so it's nonsense .
@@axa897 what doing it second time? sitting in an arm chair?
Yup. The pilot had less time to make his decision than it took the video to describe the situation.
Directional control via differential braking can be quite tricky with the antiskid turned off. That's how DAC drove a DC-9-80 off the side of the runway during the flight test program.
I'm guessing here, but I'm pretty confident that that memory item wasn't there until after this accident. I think this partly because updating procedures is something we do after every accident, and partly because there was nothing about the pilots failing to follow procedure.
I love these because they're so listenable when I can't watch a video and descriptive enough that if I am familiar with the incident I don't need to go back and watch it
There were two system problems. First, the lack of a "wheel spin" annunciation which would have got the pilots in the loop. Second, the lack of any warning about the bad brake sensor, which undoubtedly meant it was ignored until a second one failed.
I live quite near LBIA and its location is far from perfect. It's a converted wartime airfield as many airports in the UK are, but its position on top of a hill gives the runway that weird vertical profile, plus it's literally always either windy or foggy there!
I think any time a pilot manages to land a plane safely with no major injuries to passengers means that pilot made the right decision. I can't imagine the kind of stress the flight crew were under when they didn't know the source of the problem and had only seconds to make a decision to avert disaster. Hats off to this flight crew for keeping their minds focused on the basics....save the passengers.
Thanks for another great video. I love how you narrate and ask questions of the viewers. It makes it seem like we are right there with you. Love it! I think this channel has a bright future!
Amazing story. I always enjoy technical descriptions and information. Good job.
Thank you!
Yes, I think the pilot made the correct call. He did get the plane safely stopped, with no injuries to the passengers.
That wins the day for me. He was failed with a terrifying scenario and devised a solution not likely in the manual.
Absolutely he made the right decision. He then needed the steering to make his life-saving move pulling it off the runway !!
This is a classic example of unpredictable errors in complex systems. Thank goodness for skilled pilots that can catch the erratic in time!
Automation without indication is unbelievably dangerous!
With indication and override capability:
Plane: "ABS active" (on screen msg)
Pilot: "There's no way we're skidding." *turns ABS off*
...no problem...
I'm an auto tech and have dealt with this on trucks one wheel sensor will lose a signal and the abs thinks the wheel is skidding and activates but on cars it does turn on a light.
The problem with most sensors is that you will get 10 bad alerts due to sensor breakage or other, leading the pilot/driver to stop trusting the sensors.
Losing a sensor is different from having erroneous signals from a sensor due to mechanical issues. People are trying to compare apples and oranges here.
@@ImperrfectStranger yes, the core root from a "system level" is two erroneous signals that agree with each other.
If any one thinks car have better software: Michael Barr "Toyota and Unintended Acceleration".
@@ImperrfectStranger yes and no the problem i was talking about is an interment signal it's not just off its on and off.
I always assumed runways were dead flat and smooth, I didn't realise "humps" and bumpy topography was allowed
These 'bumps' are not as dramatic as you may think. Runways are very long (for commercial runways typically between one to two miles) and it is both expensive and unnecessary to smooth out gradual unevenness for their entire length. When you see the dramatic picture of such 'bumpy' runways keep in mind that this is a 'bump' that's usually less than 50ft in height (heck, even 20ft) spread over a length of several thousand feet.
To understand how much of a perspective picture 4:05 is keep in mind that each of the 'short' (from this angle) dashes down the center of that runway is almost the entire length of that A320. (check against a satellite photo of the Leeds airport on Google Maps if you don't believe me) That runway is much smoother than you think.
Yes I can't get around not having a warning for failed brakes. It would be horrific if this had gone wrong to find out. Reminds me of the Gotrorra miracle where the pilot never recovered faith in flying after that. Such incidents can be that traumatic
Car braking systems were safe. Then they added anti-lock brakes ! I'm not so sure they're safe any more !
The problem is, the brakes hadn't failed. Rather, a computer was getting corrupted data that it thought was correct, and so it eased up the brakes to get the wheels to match the expected value. The plane couldn't tell anything was wrong, so it couldn't have possibly warned the pilots that something was wrong.
@@millomweb Have you ever driven a car without ABS? On my way into work for an early-morning flight test* one day, somebody pulled out from a cross street without looking. Stopping within the available distance in my Mazda6 would have been trivial. But it was instead my '68 Mustang, and I never had a chance.
* Irony Dept: It was a heavy braking test, exercising the airliner's antiskid at 2000 psi brake pressure.
@@marcmcreynolds2827 I've driven many vehicles without ABS including my bicycle - and the lack of ABS has not caused any problems.
I have 'spun' a car in the snow - it didn't have ABS but if it did, it wouldn't have mattered as the braking was only engine braking. Car was unfortunately front wheel drive - far from ideal in snow.
I've driven a truck that THANKFULLY didn't have ABS - the front wheels were sliding but without ABS, the back brakes continued to work.
Without ABS, I have control. With ABS, I lose control.
@@millomweb Sorry to hear about your snow troubles. Sounds like you avoided collisions at least, which is more than I can say. It's been better luck with my mountain bike, the front brake adjusted so that its tire won't quite lock under most conditions. Steering authority is thus still available for oh-shoot! situations.
FWIW, the only time I know of that an airliner came out ahead without A/S was when a quirk in the DC-10-30 Center Landing Gear's braking dynamics caused a couple of incidents where the struts snapped off right as the aircraft came to a stop on the runway. The solution ending up being to disable A/S (on the CLG only) below 5 kt. But entire landing rollouts without antiskid tend not to go well.
Yup I think he made the right call. Not slowing down before heading into the ditch or taking sideways to the grass. Brave thing to do given the gear might be damaged but to me the litmus test is it stopped within the runway curtilage meaning emergency vehicles could get there simply. And everyone walked away.
How easy it would have been to freeze, standing on a useless brake peddle.
Thank you for these videos bringing lessons from experience to our knowledge.
*breaking (as promised)
I think that the captain made the best decision possible based on the knowledge he had at the time. And you were right, I did not see the case coming!
THEY SHOULD STUCK FEET THROUGH FLOOR AND DO A FLINTSTONE
@@ronniewall1481 LOL! Thanks for the laugh!👍😂😅🤣
@@joannegaughan6132 I LOVE TO WRITE BAD JOKES.
Such a well done description and analysis! I like how you lay out the events first and then get deep into the 'why'
I think the pilots did perfectly, their overwhelming mandate is to protect the safety of the passengers. They came over the hump, saw the end of the runaway and took an option (immediately) that would protect the passengers and the plane from a potentially catastrophic overrun. I for one will always choose a pilot that does something reasonable right now rather than sitting around and thinking about it With the aeroplane way fast and the end of the runway coming up surrendering control by locking the front wheel when they did not know what the problem was would have been foolhardy. They had landed long which might be held to have contributed but since they did not know the runaway that is not unexpected (it's a lot better to land long than a bit short).
Thank you for making this video! It's nice to see you post such in-depth analysis videos every time. Very neutral, thought-through and extremely enjoyable.
I saw how few views this video had, and thought “that’s weird, this sounds like a new video”. Checked the comments, and realized that YT had recommended a video that had been out for only a few minutes. Thanks CZcams!
Ever watch a whole video and THEN realize it literally just came out? CZcams recommends this stuff fast
You are very good at explaining complex systems in an understandable way.
Your videos is always entertaining, keep up the good work man👍
Oh, that's exactly how we stop real quickly when skiing! Your stop is smooth and immediate. I never though of a plane stopping like that but it is the same action so makes sense!
Thanks for keeping us updated
Never heard of this near miss, I live in Leeds and have flown out of the airport before. Glad it ended happily!
It's basically an ABS system causing a full brake failure.
Like a GM vehicle in the early 90s. When the ABS module failed you lost all braking, instead of reverting to conventional brakes.
Zero deaths, seems like the captain did it right, congratulations to him.
What baffles me is if the rods were damaged in the circumstances described why did the malfunction not show itself till this flight? Could it have been this landing that damaged them?
That’s the reason Aviation accidents are thoroughly investigated to the core. Because failure is waiting to happen and one can’t exactly predict when it’ll happen. Find the weak links and eliminate them before it hits hard.
and on both sides also. like a fork lift bumping into the rod on one side drives around the other side and bumps into the rod there too. whilst we are at it the forklift might as well bump into the front wheel.
If you do not know that you need to look for a bend rod/axle and think about resonance modes:
The plane might report a short term sensor disagreement (at a specific tire rotation rate it transitions trough during landing).
Maintenance sees that on the log.
Checks the sensor visually.
Checks the wiring.
Spins the wheels, checks the data read back and sees nothing wrong.
Sign off for "inspected and tested".
Without knowing that it is resonance at specific RPM or that bend axles are a problem, you would not come to the idea to do the relevant tests:
a: measure the dimension of the axle against drawing
b: start the wheel at 0 RPM, slowly turn up to full speed, slowly break down to 0 RPM.
Note that replacing parts is not the solutions:
When sensor data is incorrect, it is easy to just replace sensor and wire and mounting it to the defect axle.
It is really important to replicate the problem.
Sounds like there needs to be an audible warning when the system detects what it thinks is wheel-spin/skid, and a button for the pilot to press if he wants to override the system and have direct manual control on the braking.
I like that thinking but: That would require a specific training, as breaking without anti-skid means longer distances and limitations to steering.
"Better alternate breaks then no breaks" - yes, but any system needs training.
Also in climates and airports where anti-skid engagement is normal (landing on ice, wet run way and/or short runway), the "warning" should not be a warning sound, just "a sound" or haptic feedback (like car abs that audibly and in a way you feel released pressure on the breaks). Tricky. In situation where anti-skid is very helpful, knowing that anti-skid is active makes sense and no pilot would disable anti-skid, because well: How those the pilot know that antiskid is working correctly (making the breaking safer) or incorrectly (disabling the breaks for no valid reasons)?
One problem: on a plane, every single touchdown starts with a skid on all tires.
Any plane, any conditions, there'll be at least a momentary skid as each tire first touches the runway.
I have always been amazed that all airfields are not flat (except of course allowing for drainage).
Just difficult to get large chunks of flat land, I think, and even small airfields still really aren't small.
I took some lessons at my local airfield, and their main runway definitely isn't flat (even though the taxiways mostly are).
Also there's not a whole lot of choice about where to put a runway within an airfield:
- Orientation is dictated by prevailing winds
- Runway itself should be as long as possible
- Runway needs empty space beyond each end - partly for overrun, but mostly so you're in clear space just before touchdown and just after rotation/liftoff. Less of an issue if you don't need the full runway length of course, but definitely crucial if you want the runway to actually be usable anywhere close to its full length.
Gotta say though, it's really nice taking off from a runway that's /way/ longer than your plane actually needs. In our takeoff briefings, most of our plans for engine-out on takeoff were just "come back down and land a bit further down the runway" - it would have taken a pretty unlucky engine-out to make us land in a nearby farm instead.
Ekolot Topaz btw - absolute joy to fly, if you ever get the chance. And jeez it accelerates quick.
He had no other option- once reverse thrust is selected a go-around is no longer possible.
Alternate braking wouldn't have an impact on nosewheel steering.
He could have selected the parking brake on intermittently.
That was his only option.
6500hrs on Airbus.
The pilot definitely made the right call. He should be applauded for his actions.
Excellent job on this !!
I would love an aural "Hey you lost your brakes!" Good one! Great video as always!!
Of COURSE he made the right call. The airplane was not damaged and everyone walked away. Merry Christmas. It was a nice vacation.
So one of the functions of the BSCU is essentially like ABS in a car. Even in cars, the ABS light would flash on the dash to let you know the system is preventing a skid. Why wouldn't a similar thing be present in the cockpit? At least the pilots would then know the computer is erroneous in detecting a skid
Yeah, that would be a helpful addition. Although, not all cars equipped with ABS actually do illuminate the light on activation - on some its strictly an error light, even when they have a TCS light that does illuminate when traction control is triggered. There isn't any real consistency in the systems, in my experience.
That light would flash on touchdown, every single time. The tires always skid as the wheels get spun up from zero to whatever speed the plane's going - that's why you see little puffs of smoke on touchdown, and why plane tires wear out so fast and have to be re-treaded all the time.
Thanks for another great video
I wish every five days would arrive daily.
You have excellent videos MACI.
Thank you.
did he make the right call? It worked, didn't it? So, yes.
this channel has amazing quality content. Keep it up!
Yes. Great work cappy!
Excellent job by the crew
"..being fed corrupted data..."
I know how this feels.
Another great video, thanks for doing these.
This has become a bit of an essay, because automotive electronics are my jam, so, apologies.
This system would work precisely like ABS (antilock brakes) and traction and stability control in a car. Basically all four wheels have individual speed sensors (a reluctor wheel basically made of a metal ring with raised bumps in it, and a magnetic sensor which counts them), and if a wheel locks up, or if the wheels are turning at different rates outside of a predetermined limit, then the ABS will modulate the brake pressure to that wheel, or it will apply brake pressure autonomously even if you never touch the brakes. Another thing the traction control will do, is it will take control of, and retard the throttle and a couple other things (fuel, ignition timing, etc), to basically stop the engine from producing any more power. Newer systems won’t do this as much, but older systems were in for a penny, in for a pound.
It’ll rapidly release and reapply brake pressure, giving the wheel as much grip as possible for as long as possible without locking up. If you’ve ever wondered why you feel the brake pedal pulsing when you stand on them, that’s why. The modulator is basically taking control of the brakes.
These systems are so advanced that cars now have ride height sensors (which apart from a few other things, is used for roll and (I think) yaw sensing), accelerometers and gyroscopes, that all feed into your traction control, and the ABS modulator will stab at each of the four wheels in whichever way is needed to keep the car in as straight a line as possible.
The ride height sensing comes in handy because if you are in a turn and the car is leaning to one side, for example you’re performing an evasive manoeuvre, the traction control system in the car will do what it has to do, to keep you where you intend on pointing the car.
There’s another thing called brake assist. Basically the computer is constantly measuring the brake pedal; how far you move it, and how fast you move it. If you are progressively braking, even if you apply maximum pressure over a longer period of time, it will leave you alone. However if it determines you are doing a panic stop, even if you don’t stand on the brakes, the computer will stand on the brakes for you, because it knows how you tend to drive, and it will learn the difference between a normal stop and a panic stop.
All of this happens from dozens of sensors, feeding into multiple computers, hundreds of times a second. It really is amazing the amount of technology out there in every modern car on the road, and people have no idea it even exists, no less what it does.
Haha, and I unplug sensors to disable the systems so the car behaves predictably. I don't like it jamming on the outer front wheel brake to pull me wide when I'm trying to scoot around a corner. I usually keep ABS, but I stay ready to yank the parking brake lever for times when it intervenes too much. Locking the center differential lets the parking brake stop all four wheels, and the situations where I'd have to override ABS tend to be snow or ice when I probably already have the differential locked.
It was a pilot error in judgement. A320 has a loss of braking memory item, incase you suspect a loss in braking, you put the nosewheel/antiskid switch to off, enabling the ABCU to brake using alternate circuits. Had the crew done so, the tachometer inputs would be disregarded and full braking power be restored. That's why memory items exist, it has to be applied, rapidly and from memory.
The pilot monitoring (the copilot in this case) always monitors and calls out 3 things, spoilers, reversers and decel. The decel call is when he feels the deceleration and if he calls no decel, the capt has to apply the loss of braking memory item. Clearly these calls were either not performed or performed by rote
I don't know as much as you, but I think you're right. Everyone who says the pilot made the right decision because the outcome was good is displaying faulty logic. People make bad decisions with good outcomes all the time, like drunk drivers who don't crash. The video makes it sound like wanting to keep steering ability is reasonable, but pilots are supposed to read the operating handbook and understand all the systems precisely because things like this happen and you need to know what options you have when certain systems fail.
Good point, but at the same time, if the pilot applies the brakes and the plane doesn’t stop, I wouldn’t call that a safe airplane.
@@mikeguitar9769 the airplane is a machine consisting of millions of parts. It requires thorough inspection and maintainance. Somewhere, someone's small lapses may have lead to the brake failure. Airbus has considered for such failures and provided for actions to be performed from memory. It is criminal for a qualified pilot not to have performed the loss of braking memory action.
That bump is a bugger. I was cabin crew out of LBA for a while.
Wow I have never flown out of LBA so I did not know it had a hilly bit in the middle...... Great video Mr Mini 💜😁
Another great and informative video - thanks. Yes, I think the Captain did indeed make the correct decision.
Pilot kept his steering with his steering. He made the right call!!!
You have a very nice voice! I don't really listen to the videos or watch them (although they are interesting!). But I just open up your channel on "play all videos" in the background when I play online chess. So soothing :D "Their brakes faild" - "checkmate!"
Thank you
Yes, you are right - even my car detects and announces brake failure. It also seems like a horizontal accelerometer would be handy. It would have shown the the negative acceleration during braking was too low. In addition it could monitor positive acceleration during takeoff and compare it to expectations. That would fix those cases where the power was not set correctly. Perhaps they have them already - i don't know.
can't blame the jet's confidence: didn't let a tiny rod stop him.
This is the sort of error tolerant software d sign that I think is so cool. Actually figuring out how to determine that sensors are inaccurate in cases like these can be quite difficult but - as seen here - very important.
Given the information and the time he had to make it, I believe he made the right decision. Very well done video documentary.
Great job!
Coincidentally I have to write a mini report about anti-skid brake technology for one of my assignments this week (I've yet to start)! How timely that CZcams recommended this video to me today 😁
If my car's ESP can flash up a light when it is operating, that plane's equivalent can probably do the same. On the other hand, there is no indication for an ABS action, other than the back-pumping of the brake pedal.
Good job by the captain IMO.
He made the best decision with the information he had and prevented a more catastrophic event.
I agree that neither of the pilots had flown to Leeds before. But the approach / runway charts would’ve definitely indicated that abnormal bump at the near end of the runway. All is well that ends well. The captain's action is commendable as 178 people survived without injury.
I think the problem wasn't that they didn't know about the bump, but that the bump was there and prevented them from seeing the end of the runway. Just knowing that doesn't give the pilots the ability to see through the runway.
@@MrDorn123 Knowing the existence of bump could have lead to an informed decision.
Smart decisions by the crew!
This guy sure made the dam right call
Yup, right call. And yes, I'm also kinda surprise the airbus a320 decided not include an indicator for the breaks stopping, even if it wasn't an error (in other cases/ contexts)
This was a good video and I love that you explain this so well! I was critical of the last video I saw of yours, which was the first I had seen from your list, but this one has made me a subscriber to your channel.
I think the captain made the best call he could and I think it would be wrong to bring that call into judgment when it was not you or I in the pilot seat. No one was hurt and so how can we in any way suggest that what he did was wrong. I could have been a much different story here.
I think they need to add an alarm and I hope that their software update will fix that issue. The software is important and having anti skid is a good thing. Too many times planes have skidded off the runway and it doesn't always turn out well for passengers and crew.
Thankfully, their boss knew how to play the right 'deal-with-it card' as things became rather clenchworthy. Nicely done : )
This sounds similar to an anti-spin system in a car or perhaps ABS brakes.
My car flashes a light on the dashboard when the anti spin system is used, and if ABS is engaged, there's a distinct feel in the brake pedal.
If a car can provide this very basic level of feedback, why can't a plane with so much more instrumentation?
Are you sure the light isn't for traction control? That tells you when your car wheels are spinning under acceleration. If your light is flashing during braking, you have a fault. Also, you're trying to compare a 60 or 70 tonne aircraft with a 2 tonne car. The feel you get in your car's braking will be different. There are strong springs on aircraft brake pedals and long lengths of steel cabling, then long lengths of hydraulic lines. The pilots are much more detached from the actual braking surfaces on the wheels.
@@ImperrfectStranger It may be well be traction control, not anti-spin. I'm not a car expert. I never said that that was the same as ABS though, that is of course different to traction control (which I erroneously called anti spin). The point is, the systems in a car are set up in such a way that the driver gets feedback when these systems are in operation.
I greatly enjoy your videos! Truly! Unfortunately, there's a problem with your conclusion. The Airbus took the information it had available and came up with the wrong answer. It wasn't able to calculate a warning for the pilots because of the information the computer received. Hope this helps! Please keep it up! Really enjoy them!
Great graphics!
Hi, great mini reviews/investigations, really nice. Just a small technical correction if I may.
The wheels on an aircraft do dot have "Drive Shafts". They have an axel shaft or connecting shaft to connect the inside and outside wheels.
A drive shaft is only used on a vehicle to transmit power drive to the wheel(s) and vice versa, like a car's drive shaft.
Been through there many times. If you take US212 there's no truck fuel between Harding, MT and Belle Fourche, SD, 212 miles. There's only a few spots where it is safe for trucks to park. But the scenery is nice and Montana usually maintains the roads better than Wyoming in the winter.
right call. any crash landing you can walk away from is a good one.
I would’ve thought a go around would make sense if they couldn’t slow down fast enough, but given everything they weren’t able to tell that, so second that i think this was the most sensible call
Essentially an Aero version of ABS, Minus the pulse pump (at least as described here. But ABS' version of "easing off" is switching to pulsing, and here "easing off" means just easing off!
They sent the BSEU to Mr Carlson's lab.. and it needed new capacitors :D lol just kidding.. great video!
I think that he made an acceptable call with what he knew in the situation he was presented with. I'm very surprised that there isn't a wheel skid indicator for the braking system as a backup, because if the crew had had that information they may have realized much earlier that their ABS system was in error and they should override it, allowing a better call to be made.
how many gages do you want in a cockpit that the pilots have to scan regularly, will also controlling the plane? it is a tricky balance.
They should put up a sign on the runway, "The end is near!"
Oh wow, mad respect to those pilots though!
Okay, sensors get installed for known issues and problems, frequently on the statistical chances of those problems becoming catastrophic. A weird little harmonic from a tachometer shaft that causes a "dirty signal" obviously didn't sound like the level of issue that Airbus needed to address in priority. As pointed out in the video, that brake control system was being phased out, SO even with other incidents, apparently there were no disasters to speak of, throughout the brake system's life to date...
Redundancy is spoke of frequently in aviation, and Airbus probably presumed there was a "vanishingly rare" chance of the brake controller destroying the plane. SO they didn't build a "Tachometer Shaft Condition Sensor" to install. It's just that simple. They chose to rely on the Computer and Filters to decipher the "noise" out of the signal and still perform relatively normally... "With all the redundancy, what are the chances of ALL the brakes failing?"
In any case, while there's a VERY Robust error reporting system, it's ONLY going to be able to report errors that the SYSTEM knows about, and without knowing about the potential of bent tachometer shafts, it ONLY knows that the sensors have sent information that the Computer COULD use to determine brake pressure and thereby EVERYTHING "was doing the job correctly" as far as the Computer knew.
AS to the Pilots... Considering there was no good way for them to know or acknowledge the failed brakes before they were about to run out of runway, they ABSOLUTELY made the correct choice to save the plane and passengers, to avert disaster by slipping the plane into the dirt to the side, and avoiding crashing into a Suburban neighborhood. ;o)
Definetely the right call. Had the Captain used the alternate braking system and it hadn’t worked, he also wouldn’t have had steering.
At that point, considering they had no more runway (or not enough) it would have ended horribly.
Even though the plane had ABS it wouldn’t have helped because everything had failed. Consummate skill by the Captain and FO.
I do have to add that even my car has a light that tells you there is something amiss with the braking system.
On the ground, plane undamaged, no one hurt. Good calls in my opinion.
Even cars tell you if the anti-lock brakes are active... Seems a bit ridiculous that a thousand-ton flying machine with a hundred people in it wouldn't have that
It does actually tell you if the brakes are engaged, and the anti-skid system is just a button switch away. But as this wasn't apparent to the crew until it was too late, I don't really expect them to check it as they wouldn't have enough time to troubleshoot the issue given the circumstances.
The plane will have more systems that give them an approximate ground speed. These sources should be counter-checked versus the speed derived from the wheel rotation and a significant mismatch be fed to the pilots, who then can disengage the anti-skid system.
Also, cross check with the nose wheel.
Also, as an advanced feature, if a wheel is slow (skidding?) and not speeding up despite no brake being applied, the computer might want to try using the brake to see if the wheel slows down quickly (it is skidding) or not (not skidding) and on release, what it spins back up to and how fast.
There was no “malfunction” alert because the system had no way to find it may be malfunctioning - due to a lack of cross-checking with other sources.
Finally, a magnet or two (balance) on the wheel rim and a spool near them on the gear structure will give impulses hinting at the speed - allowing a simple facility to check if the tachometer for the wheel seems sane.
It weighs around 70 tonnes good buddy. I get your point though.
Are you suggesting that F=ma is more reliable than sensor data? :)
Thing is, the ABS equivalent /was/ active. It just thought it was dealing with a very slippery surface, and had no way of knowing that was unreasonable.
what about the reverse thrust braking? does this only work at higher speed? the pilot should be complemented for his quick action in using the grass as brake. no indication of anti lock operation is a case of poor design
Reverse thrust will provide some aerodynamic braking even at slow speeds, but it greatly decreases as the airplane slows. Also, the turbulence created by reversers at max power at slow speeds can cause the engine to backfire and can also lead to engine overheat. Reversers are generally stowed at 60 knots (around 70mph/110kph) to prevent this.
Aircraft brakes are far more sophisticated than car brakes. It's just that this quirky dual defect produced some resonant frequencies which told the aircraft that the wheels were slower than they actually were. In similar circumstances, I'm sure you wouldn't have got a warning on your car either. The wheelspeed sensors were still producing signals and these signals were identical.
You should make a special video just documenting all the acronyms pilots have to memorize.
Captain did excellent
What can I say about the captain. What a stud!!! Fast and the Furious Runway Drift!!! It was a creative decision that was justified in the circumstances. If the main brakes failed,he was right to not trust the back up brakes. Also why can't planes monitor the decelleration profile and alert crews if it is well below spec for a slippery runway. It can also have a dist to stop calc based on how many g's of decel is detected.
I had a car loose antilock in the middle of an emergency lane change. It resulted in a spin. We got lucky, no injuries, but we did get hit by a van.
The crew kept cool heads and because of that no one was injured; the decision made in the context of the situation marks perfect sense and reflects a clear safety-minded reasoning and follow-through. And to echo some of my fellow commenters:
"I've had a car where the anti lock brake sensor was broken, it put a warning light on right away. It's amazing that something as complex as an A320 didn't have the same thing."
"Did I hear right, there were 19 other incidents like this before, and Airbus hadn't addressed the problem?"
Yeah, the real problem here isn't in the cockpit. It's in the engineering teams at Airbus and the aviation authorities. There was enough info to address the issue, and it had not yet been. I find it a bit stunning how many near-misses or accidents occur due to lack of warning. A couple examples being Aeroflot and the lack of warning on partial autopilot disengage, and same for a plane going down in a swamp in Florida. A pilot can only work with the information they have on hand. If accurate information isn't provided, it's a bit hard for them to do anything about it.
The pilot basically did the car movie style stopping the car very close to a cliff, but in a jumbo jet! And nobody injured! I give him a lot of style points alongside the already S rank problem solving skills. So it's an S+
I would say the pilot did what he should and sounds like he averted not just a disaster but any damage to the plane. Other than likely needed some of the cessions in the cabin needing cleaning.
As for what sort of alert. There wasn't really a fault that a computer could readily detect. Because as you pointed out, the breaks didn't fail. However, what would have been useful and still would be is if there was a visible and audible alert when a wheel starts to "skid" and which one.