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Details emerge of Air France B777 landing incident (aerotime.aero)
170 points by jtc331 on April 28, 2022 | hide | past | favorite | 172 comments


As soon as I heard the plane was "unresponsive" to controls I immediately though pilot error just because how unlikely a plane is to be actually unresponsive to controls.

Edit: Wow - reading the report I see they got to a 24 degree pitch angle on go around? That seems high, I thought you topped out at 15 or so. This is Air France stuff all over again with the pitch up into a stall etc. I'd love to know how experienced the FO was.

"Eventually a point is reached whereby any further increase in angle of attack does not produce an increase in lift, and this point is called the stalling, or critical, angle of attack. Each airfoil has a different critical angle of attack, but with typical general aviation airfoils it is roughly 16 to 20 degrees. "

Pitch and AoA are different, but during a landing / go around you are in a low speed regime and it just seems like pitching to nearly 30 degrees nose up is excessive. Is that Air France's standard go around vs 10-15?

The true story might be that the captain saved this plane with his nose down inputs.


It really differs per plane, jets pitch up higher than typical general aviation aircraft during rotation and go-around. The 737 for example will command 15 degrees pitch up on the flight director when going around. If you did that on a typical general aviation trainer aircraft you would stall. We teach for example 7 degrees on the DA42 which is a typical multi-engine trainer for future airline pilots.

In a jet you'll pitch up to 15 degrees initially, reduce flaps (if landing flaps were selected, for example from 30 back to 15), then once climbing you'll retract the gear. At that point you're going to have to pitch up much more than 15 degrees if you don't want to overspeed. It all happens much faster with two big jet engines compared to an underpowered general aviation plane.

Especially if the crew thought they had an emergency and went full power combined with a light fuel load, you would expect a serious pitch up to avoid overspeeding the flaps.


Thank you! Extremely helpful.

Yes, on a small GA going to +24 degrees on a go around really jumped out as high, especially if you were starting low and very slow (on landing not uncommon). But I have zero big twin knowledge.

I wish they'd included a speed plot to go with the pitch plot. The plot does show what looks like full power. Given flight duration fuel would have been way down so plane would have been (relatively) lightish most likely.


> At that point you're going to have to pitch up much more than 15 degrees if you don't want to overspeed.

What's the risk of overspeeding? Can you actually reach speeds that are dangerous to the engines while climbing?


The problem is that the mechanisms that hold the flaps in place can be damaged resulting in loss of control over the surface. Sometimes a flap on one side of the plane will be damaged and, when you go to retract the flap, the plane will start to roll. Also the flaps can be torn off the plane.


The engines will be fine, but the airframe has a maximum speed in each configuration. For example the gear can't move above a certain speed and can't be down above a higher speed. Similar for the flaps, at a 30 degrees landing flaps setting you have a fairly low maximum speed. Have to retract flaps to be allowed to accelerate further without damaging them.


How would it be reaching such a high pitch angle with two opposite inputs on the controls? Doesn't that mean one of the pilots is still trying to increase pitch?!

Also it seems crazy that a modern aircraft can have pilots silently fighting one another for controls without realizing it. If standard practice is to have only one operating the controls at any time, why not a switch that enforces input from only one set of controls?


That is exactly what happened to Air France flight 447 (two pilots operating controls in different directions)

https://www.popularmechanics.com/flight/a3115/what-really-ha...

(https://news.ycombinator.com/item?id=31193445)


Or an alarm that says “hey, you’re fighting over the controls!”


I guess that's because the flying pilot might become incapacitated at any time (i.e. stroke, heart attack, ...), and then the other pilot has to take over as quickly as possible, and an additional switch that they have to locate and flip would need more time than just moving the controls?


Airbus planes DO have a button you can push to override and claim exclusive control through your "joystick". Otherwise, at least in normal control law I think, it averages the inputs.


In that specific plane, both control columns are physically connected. Moving one will move the other and controlling both will make you physically fight over the controls>

There is a safety feature where if you put enough force on one control column, you can break this linkage. You then have independent control, but the left column will only control the left ailerons and the right column only the right aileron. I assume the second case happened on this flight, but I cannot be sure.

There is no such switch or alarm because for Boeing planes, that's how they are built. The left column connects to the left wing, the right to the right, all via cables. In order for one column to control both, there have to be cables connecting them


You're thinking of older Boeing designs. The 777 is fly by wire.


Woops, I am indeed, thanks for the correction


There is still something weird going on with the inputs though isn't there?

How could the first officer be confused by the 7° bank angle even though he was the only one flying the descent?


Important also to remember that after the FO, who was pilot flying, first expressed surprise that something didn’t seem right, the period of confusion lasted only about ~45 seconds before the captain confirmed that he/she had taken command. Quite a long distance at about 130kts but not a long time in human problem solving terms.


> Pitch and AoA are different

Is pitch the angle of the wing, and AoA the angle of the wing relative to the fluid across the wing?


Yes


Pitch is the angle of the plane rather than that of the wing.


If the angle of the plane and the wing aren't the same and fixed relative to each other, you're probably already in thoroughly deep shit.

The only plane that ever went into production where the angle of the wing could be changed relative to the angle of the fuselage (other than on the way to the crash site) was the F-8 Crusader [0].

GGP post has it correct.

[0] https://en.m.wikipedia.org/wiki/Vought_F-8_Crusader


Except on stunt planes (and maybe fighter jets?) that are designed to fly upside-down a significant portion of the time, the wings are angled relative to the fuselage. Otherwise the whole plane needs to be in a nos-up attitude even for flying at a constant altitude, which would not be fuel-efficient because if the high drag.

The difference between the pitch angle of the plane and that of the wings is indeed fixed in any normal aircraft.


I've blacklisted Air France ever since the Damascus incident and their financial decision to attempt to divert over a war zone to Jordan rather than fly to a nearby safe location in Cyprus or Israel, especially when the company overrode the flightplan (which was to divert to Larnaca)

I'm willing to forgive the decision to not land in Beiruit on a flimsy pretext in the first place, but to not divert to Larnaca shows unforgivable decision making.


>The true story might be that the captain saved this plane with his nose down inputs.

Or the AoA was a product of the other pilot over correcting from what they thought was unintended nose down behavior. Hard to say, clearly bad procedure either way though. It's why there's clear protocol regarding who is in control of the plane.


The issue is that the REALITY was the plane was going very nose up at low speed. That is THE situation that gets you into a stall / spin situation.

Close to the ground in the pattern most folks in the US are taught to be very careful about this. Ie, when you are low and slow, don't go for a big pitch up or a steep bank. There isn't time to recover.

That said, I've got NO clue about 777's, so maybe a 25 degree pitch up on takeoff / go around is normal. Hard to imagine aerodynamically that working.


> Close to the ground in the pattern most folks in the US are taught to be very careful about this.

What makes you think it's taught differently outside of the US?


Can confirm in Europe. We don't even get taught much spin recovery, just spin avoidance, seeing that a spin can't be recovered from within final altitudes anyway


I believe Air France does their flight training completely different from the US. Here we have a healthy civilian flying culture (this really applies to the americas in general). Lots of stick time with manual controls (vs fly by wire). The French get lots of simulator time and are taught flying is more of an exercise in supervising the flight computer.


> I believe Air France does their flight training completely different from the US. Lots of stick time with manual controls (vs fly by wire).

I'm sorry, but I call BS on what you are implying here.

First, post 9/11, most European airlines killed off their Ab-Initio programmes.

Therefore for most European airlines, the only route to getting a seat in the pointy end is the so-called "Direct Entry" route. This either requires pre-existing civilian qualifications and experience (i.e. unfrozen ATPL with real-life hours in the bag), or otherwise being ex-military with equivalent qualifications and experience in that world.

For the few airlines that do offer Ab-Initio, then I'm afraid it's complete BS if you think ab-initio trainees for any European airline just get dumped in a simulator and trained how to follow the magenta line. They will follow the same route as anyone else, i.e. they will be sent off to the US or Australia (because of the consistent weather, not anything else) and will work their way through the usual route SEP -> MEP -> Hours building .... they will then come back to Europe and finish off by getting an EU license. Only once they've got their commercial qualifications and have built experience will they then start Line Training which is where things like MCC come in, and that's where sim time starts coming in.

Simulators are expensive to run, even more expensive to buy, and there are not many of them around. They typically run 24x7 and are used for refreshers for existing crew as well as training new ones. To think there's enough spare capacity floating around to train green newbies from zero is a pipe dream.

Finally, on a practical note the newbie in the right seat will always be paired with a more experienced captain in the left seat. You will never find two noobs up front.


what i wrote was the reasoning given for the Air France Brasil to Paris flight. You remember, when they stalled a perfectly good AirBus 350 and dropped it from cruising altitude into the Atlantic.


Hang on a second, are you suggesting that you can get a commercial licence in Europe by flying simulators?

I don't know about France (but Europe tends to be aligned), but a basic commercial license in the UK requires 200 hours of flying experience. On top of that you would need a multi-crew rating, an instrument rating a multi-engine rating and a type rating on the plane you are going to fly. Enough to recognise that pushing the yoke left makes the plane bank left.

My brother wanted to be a pilot and was looking at moving to the US because it is cheaper and has more consistent weather. He also told me the licences were easier to get than in Europe. I think you have fallen into the 'US is best trap'


> He also told me the licences were easier to get than in Europe. I think you have fallen into the 'US is best trap'

He has, and yes European licenses are tougher.


Indeed, to get a license in France, you actually need to fly, but I still think US pilots are among the best, but that's because the US has a stronger aviation culture.

AFAIK, a typical path for a pilot in the US is to start taking lessons in a small plane, then, after getting the private license, make money flying, typically as a flight instructor, in order to pay for flight hours in bigger planes. The result is a lot of flight hours as a pilot in command. Hours as a flight instructor are particularly important because you have to cover for your student mistakes.

In countries with a weaker aviation culture future pilots tend to go to flight schools where they do the required number of hours and pass the tests but nothing more. There is simply not enough demand for general aviation flight instructors. The number of flight hours may be significant and the tests hard, but they fly mostly as students, not as pilots in command. So while they may know the technique and procedures, they lack the experience of being in charge of the plane.

I'd say that France is not the worst in that regard, we have many "aeroclubs", but not as good as the US.


This is utter nonsense.

In the US you can't become a flight instructor with a private pilots licence. You have to pass your commercial licence first. Just like in Europe.

You have to do at least 100 of your hours as pilot in command in the UK to get your commercial license. You will have to finish that before you can be an instructor. You can't make money from flying until you have finished your commercial licence.

To be an airline pilot you will need to have flown 1500hours in Europe or the US. Nobody gets there because of culture, they get there by flying 1500 hours

The US has better flying weather so you can build his more quickly, is cheaper and because there are more trainees there are more opportunities to build hours at someone else's expense. But cheaper does not mean better.


Yeah, that’s the stereotype of the fighter jock or, as someone on HN once put it, „fixed-wing enthusiast“. A man (always), flying with enthusiasm, intuition, not too much alcohol, direct controls etc.

It’s bullshit, of course. The archetype, if it ever existed, has been in decline since 1945 at the latest. Within that time, miles traveled have increased 15-fold, accidents have been reduced by 95 % (for a combined risk reduction of factor 300) while costs have come down by 80 %.

The adrenaline junkie will get bored and kill everyone with carelessness or controlled-flight-into-terrain. Because the total number of exciting situation in your 30 year career is, to a near approximation, zero. A good pilot today is a bureaucrat, meticulously running through checklists day after day.

There was at some point a philosophical split between Airbus and Boeing, the former going for fly-by-wire including automatic modification of pilot inputs etc., while Boeing was culturally invested that archetype of a pilot and preferring more direct controls. The outcome: no discernible difference in the safety records of these supposedly different approaches. Pilots from very different backgrounds? No difference. What matters for safety isn’t character, it’s process. And that’s great because processes scale, natural-born aviators don’t.


Newer Boeing models including the 777 are also fly-by-wire.


> healthy civilian flying culture.

I wonder if this is sustainable. The era of affordable general aviation aircraft is over, people are flying 50 year old planes because the new basic cessnas costs $400K each.


>people are flying 50 year old planes because the new basic cessnas cost $400K each

This wasn't always the case though. There's a chapter in the book Where is My Flying Car? that explains how this was a result of the early 70s explosion of product liability regulations + a FAA that was and continues to be completely apathetic to general aviation


That doesn't seem like that much if split with 4 people over 15 years.


If four people need fifteen years, or one person needs to be a successful forty- or fifty-year-old neurosurgeon, to afford owning and operating a Cessna 172 - what effect do you think that has on the commercial pilot training funnel?


> If four people need fifteen years, or one person needs to be a successful forty- or fifty-year-old neurosurgeon, to afford owning and operating a Cessna 172 - what effect do you think that has on the commercial pilot training funnel?

Little, because you don't have to own a plane to fly it; the commercial pilot funnel comes through private flight schools and military aviation (over time shifting from the former from the latter), not mainly from I-bought-a-plane-with-cash non-commercial private pilots.


Yeah, but do I learn more from a program of study at a private flight school, or from that plus having grown up flying the plane my folks bought when I was five, because it was that or a speedboat and Mom doesn't trust the water?

Not that this is me - if nothing else, you probably can't get my mom into an aircraft even at gunpoint - but it is more like the question that wants to be considered here.


I'm not sure what you're asking? There are a few commercial airline pilots whose parents owned airplanes, but those are rare. Most got their required flight hours either in the military, or by training in private flight schools and then working as flight instructors themselves.


> training in private flight schools and then working as flight instructors themselves

Who attends those private flight schools? Unaffordable aircraft obviously won't improve things and seem quite likely to make things worse.


I believe the "bootcamp followed by effective indenture" model has been widely favored among the regional airlines that act as feeders for the big players, dating back well before the software industry first happened upon it.

If I recall correctly, Patrick "Ask the Pilot" Smith has had some things to say based on his own experience here. In any case, whether or not that model is actively used today, I would be entirely unsurprised to see it spread widely in the next couple of decades, and maybe not only in the airline industry.


Aircraft rental fees are the most expensive part of getting an ATP license, but all sorts of people manage to afford it. They get support from parents or work other jobs or take out loans. Midway through the training program many of them get a CFI license and then work for the flight school training new pilots, which helps defray the cost of building up the necessary 1500 flight hours.

At some point the pilot shortage might get severe enough that airlines have to hire pilot trainees with little or no experience and then pay them to go through a training program. So far that hasn't been necessary but it's a common model in other countries.


Just how high class of job do you think commercial airline pilot is, exactly?


The point is exactly that owning a small airplane has not always been the signifier of necessarily enormous wealth it is today, and that it's worth asking whether that has had a deleterious effect on the ways in which commercial pilots learn to be pilots at all.

I suppose the larger discussion is properly around the vast increase in income inequality over recent decades, and I'd have done well to contextualize it there before now.

(In my defense, I've had such a day that the early root canal appointment, which played out like something from Marathon Man - not that my dentist is less than excellent, but I'm glad I already knew that because we had about half an hour there during which the least surprising thing in the world would have been for him to ask me "is it safe?" - that was the second most significant thing to happen since the sun last rose. So it's quite possible I am bringing less than my best to this discussion that I'm using to help me wind down toward sleep.)


I'd guess absolutely no effect at all; I don't think that kurupt213 was trying to suggest that commercial pilots commonly buy planes, and indeed I don't think it's true. I'd guess that the vast majority of commercial pilots have never owned a plane, and that small plane ownership is not at all a part of the commercial pilot training funnel. I actually think this whole subthread mistook "civilian flying culture" to be talking about general aviation when he was talking about commercial airlines (as opposed to the military).


No, but I think you may have the arrow of time reversed here. The argument in its essence - not that I'm reading GP's mind, nor need to, as the argument is not novel - is that, with access to general aviation as narrow and difficult as it's become in the past five or so decades, commercial pilots will still learn the technical aspects of operating a commercial flight during their airline-provided training, but rarely have much opportunity to learn how to fly, that is, to develop the intuitive understanding of aerodynamics and aircraft behavior that can enable a pilot to react correctly and without excess need for thought in situations and circumstances where that can make the difference between life and death for everyone aboard their aircraft.

Whether or not I fully buy the argument, I don't suppose I know. I do know that a lifetime of reading, study, and home simulation taken together taught me less about what an airplane does when it's flying than did one fifteen-minute discovery flight in a Piper Archer. It's different for professionals than for an aviation-nerd amateur, of course. But I see no reason in principle to assume there aren't things you only really learn from spending enough time flying a plane too small and simple to lie to you, and every reason from experience to assume that there are.

(Having just seen your edit, I'm no longer sure this qualifies as a response on point, but I'm going to let it stand and finish my supper.)



> what effect do you think that has on the commercial pilot training funnel?

It'll be fine regardless, there'll be no shortage in the military -> commercial pilot funnel of the most militarized country in the world.


That has been true, but the military is rapidly drawing down their manned aircraft fleet. I would expect commercial airline pilots to increasingly come from private flight schools in the future.

https://www.thedrive.com/the-war-zone/units-flying-f-15c-ds-...


These aren't large numbers compared to stuff like transport, for both cargo and airmobile force components. You replace manned combat aircraft with remotely operated ones because you're at the point where that's the next thing you need to do to stay in the race, but that's not a race transport aircraft are running.


The overwhelming majority of military aircraft aren't fighter jets, they are transport aircraft - and are also a better proxy for civilian aviation.


No the Air Force has far more fighter jets than transport aircraft.

https://www.airforcemag.com/article/2021-usaf-ussf-almanac-e...


I stand corrected.


Likewise, but now I'm wondering how they compare in terms of total flight hours by type.

Granted, this is transparently an attempt to recover some remnant of a meaningful argument from the wreckage of the one I was trying to make, but it might still be interesting for someone more familiar than I with where to find the relevant data.


Transport pilots fly only slightly more hours than fighter pilots.

https://www.airforcetimes.com/news/your-air-force/2018/03/01...


Oh, well, it was worth a shot. Impressively quick followup!


That's fair. Too, I suppose it's not reasonable to assume we'll remain able to afford widespread civil aviation once we're no longer able to afford the world's most luxurious war machine. In that case, we won't need so many professional pilots anyway.


They don't need 15 years because they can get financing and take ownership of the plane for a 20% down payment.


80k downpayment + $2200/month sounds just as inaccessible as a 400k lump sum. That’s before fuel, maintenance, storage and operation costs…


But the point of general aviation is that it should be affordable as a personal hobby for a significant amount of people. tbh, I've actually considered owning a plane but dropped the idea entirely after realizing the only really affordable option is 50 years old and I don't really want to fly something that old.


I see a listing here for a 50% ownership stake in a 2005 Cessna 182T Skylane for $180k. Financing is available for 20% down. With financing, the listed monthly price is < $2k. That seems somewhat reasonable to me. https://www.controller.com/listing/for-fractional-ownership/...


This is a real HN comment. $2k a month for a hobby (before gas, garage, fees, ??) is nothing but a dream for most people.


Yes but where is that idea coming from that flying needs to be cheap enough to be a hobby?


I think the point is that it used to be much more affordable than it is today, and GA is quickly becoming the exclusive domain of the 1%.


That's not even the dominant cost -- the running costs are ~$150-200 per hour in addition. That covers fuel, maintenance, inspections, parking, insurance, prop overhauls, and accruing for an engine replacement every 2,000 hours.


> But the point of general aviation is that it should be affordable as a personal hobby for a significant amount of people.

Why?


For starters, it's called general aviation.


Most people that want a new aircraft for GA for less than 6 figures are kit building them. Also there’s the “sport” flying market and ultra-light market as well.


Building a kit airplane is probably not going to save you any money when you consider the space, time, and skill needed.


That's the same price as new 40' boat - which seems about right.


Yes, but if you can't afford a 40' boat you can always go with a 15' one, or a skipper with cost on par of a large vehicle. Jetskis are even cheaper.


No idea how true this can be. I know only one airfrance pilot but he did regular civilian flying school and flied for the french Army before applying for Air France training. Memory is blurry but I think at the time he needed some creds from previous flying experience to apply.


> I believe Air France does their flight training completely different from the US

Why do you believe so? Honest question.


For now. The French are just ahead of the curve.


Interesting to read this, as I have some experience sailing - and that sometimes involves people changing control of the tiller/wheel. The procedure that was drilled into my head at an early stage was this:

  A: B, take the helm 
  B: I have the helm
or for tacking:

  Skipper: Prepare to tack 
  Crew: Ready to tack 
  Skipper: Helm's a lee 
  Skipper tacks, crew does their stuff
If you don't get a response at any point don't continue. Communicate.


Yeah, I was trained to say:

P1: Take the controls

P2: I have the controls

P1: You have the controls

It’s basically syn:ack


That's standard procedure in flying as well, drilled into pilots' heads from their very first flight lesson:

  A: "You have the flight controls."
  B: "I have the flight controls."
  A: "You have the flight controls."


It’s weird I’d thought they use different terms for A’s two phrases, because it’s the same words but the first is an instruction and the second a statement! Different meanings but same words - why’d you do that in designing a protocol!


Just like TCP, it’s a stateful protocol.


TCP got it right tho:

    SYN

    SYN-ACK

    ACK


Seems like a terrible idea - what if you’re mistaken about the other person’s understanding of the current state?


I'm trying to think how this could possibly be misconstrued


What if A didn't hear B's response, and was reiterating their first instruction? B wouldn't respond because they think A is already at step 3 of the handshake, whereas A thinks they are at step 1. A thinks A has control of the plane, whereas B thinks B has control of the plane.


Won't A just repeat until he gets a response? A doesn't want control, if they think they have it, they will probably retry the whole thing, meaning the confusion is probably brief.

He might also just see that B is making inputs and assume, if they are being lax, but I assume they wouldn't.


Even if A says the same words (he probably wouldn't) it definitely wouldn't be in the same tone. B would understand that it was a repeated command and not an acknowledgement.


Commands that can only be disambiguated via tone sounds insane to me.

Imagine being in an emergency, possibly listening to someone speaking while wearing an oxygen mask, in a smoke filled cabin, with alarms going off, and asking yourself - "wait did they say 'you ^have^ the controls', or 'you _have_ the controls'".


That seems tricky. Climbing, I was always taught to make the commands unambiguous. You never say "take in the slack" because on a windy day that can sound awfully like "I need slack". Each command should be distinct.


A is supposed to watch the other person and see their hands move to the controls.


responding to sibling, in my experience it actually goes “i have controls, you have controls, i have controls”. always ending on someone saying “i have controls.” so if someone doesn’t hear a call or response, it ends with either two people on the controls (not a disaster), or the person relinquishing controls repeating his line.


> two people on the controls (not a disaster)

Err… isn’t that exactly how Air France Flight 447 crashed? Both people thought they were flying, doing opposite things, the plane cancelled out their inputs and did nothing.


I mean, TFA is about two people on the controls. So that sounds like an ambiguity to be avoided.


Then you send a letter to Byzantine and ask the Generals if they have any bright ideas?


Communication was also the main cause of the Tenerife airport disaster [0], leading to an overhaul of communication protocols.

"As a consequence of the accident, sweeping changes were made to international airline regulations and to aircraft. Aviation authorities around the world introduced requirements for standard phrases and a greater emphasis on English as a common working language."

[0] https://en.wikipedia.org/wiki/Tenerife_airport_disaster#Comm...


Yeah, in flying this is usually called three way positive exchange of controls, with A repeating that B has the controls.


There's no real reason to not have this exchange digitally/mechanically intermediated, in my estimation.

A plane doesn't need to have both controls mechanically linked, or both active at the same time. You could have a nice big toggle in the middle of the cockpit that is either 2 or 3 positions (L/R/Both). Toggling it will announce "Left/Right in control" and activate the stick shaker on the dead side and re-announce if any input is received.

Panic isn't something that you can remove by training nor train for. It needs to be factored into the design that only one set of inputs is effective at a time.


> Panic isn't something that you can remove by training nor train for.

Of course it is. It's probably 50% of training.

Panic increases the impact of mental workload and induces a kind of "tunnel thinking" similar to tunnel vision: you become fixated on one problem and one solution, without considering other parameters and options.

But panic is caused, many times, by surprise and lack of competence.

You avoid panic by becoming more familiar with specific emergency situations.

And you fight panic by learning to recognize it early, reduce mental workload, organize and follow procedures.

I find it worrying that this incident shows a lack of professionalism from the crew. When something unexpexted happened, they simply jumped on the controls at once, didn't communicate and simply blamed the plane. This is amateurish, and somehow... quite French (I am French).


> Panic isn't something that you can remove by training nor train for.

On the contrary, that's exactly what repetitive training of emergency scenarios is about.

Panic happens when you get overwhelmed with multiple bad things happening and each one requires dedicated concentration, you don't have that much attention to give so panic sets in and you do all of the tasks badly. The solution is to train repeatedly so all the reactions are muscle memory (or mental "muscle memory"), which lets you remain comfortable and in control because you've done this a hundred times before.

In SCUBA diving for example many fatal accidents are the overlap of simple problems that end up overwhelming the diver because they had not practiced it enough or recently enough.


> A plane doesn't need to have both controls mechanically linked, or both active at the same time.

If you have a switching control, mechanical or digital, it is a thing that can fail, and even if you assume it would be good before considering that, you have to consider the impact failure has on net utility, especially if a plausible failure mode renders both controls inoperable.


Inevitably you will get "Plane crashed as pilot in command attempted to control plane while toggle was in opposing position" and someone will say "okay, you should add a warning light" and then the same thing will happen and someone will say "there are too many warning lights" and so on and so forth.


Panic is absolutely something you can train for and the human factor of flight controls is a central part of the design. Accidents heavily inform this design and training and control characteristics are always on the table as a response to incidents.


Didn't that switchable controls scheme contribute to one of the us navy destroyer collisions recently?


Yes, although in that case it wasn’t a big mechanical toggle, just a software setting. And the bridge crew were not trained in how to use it safely, or to check if the controls they were using were actually operable.


A less extreme(Since change can be it's own danger) solution would be an audible pilots fighting warning system.


Maybe instead some equivalent of the stick shaker that indicates your controls are being overridden


Sometimes you have to tack now. Then you’re lucky if you hear, “tacking!”


Echoes of AF447 here. I thought that Airbus makes the only airliners with no feedback when there are dual inputs applied, and Boeing takes a decidedly different approach. Can someone experienced with this explain how this could have happened?


Entirely speculating, but it sounds like the fundamental problem is that they had a confused Captain and First Officer who both thought they were the Pilot Flying. Human factors / psychology issue. Sure, on a Boeing you'll feel the other pilot's input, but if you're tired enough, or panicking because the plane's not doing what you expected, you might not get the hint.

Task saturation - followed by loss of situational awareness - is a very real problem in today's airliners, particularly during takeoff and approach/landing. You're trying to do a ton of things in a small amount of time, while dealing with a dynamic situation outside, and in this case after a long, tiring flight over the Atlantic.

There are a great series of (dated but still good) videos from American Airlines about automation dependency, human factors and the simple but very real problems that develop as a result - often leading to panic and disaster when things go wrong. Search YT for "children of the magenta".


In the AF447 case, the lack of feedback/linkage of the Pilot Flying / Nonflying sidesticks was a big contributing factor. It is true that the Pitot tubes froze up. But the Pilot was roused from his sleep, entered the cockpit, and correctly pointed out that the plane was actually in a dive. It's just that the guys flying were making opposite inputs over an extended period, and it was too late to recover, which doomed AF447. Overall, Airbus and its delinked sidesticks was a factor in the accident.

I thought Boeing did not have sidesticks, and the yokes/control columns are linked to give actual feedback (to emulate most airplanes, which do this with mechanical controls). Is that not the case?


The transcripts of AF447 include the pilot telling the right seater to stop. More than once. But he keeps doing inputs.

Airbus 320 pilot told me there is a light that comes on when inputs dont match.

Now reread the transcripts with the assumption that the right seater might not have the best intentions.


What do you mean by best intentions? There are more efficient ways to crash a plane.

But also isn't the right seater the first officier, surely he should obey a repeated direct order from the captain.


The captain was asleep. Maybe there were no clear consensus on chain of command in the cockpit.


By convention the left seater is the captain. In the case of AF447, the captain was asleep, and the FO and a relief pilot were flying the plane.


There were lots of things that went wrong with AF 447 but the side sticks were a minor detail. If anything the stall warning going on and off was a much bigger factor because the one pilot kept pulling back on the stick which is the exact opposite of what he should've done. Had the pilot flying simply flown pitch and power they would've been fine and had plenty of time to calmly troubleshoot the situation.

> I thought Boeing did not have sidesticks, and the

> yokes/control columns are linked to give actual feedback

> (to emulate most airplanes, which do this with mechanical

> controls). Is that not the case?

Boeing's philosophy seems to be to provide physical feedback for most or all of the controls. So, yeah, the control columns are linked (even on fly-by-wire planes like the 777 and 787). But that's not very useful once you're dealing with startled and/or panicked pilots. Take a look at the Atlas Air or Sriwijaya Air crashes.

The problem with Air France has nothing to do with Boeing or Airbus and everything to do with pilot standards and training. At this point Air France is lucky. Look at the Air France incident in 2020 (A318). Or their incident in Bogota in 2017 (A340). Or the 2011, 2012 x2, and 2013 incidents where the Airbus (A320/321) alpha floor protection prevented an Air France crew from crashing on approach to Marseille x2, Hamburg, and Tel Aviv. At some point Air France's luck will run out.


> If anything the stall warning going on and off was a much bigger factor because the one pilot kept pulling back on the stick which is the exact opposite of what he should've done.

Private pilot here.

This is so hard. It’s not an excuse, especially for professional pilots.

But I can share from experience how much your “animal brain” fights you in this situation. Pulling back leverages lift in most normal flight, until you go too slow (stall), and then you suddenly very much need to do the opposite. But the normal behavior becomes second nature, like walking.

My examiner in 2020 said the biggest thing the FAA was stressing about was a serious uptick in incidents with slow flight (and stall) handling during takeoff/landings.

A year ago, we had an experienced local private pilot wreck his plane (lucky no major injuries) succumbing to exactly this. Took off, lift conditions a little worse than normal, started to leave ground effect, felt the plane stall, pulled back, started losing altitude, panicked and pulled back harder, tailed down and fell side wards. Plane totaled. He recounted to me after how he knew what to do. He’s trained multiple times. Done lots of stall recovery. Has done many many short field takeoffs (which is similar, pop the plane off the ground and then stay low to build speed). But was still chagrined at how panick/situation management got the better of him that time.

Being master of your animal brain in all situations is hard. And you never know, because you can never test all situations.


Sure. There are some things in aviation that are counterintuitive: recovering from a stall is one of those. That's why commercial aviation in the United States places such a strong emphasis on regular training (and why commercial aviation in the US is as safe as it is). Unfortunately stall physics are something that flight simulators don't tend to do so well at.

Another counterintuitive thing is that tactile feedback isn't necessarily helpful. There's a lot of whinging about how Airbus doesn't provide any feedback in the sidestick when both pilots are doing conflicting things, same with the thrust levers (or whatever they're called in Airbus land). Pilots have crashed Boeing airliners that give you this "important" feedback.

Anyways, my point was that stall recovery is something that's usually drilled into pilots. Unfortunately for the AF 447 crew, nobody told them that the stall warning would turn off when they flew so far outside the envelope that they were in "undefined behavior" territory. And that led to at least one of the pilots not recognizing that they'd stalled in the first place. But like any crash there are many contributing factors, and if any one of those had been different the plane wouldn't have crashed.

If it were just one or two examples of poor airmanship at Air France then sure, it'd be easy to chalk it up to "flying is hard". And yeah, the pandemic has robbed a lot of pilots of their necessary practice. But the four or five cases I cited where Airbus' "alpha floor protection" saved Air France flights were all pre-pandemic. At some point you've gotta look at what those incidents and accidents have in common (hint: it's not the airplane and not the crew). And that's why my main concern is with Air France's lack of safety culture and by extension their pilot training.


> commercial aviation in the United States places such a strong emphasis on regular training

This in a nutshell is why I never completed my Private Pilot training. As I got close to taking my checkride I began to think about finances going forward. And I realized that I probably couldn't afford to fly often enough to keep my skills sharp and a dull pilot is a dangerous pilot.

25 years later I'm still alive so I think I made the right decision :-)


> Overall, Airbus and its delinked sidesticks was a factor in the accident.

Confused, Bonin exclaimed, "[Expletive] I don't have control of the airplane any more now", and two seconds later, "I don't have control of the airplane at all!"[29]

Robert responded to this by saying, "controls to the left", and took over control of the aircraft.[73][32]

He pushed his side-stick forward to lower the nose and recover from the stall; however, Bonin was still pulling his side-stick back.

The inputs cancelled each other out and triggered an audible "dual input" warning.

--

So in an Airbus this situation is unambiguous - the plane tells you plain and simple: Both pilots are trying to fly at the same time. With a mechanically linked set of controls, you don't necessarily know whether you're fighting the other pilot or the plane.


That does seem to be what was happening here, as both pilots thought the plane was fighting their inputs, but in reality they were fighting each other.


> my airplane

> your airplane [lets go controls]

Those are the words to be exchanged to avoid confusion.


Sure, just make sure that happens exactly that way 1,000,000 times without any failures…

And that’s the root of many issues in aviation. It works 99.99% of the time is not always good enough.


I wonder if this was part of some rare coincidence where their inputs were perfectly synchronized but out of phase in such a way that it made it difficult to consider the obvious. If you pull back but feel the plane and/or stick move laterally, and especially across multiple inputs without a clear pattern, it might more easily occur to you to think the person sitting next to you is also providing inputs. Whereas if you're synchronized across many inputs, that's just something that doesn't typically happen in nature, which tends to always have some stochastic quality; instinctively it's something you might assume would only involve a machine.


"I have the airplane" or "my airplane" is an established practice, but over and above that, the stick/yoke/rudder pedals all actually give you feedback when the other guy is also handling them. That feedback gives the fliers another level of protection.


Agreed, but also given they initially thought the aircraft itself was deviating from a stable approach (or at least the ATC transcription appears to suggest that?), perhaps the pilots may have thought the feedback was due to autopilot and not the person sitting next to them.


Yeah, simple enough. Also simple enough to go-around when you're obviously slow and going to be short of the runway, but look at Asiana 214.

I do wonder if there's some training deficiency or cultural issue that leads to this scenario in Air France flights.


This makes me think of Loic Suberville's videos on language...


> my airplane

> your airplane

> my airplane


Well this is terrifying. Their only job is to pay attention and communicate clearly…especially during takeoff and landings


Most people are not good at their jobs...


Most people don't get to fly airplanes.


As pointed out by a sibling comment, cockpit resource management training solves this very simply by verbally declaring who should have control.


As usual, Star Trek was out in front with CRM on how to verbally switch commands:

1. I'm losing command

2. I've got command

https://www.youtube.com/watch?v=RAvRBDQqSmY


> I thought that Airbus makes the only airliners with no feedback when there are dual inputs applied

This factoid will not die on HN. Conflicting inputs on an Airbus are handled by averaging and an audible "DUAL INPUT" cockpit warning.[1]

In the case of AF447, the co-pilot used his "Priority Takeover" button which meant only his control inputs were in effect.

If you wanted to say there is no physical feedback, then you would be correct.

[1] https://safetyfirst.airbus.com/app/themes/mh_newsdesk/docume...


Yes, that is what I meant. And any other type of feedback would be likelier to be ignored. That's why there's a stick shaker in addition to auditory and other warnings when the plane stalls, even in fly-by-wire planes.


AF447 was (I read the WP article on it) at 38,000 feet and ice seems to be implicated and quite a few other things.

This incident was at 1670 ft. My reading of the article is a P and CP being twats:

"During the go-around on the Air France flight, the captain was making nose-down inputs, while the first officer was pulling back on the controls."

I'm just a simple civvy but I was an air cadet and learned enough about flying in a single engine trainer to know that only one person should have control. You literally say "I have control" - "You have control" - "I have control". These muppets didn't seem to do that:

"It took until 07:52:06, for the captain to become the only person making control inputs."

In the very guarded language of accident review I would say that is a damning indictment of the behaviour of the pilot and co-pilot as being completely reckless and bloody stupid.


That’s all correct, but AF447 was exacerbated by the pilot and copilot (actually 2 copilots, IIRC, the senior pilot was on break) fighting each others controls as the plane flew towards the ocean. The pitot tube was giving bad readings (frozen over), but from what investigators can tell, one control was trying to pull up and even out and the other was still pitching down to gain speed (per the warnings given by the faulty pitot tube).


The tragic thing about that is all they had to do was simply let go of the controls completely and the plane would've been fine. The transcript of that flight still gives me chills: https://tailstrike.com/database/01-june-2009-air-france-447/


For anyone who hasn't read it: Imagine waking up, and a few moments later saying "I can't believe this is happening" right before you reach altitude zero.

That transcript is so sad.


A car, plane or whatever should only have one driver/pilot. Planes have dual controls by default but this sort of nonsense should not be allowed to happen.

This was not AF447 so what on earth happened? I'm guessing inadequacy of some sort and that's on the industry as a whole.


In cases like this it's almost always some variation of normalization of deviance.

If company culture doesn't strictly enforce callouts 100% of the time, it's easy to get into a routine of everything being just fine 100's of times until it isn't.

Really these sorts of things show there should be a failsafe mechanism that provides tactile/haptic feedback to the pilots if the other inputs are "fighting" theirs.

Even an audible alarm isn't enough, as you'll likely get more than a few of those during events where it matters.

Proper CRM of course should make this "impossible" - but in high stress moments any more layers of swiss cheese you can add the better.


Agreed. There should be a stick-shaker or similar to let pilots know the other control is being used. Maybe not the existing stick-shaker, since that's usually for stalls, but something similar.

I have no idea why the pilot-monitoring would have taken his controls. Or why the pilot-flying wouldn't have called him out for it. Possibly a seniority issue - we've seen similar issues before. Hopefully the french aviation authorities can determine the root cause.


Ever see those really long fire trucks?

Two drivers


But the second driver of a tiller truck only steers the rear wheels, more like the pilot of a glider being towed.


> In the very guarded language of accident review I would say that is a damning indictment of the behaviour of the pilot and co-pilot as being completely reckless and bloody stupid.

Well, yes, but these kind of incidents keep happening at AF. Everyone talks about AF447 because it ended in the ocean, but there have been many incidents with AF since AF447, involving serious pilot error which nonetheless ended in a safe landing. So you have to look a bit beyond the "muppets" in the front seats and start to wonder about company culture and training.


I've repeatedly heard stated that after a sufficient amount of force is applied to controls, "the link" between the controls is severed or deactivated, without any details regarding how this is done or what the actual effect is.

Here's an article stating exactly that: https://english.alarabiya.net/News/world/2022/04/28/Pilots-p...

> If opposing forces on the two columns pass a certain limit, the link between them is deactivated or “desynchronized” to prevent accidents in the case of one side getting jammed.


It's a purely mechanical linkage. I've been trying to read the patent (US 5782436A). The USPTO has a new single-page web app. It's awful for finding by patent number, and worse when you want a full screen image of a drawing. It's clear that if one yoke is jammed and the other is moved with enough force, a spring loaded pin is forced out of a notch and the connection between the two yokes releases.

What's not clear is how the linkage still connects to the flight controls. The idea seems to be that the one which is moving wins. What is clear is that, if your side becomes disconnected, your yoke doesn't do anything. No wonder one pilot was frantic. It seems that you get reconnected by moving the disconnected yoke to agree with the one in control. Then the pin falls into the notch and the yokes are connected again. Not sure about that. You can see the pin and notch in the patent drawings.

This is independent of the fly-by-wire system. That's downstream from these mechanical devices.

I wonder if pilot training includes knowledge that yoke disconnection is possible.


They are trained in this. If disconnected, each yoke will control "their" half of the plane. This is mostly intended to maintain some level of controllability if one of the yokes were to get blocked or seized mechanically, this is not intended for human issues


> I wonder if pilot training includes knowledge that yoke disconnection is possible.

Probably, I've heard https://www.youtube.com/c/MentourPilotaviation talk about it as well.


If the linkage breaks, then each pilot gets to control the control surfaces on one side of the aircraft.


In the 777 it's a direct mechanical linkage between the controls, with a torque-driven breakout which temporarily severs the link if there's too much difference in the two pilots' inputs

That still leaves the question of how to interpret opposing inputs for the physical control surfaces, though


On the 757, the two control columns are linked with a roller bearing in a detent (notch). With enough torque applied, the bearing will come out of the notch and the columns can move independently.


Does sound like 447, and a result of the airbus’ dual stick system. Boeing’s yoke system is connected between the pilot and copilot, so much easier to detect opposite inputs. Also the yoke is right in front of each pilot, instead of on the opposite sides as is the case with the dual sticks in airbus planes, which could be a source of confusion/opposite input problems.


the plane involved in a Boeing 777. That's right in the title of the article.


Nowadays planes will yank on the controls on their own initiative, most destructively e.g. in the case of a certain pair of 737MAXs.

They probably assumed that is what was going on. That the other pilot was doing something obviously wrong is not a natural assumption, when there is an alternative.

It seems like Air France has got some procedural drills to work on. One would have hoped that happened already. Somebody should check, this time.


Technicality, but the 737MAX MCAS was rolling a trim wheel, not moving the yoke.


Exerted force on the yoke via the elevator, driven by the trim tab. But they also yank directly on the yoke, for lots of reasons.


Maybe this is a UX issue?

If you're trying to fly the plane, but your buddy is also doing it — it should light up / make noise "hey y'all can't fly the plane at the same time"


Yeah, that was my first thought too. Why wouldn't it do that?!


Yes, this UX issue killed before (AF447) I was told at the time that this was an AirBus issue and that Boeing doesn't have the issue, but apparently both have bad UX..

That's surprising: this seems to be a simple check to implement and a very useful one too!


To some extent, Boeing doesn't. The controls are physically linked; you can feel the other pilot moving them. In order to make opposing inputs you have to physically fight each others' inputs.

It seems in this case there was maybe some additional confusion about automation thrown into the mix; the pilots perhaps thought they were fighting the aircraft rather than each other. This is worrying, since if you want the autopilot disconnected, it would be typical to disconnect it, rather than try to override it (the autopilot will disconnect if manual inputs are made beyond a threshold, but that's not a typical way to disconnect it).


Or perhaps train pilots better so they actually provide the same inputs, not opposing ones.


Why does this sound so similar to Air France 447[1]? Iirc a major difference between Boeing and airbuses, was specifically the control inputs. In Boeing, the pilot and copilot controls were physically linked. In Airbus, they each fed into the autopilot and were averaged. This horrendous functionality was later deemed a contributing factor in the Air France 447 crash. Did Boeing at some point switch to similar controls as Airbus? (I.e. average pilot and copilot controls?)

[1]https://en.m.wikipedia.org/wiki/Air_France_Flight_447

P.s. Tangent: apropos the air france 447 flight, 99% invisible did a solid episode on it some years back, including a bunch of discussion on the terrible HMI: https://99percentinvisible.org/episode/children-of-the-magen...


You would think that after AF 447, AF would have mandated clear "I have the airplane" procedures in the cockpit. This sounds like a near replay of that accident, and it was a miracle they didn't crash because they were so near the ground.


Is it normal for ATC and pilots to converse in French? I thought everything in aviation had to be in English after some lost in translation accidents...


I expect that French was the first language for all concerned since it was a French flag carrier landing at a French airport.



Do we have an explaination why the pilot flying applied that much roll on the left side before go around ?


[flagged]


What do you mean? They landed this one safely


"AeroTime columnist and pilot Captain Michel Treskin commented that the update shows there was no problem with the aircraft but does paint a scene of confusion in the flight deck. "

It shows there is a huge problem with the control systems. Am I the only one who sees it?

It used to be (did it? I am not an engineer) that the controls were hydraulic and connected. So if you tried opposing moves it was immediately apparent. With "fly by wire" not so much.

A good thing the aeroplane landed safely. Others have not


You're the only one who "sees" it because you are mistaken. The controls are still connected, as per the Boeing philosophy. Moving one moves the other, unless so much force is applied that the link opens (by design, to allow controlling the aircraft if one set of controls is stuck for some reason).

This is a pretty clear example of pilot error; they had all the information needed to understand what was going on (and, unlike on an Airbus, the additional information of needing to fight each other physically through the controls), and failed to process that information into a correct understanding of the situation. The fact that these type of events keep happening at Air France tells you it's not the individual pilots, but rather a training / company culture issue.




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