10 ms·

Poor UI Design Can Kill – Air Inter Flight 148, a Harsh Lesson Learned

138 points by damian2000 12y ago

jacquesm 12y ago
Making mistakes with blender won't kill you but the modes are enough to drive anybody nuts. Another instance of a very poor choice that led to people being killed in aviation was the one where 'take-off power' was interpreted as 'take power off'. I can't find a reference to that accident but the essence was that during a go-around instead of full throttle the pilot reduced power causing the aircraft to stall and crash.
- WalterBright 12y ago
  That incident happened in the Air Force. It caused "take-off power" to be renamed "full power".
  - VBprogrammer 12y ago
    Interestingly the word 'take-off' is only ever used in conjunction with a take-off clearance over the radio (e.g. "Speedbird 101, cleared for take-off") where as any other reference will use the word 'departure' (e.g. "After departure contact London control on 123.12").
    - jorgis 12y ago
      Isn't departure the term for leaving the controller's airspace?
      - VBprogrammer 12y ago
        Not that I'm aware (though I'm not an expert). It is certainly used for one of the many air traffic control units you can encounter at larger airports (e.g "Contact departure on 123.45"). My understanding is that the word 'take-off' over the radio is (or at least should be) treated like a loaded gun, you only say it when you mean it. Departure is used in place of take-off where appropriate (e.g. "Speedbird 101, holding short of runway 13, ready for departure.")
      - artmageddon 12y ago
        VBprogrammer's post is pretty spot on. In my experience around towered airports, I can't say I've heard "take-off" used in any radio comms I've had. In the example you've given, "departure" would be used instead of take-off as you've said. Towers are encouraged to use other terms[0], like the following: "N1234 cleared onto the active runway" which means you're free to proceed with your take-off roll. When you leave the airspace(at least at a class D airport), the controller will contact you with "N1234 frequency change approved", which means you either contact the next frequency planned in flight(such as flight following, or no frequency if you're just flying around in class E). [0] http://www.faa.gov/air_traffic/publications/atpubs/atc/atc0403.html http://www.faa.gov/air_traffic/publications/atpubs/atc/atc04...
    - underwater 12y ago
      This was a change made after the Tenerife crash: http://en.wikipedia.org/wiki/Tenerife_airport_disaster http://en.wikipedia.org/wiki/Tenerife_airport_disaster
tboerstad 12y ago
This same example, along with many others, are covered in Don Norman's classic "The Design of Everyday Things".
- sehr 12y ago
  He made a course on it over at Udacity as well if you're into videos > text
bagels 12y ago
More Airbus deadly UI: http://en.wikipedia.org/wiki/Air_France_Flight_447 http://en.wikipedia.org/wiki/Air_France_Flight_447 The two sticks can be pointed in different directions. The plane does not complain about this and averages the inputs. One pilot is pulling back, one is pushing forward, plane crashes. Clearly there are some human factors here, but from what I've read, on Boeing's aircraft pushing one stick causes the other to move, much more intuitive.
- dredmorbius 12y ago
  Boeing also uses a classic control column rather than a side-stick, emulating physical controls even though the actual mechanism is largely fly-by-wire.
- ern 12y ago
  It isn't only Airbus that has deadly UI. Boeing came in for some flak in the design of the 777's non-intuitive autothrottle modes in the Asiana 214 crash report. Pilot confusion with Boeing's autothrottle has also been implicated in other crashes.
  - idlewords 12y ago
    Nothing about flying a plane is really intuitive. The Asiana crash was a pretty clear case of pilot error. At some point you have to either trust the pilots or just enable autoland.
    - ern 12y ago
      That's a fair point, and it was also made by an NTSB board member who appended a partial dissent to the report.
- idlewords 12y ago
  The Airbus vs Boeing approach to fly-by-wire is a bit of a religious issue, like type safety or memory management in our world. Many words have been written on both sides. I think the UI issue in AF447 is much less clear cut. It's more a lack of any indicator that pilots are making opposite inputs, rather than a misleading or confusing display. Airbus did not anticipate that a pilot would stall a plane and fly it directly into the ocean. There was a whole chain of events (including some appalling human factors) that led to the tragedy there. The avionics teams at both companies have put an incredible amount of thought into how these systems are designed, and how they fail. The differences are instructive, but we should refrain from being quick to judge which is more or less intuitive.
shoyer 12y ago
the moral of the story is avoid modes whenever possible We try to avoid using global state (and state in general) in software engineering for this exact same reason. Humans just aren't good at keeping track of more than a few things at once, even if they are the ones who designed the system in the first place.
- damian2000 12y ago
  There's nothing at all wrong with state (i.e. variables) in programs - relatively few programs don't use state. The issue is with UI modes ... reusing the same UI which means two different things according to the mode its in.
  - shoyer 12y ago
    By "state in general", I particularly meant mutable or nonlocal state in general. There is obviously nothing wrong with using variables. To restate my analogy: the problem is when you can run the same function twice with the same input and get a different result. Or when the same variable can mean two totally different things depending on some external context.
dredmorbius 12y ago
I'd argue that modal behavior isn't a bad thing so long as those modes are very clearly distinguished. It doesn't hurt if they're encountered frequently enough that the user / operator has a clear sense of their distinction. vi/vim is a modal editor. There are two ways of interacting with it: "insert" mode, and "normal" (command) mode. In one, you're editing your document, in the other you're operating on it. While frustrating for new users, with experience using modes becomes transparent, as they're switched in and out of all the time. Though the visual distinction of modes isn't always clear. In a non-programming context, most sailboats have two primary operating modes: under sail, and under power. Here, the contexts are evident from a large number of cues in the environment, and how the boat is skippered is evident from these cues. Other tools have many modes of operation -- the various apps on a smartphone/tablet effective change the mode of the device. Is it a phone? A music player? A messaging tool? A web browser? The "mode" is specified by the application. Usually visual cues of the display indicate which specific mode is operative.
- MrBuddyCasino 12y ago
  Everyone I've seen has trouble with this in the beginning. I'm not an advanced vim user, would it really be impossible to make it modeless without losing too much power?
  - ben0x539 12y ago
    You could probably make an equally powerful modeless editor but I don't see how it could be anywhere near vim-like. Maybe if you had a foot pedal to indicate what modes to interpret input sequences in.
    - TheZenPsycho 12y ago
      What about ditching the caps-lock key and making it a "command" key, that you hold down to type in a command?
      - icebraining 12y ago
rbanffy 12y ago
http://www.amazon.com/Set-Phasers-Stun-Design-Technology/dp/0963617885 http://www.amazon.com/Set-Phasers-Stun-Design-Technology/dp/... has many stories about user interfaces, bugs and their occasional lethality.
ExpiredLink 12y ago
> but I guess the moral of the story is avoid modes whenever possible. Not a story for Vim aficionados.
cnvogel 12y ago
See also this report at the FAA regarding the exact accident being discussed in this blog post: http://lessonslearned.faa.gov/ll_main.cfm?TabID=2&LLID=57&LLTypeID=2 http://lessonslearned.faa.gov/ll_main.cfm?TabID=2&LLID=57&LL... This also includes pictures of the displays without (-3.3 and -33) and with (appending two small zeroes for the latter) the fix employed by Airbus. (I also commented on the original article, but await moderation.)
gear54rus 12y ago
I, for one, fail to realize how can one design any half-complex app (gadget, whatever) to be stateless. I mean, modes are literally everywhere. So long as you can always tell which mode is the current one, I feel modes are fine. That said, the example in the article seems like a pretty severe oversight (crucial indicator, completely identical modes) by itself.
- dunmalg 12y ago
  >I, for one, fail to realize how can one design any half-complex app (gadget, whatever) to be stateless. It's fairly obvious, isn't it? A keyboard with no shift key is going to need twice as many keys... but of course you'll also never find yourself accidentally typing with caps lock on. That's the trade off. The UI becomes more complicated.
  - bernardom 12y ago
    That's the nicest short explanation of the mode tradeoff I've ever seen.
  - SideburnsOfDoom 12y ago
    The shift mode key is usable, as the position of your finger gives you tactile feedback of which mode you are in; and it enters a predictable state when you let go. The caps lock key does a very similar thing to shift, and is not very useful on a modern keyboard. In my experience it is more often engaged by accident than on purpose.
- sgustard 12y ago
  My car has a "reverse" mode which tries to kill me every once in a while when I hit the gas. I think a separate reverse pedal to the left of the brake would do the trick instead, and be nicely symmetrical.
  - wiredfool 12y ago
    That would play havoc with people used to clutches. As it is, I often have a couple go-rounds with 'the brake is not a clutch' when I get a rental.
_pmf_ 12y ago
The question is whether a mode-less interface (that necessarily displays more information at once and is therefore inherently more complex) would have caused more problems than this single instance of a problem caused by the mode mechanism.
camperman 12y ago
Coincidentally, I watched an episode of Channel 4's Black Box series just last night that discusses this accident. The whole series is worth watching but this episode is here: https://www.youtube.com/watch?v=0wp-Dbb2CO4 https://www.youtube.com/watch?v=0wp-Dbb2CO4 Start at 3:34. Very revealing comments at 5:20 about pilots having to fight with the "strong but silent partner" in the cockpit.
userbinator 12y ago
Something doesn't look quite right... in the study linked to from the article, the two figures (archived because the site no longer exists) are: http://web.archive.org/web/20050914030410/http://web.mit.edu/aeroastro/www/labs/ASL/MODE_AWARENESS/figure2a.JPG http://web.archive.org/web/20050914030410/http://web.mit.edu... http://web.archive.org/web/20050412110614/http://web.mit.edu/aeroastro/www/labs/ASL/MODE_AWARENESS/figure2b.JPG http://web.archive.org/web/20050412110614/http://web.mit.edu... Notice that the mode indicator is only in the middle, far from the value it's indicating the mode of, but in the cockpit picture in the article ( http://blog.martindoms.com/wp-content/uploads/2011/01/IMG_8281.jpg http://blog.martindoms.com/wp-content/uploads/2011/01/IMG_82... ), you can see that there are actually two mode indicators, one in the same position as the one in the study and one right above the value where it should be. A quick Google of other cockpit images shows that the plane does have two. I wonder if this was an oversight?
- sengstrom 12y ago
  In the first two images you link there are dual mode indicators - one in the middle and one just by the value itself - in what looks like a manual they are both shown lit up at the same time which seems more like a problem with the documentation than what is shown in the actual aircraft picture (your third link). I'd venture a guess that in "V/S" mode you'd see that indicated next to the number just as you see "FPA" in the cockpit image.
lordnacho1980 12y ago
Everyone who is typing on a keyboard is using a mode. For instance, my "mode" is the HN comment box. Now of course that's clear to me because I can see the text appearing in the correct place. As for the airplane example, isn't it quite natural to expect the pilots to have gone through extensive training? I understand consumer websites need to be intuitive, but highly specialized things can't really be intuitive. One big problem with complex things like a cockpit is that the guys who build it are specialists in a different field from the guys who use it. So how are they going to know if the thing is intuitive? I would imagine a pilot mostly touches the same few commands each day, leaving most modes out of use most of the time. By contrast, the developer needs to build the whole thing.
- DanBC 12y ago
  Sure, pilots get trained. A cockpit is going to be complex. But there's a big difference between complex and confusing, and some examples shown are not particularly complex but are confusing.
nkozyra 12y ago
UI/UX in general is extraordinarily complex. I think we can all agree on that. With something as complex and data-driven as air flight, managing a UI will always be complex as a result. As any given control needs to be available at any given moment, you cannot obfuscate too much in the interest of cleanliness. With all that said, this issue is still not a UI issue, but a training issue and perhaps also an issue with a lack of standards (I'm assuming, not in flight) with jet UI. Even with poor UI, understanding what you're changing and verifying it should boil down to training. Based on this article, it seems like there's a lack of continuity between aircraft in where controls are, and I wonder if there's ever been any push for standardization. I realize not all craft could be complete mimics, but general controls and indicators should be in the same general area, right?
- jonahx 12y ago
  > Even with poor UI, understanding what you're changing and verifying it should boil down to training. Absolutely not! Yes, I want the pilots flying my plane to be as well trained as possible, but there also better damn well be a good UI in place to prevent human error, because that's the one thing we can count on, no matter how good training is or how well-intentioned people are.
roma1n 12y ago
As the article points out, there are other factors involved in this accident. IIRC, Air Inter did not equip its fleet with GPWS, for instance.
deleted 12y ago
[deleted]
josefresco 12y ago
Someone closer to the browser development at Mozilla etc. could answer this better, but wasn't the original implementation of private/incognito or "safe" modes meant to be subtle? Before we were all concerned for our privacy these modes were (and prob still are) mostly used for surfing porn. When one is surfing for porn in "private" mode it would benefit to have the UI not scream "I'M DOING PRIVATE STUFF".
SG- 12y ago
On OSX, Chrome incognito mode is way more obvious since the top of the window is a dark shade of blue/grey.

138 points by damian2000 12y ago

Making mistakes with blender won't kill you but the modes are enough to drive anybody nuts. Another instance of a very poor choice that led to people being killed in aviation was the one where 'take-off power' was interpreted as 'take power off'. I can't find a reference to that accident but the essence was that during a go-around instead of full throttle the pilot reduced power causing the aircraft to stall and crash.

WalterBright 12y ago
That incident happened in the Air Force. It caused "take-off power" to be renamed "full power".
- VBprogrammer 12y ago
  Interestingly the word 'take-off' is only ever used in conjunction with a take-off clearance over the radio (e.g. "Speedbird 101, cleared for take-off") where as any other reference will use the word 'departure' (e.g. "After departure contact London control on 123.12").
  - jorgis 12y ago
    Isn't departure the term for leaving the controller's airspace?
    - VBprogrammer 12y ago
      Not that I'm aware (though I'm not an expert). It is certainly used for one of the many air traffic control units you can encounter at larger airports (e.g "Contact departure on 123.45"). My understanding is that the word 'take-off' over the radio is (or at least should be) treated like a loaded gun, you only say it when you mean it. Departure is used in place of take-off where appropriate (e.g. "Speedbird 101, holding short of runway 13, ready for departure.")
    - artmageddon 12y ago
      VBprogrammer's post is pretty spot on. In my experience around towered airports, I can't say I've heard "take-off" used in any radio comms I've had. In the example you've given, "departure" would be used instead of take-off as you've said. Towers are encouraged to use other terms[0], like the following: "N1234 cleared onto the active runway" which means you're free to proceed with your take-off roll. When you leave the airspace(at least at a class D airport), the controller will contact you with "N1234 frequency change approved", which means you either contact the next frequency planned in flight(such as flight following, or no frequency if you're just flying around in class E). [0] http://www.faa.gov/air_traffic/publications/atpubs/atc/atc0403.html http://www.faa.gov/air_traffic/publications/atpubs/atc/atc04...
  - underwater 12y ago
    This was a change made after the Tenerife crash: http://en.wikipedia.org/wiki/Tenerife_airport_disaster http://en.wikipedia.org/wiki/Tenerife_airport_disaster

tboerstad 12y ago

This same example, along with many others, are covered in Don Norman's classic "The Design of Everyday Things".

sehr 12y ago
He made a course on it over at Udacity as well if you're into videos > text

bagels 12y ago

More Airbus deadly UI: http://en.wikipedia.org/wiki/Air_France_Flight_447 http://en.wikipedia.org/wiki/Air_France_Flight_447 The two sticks can be pointed in different directions. The plane does not complain about this and averages the inputs. One pilot is pulling back, one is pushing forward, plane crashes. Clearly there are some human factors here, but from what I've read, on Boeing's aircraft pushing one stick causes the other to move, much more intuitive.

dredmorbius 12y ago
Boeing also uses a classic control column rather than a side-stick, emulating physical controls even though the actual mechanism is largely fly-by-wire.
ern 12y ago
It isn't only Airbus that has deadly UI. Boeing came in for some flak in the design of the 777's non-intuitive autothrottle modes in the Asiana 214 crash report. Pilot confusion with Boeing's autothrottle has also been implicated in other crashes.
- idlewords 12y ago
  Nothing about flying a plane is really intuitive. The Asiana crash was a pretty clear case of pilot error. At some point you have to either trust the pilots or just enable autoland.
  - ern 12y ago
    That's a fair point, and it was also made by an NTSB board member who appended a partial dissent to the report.
idlewords 12y ago
The Airbus vs Boeing approach to fly-by-wire is a bit of a religious issue, like type safety or memory management in our world. Many words have been written on both sides. I think the UI issue in AF447 is much less clear cut. It's more a lack of any indicator that pilots are making opposite inputs, rather than a misleading or confusing display. Airbus did not anticipate that a pilot would stall a plane and fly it directly into the ocean. There was a whole chain of events (including some appalling human factors) that led to the tragedy there. The avionics teams at both companies have put an incredible amount of thought into how these systems are designed, and how they fail. The differences are instructive, but we should refrain from being quick to judge which is more or less intuitive.

shoyer 12y ago

the moral of the story is avoid modes whenever possible We try to avoid using global state (and state in general) in software engineering for this exact same reason. Humans just aren't good at keeping track of more than a few things at once, even if they are the ones who designed the system in the first place.

damian2000 12y ago
There's nothing at all wrong with state (i.e. variables) in programs - relatively few programs don't use state. The issue is with UI modes ... reusing the same UI which means two different things according to the mode its in.
- shoyer 12y ago
  By "state in general", I particularly meant mutable or nonlocal state in general. There is obviously nothing wrong with using variables. To restate my analogy: the problem is when you can run the same function twice with the same input and get a different result. Or when the same variable can mean two totally different things depending on some external context.

dredmorbius 12y ago

I'd argue that modal behavior isn't a bad thing so long as those modes are very clearly distinguished. It doesn't hurt if they're encountered frequently enough that the user / operator has a clear sense of their distinction. vi/vim is a modal editor. There are two ways of interacting with it: "insert" mode, and "normal" (command) mode. In one, you're editing your document, in the other you're operating on it. While frustrating for new users, with experience using modes becomes transparent, as they're switched in and out of all the time. Though the visual distinction of modes isn't always clear. In a non-programming context, most sailboats have two primary operating modes: under sail, and under power. Here, the contexts are evident from a large number of cues in the environment, and how the boat is skippered is evident from these cues. Other tools have many modes of operation -- the various apps on a smartphone/tablet effective change the mode of the device. Is it a phone? A music player? A messaging tool? A web browser? The "mode" is specified by the application. Usually visual cues of the display indicate which specific mode is operative.

MrBuddyCasino 12y ago
Everyone I've seen has trouble with this in the beginning. I'm not an advanced vim user, would it really be impossible to make it modeless without losing too much power?
- ben0x539 12y ago
  You could probably make an equally powerful modeless editor but I don't see how it could be anywhere near vim-like. Maybe if you had a foot pedal to indicate what modes to interpret input sequences in.
  - TheZenPsycho 12y ago
    What about ditching the caps-lock key and making it a "command" key, that you hold down to type in a command?
    - icebraining 12y ago

rbanffy 12y ago

http://www.amazon.com/Set-Phasers-Stun-Design-Technology/dp/0963617885 http://www.amazon.com/Set-Phasers-Stun-Design-Technology/dp/... has many stories about user interfaces, bugs and their occasional lethality.

ExpiredLink 12y ago

> but I guess the moral of the story is avoid modes whenever possible. Not a story for Vim aficionados.

cnvogel 12y ago

See also this report at the FAA regarding the exact accident being discussed in this blog post: http://lessonslearned.faa.gov/ll_main.cfm?TabID=2&LLID=57&LLTypeID=2 http://lessonslearned.faa.gov/ll_main.cfm?TabID=2&LLID=57&LL... This also includes pictures of the displays without (-3.3 and -33) and with (appending two small zeroes for the latter) the fix employed by Airbus. (I also commented on the original article, but await moderation.)

gear54rus 12y ago

I, for one, fail to realize how can one design any half-complex app (gadget, whatever) to be stateless. I mean, modes are literally everywhere. So long as you can always tell which mode is the current one, I feel modes are fine. That said, the example in the article seems like a pretty severe oversight (crucial indicator, completely identical modes) by itself.

dunmalg 12y ago
>I, for one, fail to realize how can one design any half-complex app (gadget, whatever) to be stateless. It's fairly obvious, isn't it? A keyboard with no shift key is going to need twice as many keys... but of course you'll also never find yourself accidentally typing with caps lock on. That's the trade off. The UI becomes more complicated.
- bernardom 12y ago
  That's the nicest short explanation of the mode tradeoff I've ever seen.
- SideburnsOfDoom 12y ago
  The shift mode key is usable, as the position of your finger gives you tactile feedback of which mode you are in; and it enters a predictable state when you let go. The caps lock key does a very similar thing to shift, and is not very useful on a modern keyboard. In my experience it is more often engaged by accident than on purpose.
sgustard 12y ago
My car has a "reverse" mode which tries to kill me every once in a while when I hit the gas. I think a separate reverse pedal to the left of the brake would do the trick instead, and be nicely symmetrical.
- wiredfool 12y ago
  That would play havoc with people used to clutches. As it is, I often have a couple go-rounds with 'the brake is not a clutch' when I get a rental.

_pmf_ 12y ago

The question is whether a mode-less interface (that necessarily displays more information at once and is therefore inherently more complex) would have caused more problems than this single instance of a problem caused by the mode mechanism.

camperman 12y ago

Coincidentally, I watched an episode of Channel 4's Black Box series just last night that discusses this accident. The whole series is worth watching but this episode is here: https://www.youtube.com/watch?v=0wp-Dbb2CO4 https://www.youtube.com/watch?v=0wp-Dbb2CO4 Start at 3:34. Very revealing comments at 5:20 about pilots having to fight with the "strong but silent partner" in the cockpit.

userbinator 12y ago

Something doesn't look quite right... in the study linked to from the article, the two figures (archived because the site no longer exists) are: http://web.archive.org/web/20050914030410/http://web.mit.edu/aeroastro/www/labs/ASL/MODE_AWARENESS/figure2a.JPG http://web.archive.org/web/20050914030410/http://web.mit.edu... http://web.archive.org/web/20050412110614/http://web.mit.edu/aeroastro/www/labs/ASL/MODE_AWARENESS/figure2b.JPG http://web.archive.org/web/20050412110614/http://web.mit.edu... Notice that the mode indicator is only in the middle, far from the value it's indicating the mode of, but in the cockpit picture in the article ( http://blog.martindoms.com/wp-content/uploads/2011/01/IMG_8281.jpg http://blog.martindoms.com/wp-content/uploads/2011/01/IMG_82... ), you can see that there are actually two mode indicators, one in the same position as the one in the study and one right above the value where it should be. A quick Google of other cockpit images shows that the plane does have two. I wonder if this was an oversight?

sengstrom 12y ago
In the first two images you link there are dual mode indicators - one in the middle and one just by the value itself - in what looks like a manual they are both shown lit up at the same time which seems more like a problem with the documentation than what is shown in the actual aircraft picture (your third link). I'd venture a guess that in "V/S" mode you'd see that indicated next to the number just as you see "FPA" in the cockpit image.

lordnacho1980 12y ago

Everyone who is typing on a keyboard is using a mode. For instance, my "mode" is the HN comment box. Now of course that's clear to me because I can see the text appearing in the correct place. As for the airplane example, isn't it quite natural to expect the pilots to have gone through extensive training? I understand consumer websites need to be intuitive, but highly specialized things can't really be intuitive. One big problem with complex things like a cockpit is that the guys who build it are specialists in a different field from the guys who use it. So how are they going to know if the thing is intuitive? I would imagine a pilot mostly touches the same few commands each day, leaving most modes out of use most of the time. By contrast, the developer needs to build the whole thing.

DanBC 12y ago
Sure, pilots get trained. A cockpit is going to be complex. But there's a big difference between complex and confusing, and some examples shown are not particularly complex but are confusing.

nkozyra 12y ago

UI/UX in general is extraordinarily complex. I think we can all agree on that. With something as complex and data-driven as air flight, managing a UI will always be complex as a result. As any given control needs to be available at any given moment, you cannot obfuscate too much in the interest of cleanliness. With all that said, this issue is still not a UI issue, but a training issue and perhaps also an issue with a lack of standards (I'm assuming, not in flight) with jet UI. Even with poor UI, understanding what you're changing and verifying it should boil down to training. Based on this article, it seems like there's a lack of continuity between aircraft in where controls are, and I wonder if there's ever been any push for standardization. I realize not all craft could be complete mimics, but general controls and indicators should be in the same general area, right?

jonahx 12y ago
> Even with poor UI, understanding what you're changing and verifying it should boil down to training. Absolutely not! Yes, I want the pilots flying my plane to be as well trained as possible, but there also better damn well be a good UI in place to prevent human error, because that's the one thing we can count on, no matter how good training is or how well-intentioned people are.

roma1n 12y ago

As the article points out, there are other factors involved in this accident. IIRC, Air Inter did not equip its fleet with GPWS, for instance.

deleted 12y ago

[deleted]

josefresco 12y ago

Someone closer to the browser development at Mozilla etc. could answer this better, but wasn't the original implementation of private/incognito or "safe" modes meant to be subtle? Before we were all concerned for our privacy these modes were (and prob still are) mostly used for surfing porn. When one is surfing for porn in "private" mode it would benefit to have the UI not scream "I'M DOING PRIVATE STUFF".

SG- 12y ago

On OSX, Chrome incognito mode is way more obvious since the top of the window is a dark shade of blue/grey.