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USS McCain collision ultimately caused by UI confusion

arstechnica.co.uk

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Re: USS McCain collision ultimately caused by UI confusion

#241

Post by foldr »

dredmorbius wrote: post #235
foldr wrote: post #222

Earlier quoted context omitted.

I've addressed the popular mechanics article in other comments. It's difficult to square some of its key claims with the description of events in the accident report. In particular, the report gives no indication that any of the three pilots successfully identified that the plane was stalled. The fundamental issue here is that if only one pilot has his hand on the stick (which should always be true) then linked stick…

Pilot error based on the actions of a single pilot, or even, in extreme cases, two pilots, might reasonably be attributed. To have three pilots fail to grasp a situation central to principles of flight, and to have similar situations arise in other aircraft, suggests exogenous factors at play. You've repeatedly made the case that multiple pilots fighting for control indicates a breakdown of cockpit discipline. You've…

It's clear from the available transcripts that there were only brief moments when both pilots were making stick inputs, as otherwise the "dual input" alarm would have sounded repeatedly. So it seems likely that for the most part, the pilots knew which of them was in control. That would makes sense, as there are clear audio and visual indications of this.

I have not been able to find any source other than the popular mechanics article (and its descendants) suggesting that there were extended periods of time where both pilots had their hands on their sticks and were making conflicting inputs.

Accidents almost by definition involve rare confluences of factors. This one seems to have involved two incompetent pilots in the cockpit, and a captain who came in too late to resolve the situation. Pilot error does happen. There have previously been accidents caused by pilot error when three or more people were present in the cockpit.

I'm not "litigating" the use of position. My point is that if you looked at the position of the pilot's stick, it would usually be in the center position, even if the control surfaces were significantly deflected. For example, if you push the stick forward and then let it return to the center, the plane will pitch down, and remain in that attitude until the stick is pushed again. To know the deflection of the control surfaces, you'd have to mentally track "number * length of forward movements - number * length of backward movements".

Re: USS McCain collision ultimately caused by UI confusion

#242

Post by cesarb »

thaumasiotes wrote: post #177
foobarian wrote: post #129

Earlier quoted context omitted.

Don't get me started about TVs. When I grew up our family TV turned on in seconds, and pressing channel up/down reacted in tens of milliseconds.

We have some recent TVs. They have no buttons. Including power buttons. If you want to turn them on, you need the remote control.

The ones I've seen don't have physical buttons, but have nearly invisible capacitive buttons, at least for power/channel/volume. For most other functions, you do need the remote control.

Re: USS McCain collision ultimately caused by UI confusion

#243

Post by gsnedders »

inferiorhuman wrote: post #78
cyberferret wrote: post #61

Earlier quoted context omitted.

I believe the warning can change depending on which of the 3 flight modes the aircraft is in at the time. Big contribution to AF447's demise was that the aircraft was in 'alternate flight' mode and the crew assumed it was still in 'normal flight' mode and made a lot of their judgement calls accordingly. For an industry that is so safety conscious, I believe this is a huge flaw in disaster control. To put it in contex…

I'd argue it's more like getting dropped into single user mode. No friendly GUI, but the underlying systems are the same. The flaw with any sort of safety net is that you get used to it and forget the basics of aviation. The big problem was that the pilot-in-command simply forgot (or did not know) how to fly the plane. He overcorrected in reaction to turbulence and the rest is history. Normal law does not allow the p…

> The big problem was that the pilot-in-command simply forgot (or did not know) how to fly the plane.

The pilot flying wasn't the pilot-in-command. Half the problem was the PIC was out of the cockpit at the time and the lack of any clear command structure between the two first officers in the cockpit. You can also argue that it may have been recoverable if the PIC took over as PF when he returned to the cockpit (had he acted rationally, etc.), instead of being confused by the situation they were in and unable to get out of, likely without knowing what the PF was doing.

> My understanding is that most long-haul pilots will fly a fairly small number of segments each month, and that most of those segments are going to involve a huge amount of time spent in the middle of nowhere with autopilot on. This leads to atrophying of skills needed to manually fly a plane.

Much flying nowadays is through RVSM (reduced vertical separation minima) airspace, and you're not allowed to hand-fly the aircraft there (in general, modern autopilots can maintain altitude better than a pilot can).

Re: USS McCain collision ultimately caused by UI confusion

#244

Post by foldr »

dredmorbius wrote: post #236
foldr wrote: post #231

Earlier quoted context omitted.

You insinuated that I had some kind of ulterior motive, in the same way that you are now insinuating that the accident report was a cover up. As for expert opinion, could you give references? All I can find are articles in the popular press where a journalist emailed someone in the know to confirm that yes, indeed, Airbus control columns are not linked -- which is not a point in dispute. There's a really simple expla…

I've asked you to state your interests. You've declined to do so.

What a gloriously absurd thing to say.

Look, this is me:

http://adrummond.net

If you're willing to put your real name up here, then we can start speculating on who's being paid by whom to shill for what. Until then, I'll assume that you're on the Boeing payroll...

(I don't in general intend this account to be associated with my real identity, so I may remove the link above in a day or two.)

Re: USS McCain collision ultimately caused by UI confusion

#245

Post by themaninthedark »

gambiting wrote: post #214
ams6110 wrote: post #108

Earlier quoted context omitted.

It makes some sense to me. Conning officer instructs helmsman which direction to go. Helmsman then executes that and monitors/adjusts to stay on that heading without further attention. Same for speed. The officer is then free of the tasks of monitoring and adjusting speed and direction and can focus on what's happening outside of that.

What I don't get is that obviously on a military vessel the chance of someone getting injured or incapacitated are rather high - so why would you want critical things like speed to be controlled by a separate person from the one steering? If they get knocked out and the controls for speed/direction/depth are in a physically different location, doesn't that result in a complete loss of control?

On the flip side, if there is an event that incapacitates one person it might not affect all 3 so you still have some control during and right after the event instead of waiting for someone to make their way to the control station

Re: USS McCain collision ultimately caused by UI confusion

#246

Post by userbinator »

Yaggo wrote: post #152
userbinator wrote: post #135

Earlier quoted context omitted.

Automotive "climate control" has been around since the mid-60s, and the controls of the early versions were also far more straightforward; basically, one knob for temperature and another for turning the system on/off at various settings. Here's one from 1973: http://i44.servimg.com/u/f44/16/54/79/13/1973_c12.jpg

I had no idea that automatic climate control (i.e. user just sets the target temperature) dates back to 1970, because it was not a standard option for low/mid-price cars yet in 90s (at least in Finland). Heck, my parents bought a Toyota Corolla in 2003 with no automatic climate control. Fascinating to see it implemented with old-style analogous controls. Same for 6-way power seat.

Indeed, it was originally only on luxury models --- Cadillac introduced it in 1964.

https://ccco.s3.amazonaws.com/kb_photos/290/2284_1964_Cadill...

Re: USS McCain collision ultimately caused by UI confusion

#250

Post by rangibaby »

btgeekboy wrote: post #122
rangibaby wrote: post #112

Earlier quoted context omitted.

Is there a purpose to the display being so colorful? If AP were the only green thing and the others were monochrome it would stand out more.

Most of the colors on that display have a rationale. For example, on the speed tape on the left, the white, green, and yellow colors all map to colors of a standard airspeed indicator. That the course (CRS) is green instantly tells me I'm navigating by a ground-based VOR, not GPS (which would be magenta). Same with the green diamond on the right by the altitude indicator. The waypoints at the top are all GPS-calculat…

yes, thanks for your reply. It's why I asked my question that way (Chesteron's fence etc).

Would it be possible to display that same information using a traffic light system?

(Red=Immediate action required, Yellow=keep an eye on this, Green decaying to grey=something that changed (eg AP OFF green then turns gray after 10 seconds or so). It would need to be applied with discipline to avoid every single piece of information being red and hence useless. (cf phone notifications or people who click OK to every dialog box).

Information overload / fatigue is a real thing and something designers need to concentrate on more, the ugly brother of "minimalism" which looks pretty but is frustratingly useless.

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