USS McCain collision ultimately caused by UI confusion • Hacker News Board

Re: USS McCain collision ultimately caused by UI confusion

#211

Post by jabl » Fri, Nov 03, 2017, 8:50 AM UTC

mjlee wrote: post #62

csours wrote: post #24

Earlier quoted context omitted.

The path to a disaster has been compared to a tunnel [0]. You can escape from the tunnel at many points, but you may not realize it. Trying to find the 'real cause' is a fool's errand, because there are many places and ways to avoid the outcome. I do take your meaning, reducing speed and following well established rules would have almost certainly have saved them. 0. PDF: http://www.leonardo-in-flight.nl/PDF/FieldGui…

I prefer the swiss cheese model. https://en.wikipedia.org/wiki/Swiss_cheese_model "In the Swiss Cheese model, an organisation's defenses against failure are modeled as a series of barriers, represented as slices of cheese. The holes in the slices represent weaknesses in individual parts of the system and are continually varying in size and position across the slices. The system produces failures when a hole in each s…

Aha! I sense an opportunity for an enterprising statistical physicist to model this with https://en.wikipedia.org/wiki/Percolation_theory :)

Re: USS McCain collision ultimately caused by UI confusion

#212

Post by jabl » Fri, Nov 03, 2017, 8:55 AM UTC

jordanb wrote: post #134

eternalban wrote: post #120

Earlier quoted context omitted.

> The USS McCain was traveling at over 20 knots at the time of the collision http://cdn.cnn.com/cnnnext/dam/assets/170821080742-04-uss-jo... Sorry. That does not compute. Based on that visual, the ship was dead in the water.

http://s3.amazonaws.com/CHINFO/USS+Fitzgerald+and+USS+John+S... The McCain entered the TSS at 20 knots and varied between 20 and 18 knots until the steering problem began. The OOD ordered the vessel slowed to 5 knots but due to confusion on the bridge the orders weren't carried out properly and the vessel was still making 11.8 knots and turning to port at the moment of impact. The Fitzgerald was also traveling throug…

Sounds like some kind of cowboy culture. "Hey, we have this fast and maneuverable ship moving along these lumbering civilians. We can handle it, we're the best of the best!".

A bit like those organ donors, err.. motorcycle drivers, that swerve among the traffic at high speed.

Re: USS McCain collision ultimately caused by UI confusion

#213

Post by dredmorbius » Fri, Nov 03, 2017, 8:57 AM UTC

foldr wrote: post #51

dredmorbius wrote: post #48

Earlier quoted context omitted.

I have read it. Several times.

Great, the pages and sections are numbered, so it's easy to refer to the parts of it that support your theory. Or alternatively, you can direct us to whatever conflicting sources of information you believe are more reliable than the official accident report.

You seem awfully invested in quashing this particular line of argument. Mind my asking why?

Re: USS McCain collision ultimately caused by UI confusion

#214

Post by gambiting » Fri, Nov 03, 2017, 8:58 AM UTC

ams6110 wrote: post #108

Animats wrote: post #73

There was a ferry accident involving a similar transfer of control problem in New York harbor.[1] Ferries have a lot of maneuvering modes and directional thrusters, because they do so many dockings, and so they have a more complex control problem. The pilot put the system into a backup dumb mode while in cruise, then changed stations to where he could best see the dock while still in the wrong mode. Rammed the dock a…

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?

Re: USS McCain collision ultimately caused by UI confusion

#215

Post by gambiting » Fri, Nov 03, 2017, 9:08 AM UTC

NickNameNick wrote: post #168

lucaspiller wrote: post #162

Earlier quoted context omitted.

I’d say it’s the same reason why manual transmission vehicles are still more popular than automatic transmission in some countries. Automatic transmission of modern cars is easier (you can give more attention to the road than having to think about changing gears), gives a smoother ride, is more fuel efficient and causes less wear and tear on the engine. It’s a habit that the organisation is used to, so there is resis…

Automatics are usually less efficient than manuals - the Hydraulic torque converter has to slip to function. That said, the automatic might beat a manual in other metrics.

Torque converts are the niche choice nowadays, a lot of modern cars have dual-clutch transmissions which are always more efficient than manuals. They use less fuel, shift quicker and commonly have more gears for less strain and better efficiency(almost all new MB cars ship with 9-gear dual clutch tranmissions nowadays for example).

But yes, after owning manuals for years I would never go back, an automatic allows you to be so much more focused on the road and enjoy it more - I love driving and have a sports car, would never ever swap the transmission in that back for a manual.

Re: USS McCain collision ultimately caused by UI confusion

#216

Post by eternalban » Fri, Nov 03, 2017, 9:10 AM UTC

jordanb wrote: post #134

eternalban wrote: post #120

Earlier quoted context omitted.

> The USS McCain was traveling at over 20 knots at the time of the collision http://cdn.cnn.com/cnnnext/dam/assets/170821080742-04-uss-jo... Sorry. That does not compute. Based on that visual, the ship was dead in the water.

http://s3.amazonaws.com/CHINFO/USS+Fitzgerald+and+USS+John+S... The McCain entered the TSS at 20 knots and varied between 20 and 18 knots until the steering problem began. The OOD ordered the vessel slowed to 5 knots but due to confusion on the bridge the orders weren't carried out properly and the vessel was still making 11.8 knots and turning to port at the moment of impact. The Fitzgerald was also traveling throug…

Sure, don't believe your lying eyes. Point out a single scratch that indicates anything other thana 90 degree impact with a stationary vessel.

Re: USS McCain collision ultimately caused by UI confusion

#217

Post by foldr » Fri, Nov 03, 2017, 9:11 AM UTC

dredmorbius wrote: post #213

foldr wrote: post #51

Earlier quoted context omitted.

Great, the pages and sections are numbered, so it's easy to refer to the parts of it that support your theory. Or alternatively, you can direct us to whatever conflicting sources of information you believe are more reliable than the official accident report.

You seem awfully invested in quashing this particular line of argument. Mind my asking why?

I think it's wrong. If you think I am some kind of shill (?), then I guess it makes sense that you would be some kind of conspiracy theorist, given your unwarranted skepticism about the conclusions of the official report.

Re: USS McCain collision ultimately caused by UI confusion

#218

Post by masklinn » Fri, Nov 03, 2017, 9:11 AM UTC

chrisseaton wrote: post #107

a_t48 wrote: post #104

Earlier quoted context omitted.

This would mean wasting fuel, no?

What's that got to do with anything? The comment was about the ability to vary power at all, not doing it efficiently. Are you going to choose to crash into something because it's wasting fuel to vent part of the steam?

> Are you going to choose to crash into something because it's wasting fuel to vent part of the steam?

Under emergency you will vent, but under normal operations where you just want to slow down you care very much about efficiency.

Not just for monetary reasons either (though that's a factor) but because the lumps of coal you're not burning now could save your ass in bad weather and make you reach safety instead of being stranded in the middle of the ocean.

Re: USS McCain collision ultimately caused by UI confusion

#219

Post by foldr » Fri, Nov 03, 2017, 9:14 AM UTC

avar wrote: post #209

foldr wrote: post #51

Earlier quoted context omitted.

Great, the pages and sections are numbered, so it's easy to refer to the parts of it that support your theory. Or alternatively, you can direct us to whatever conflicting sources of information you believe are more reliable than the official accident report.

This theory isn't citing the report itself, but independent analysis that's been done on the same data. The Wikipedia article on the topic has a whole section for these [1], and a section about this theory in particular [2]. Furthermore. The official accident report for crashes is not always considered the authoritative source for what happened. One good example is EgyptAir Flight 990 which the official report claims…

The theory is generally sourced from a popular mechanics article. There's nothing particularly authoritative about that "independent analysis". Goodness knows what you mean by the "same data". No third party has access to all the data recovered from the flight recorders and the wreckage.

>conclusions that could result in the grounding of the entire worldwide Airbus fleet

Concluding that the sidesticks were a contributing factor would not have resulted in the grounding of the fleet. That only happens in the case of extremely severe and extremely immediate threats to safety. UX tweaks would more likely just be included as recommendations. And in fact the report does make some UX recommendations, IIRC.

Re: USS McCain collision ultimately caused by UI confusion

#220

Post by misnome » Fri, Nov 03, 2017, 9:17 AM UTC

toomanybeersies wrote: post #128

tlb wrote: post #77

Earlier quoted context omitted.

In the steam days, it was a major operation to adjust the output of an engine. Valve linkages had immediate effect on the output, but you also had to adjust the boiler heat input to keep the temperature within limits. Far enough back, there were men shoveling coal into the boilers who had to be told to slow down or speed up. Do you think it's mainly bureaucratic inertia that keeps it separate? Or is there something m…

On a nuclear powered ship, yes, since you still essentially have a steam engine, the engine telegraph (throttle) isn't actually linked directly to the engine. On a modern diesel or gas turbine ship, no there's not. Obviously there are limits to what the engine can do still.

The nuclear part isn’t just used to generate electricity for the motors?