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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

#331

Post by digi_owl »

avar wrote: post #266
pbhjpbhj wrote: post #251

Earlier quoted context omitted.

Which presumably drives a turbine to make electric which can run motors, charge batteries, run scrubbers, run heaters, etc., presumably. They're not direct driving the screw with steam power from the reactor heat-exchange, surely.

It's hard to find anything like a schematic of a Nimitz-class carrier for obvious reasons, but as far as I can tell yes, it's all directly steam powered. The reactor boils (sea)water, which is used to power 4 steam turbines[1][2][3], those turbines drive the propellers. You've probably seen aircraft carrier decks covered in smoke. This is because the Nimitz's catapult system is directly steam powered, service steam i…

I love the way they did the electromagnetic catapult.

https://en.wikipedia.org/wiki/Electromagnetic_Aircraft_Launc...

Basically they spin up flywheels that then dump their kinetic energy back into electric power as the catapult is released.

And it allows them to finely adjust the speed of the catapult depending on the kind of aircraft they are launching.

Re: USS McCain collision ultimately caused by UI confusion

#332

Post by manigandham »

saulrh wrote: post #306
zentiggr wrote: post #301

Earlier quoted context omitted.

Navy sub vet and almost licensed as a pilot: The small aircraft case - one mind, one set of hands, to reduce the feedback loop to fractions of a second overall. Things other than throttle/ailerons/elevators get timeshared in when all else is stable momentarily. Larger ship - water is never still, and any vessel's helm left untended results in drift, both in heading and real speed vs ordered. Depending on traffic and…

I understand that keeping on a desired course is not a simple task and requires prediction and understanding of the surrounding waters... But you can say the same thing about crosswinds and thermal layers and pockets of turbulence in the air over a runway, and autopilots land 747s every day. In a far more computationally intensive and less recoverable domain, with more complex system dynamics and controls even discou…

Aircraft, even big ones, are still far more maneuverable than large navy vessels. That extra Z dimension gives you more space to work through problems, even if it adds complexity.

Re: USS McCain collision ultimately caused by UI confusion

#333

Post by saulrh »

zentiggr wrote: post #327
saulrh wrote: post #306

Earlier quoted context omitted.

I understand that keeping on a desired course is not a simple task and requires prediction and understanding of the surrounding waters... But you can say the same thing about crosswinds and thermal layers and pockets of turbulence in the air over a runway, and autopilots land 747s every day. In a far more computationally intensive and less recoverable domain, with more complex system dynamics and controls even discou…

TL/DR: I have to boil this down to a gut feel, but I'd rather fly a known takeoff/landing profile at any airport, than take a n-thousand ton vessel through a port departure/arrival, simply because the overall situation in the air is so much simpler. Entering/leaving any decent sized port that handles larger vessels is a much more intense collision avoidance situation than any airspace management situation I can imagi…

I'm not advocating full autopilot; I agree that safe trajectories can be harder to plan in dense 2d than in sparse 3d, and that military ships in particular often have high-level objectives that would be extremely difficult to formalize for input into a planner.

Rather, I'm doubting that going in a straight line at a target speed is correctly handled with a three-person steering wheel. My understanding is that the current OOD already has a trajectory planned through the workspace coordinate system (space, time) and gives orders in workspace coordinates ("go this fast") that are then translated into low-level control outputs ("set the rudder to X"). It sounds like in some cases the OOD even gives direct control outputs - "Prepare for X thrust in Y minutes". Certainly these low-level controllers can't be a good thing for the OOD to be spending cognitive resources on, and I'd be astounded if we can't replace that with a computer that translates directly from that trajectory to the control outputs.

That's why I used airplanes as my example, rather than, say, autonomous vehicles. A commercial airliner's path through the air to a safe landing is basically hard-coded. The task of the airplane's autopilot, then, is simply to follow that trajectory - and I'd guess that it's far more difficult for an airliner to follow a workspace trajectory than it is for a ship to do so.

Really, the hard part is going to be getting the trajectory out of the OOD's head. And even then, it'd be so much easier if the helmsman could execute "go this way" by punching "this way" into a computer instead of staring at a compass and directly and continuously controlling the rudder.

Re: USS McCain collision ultimately caused by UI confusion

#334

Post by [deleted] »

marcosdumay wrote: post #321
Zeebrommer wrote: post #286

Earlier quoted context omitted.

Although I think ship control can definitely be made more user-friendly, what you are asking for is of similar complexity as a self-driving car.

Looks more like an aircraft's auto-pilot. It's not something that would look for obstacles, read signs, or take any kind of input from the environment besides current position.

[deleted]

Re: USS McCain collision ultimately caused by UI confusion

#335

Post by lucaspiller »

Supernaut wrote: post #233
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…

I drive a manual transmission car every day and I'm bemused by your reference to "having to think about changing gears". For an experienced and competent driver, registering and acting upon the need to move up or down a gear usually requires no conscious thought whatsoever. The mechanical process itself literally takes a split second. By contrast, in my one experience with an automatic transmission, it proved to be a…

I agree it's not something you really think about (I used to think automatic was for lazy people), but when you don't have to think about it, it's a load off your mind. This is exactly my point though - it's a habit that people are used to, and don't see why (or don't want to know why) changing it might be beneficial.

Re: USS McCain collision ultimately caused by UI confusion

#336

Post by zentiggr »

saulrh wrote: post #333
zentiggr wrote: post #327

Earlier quoted context omitted.

TL/DR: I have to boil this down to a gut feel, but I'd rather fly a known takeoff/landing profile at any airport, than take a n-thousand ton vessel through a port departure/arrival, simply because the overall situation in the air is so much simpler. Entering/leaving any decent sized port that handles larger vessels is a much more intense collision avoidance situation than any airspace management situation I can imagi…

I'm not advocating full autopilot; I agree that safe trajectories can be harder to plan in dense 2d than in sparse 3d, and that military ships in particular often have high-level objectives that would be extremely difficult to formalize for input into a planner. Rather, I'm doubting that going in a straight line at a target speed is correctly handled with a three-person steering wheel. My understanding is that the cu…

Well said, that gives me a perfect frame to say that the inherent complication in handling the ship's trajectory is how rapidly the trajectory may need to completely change, contrasted against the reaction time of the vessel itself.

The OOD is estimating a best trajectory given an analysis of the navigation constraints and the behavior of every possible contact in the vicinity. Orders at every level of detail are possible at any time... from 'resume best course for point "X-Ray"' to 'allaheadflankfullrightrudderbraceforimpactport!'. That is the point of resistance to most levels of automation past 'ship's wheel mirrors rudder angle' and 'engine order repeater indicates desired engine rpm'.

Re: USS McCain collision ultimately caused by UI confusion

#337

Post by CamperBob2 »

foldr wrote: post #28
CamperBob2 wrote: post #26

Earlier quoted context omitted.

And why didn't they figure it out...?

Read the report. There is no simple answer to that question. It was a complicated and confusing situation, and the pilots in the cockpit made a number of mistakes.

It was a complicated and confusing situation

It's the job of the UI/UX designers to make that less likely.

Like most air crashes, it took at least two things going wrong to make this one happen. Three in this case. Factor #1, a couple of morons were flying the aircraft. Factor #2, pitot tube icing. Factor #3, the aircraft was designed with certain unintuitive control features that depart from longstanding industry practices. The sticks that everybody's talking about were only one of those elements.

An arguable (if perhaps not politically-acceptable) conclusion is that if the pilots aren't sure who's doing what, the control system engineers and the pilots need to go back to school.

Re: USS McCain collision ultimately caused by UI confusion

#338

Post by inferiorhuman »

avar wrote: post #206
inferiorhuman wrote: post #53

Earlier quoted context omitted.

Basic airmanship could've prevented the crash too. The pilot-in-command got a stall warning and pulled back on the stick, climbing to 38,000 feet. That's not a UI issue, it's a forgetting one of the most fundamental rules of flying issue. https://aviation.stackexchange.com/questions/1418/what-happe...

You normally can't stall an Airbus aircraft, except in cases where the flight mode changes as it did in this situation. This was a huge part of the problem, an emergency occurred and the pilots were effectively flying an aircraft they hadn't flown before. Fully pulling back the stick is what you'd normally do in an Airbus to gain altitude. It's guaranteed not to stall the plane.

> Fully pulling back the stick is what you'd normally do in an Airbus to gain altitude. It's guaranteed not to stall the plane.

I'd love to see some documentation on "pull back in a stall". In fact, this is all I could find:

http://www.pprune.org/tech-log/415373-new-airbus-stall-recov...

Re: USS McCain collision ultimately caused by UI confusion

#339

Post by chrisbennet »

mrguyorama wrote: post #328
chrisbennet wrote: post #259

Earlier quoted context omitted.

Microwave oven UI's are terrible but they weren't always that way. My old Amana had 5 controls: a knob for intensity (never changed it) and a knob for the timer, plus start, stop and light buttons. When the the start button broke we just jammed it in the "on" position with a penny making the UI even simpler: put the food in, and turn the knob for the time. https://www.ebay.com/itm/Vintage-Cookmatic-Radarange-Made-by.…

I don't have the same feeling. Different brands have different UI's, and some are as simple as "Press then numbered button for how many minutes of full power cooking you want"

Unless you want more than 10 minutes, then you have to press a different button and then type in the time. Fortunately, there are only something like 20 buttons...a big improvement over a knob and a button that is immediately usable by anyone.

Re: USS McCain collision ultimately caused by UI confusion

#340

Post by foldr »

CamperBob2 wrote: post #337
foldr wrote: post #28

Earlier quoted context omitted.

Read the report. There is no simple answer to that question. It was a complicated and confusing situation, and the pilots in the cockpit made a number of mistakes.

It was a complicated and confusing situation It's the job of the UI/UX designers to make that less likely. Like most air crashes, it took at least two things going wrong to make this one happen. Three in this case. Factor #1, a couple of morons were flying the aircraft. Factor #2, pitot tube icing. Factor #3, the aircraft was designed with certain unintuitive control features that depart from longstanding industry pr…

The report examined UX issues but didn't identify the side sticks as a significant factor. You can keep insisting that they were a factor if you like, but you haven't actually provided any evidence in support of that contention.
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