SFO near miss might have triggered aviation disaster • Hacker News Board

Re: SFO near miss might have triggered aviation disaster

#391

Post by wfunction » Tue, Jul 11, 2017, 6:39 PM UTC

phdp wrote: post #321

wfunction wrote: post #260

Earlier quoted context omitted.

Thanks for the detailed response. > Automatic landing systems rely on ground support by way of microwave signals from transmitters installed near autoland-capable runways. There's no general position information, and the airborne part of the system can't operate independently of the part on the ground. Yes, I understand the landing portion has other kinds of support. However, I don't understand how it can not have th…

> OK, so I don't have much of an expectation for older plane models, but my interpretation of the above is that in newer models, autopilot need not disengage before landing and require manual intervention in order to align the plane with the correct track (barring bad weather or other unusual situations like bird collisions, etc.). What is your definition of manual intervention? Pilots get updated instructions from t…

> What is your definition of manual intervention?

I was thinking of autopilot disengaging, but that's not really important here. I'll go along with what you just said.

> Pilots get updated instructions from the tower - the GPS path of the flight within 10 m is not programmed from the beginning

not in the beginning... so it is later?

> due to weather issues, turbulence, traffic at the terminal ends, etc.

Uhm, "traffic at terminal ends" suggests the real problem is that the correct path is not known in the beginning, or that autopilot might not be able to avoid collision on its own... which is quite a bit different from the plane being unable to locate itself accurately and follow the correct path even if it were known a priori. Are we even discussing the original issue at this point?

> Autopilot landings require a Cat III approach.

I have no idea what that means. I'm not sure what gave you the impression that I know what that means either.

> The autopilot when landing is not using GPS for final approach.

> The person you're trading comments with has said twice that GPS is not responsible for the autolanding portion of the flight.

> You twice try to refute it. And then in your last paragraph you do exactly what he says the software engineers here do and you take offense to!

I think you didn't read my last comment carefully because, as I already said, I understood this. My problem is whether GPS is accurate/reliable enough to lead the plane to the place where the next system can take over, which to me implies GPS is already certified to be accurate and reliable enough to get the plane near the correct runway. Read it again. There shouldn't be a single sentence there where I "refute" the microwave transmissions or claim GPS is actually used on the final approach.

> If you have a system that is designed to cut out the human component, it has to be all or nothing.

Wha..? Autopilot isn't perfect either, and can disengage in various situations that it can't handle, but they approve it and pilots manage to use it just fine. When it's GPS's turn, suddenly it has to be 100% perfect?

And when did I ever suggest you have to cut out the human component? For goodness's sake all I'm asking for is a little display with a map that shows where the plane thinks it's going. That's "cutting out the human component" to you?

Re: SFO near miss might have triggered aviation disaster

#392

Post by lisper » Tue, Jul 11, 2017, 6:44 PM UTC

mikeash wrote: post #378

lisper wrote: post #362

Earlier quoted context omitted.

Can you post/link the unedited version? I can't find it. Notwithstanding the timing on the tape, the AC jet could not have been very far away because the fact that he was lined up with the taxiway was first noted by a plane on the ground. That would not have been evident unless the plane was very close.

There's a less-edited version here: http://archive-server.liveatc.net/ksfo/KSFO-Twr2-Jul-08-2017... The action starts at about 14:45. I suspect there isn't much silence removed in this particular area, so 40 seconds may be close to the actual time. I haven't been able to find a pure unedited version. They may not be saved.

What makes you think this version has been edited?

Re: SFO near miss might have triggered aviation disaster

#393

Post by mysterydip » Tue, Jul 11, 2017, 6:44 PM UTC

scrooched_moose wrote: post #366

Tloewald wrote: post #317

Earlier quoted context omitted.

UX is the bane of usability (at least as practiced). E.g. We've had professional "UX" designers seriously contend that "cancel" buttons should be made to not look like buttons. The joke at a certain large company was that if the UX designers had their way every default button would be big and green and every other button would be invisible. True usability is about helping people make the correct decision, not just be…

I'm a daily user of some of the most complicated engineering software on the market. Every single release promises "Easier to use!" but all they do is make the most basic beginner-level actions more prominent and hide all medium to advanced level important functionality behind 3 extra clicks. The end result is a beginner can do a tutorial exercise in 20 minutes instead of 30, while any true day to day work in the sof…

From the company's perspective, getting more beginner users on the software (and converting them to regularly paying users) is probably the priority.

That doesn't mean they couldn't put an "advanced mode" setting/option that makes the UI streamlined towards users like yourself, though.

Re: SFO near miss might have triggered aviation disaster

#394

Post by waqf » Tue, Jul 11, 2017, 6:45 PM UTC

konschubert wrote: post #154

Animats wrote: post #144

Earlier quoted context omitted.

Too soon to tell what the problem was. Possibly there was some other problem in the aircraft that was taking some pilot attention. Give this some time.

Then it would still be pilot error, no? I mean, pilot error doesn't mean that the pilot is to be blamed. It just means that he made a mistake.

Yes, the pilot made a mistake, but no, the cause of the accident isn't pilot error. From the point of view of preventing similar accidents in future, the cause of the accident is whatever caused the pilot to make the mistake.

Re: SFO near miss might have triggered aviation disaster

#395

Post by lisper » Tue, Jul 11, 2017, 6:49 PM UTC

pdelbarba wrote: post #335

dx034 wrote: post #271

Earlier quoted context omitted.

But they have radar and usually extended centerlines. That should've been clearly visible for him on the screen.

Radar displays are not going to accurately display a displacement of 150m. They're set up for broader area surveillance. Edit: here's a good example of a terminal radar display. The two parallel diagonal lines are the extended centerlines of two runways that are about 1570m apart (Athens airport, LGAV). https://www.hvacc.gr/site/images/content/events/2003/athens-...

And that's the spacing between the runways. There is less space between the runway and the taxiway.

http://flightaware.com/resources/airport/SFO/APD/AIRPORT+DIA...

Re: SFO near miss might have triggered aviation disaster

#396

Post by rdtsc » Tue, Jul 11, 2017, 6:51 PM UTC

woliveirajr wrote: post #285

rdtsc wrote: post #13

Without knowing the cause but if I had to guess this looks like pilot error. At least statistically that the leading cause of crashes. I am surprised pilots still manually land planes. Is the auto-landing feature not implemented well enough? But then it's relied upon in low visibility. So it has to work, they why isn't it used more often?

The point is that it doesn't help to know that it was a pilot error, because a pilot is human, and humans in the same situation might make the same mistake - and the main goal is to prevent accidents, not to have accidents happening all the time and saying "it was again human error". It boils down to: 1 - Was the "error" intentional? If so, how to prevent someone from doing it again? 2 - Was it a real error, with no…

> doesn't help to know that it was a pilot error, ... and the main goal is to prevent accidents,

You can't prevent accidents if you don't understand their cause. Saying well we don't know what caused it but we'll just tighten all the screws a bit more and send the pilots for more general training. It just doesn't work that way.

Everything is analyzed and tracked to discover the exact root cause. It can often take many years and then new laws or guidelines are usually issued based on findings.

Re: SFO near miss might have triggered aviation disaster

#397

Post by mikeash » Tue, Jul 11, 2017, 6:58 PM UTC

lisper wrote: post #392

mikeash wrote: post #378

Earlier quoted context omitted.

There's a less-edited version here: http://archive-server.liveatc.net/ksfo/KSFO-Twr2-Jul-08-2017... The action starts at about 14:45. I suspect there isn't much silence removed in this particular area, so 40 seconds may be close to the actual time. I haven't been able to find a pure unedited version. They may not be saved.

What makes you think this version has been edited?

It's an archive of a 30-minute period but the file is only 18 minutes long.

Re: SFO near miss might have triggered aviation disaster

#398

Post by wolfgang42 » Tue, Jul 11, 2017, 6:59 PM UTC

Karunamon wrote: post #384

anovikov wrote: post #212

Earlier quoted context omitted.

This is facilitated by the fact that in some airports, taxiways and runways are similar and sometimes even used interchangeably (!), i.e. a runway may be remarked as taxiway and vice versa. So it's not 'how can he be so dumb' moment, in some case you have no way to tell the difference unless you just know.

Yeowch. I was about ready to make a comment about how the airport/approach plates should make something like this impossible, but then I looked up the diagram for SEA: https://flightaware.com/resources/airport/SEA/APD/AIRPORT+DI... Basically, you've got a runway, the taxiway of the same length as the runway! , and then two longer runways from left to right. I totally see how someone could make this mistake in bad lig…

And a note on that diagram:

    CAUTION:
    Pilots are cautioned not to
    mistake Twy T for a landing
    surface.

Re: SFO near miss might have triggered aviation disaster

#399

Post by AnimalMuppet » Tue, Jul 11, 2017, 6:59 PM UTC

FussyZeus wrote: post #307

peteretep wrote: post #286

Earlier quoted context omitted.

I'm surprised there isn't more explicit tooling in the cockpit to stop that happening

As I understand it, planes are largely automated but the automated components will always defer to the pilots whenever action is taken. I would hope with the amount of training required to do that job that the pilot would be the half of that equation to defer to.

As I understand it (but I am not a pilot), that's true of Boeing planes, but not true of Airbus. Airbus makes the pilots defer to the automation.

Re: SFO near miss might have triggered aviation disaster

#400

Post by mturmon » Tue, Jul 11, 2017, 7:00 PM UTC

verytrivial wrote: post #252

hueving wrote: post #188

Earlier quoted context omitted.

I suggest you read ntsb investigations of some major commercial aviation events like this. It is never just "human error. Happens." They are always full of excellent recommendations, points of failure, etc.

I agree. Check out the NTSB report[1] for the crash into a neighborhood in Queens[2]. 200-odd pages of very sober, rational (and interesting) discussion of how a pilot ended up snapping the vertical stabilizer off an A300. There are many factors leading up to what ends up being summarized as pilot error. [1] https://www.ntsb.gov/investigations/AccidentReports/Reports/... [2] https://en.wikipedia.org/wiki/American_Air…

The Columbia shuttle accident report is a masterpiece of the genre. It's available at:

http://www.nasa.gov/columbia/home/CAIB_Vol1.html

It's detailed, but well-written and the quality of the analysis is extraordinary.

For a sample, take a glance at the debris maps on page 45, followed up with amazing results on page 75. If you like understated drama, start at the comm transcript on page 42. ("Lock the doors.")