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

Re: SFO near miss might have triggered aviation disaster

#211

Post by Piskvorrr » Tue, Jul 11, 2017, 9:18 AM UTC

wfunction wrote: post #181

PhasmaFelis wrote: post #175

Earlier quoted context omitted.

In their defense, I would guess that making such a system 100% reliable and unintrusive may be a lot harder than we realize. It's not uncommon for Google Maps to be off by a few blocks for 10 seconds or more, and that could very easily be fatal if you're using it to land an airplane.

Are you suggesting their current GPS systems have that kind of issue though? I'm just asking for an interface to be added, not a entire concept of GPS functionality to be added. I'm assuming the latter is already used. It's not like I was suggesting they use Google Maps.

Indeed. GPS (and friends) are a best-effort affair - works great, most of the time.

Re: SFO near miss might have triggered aviation disaster

#212

Post by anovikov » Tue, Jul 11, 2017, 9:19 AM UTC

ddeck wrote: post #14

Attempts to take off from or land on taxiways are alarmingly common, including those by Harrison Ford: Harrison Ford won't face disciplinary action for landing on a taxiway at John Wayne Airport [1] Serious incident: Finnair A340 attempts takeoff from Hong Kong taxiway [2] HK Airlines 737 tries to take off from taxiway [3] Passenger plane lands on the TAXIWAY instead of runway in fourth incident of its kind at Seattl…

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.

Re: SFO near miss might have triggered aviation disaster

#213

Post by pluma » Tue, Jul 11, 2017, 9:20 AM UTC

acchow wrote: post #18

mc32 wrote: post #10

Earlier quoted context omitted.

The tense/mood is wrong. It implies it could have been the cause of something that did happen rather than it having had a possibility of causing something that did not happen. Text of article has correct tense: "In what one aviation expert called a near-miss of what _could have been_ the largest aviation disaster ever..."

But the aircraft did actually align for Taxiway C and start an approach. That did happen.

Yes, but the aviation disaster didn't happen.

Might have triggered: SFO near miss happened, either it's unknown whether the aviation disaster happened (but there are suspicions it did), or it's unknown whether the two events were related (but there are suspicions they are).

Would have triggered: SFO near miss did not happen, but if it had happened, it would have triggered the aviation disaster.

Could have triggered: SFO near miss did happen, but there was no aviation disaster, though there could easily have been one if it hadn't been actively averted.

Re: SFO near miss might have triggered aviation disaster

#214

Post by pluma » Tue, Jul 11, 2017, 9:24 AM UTC

petre wrote: post #187

Paint the runway and the taxiway in different colors and also use different colors for the light signals that illuminate them at night. Blue/white is rather confusing. Use clearly distinguishable colors such as red/blue or orange/blue or magenta/yellow.

Another comment mentioned green vs white. Even though it's practically impossible to get an aviation license with deuteranopia that just seems like it's asking for trouble. White light is rarely pure white and depending on the weather conditions I have a hard time believing the contrast is unambiguous.

Heck, maybe aviation should take a page from basic accessibility and figure out that information should be conveyed more than one way. Don't rely on color alone (and no, spacing of the rows of lights isn't unambiguous either, especially when looking at varying distances and angles).

Re: SFO near miss might have triggered aviation disaster

#215

Post by [deleted] » Tue, Jul 11, 2017, 9:26 AM UTC

cyberferret wrote: post #33

wfunction wrote: post #21

Earlier quoted context omitted.

Why in the world is this even a problem? Shouldn't what's a taxiway and what's not be indicated on maps or diagrams or something that pilots can see?

Because the pilot is almost never looking at a map on final approach. He is looking out the window, and in the dawn/dusk light, or with a setting sun in the background or inclement weather etc., a taxiway can look exactly like a runway. Don't forget that almost all taxiways run parallel to the runway, for about the same length. (NB: I used to be a commercial pilot.) In most airports I flew into, the surface material…

[deleted]

Re: SFO near miss might have triggered aviation disaster

#216

Post by Piskvorrr » Tue, Jul 11, 2017, 9:27 AM UTC

konschubert wrote: post #139

tmsh wrote: post #92

The moral of this story for me is: be that "another pilot." To be clear, "another pilot" of another aircraft. Not as clear as it could be just like the title of this article is ambiguous. The moral of this story for me is: call out immediately if you see something off. He's the real hero. Even if the ATC controller immediately saw the plane being misaligned at the same time - that feedback confirming another set of e…

The moral might also be that automatic guided landing approaches should be mandatory whenever they are available.

And then your Cat-IIIc equipment is offline for whatever reason, and nobody had landed a plane by hand for years at that point. Now what?

(In other words, automation has its own set of failure modes)

Re: SFO near miss might have triggered aviation disaster

#217

Post by amelius » Tue, Jul 11, 2017, 9:30 AM UTC

URSpider94 wrote: post #162

wfunction wrote: post #66

Earlier quoted context omitted.

Fantastic explanation, and the question on my mind the entire time is "but why??"! Surely the copilot can look at a map (when I say map I don't mean a piece of paper -- I mean a digital one with GPS and everything) and see their trajectory while the pilot is landing, right? Like I'm imagining there should be something on the plane that shows them their trajectory and the runway information. If there is, why isn't it…

I don't think a map or chart would necessarily solve the problem. The taxiway runs parallel to the runway, in the same direction, is the same length, and is similar in width. Similar to how a map or GPS won't stop you from turning down the wrong way on a divided highway. Or how there have been many cases of people following GPS and turning onto railroad tracks that parallel roads. https://www.google.com/search?q=driv…

When the GPS in my car shows two lanes, it clearly marks whether I should take the left or right one.

Re: SFO near miss might have triggered aviation disaster

#218

Post by tialaramex » Tue, Jul 11, 2017, 9:32 AM UTC

Aloha wrote: post #70

desdiv wrote: post #43

Earlier quoted context omitted.

.

There is a very good technical reason we still use AM. AM is not prone to capture effect, wherein the loudest signal captures the receiver. With AM, you can hear multiple people talking on top of each other at the same time. https://en.wikipedia.org/wiki/Capture_effect For uncontrolled radio situations where you have a number of unknown people who need to access a radio channel, neither digital nor encryption bring a…

Mmm. Here's the thing, I think we heard a lot of the same arguments before DSC took off for marine radio.

They too have uncontrolled radio, a large number of unknown people who need to communicate with whoever happens to be nearby, they have more powerful transmitters owned by governments that "need" to shout down less powerful ones on transport vessels occasionally.

Now, maritime radio IS a different environment. I'm not suggesting that DSC should just be dropped in as a replacement for AM analogue transceivers on planes, but I _am_ saying that I don't buy the theory that it so happens AM analogue is the right choice and not just the result of inertia.

Re: SFO near miss might have triggered aviation disaster

#219

Post by mate_soos » Tue, Jul 11, 2017, 9:33 AM UTC

Before crying pilot error, we must all read Sydney Dekker's A Field Giude to Understading "Human Error" (and fully appreciate why he uses those quotes). Don't immediately assign blame to the sharp end. Take a look at the blunt one first. Most likely not a pilot error. Assigning blame is a very human need, but assigning it to the most visible and accessible part is almost always wrong.

Re: SFO near miss might have triggered aviation disaster

#220

Post by ubernostrum » Tue, Jul 11, 2017, 9:34 AM UTC

narrator wrote: post #78

charlietran wrote: post #3

There's an mp3 of the radio chatter here: https://forums.liveatc.net/atcaviation-audio-clips/7-july-ks... > Audio from the air traffic controller communication archived by a user on LiveATC.net and reviewed by this newspaper organization showed how a the confused Air Canada pilot asks if he’s clear to land on 28R because he sees lights on the runway. > “There’s no one on 28R but you,” the air controller responds. > A…

The "Where's this guy going" unidentified person on the channel prevented the worst accident in aviation history. Great Job! Give that guy a medal and a movie.

Listen to this recording:

https://www.youtube.com/watch?v=SgPuyzogFuI

It's from a Delta flight a few years ago that slid off the runway at LaGuardia in snow. The action starts about 5 minutes into that recording; Tower has just set up another incoming Delta flight to land, and is trying to confirm Delta 1086 has cleared the runway. Delta 1086 is poking its nose out over the water at this point, and the controller can't see it.

At around 5:56 a ground vehicle calls in to ask permission to cross the runway and gets it. Then the ground vehicle sees what's happened (Delta 1086 slid off the end of the runway), and this is where it gets interesting, because you see very quickly two important things:

1. Trusting the report: the guy up in the tower does not have a perfect view, and in fact in this incident he can't see what has happened to this Delta plane. He's getting an unsolicited report from a ground vehicle, but he believes it and acts immediately on it. If the report's mistaken, worst outcome is some planes circle a bit more before they finally land. If the report's right, though, the worst outcome is planes trying to land on a crash site.

2. Division of responsibility. From the moment the crash becomes known, it's the job of the emergency/rescue teams to figure out what's happened and deal with it. The guy in the tower probably desperately wants to know more about what's going on, but he's got planes stacked up waiting to land, and his curiosity is going to have to wait. Beyond getting confirmation of a couple unusual orders, Tower just lets the folks on the ground do their job, and sticks to doing his.

Here's a rough annotated transcript (timestamps are from the video), since I know people complain that ATC recordings are hard to make out:

6:08: Delta 1086, Tower? (trying to contact the plane that's just gone off the end of the runway -- Tower still doesn't know what's happened)

Tower, call 100, Runway 13 is closed. (ground vehicle has seen the accident)

Tower, red team to go onto 13.

Tower, you copy? Call 100, Runway 13 is closed.

Call 100, you said Runway 13 is closed? (Tower confirms what he's just heard)

Affirmative, 13 is closed.

Team red, Tower?

Tower, you have an aircraft off the runway.

6:45: Delta 1999, go around!

1999, going around.

6:50: The airport is closed. The airport is closed. We've got a 34. (ground crew saying this is bad enough the airport needs to close)

Call 100, say again?

6:59: Tower, you have an aircraft off 31 on the north vehicle service road, please advise crash rescue, LaGuardia Airport is closed at this time.

7:12: Good afternoon, Tower, Delta 2522's on the ILS for 13 (another Delta flight is lining up to land on the runway where the crash happened* -- they can't hear what's happening below)

Delta 2522, LaGuardia Tower, go around!

Go around, Delta 2522. (pilot confirms that he's going around)

From there on out, it's just Tower giving instructions to other planes on what to do, and a report from the ground to tell the pilot of the crashed plane (if he does get on the radio again) that the plane is leaking fuel from a ruptured wing.

Now: what if the ground vehicle hadn't gone out there? Or hadn't seen the crash in time, or hadn't been able to get a report to the tower in time, or the tower had hesitated a bit more in accepting the report and starting to reroute planes? A similar problem to the SFO incident, only instead of an occupied taxiway it would've been an occupied runway (and one that had already caused one plane to slide off in the snow, and now had emergency vehicles converging on it).

The point is, though, that this isn't necessarily a miracle or a lucky escape -- everybody is involved in ensuring safety, and that's what happened in both cases, providing extra layers of watchfulness which averted much more serious trouble.

* The runway is referred to as both "13" and "31" at different points; runways are numbered according to compass heading, so "13" means it's aligned to a heading of 130 degrees. The dual numbers are because you can take off or land from either end; the other number is always +/- 18, since it's 180 degrees around from the first one. In this case, the designation of the runway is 13 from one end, and 31 (for 310 degrees, 130 + 180) from the other end.