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SFO near miss might have triggered aviation disaster

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Re: SFO near miss might have triggered aviation disaster

#51

Post by kobeya »

hyperbovine wrote: post #42
FiloSottile wrote: post #4

I am just a passenger, but this looks very over-blown. A pilot aligned with the taxiway, that's bad. But no pilot would ever land on a runway (or taxiway) with 3 planes on it. Just search the Aviation Herald for "runway incursion". And indeed, he spotted them, communicated, went around. Aviation safety margins are so wide that this does not qualify as a near-miss.

> But no pilot would ever land on a runway (or taxiway) with 3 planes on it. Just like no pilot would ever crash into the seawall short of 28L in broad daylight with unlimited visibility. In that case the pilots knew what was about to happen seconds before impact and they were powerless to stop it. I could easily see the same thing happening here. Airplanes are big cumbersome objects with a ton of inertia.

When did that happen?

Re: SFO near miss might have triggered aviation disaster

#53

Post by kobeya »

cyberferret wrote: post #45
willidiots wrote: post #38

Earlier quoted context omitted.

Seems like a design flaw. Do any taxiways have markings etc. to make them more distinguishable?

They do. They have different lighting systems/colours etc. to differentiate them. Taxiways generally have green lights along the centerline to guide aircraft rolling on the ground, but runways usually have white (bright) lights along the edges . There are times when even THAT causes confusion, because sometimes the taxiway centreline lights can look like the edge lights of the runway - especially if the light is refr…

Seems like a very good argument for autopilot landings.

Re: SFO near miss might have triggered aviation disaster

#54

Post by cyberferret »

wfunction wrote: post #40
cyberferret wrote: post #33

Earlier quoted context omitted.

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…

Thank you! That raises the question, (a) why is there no kind of warning system for when you're about to land on the wrong runway (there's a GPS system in the aircraft that knows where you're going, right?) and (b) why is the pilot (or at least co-pilot) never looking at a map on final approach? Is it really that dangerous for anyone to take a quick glance?

Yes, autolanding, or if the pilot was using ILS (Instrument Landing System), then this problem would almost never happen, as they would be aware there was a problem.

However, most pilots eschew automation especially on short finals, and prefer the 'hand fly' the aircraft in so that they can maintain complete control over the aircraft. Not a bad thing, and pilots want to actually fly the plane at crucial times.

When hand flying on final approach, your eyes and senses are 75% outside the aircraft. All you are worried about is your airspeed, your rate of descent and whether the runway is remaining visible at all times. Your eyes are darting from your primary instruments in front of you to the runway outside, and your arms and legs are busy working the throttles, control stick and rudder pedals.

Maps and charts are well stowed away at this point. In fact, once you enter the main airport traffic pattern, they are put away as all the details should be memorised by then. At best, the pilot will have the approach plate on his/her control column. But this just gives the instrument approach paths and radio frequencies etc. and not really a detailed topography of the runways/taxiways.

Ironically, AFTER the plane is on the ground, the non commanding pilot will usually pull out the airport plate which details all the taxiways and routes to gates etc., especially if they are unfamiliar with the airport and have to find their way around.

Re: SFO near miss might have triggered aviation disaster

#55

Post by rl3 »

kobeya wrote: post #51
hyperbovine wrote: post #42

Earlier quoted context omitted.

> But no pilot would ever land on a runway (or taxiway) with 3 planes on it. Just like no pilot would ever crash into the seawall short of 28L in broad daylight with unlimited visibility. In that case the pilots knew what was about to happen seconds before impact and they were powerless to stop it. I could easily see the same thing happening here. Airplanes are big cumbersome objects with a ton of inertia.

When did that happen?

https://en.wikipedia.org/wiki/Asiana_Airlines_Flight_214

Re: SFO near miss might have triggered aviation disaster

#56

Post by cyberferret »

wfunction wrote: post #35
Tuxer wrote: post #29

Earlier quoted context omitted.

(pilot here) Yes, they are very well shown on maps, but it can be hard to map your diagram to what you're seeing, especially if it's raining or if it's at night, and even more if you're tired. I never made the mistake, but can see how somebody in bad conditions would.

Thanks! But why do you even have to map your diagram to what you're seeing? Isn't there a GPS system that shows you exactly where you are on the map and where you are going to go in the next few minutes? It doesn't seem like there should be any mental or visual processing to figure out that you're heading toward the wrong runway, right?

It's a matter of scale. Even on a modern HSI, the difference in distance between the runway and the parallel taxiway is probably the width of the indicator icon. Very hard to see on instruments. Much easier to see by looking out the windscreen.

Re: SFO near miss might have triggered aviation disaster

#57

Post by TacticalMalice »

kobeya wrote: post #51
hyperbovine wrote: post #42

Earlier quoted context omitted.

> But no pilot would ever land on a runway (or taxiway) with 3 planes on it. Just like no pilot would ever crash into the seawall short of 28L in broad daylight with unlimited visibility. In that case the pilots knew what was about to happen seconds before impact and they were powerless to stop it. I could easily see the same thing happening here. Airplanes are big cumbersome objects with a ton of inertia.

When did that happen?

2013, see https://en.wikipedia.org/wiki/Asiana_Airlines_Flight_214

Re: SFO near miss might have triggered aviation disaster

#58

Post by will_hughes »

csours wrote: post #25
FiloSottile wrote: post #4

I am just a passenger, but this looks very over-blown. A pilot aligned with the taxiway, that's bad. But no pilot would ever land on a runway (or taxiway) with 3 planes on it. Just search the Aviation Herald for "runway incursion". And indeed, he spotted them, communicated, went around. Aviation safety margins are so wide that this does not qualify as a near-miss.

> Aviation safety margins are so wide that this does not qualify as a near-miss. I think you have this kind of backwards here. If you were going in for an amputation, and they only prepped the wrong leg, would that not be a near miss? Rare incidents are hard to reason about and measure because they are so rare; but there are things that lead up to rare events - like being on approach to the wrong runway, that are les…

More recently: https://www.youtube.com/watch?v=Cj192PZ_riE

Re: SFO near miss might have triggered aviation disaster

#59

Post by tjohns »

cyberferret wrote: post #41
FiloSottile wrote: post #23

Earlier quoted context omitted.

Right, I meant that if pilots sort-of-routinely spot runway incursions, they surely won't land on 3 wide-body jets sitting there. This is why you want human pilots, instead of computers, not the opposite. A human can apply common sense and decide not to land on three planes after all even if it looks like a cleared runway.

> This is why you want human pilots, instead of computers I actually believe the opposite is true. Systems like ACARS have managed to avoid the prevalence of air to air incidents that used to be almost an epidemic in the 60's and 70's. Autolanding technology has brought planes home safely where a pilot would have had to go around and find an alternate aerodrome.

Are you sure you're not thinking of TCAS?

(ACARS is used for delivering clearances and other routine operational/maintenance messages. Basically text messaging for airplanes.)

Re: SFO near miss might have triggered aviation disaster

#60

Post by ryandrake »

wfunction wrote: post #40
cyberferret wrote: post #33

Earlier quoted context omitted.

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…

Thank you! That raises the question, (a) why is there no kind of warning system for when you're about to land on the wrong runway (there's a GPS system in the aircraft that knows where you're going, right?) and (b) why is the pilot (or at least co-pilot) never looking at a map on final approach? Is it really that dangerous for anyone to take a quick glance?

When flying visually (VFR), taxiway lighting and runway lighting are visually very different. Taxiway lighting is almost always blue, whereas runway lighting is white (with any displaced threshold marked with red lights). In daylight, the markings on the runway are unmistakably different.

I'm not instrument rated but my understanding is that with ILS, instrument approaches can handle multiple parallel runways precisely and therefore the pilot has the tools necessary to distinguish between a runway and taxiway when in instrument conditions. Someone please correct me if I'm wrong.

Let the investigation happen, but from the reported facts, this seems to be a pretty clear case of pilot error.

And I think you meant to say "raises the question" rather than "begs the question."

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