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NTSB Issues Investigative Update on San Francisco Airport Near Miss

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Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#91

Post by akavel »

modeless wrote: post #3

Before I couldn't imagine how anyone could make this mistake, but now I see it. The pilots were familiar with SFO and knew that there were two runways, but didn't realize the left hand runway lights were turned off, so they had an off-by-one error when choosing the runway.

Yeah, that's the key new info for me too, something I missed during the previous discussion - I think it wasn't mentioned at all then. The key quotes from the OP article:

"Runway 28L was closed to accommodate construction; its approach and runway lights were turned off, and a 20.5-ft-wide lighted flashing X (runway closure marker) was placed at the threshold. Runway and approach lighting for runway 28R were on and set to default settings, which included a 2,400-foot approach lighting system [...]

Both pilots said, in post-incident interviews, they believed the lighted runway on their left was 28L and that they were lined up for 28R. They also stated that they did not recall seeing aircraft on taxiway C but that something did not look right to them."

Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#92

Post by sjg007 »

throw2016 wrote: post #74

Wouldn't this whole problem disappear if runways were designed differently, at the minimum one exclusive for landing and one for takeoff with no chance for planes landing and planes taking off to meet, like 2 parallel hockey sticks. Both runways would be painted and lit up completely differently with large lettering explicitly saying take off and landing.

Lack of space, weather conditions and also a lot more planes to get through the system means they use multiple runways for both takeoff and landing.

Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#93

Post by idlewords »

viraptor wrote: post #20

I've seen people mentioning this could be a big disaster, but I'm curious exactly what the effects could be. Specifically, ignoring the wheels for the moment, would the hull of the landing plane slide off on contact at all, or would the planes just get squashed? I have no intuition about friction / stiffness of materials at that scale. (I'm also assuming the planes were at least a little bit offset to the side) With…

The hull of a jetliner is about the thickness of sheet metal and disintegrates. The engines are denser and plow through things. Here's NASA footage of a controlled crash:

https://www.youtube.com/watch?v=Y33N0raKZBo

[EDIT: fixed link]

Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#94

Post by krallja »

throw2016 wrote: post #74

Wouldn't this whole problem disappear if runways were designed differently, at the minimum one exclusive for landing and one for takeoff with no chance for planes landing and planes taking off to meet, like 2 parallel hockey sticks. Both runways would be painted and lit up completely differently with large lettering explicitly saying take off and landing.

No. The captain was not attempting to land on a runway. He was attempting to land on a taxiway, which is painted and lit up completely differently, and also covered in airplanes.

Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#95

Post by garduque »

LittlePeter wrote: post #62

How about using different colour lights for taxiways and runways. They are already using different colour tarmac lines: yellow vs white.

Am not a pilot, but the difference looks pretty clear to me: https://www.youtube.com/watch?v=MnzNvhQxu90

Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#96

Post by avh02 »

idlewords wrote: post #93
viraptor wrote: post #20

I've seen people mentioning this could be a big disaster, but I'm curious exactly what the effects could be. Specifically, ignoring the wheels for the moment, would the hull of the landing plane slide off on contact at all, or would the planes just get squashed? I have no intuition about friction / stiffness of materials at that scale. (I'm also assuming the planes were at least a little bit offset to the side) With…

The hull of a jetliner is about the thickness of sheet metal and disintegrates. The engines are denser and plow through things. Here's NASA footage of a controlled crash: https://www.youtube.com/watch?v=Y33N0raKZBo [EDIT: fixed link]

you just linked back in to the ntsb report - clipboard mistake?

Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#97

Post by joezydeco »

Animats wrote: post #4

This was a very close call. Initial reports indicated it was like an ordinary go-around. No. "The incident pilots advanced the thrust levers when the airplane was about 85 feet above ground level. Flight data recorder data indicate the airplane was over the taxiway at this time. About 2.5 seconds after advancing the thrust levers, the minimum altitude recorded on the FDR was 59 feet above ground level." They overflew…

Mercury News did a good visualization of how close the AC flight came to contact:

http://www.mercurynews.com/2017/07/18/watch-exclusive-animat...

Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#98

Post by joezydeco »

mseebach wrote: post #35
notatoad wrote: post #23

Earlier quoted context omitted.

i'm not a pilot and have no idea what it looks like when landing a plane at night, so i really shouldn't be commenting here, but: the report says the one operational runway had 2400 ft of approach lighting that was functional. The disabled runway had no approach lighting, and presumably the taxiway didn't have any approach lighting because nobody should be approaching a taxiway. So yes, they were just "off by one", b…

Well, they were off by one in adjusting the length of their internal model of the dataset (two runways) with the currently active model (one) and thus suffered a buffer overflow. Anyway, score one (more) for the robots, who would have picked up the correct ILS localizer.

So this flight had no ILS, or ILS was turned off?

Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#99

Post by jve »

modeless wrote: post #3

Before I couldn't imagine how anyone could make this mistake, but now I see it. The pilots were familiar with SFO and knew that there were two runways, but didn't realize the left hand runway lights were turned off, so they had an off-by-one error when choosing the runway.

Um, where were they supposed to land if 28L had lights off and an 'X' marker indicating runway closure? And where did they land afterwards?

Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#100

Post by rrmm »

slavak wrote: post #68
mathgenius wrote: post #18

Earlier quoted context omitted.

> but will add another safety catch. The problem with these things is how do they interact: what do you do in the cockpit when several alarms are going off at the same time? Just adding "one more alert" seems easy but... This is actually a deep problem with automation, how do the parts interact. When writing software this is a constant battle, between modularity and connection.

It's actually even worse than that: In more than one aviation accident multiple alarms and alerts actually served to confuse the pilots as to what's going on, causing them to not perform the action that would have saved the flight. Information overload in the cockpit is a very real thing, particularly in an already task-saturated time like the landing approach. It's entirely unclear that adding yet another alert chim…

Yeah I definitely agree with this concern. Rather than an alarm it could be part of the landing checklist. The person not flying would say, "Check approach on ", the person flying would check the display and respond "Confirm approach on ".
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