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Comment by notatoad | Hacker News Reader

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", but they were off by one on a dataset of one.

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Yeah, but once you decide that the leftmost runway you see (with the dark void on its left) is the left runway, then obviously the parallel strip of lights to the right of it is the right runway. Sure, the lights look odd, and your gut's giving off this feeling, but you see, that's the left runway, and I don't see the right runway anywhere else, so this must be the...

They probably got stuck in several cycles of that before the contrary evidence was overwhelming enough to break them out of their off-by-one mental model.

Yup. Humans are very good at fitting information into what they already know about a situation even if it doesn't fit perfectly.

Can you see the X at the beginning of the runway while sitting in the pilot seat? I was told the pilots' eyes are expected to be at mid-windshield height, but pilots prefer their seats in slightly reclined position and no position is compulsory.

It's meant to be seen when approaching the disabled runway, not as a generic landmark to help the pilots orient themselves. So it's not prominently visible when approaching the taxiway.

>> Can you see the X at the beginning of the runway while sitting in the pilot seat?

On approach you should be looking at the threshold and the numbers. That's right around where the X was, so it would be clearly visible to anyone trying to land on the closed runway. They were not trying to land on that one, and since they were over the taxiway the X was actually two "lanes" away from where they were. I don't think the X is terribly relevant to what happened here.

I a am a pilot. At night, after a long flight to a place you don't live at, you are desperately looking to orient yourself. They looked at the charts, saw 2 runways, and found them. It can be extremely disoritening, especially at a place like sfo where there are two parallel sets of runways.

What we need is better computer guidance. The tech is available, our legislature is not. Look at the incredible "taking out freedoms" pushback against adsb to see what I'm talking about.

Isn't ADS-B already on these planes? Shouldn't they have gotten some indication they were about to hit several other planes?

Only ADS-B Out (which refers to an aircraft broadcasting its position and other information) will be required in the near future. ADS-B In (which refers to an aircraft receiving the broadcasts and messages) remains optional.

Also, due to the common airport design of runways and parallel taxiways, it isn't uncommon to fly either near or over waiting planes on final approach, so this may not have been cause for alarm even if they were equipped with ADS-B In.

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?

The crew flew a visual approach (guided by human eyes) instead of an ILS approach.

In the words of the investigation: "At 2346:30 PDT, Northern California TRACON cleared ACA759 for the FMS bridge visual runway 28R approach."

28L was dark apart from the X, and the taxiway was lit (albeit with taxi Lane instead of runway lights). Expecting two lit lanes and approaching the one on the right, they certainly saw something "off" but this wasn't a case of pilots choosing to avoid the only lit lane.

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