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NTSB Issues Investigative Update on San Francisco Airport Near Miss

ntsb.gov

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

#81

Post by marcins »

pjc50 wrote: post #69
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…

Large objects tend not to be stiff against collision. It would look like a high speed road crash - remember that the landing plane is travelling at over 150km/h.

It’s closer to 150 knots, that’s 277km/h.

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

#82

Post by throwanem »

mseebach wrote: post #78
throwanem wrote: post #76

Earlier quoted context omitted.

Trouble there is that, at least to the best of my knowledge, ILS glide slope and localizer are generally only surfaced in the cockpit as a pair of bugs vertically and horizontally peripheral to the artificial horizon indicator. If you're already having a helmet fire, these are likely easy to overlook, and there's no horn or anything. (But as has been pointed out here by several other commenters before now - if you're…

I don't think there's any indication that these pilots were under any kind of undue stress when they lined up their approach? If at any point during the several minutes of their final approach they'd looked even once at their ILS they'd have seen that they were way off.

Final approach is the most stressful two or three minutes of an otherwise unexceptional flight; there's a great deal to do, and very little time in which to do it, during a period in which the aircraft's proximity to the ground, and low available energy, make it very easy for what would otherwise be a minor mishap to instantly place everyone aboard in imminent danger of death.

I don't suppose I would call such stress "undue", since every commercial flight ideally ends with a landing. But the probability of helmet fire is directly proportional to the degree of cockpit stress, and the ILS alignment indicators are very easy to overlook. I suspect the user interface could be improved, but I'm not nearly familiar enough with the subject domain to imagine how.

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

#83

Post by tacostakohashi »

rcthompson wrote: post #13

Maybe taxiways parallel to runways shouldn't be a thing.

That's been my takeaway from this incident too.

Can't the taxiways be not straight, like have a slight zig zag to them, so that they're easily distinguishable from a runway? Not ridiculously zigzagged, but maybe 3 or 4 angles of 15 degrees along the length or something would do it.

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

#84

Post by tajen »

mosheroperandi wrote: post #34
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…

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…

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.

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

#85

Post by dsfyu404ed »

princekolt wrote: post #77
ssambros wrote: post #31

Earlier quoted context omitted.

If you listen to the recording the pilot suspected something was not right, that's why he asked for confirmation that the runway is clear. Most likely he already anticipated a high probability of a go-around.

They teach you in driving school to never overtake in a two-way road unless you are 100% sure you can make it. I'd assume pilots would he held to at least equal standards...

Driving school does everything it can to dissuade you from ever overtaking on a 2-lane because driving in a big, slow line is what's acceptable for the lowest common denominator.

Driving school treats people like idiots by default.

Professional training assumes people have the capacity to evaluate situations and make their own decisions on the appropriate course of action.

Comparing training intended for the general public and training for professionals is very much a stretch IMO.

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

#86

Post by dmurray »

tajen wrote: post #84
mosheroperandi wrote: post #34

Earlier quoted context omitted.

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…

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.

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

#87

Post by dsfyu404ed »

mosheroperandi wrote: post #34
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…

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…

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

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

#88

Post by tajen »

stordoff wrote: post #38
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…

We're discussing a matter of 10s of feet between the near-collision we saw, clipping the tail of one plane, or hitting the plane behind at landing speed, so I imagine the set of "what could have happened" is rather large. That said, I suspect the following three crashes give _some_ indication of what might have happened: USAir 1493 - 737 collides with a turbo-prop on landing; the smaller plane is essentially crushed…

I highly recommend watching the related episode of "Mayday" Air Crash Investigation about Tenerife.

Hulls are so fragile that they've often shred up in flight (De Havaillan, DC-9). Landing is around 200-250kmh only, but planes have caught fire just sliding on runways or terrain. The quantity of jet fuel immediately means catastrophe.

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

#89

Post by abaillargeon »

rrmm wrote: post #12
Flammy wrote: post #2

Previous discussion on this topic: https://news.ycombinator.com/item?id=14741605 This literally could have been one of the worst accidents in American aviation history had the pilots of the landing airplane failed to react in time. There were 4 fully loaded and fueled passenger jets directly ahead of them.

Ugly stuff. I'm glad it ended up as a miss. This incident as well as the previous ones shows that pilots need better support in these conditions. Lots of airports are set up with multiple parallel runway configs. It wouldn't be all that difficult to add computer driven confirmations of the runway an aircraft is approaching on. Given the frequency of these incidents as well as the cost of the consequences it seems lik…

Me too. This is something that already exists today [0]. It can detect when the aircraft is not lined up with a runway and issues a "Taxiway Landing" aural and visual alert.

[0] https://buy.garmin.com/en-US/US/p/545578 , see SurfaceWatch at the bottom.

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

#90

Post by mseebach »

throwanem wrote: post #82
mseebach wrote: post #78

Earlier quoted context omitted.

I don't think there's any indication that these pilots were under any kind of undue stress when they lined up their approach? If at any point during the several minutes of their final approach they'd looked even once at their ILS they'd have seen that they were way off.

Final approach is the most stressful two or three minutes of an otherwise unexceptional flight; there's a great deal to do, and very little time in which to do it, during a period in which the aircraft's proximity to the ground, and low available energy, make it very easy for what would otherwise be a minor mishap to instantly place everyone aboard in imminent danger of death. I don't suppose I would call such stress…

Agreed. Just to be clear, I'm not suggesting that we gang up and witchhunt the pilots for not checking the ILS, my agenda was simply to point out that the technology does indeed exist.
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