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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

#121

Post by coldtea »

acchow wrote: post #103
dmitrygr wrote: post #64

Earlier quoted context omitted.

It is a very Silicon Valley thing to assume that everyone else is an idiot and needs to be disrupted, with not a thought given as to why things are the way they are. Sort of funny to watch it from the side I assure you that there is a reason AM is used. The reason is that in the case that two stations are transmitting, everyone will be aware of it and the stronger signal may be heard. This is not something that FM ca…

> It is a very Silicon Valley thing to assume that everyone else is an idiot and needs to be disrupted, with not a thought given as to why things are the way they are. This kind of thinking has also lead to a ton of success in Silicon Valley. See Tesla for example.

>This kind of thinking has also lead to a ton of success in Silicon Valley. See Tesla for example.

Well, not exactly a role model for success. 2016 was the first time they made any profit in all those years -- and its uncertain if 2017 will follow.

And it might still be beaten up in all its markets (electric cars and eventually self-driving ones), not a sure winner yet.

Re: SFO near miss might have triggered aviation disaster

#122

Post by CaliforniaKarl »

CaliforniaKarl wrote: post #81
milesf wrote: post #2

How is this even possible? Is it gross negligence on the part of the pilot, a systems problem, or something else? (IANAP)

I'm not a pilot, or real-world ATC, but I was one a _virtual_ air traffic controller, on VATSIM[1]. I was a member of the virtual Indianapolis ARTCC[2], and have worked positions from Dispatch up to & including Center. Listening to the LiveATC clip, the important bit is the phrase "visual 28 right", meaning the Air Canada pilot had been assigned a visual approach to runway 28 Right. The clip sounds like it's from Tow…

So, I should clarify something: A visual approach is pretty simple from the controller's point of view; it's more work for the pilot. But, the pilot is always the one in command of the plane: If the pilot is unwilling to accept a particular approach, they just need to say so. It may lead to delays, but controllers will accommodate.

I originally said that the pilot had been assigned a visual approach to runway 28 Right. Looking at the charts for SFO[1], and the FlightAware trace[2], I have an alternative: The pilot may have been flying the LDA PRM runway 28 Right approach[3].

(You should open up [3] to look at while reading the rest of this comment.)

As has been mentioned, SFO is a bit weird: The two main runways are close enough together that it's not possible for you to have normal simultaneous approaches. For example, have a look at the diagram for Cincinnati/Northern Kentucky International (CVG)[7], another Class B field. Now, compare that to SFO[8]. At CVG, the parallel runways are far-enough apart that simultaneous approaches are possible, but with SFO, that's not possible. So, the FAA came up with the PRM (perimeter) approach.

Essentially, the plane approaching runway 28 Left is on an ILS approach. The plane on approach to Runway 28 Right is on an approach that is kindof like an ILS approach, but the plane isn't heading towards the runway, the plane is heading to a point to the right of the runway. Notice on [3], the point labelled "CFFKC". That's a fix (a point in lateral space), marking the point that you're being guided to. Note how the fix doesn't line up with the runway; that's why this approach is an "LDA (Localizer-type Directional Aid) with Glideslope" approach.

As per the detailed instructions (in [4], and point 4 in [6]), pilots on the LDA PRM runway 28 Right approach switch to a visual approach after the DARNE waypoint (3.4 nautical miles from the runway end). For most of the approach, they are monitoring a second frequency, which is only used if planes get too close together. But, once you pass DARNE, you no longer need to listen on that frequency. And although tower might have a radar view of surrounding traffic, it's not their primary tool (their eyes are).

If the Air Canada pilot was flying the LDA PRM RWY 28R approach, I think the final sidestep (from the LDA to the runway) may have been missed, or not completely executed, causing the pilot to line up with what he thought was the runway, but what was actually the taxiway.

[1]: http://www.airnav.com/airport/KSFO

[2]: https://flightaware.com/live/flight/ACA759/history/20170708/...

[3]: http://155.178.201.160/d-tpp/1707/00375LDAPRM28R.PDF

[4]: http://155.178.201.160/d-tpp/1707/00375PRMAAUP.PDF

[5]: http://155.178.201.160/d-tpp/1707/00375PRMAAUP_C.PDF

[6]: http://155.178.201.160/d-tpp/1707/00375PRMAAUP_C2.PDF

[7]: http://155.178.201.160/d-tpp/1707/00655AD.PDF

[8]: http://155.178.201.160/d-tpp/1707/00375AD.PDF

Re: SFO near miss might have triggered aviation disaster

#123

Post by djsumdog »

codeonfire wrote: post #61
milesf wrote: post #2

How is this even possible? Is it gross negligence on the part of the pilot, a systems problem, or something else? (IANAP)

In Seattle, there have been taxiway landings in 2005 and 2015 because the taxiway looks similar to the runways. Presumably the ILS system should align them with the correct runway, but I guess that in these cases, ILS is not being used. Even it it were, the runways are the same heading and just a few hundred yards apart, so the mistake would not be realized until short final.

I'm kinda surprised manufactures don't have full HUDs in commercial airliners yet. For airports that support ILS, it seems like using it should be mandatory, with a HUD providing a visual guide to ensure the pilot is lined up with the correct runway.

I mean sure, you could still have mistakes (pilot types in the wrong runway in a parallel runway airport and lands on the wrong one), but it'd be another check/safety system in place.

Re: SFO near miss might have triggered aviation disaster

#124

Post by justinjlynn »

acchow wrote: post #103
dmitrygr wrote: post #64

Earlier quoted context omitted.

It is a very Silicon Valley thing to assume that everyone else is an idiot and needs to be disrupted, with not a thought given as to why things are the way they are. Sort of funny to watch it from the side I assure you that there is a reason AM is used. The reason is that in the case that two stations are transmitting, everyone will be aware of it and the stronger signal may be heard. This is not something that FM ca…

> It is a very Silicon Valley thing to assume that everyone else is an idiot and needs to be disrupted, with not a thought given as to why things are the way they are. This kind of thinking has also lead to a ton of success in Silicon Valley. See Tesla for example.

A broken clock is correct at least once a day.

Re: SFO near miss might have triggered aviation disaster

#125

Post by dx034 »

acchow wrote: post #103
dmitrygr wrote: post #64

Earlier quoted context omitted.

It is a very Silicon Valley thing to assume that everyone else is an idiot and needs to be disrupted, with not a thought given as to why things are the way they are. Sort of funny to watch it from the side I assure you that there is a reason AM is used. The reason is that in the case that two stations are transmitting, everyone will be aware of it and the stronger signal may be heard. This is not something that FM ca…

> It is a very Silicon Valley thing to assume that everyone else is an idiot and needs to be disrupted, with not a thought given as to why things are the way they are. This kind of thinking has also lead to a ton of success in Silicon Valley. See Tesla for example.

Did Tesla really disrupt the car market? Sure, everyone is now building EVs but that already started before Tesla became successful. They have no market power on the overall car market.

Companies like Uber, Google, Amazon certainly disrupted markets but I wouldn't be so sure about Tesla.

Re: SFO near miss might have triggered aviation disaster

#126

Post by vintageseltzer »

acchow wrote: post #103
dmitrygr wrote: post #64

Earlier quoted context omitted.

It is a very Silicon Valley thing to assume that everyone else is an idiot and needs to be disrupted, with not a thought given as to why things are the way they are. Sort of funny to watch it from the side I assure you that there is a reason AM is used. The reason is that in the case that two stations are transmitting, everyone will be aware of it and the stronger signal may be heard. This is not something that FM ca…

> It is a very Silicon Valley thing to assume that everyone else is an idiot and needs to be disrupted, with not a thought given as to why things are the way they are. This kind of thinking has also lead to a ton of success in Silicon Valley. See Tesla for example.

This kind of thinking led to Juicero.

Re: SFO near miss might have triggered aviation disaster

#127

Post by CaliforniaKarl »

wfunction wrote: post #115
dotancohen wrote: post #90

Earlier quoted context omitted.

> Safety margins are wide when pilots don't screw up. But this one did. Royally. And the safety margin was wide enough to absorb that screw up. This is _why_ we have wide safety margins. So that one screw up doesn't absorb all of it. People will always screw up, and policy accounts for that fact.

Can you tell me what the second safety margin that kicked in here and saved them was? Seems to me that it was another pilot noticing them and asking "Where's this guy goin'?" which is not something I'd consider to be a safety margin kicking in... it sounds like sheer dumb luck, where the last margin had already failed.

Unfortunately we don't have enough information here to know for sure.

For example, the approach controller may have noticed that a plane they recently handed off to Tower was not yet lined up. The controller would then call up to Tower to make Tower aware of the issue.

Or, Tower may have a screen showing them a radar view of the approach, similar to Approach's screen. They may have noticed it there.

But, the nature of aviation radio is such that you use one frequency to transmit and receive. That means you can't speak over anyone else; you have to wait for them to stop talking before you can start. And if you mess up, there's no easy way for you to know (except when someone else on frequency says "blocked").

Re: SFO near miss might have triggered aviation disaster

#128

Post by dx034 »

dbroockman wrote: post #36
blhack wrote: post #34

People "could" run their cars off of bridges every day, but they don't because they can see, and because roads have signs warning them of curves. This sounds like a story of how well the aviation system works more than anything. The pilot is in constant communication with the tower. The system worked as intended here and he went around. It seems like a non story.

Seems like disaster was only avoided because there was good visibility. If there was fog that day, it sounds like this wouldn't have been avoided.

In a foggy situation they would've used ILS or even autoland. Looking at instruments instead of out of the window would've prevented this much earlier.

Re: SFO near miss might have triggered aviation disaster

#129

Post by CaliforniaKarl »

exDM69 wrote: post #46
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.

Assuming the liveatc audio in the article has not been edited, it sounds like there's about 10 seconds between ATC giving go around and the United pilot saying they flew right over. With instructions given to Air Canada in between so it might have been seconds earlier. Based on that, it was seconds away from a collision. It seems like a near miss when considering aviation safety margins.

What's missing is, when (relative to radio traffic) did the pilot begin the go-around maneuver. Did they begin doing so before being told to go around, or did they only start to do so after?

Re: SFO near miss might have triggered aviation disaster

#130

Post by jiqiren »

chrisper wrote: post #44
dbroockman wrote: post #36

Earlier quoted context omitted.

Seems like disaster was only avoided because there was good visibility. If there was fog that day, it sounds like this wouldn't have been avoided.

If there is fog you do not fly by hand. You use an automated landing system (ILS) in that case.

SFO's ILS isn't always functioning. It was turned off for months when Asiana crashed (June 1st - Aug 2nd)[1].

[1] http://www.popularmechanics.com/flight/a9124/what-went-wrong...

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