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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

#81

Post by CaliforniaKarl »

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 Tower, so you're not hearing the point where the pilot was assigned that approach (that would've happened with Approach).

A visual approach is pretty simple: The controller sets you on a heading & altitude. Then, the controller confirms that you have the runway/field in sight, as well as any other air traffic that may potentially pose a conflict. Once the pilot verbally confirms those things are in sight ("traffic in sight" / "field in sight"), the approach controller will clear the pilot for the "visual runway XXX approach", also issuing appropriate warnings regarding wake turbulence.

Once the visual approach has been cleared, and the pilot has acknowledged, it is now the pilot's responsibility to navigate the plane to the runway, while keeping the plane clear of the traffic that has been pointed out to them.

If the pilot were assigned an ILS, LOC (localizer), LDA (localizer-type directional aid), or RNAV (area navigation) approach, that approach would have included a lateral component, which would have ensured that the plane was lined up with the runway, and not the taxiway.

So, why do a visual approach, when you have so many other options? Mainly because it allows more planes to be put into the same space. If a plane is on a different approach, or is enroute, or is being vectored by the controller ("turn right heading 350"), the controller is responsible for maintaining proper lateral (3 or 5 miles) and vertical (500, 1000, or 2000 feet) separation from other traffic. But traffic cleared on a visual approach does not have that restriction. Visual approaches are an important part of maintaining the high flow rates that Class B airports (SFO, ORD, etc.) want.

This comment's gotten pretty long, so I'll post another one with another possibility as to what may have happened! I'll leave you with the FlightAware radar trail, where (if you zoom in on SFO) you can see the go-around taking place.

[1]: https://www.vatsim.net [2]: http://zidartcc.org [3]: https://flightaware.com/live/flight/ACA759/history/20170708/...

Re: SFO near miss might have triggered aviation disaster

#82

Post by jackweirdy »

narrator wrote: post #78
charlietran wrote: post #3

There's an mp3 of the radio chatter here: https://forums.liveatc.net/atcaviation-audio-clips/7-july-ks... > Audio from the air traffic controller communication archived by a user on LiveATC.net and reviewed by this newspaper organization showed how a the confused Air Canada pilot asks if he’s clear to land on 28R because he sees lights on the runway. > “There’s no one on 28R but you,” the air controller responds. > A…

The "Where's this guy going" unidentified person on the channel prevented the worst accident in aviation history. Great Job! Give that guy a medal and a movie.

This is like Sully all over again, but with only seconds to extract story from instead of minutes!

Re: SFO near miss might have triggered aviation disaster

#83

Post by tuxxy »

wfunction wrote: post #79
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…

Okay, but do military-grade systems use AM like this too? I imagine their needs aren't any less than those of civilians, and I imagine they've gotten their communication systems to work just fine. So what's the issue?

Airlines don't need military systems which are used more for confidentiality and OPSEC than other things. In the field, militaries tend to avoid radio communications for various tactical reasons. Submarines are a great example of this.

Re: SFO near miss might have triggered aviation disaster

#84

Post by PeCaN »

desdiv wrote: post #43
charlietran wrote: post #3

There's an mp3 of the radio chatter here: https://forums.liveatc.net/atcaviation-audio-clips/7-july-ks... > Audio from the air traffic controller communication archived by a user on LiveATC.net and reviewed by this newspaper organization showed how a the confused Air Canada pilot asks if he’s clear to land on 28R because he sees lights on the runway. > “There’s no one on 28R but you,” the air controller responds. > A…

.

I will never understand this mentality of Silicon Valleetards to take something that already works rather well and make it 100× more complicated for questionable benefit.

Re: SFO near miss might have triggered aviation disaster

#85

Post by ptaipale »

wfunction wrote: post #79
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…

Okay, but do military-grade systems use AM like this too? I imagine their needs aren't any less than those of civilians, and I imagine they've gotten their communication systems to work just fine. So what's the issue?

Military-grade systems may not be any "less" but their needs and priorities may be different (e.g. secrecy). So different technology may be used, without any contradiction to why the current one is good for civilian air traffic.

Re: SFO near miss might have triggered aviation disaster

#86

Post by Aloha »

wfunction wrote: post #79
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…

Okay, but do military-grade systems use AM like this too? I imagine their needs aren't any less than those of civilians, and I imagine they've gotten their communication systems to work just fine. So what's the issue?

Generally, yes. There are some digital systems used for aircraft to aircraft communications and for a tactical datalink, but yes its AM for landing.

Re: SFO near miss might have triggered aviation disaster

#87

Post by bake »

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.

ILS does not entail automation -- it provides guidance to humans operating the controls.

Re: SFO near miss might have triggered aviation disaster

#88

Post by saurik »

wfunction wrote: post #79
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…

Okay, but do military-grade systems use AM like this too? I imagine their needs aren't any less than those of civilians, and I imagine they've gotten their communication systems to work just fine. So what's the issue?

I don't understand what is so wrong with the transmission quality in that MP3. The issues I hear sound like they are simply due to trying to transmit from an extremely noisy environment (the cockpit of an airplane); they are mitigating the pilot's voice being entirely drowned in the background noise by placing the microphone right next to their mouth, but that then causes the sound of their breath to be extremely noticeable. I am not sure how to fix these issues but they don't seem to have anything to do with the usage of AM radio.

Re: SFO near miss might have triggered aviation disaster

#89

Post by klodolph »

wfunction wrote: post #79
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…

Okay, but do military-grade systems use AM like this too? I imagine their needs aren't any less than those of civilians, and I imagine they've gotten their communication systems to work just fine. So what's the issue?

"Military-grade" systems use complicated techniques like frequency-hopping spread spectrum. They're designed to be encrypted and resistant to jamming. The jamming resistance is not something we care about (if someone is jamming the signal you just make them turn off their radio), and the whole point of encryption is to prevent interoperability when you don't have the right key.

So sure, you could pay a bunch of extra money for military features and end up with a product that is even less what you want than AM radio. And then you'd have to retrofit everything with these systems.

AM is wonderful. You put a bunch of people on the same channel and it just works.

Re: SFO near miss might have triggered aviation disaster

#90

Post by dotancohen »

lisper wrote: post #48
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.

I'm a private pilot who has flown into SFO once, and flies over SFO on a regular basis (I'm based at Palo Alto airport). This is not being overblown. If you listen to the audio tape, the tower orders the go-around at the 33 second mark, and United 1 reports that "Air Canada flew directly over us" 16 seconds later. That is a breathtakingly close call. Safety margins are wide when pilots don't screw up. But this one di…

> 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.

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