Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

SFO near miss might have triggered aviation disaster

mercurynews.com

Post reply on HN
Print view View original

91–100 of 435 posts

Re: SFO near miss might have triggered aviation disaster

#91

Post by cyberferret »

wfunction wrote: post #76
cyberferret wrote: post #56

Earlier quoted context omitted.

It's a matter of scale. Even on a modern HSI, the difference in distance between the runway and the parallel taxiway is probably the width of the indicator icon. Very hard to see on instruments. Much easier to see by looking out the windscreen.

I can't tell if my expectations are just too high, but the impression I'm getting from all your answers is that pilots just don't have a dynamically updating (i.e. digital) map. It seems like everything is a bunch of numbers the poor pilots have to crunch or ticks that they have to count correctly or sheets of paper they have to pass to each other with diagrams. Why in the world is the system so ancient in 2017? Goog…

Ironically, it is mainly because of reliability. Every system on an aircraft HAS to have double or triple redundancy by law, and a lot of these systems ARE antiquated by usual consumer standards.

A lot of pilots these days have iPads in the cockpit to assist with this, but in nearly all airlines and aircraft types, these are unauthorised devices that are not part of the certification. Generally they are used for non critical things like manuals or checklists, but I know of pilots that use them for situational awareness as well. In an accident though, this may work against them, badly.

Yes, it is the old legal and liability issue. Aircraft systems should be upgraded, but the cost of upgrading an entire fleet is prohibitive for most airlines that are already operating on the smell of an oily rag. New generation aircraft are getting better at it though. Like I mentioned before, I believe the 787 now has a HUD of sorts, which is long overdue.

Re: SFO near miss might have triggered aviation disaster

#92

Post by tmsh »

The moral of this story for me is: be that "another pilot." To be clear, "another pilot" of another aircraft. Not as clear as it could be just like the title of this article is ambiguous.

The moral of this story for me is: call out immediately if you see something off. He's the real hero. Even if the ATC controller immediately saw the plane being misaligned at the same time - that feedback confirming another set of eyes on something that is off couldn't have hurt. All 1000 people on the ground needed that feedback. Always speak up in situations like this.

Re: SFO near miss might have triggered aviation disaster

#93

Post by WalterBright »

In the early 1960s, a pilot mistook a WW2 airfield for Heathrow, and landed his 707 on it, barely stopping before the end of the runway.

The runway being too short to lift a 707, mechanics stripped everything out of it they could to reduce the weight - seats, interiors, etc. They put barely enough gas in it to hop over to Heathrow, and managed to get it there safely.

The pilot who landed there was cashiered.

Re: SFO near miss might have triggered aviation disaster

#94

Post by lisper »

dotancohen wrote: post #90
lisper wrote: post #48

Earlier quoted context omitted.

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.

> And the safety margin was wide enough to absorb that screw up.

Barely.

Re: SFO near miss might have triggered aviation disaster

#95

Post by cyberferret »

wfunction wrote: post #76
cyberferret wrote: post #56

Earlier quoted context omitted.

It's a matter of scale. Even on a modern HSI, the difference in distance between the runway and the parallel taxiway is probably the width of the indicator icon. Very hard to see on instruments. Much easier to see by looking out the windscreen.

I can't tell if my expectations are just too high, but the impression I'm getting from all your answers is that pilots just don't have a dynamically updating (i.e. digital) map. It seems like everything is a bunch of numbers the poor pilots have to crunch or ticks that they have to count correctly or sheets of paper they have to pass to each other with diagrams. Why in the world is the system so ancient in 2017? Goog…

Oh, and aircraft DO have moving maps etc. now, but these are usually dialled out to show a range of hundreds of miles in cruise, and are not usually adjusted to show distances in mere metres when on final approach.

Once again, because these displays are usually on the centre floor console or located below the HSI, they are outside the 'scan zone' of a pilot on short finals.

Re: SFO near miss might have triggered aviation disaster

#96

Post by wfunction »

saurik wrote: post #88
wfunction wrote: post #79

Earlier quoted context omitted.

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 not…

I wasn't complaining about the transmission quality, I was just trying to understand the parent comment. The person who complained about the former was someone else.

Re: SFO near miss might have triggered aviation disaster

#97

Post by wfunction »

Aloha wrote: post #86
wfunction wrote: post #79

Earlier quoted context omitted.

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.

Wow, did not know. Thank you.

Re: SFO near miss might have triggered aviation disaster

#98

Post by wfunction »

klodolph wrote: post #89
wfunction wrote: post #79

Earlier quoted context omitted.

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…

> "Military-grade" systems use complicated techniques like frequency-hopping spread spectrum

Note that that technology has been around since World War II. And fun fact, while we're on that topic, this page is worth a read: https://en.wikipedia.org/wiki/Hedy_Lamarr

Re: SFO near miss might have triggered aviation disaster

#99

Post by lb1lf »

Aloha wrote: post #70
desdiv wrote: post #43

Earlier quoted context omitted.

.

There is a very good technical reason we still use AM. AM is not prone to capture effect, wherein the loudest signal captures the receiver. With AM, you can hear multiple people talking on top of each other at the same time. https://en.wikipedia.org/wiki/Capture_effect For uncontrolled radio situations where you have a number of unknown people who need to access a radio channel, neither digital nor encryption bring a…

-Agreed, intelligibility is pretty good.

I've been into amateur radio for ages, presumably that has trained my ear. I routinely copy voice signals which are just a garbled gibberish to innocent bystanders. (Same obviously goes for ATCs and pilots to an even larger degree, being exposed to comms several hours a day)

Re: SFO near miss might have triggered aviation disaster

#100

Post by dingaling »

bake wrote: post #87
chrisper wrote: post #44

Earlier quoted context omitted.

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.

ILS does not necessarily indicate automation, but about 5% of ILS approaches are autolandings.
Post reply on HN