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Abstract of the NTSB Report on Air Canada flight 759's taxiway overflight at SFO [pdf]

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Re: Abstract of the NTSB Report on Air Canada flight 759's taxiway overflight at SFO [pdf]

#121

Post by tialaramex »

cpitVoxRec wrote: post #118
tialaramex wrote: post #65

Earlier quoted context omitted.

What I'd expect the CVR to provide good evidence of is the extent to which crew were actually doing the checks that should have caught this error, and their reaction when they belatedly discovered their true position. Without even trying to mislead investigators a human will report a sanitised version of events when not cued by facts. "Then I scratched my arse and sniffed my finger" is not going to appear in this san…

I struggle to believe that it took over 30 minutes to get this thing back down after the incident If your inferring that a 30 minute offset was introduced, in order to dump the stale audio buffer, before permitting access to the CVR instrument on the ground, I'd offer the idea that there were 4 other planes on the taxiway, waiting to take off, and that the intervening 30 minutes could be eaten up by letting those pla…

No, I'm _implying_ that I don't believe it took 30 minutes to get down. Based on the abstract I would say you're going to find out it came back down in under 30 minutes, and then "oops" they let the CVR be re-used, overwriting the recording anyway.

The text from the linked abstract says: "Cockpit voice recorder (CVR) information was not available for this incident because the data were overwritten before senior Air Canada officials became aware of the severity of this incident"

One of the nice things about working in the Web PKI is that this crap doesn't get you anywhere since keeping records is one of the requirements, and any time the options are "This issuer might be crooked or they might be incompetent" both are disqualifiying anyway, no need to figure out which it is to make a determination.

It lets me sleep easier, were people at Symantec reckless, or were they so greedy that they actively tolerated fraud? Don't care, not my problem now, let their shareholders worry about it.

Re: Abstract of the NTSB Report on Air Canada flight 759's taxiway overflight at SFO [pdf]

#122

Post by abaillargeon »

oh_sigh wrote: post #99
abaillargeon wrote: post #86

Earlier quoted context omitted.

Good question. We've run into similar issues while developing a related feature that helps pilots perform a stable approach. Sometimes pilots were performing a circling approach to a different runway, and a naive approach to determining lateral deviations would have caused a nuisance alert. For this particular system, the alerting threshold is only met when we've determined that the aircraft is "landing". As I mentio…

What's your market? Light aircraft? airliners?

Our market right now is general aviation and business jets. I believe our biggest customer is the Cessna Citation Longitude (max takeoff ~40,000lbs). I noticed the NTSB abstract had some recommendations for inclusion and certification of a system on a broader range of aircraft. Larger aircraft are required to have similar safety-related systems such as terrain, reactive windshear, etc so this could be the next step.

Re: Abstract of the NTSB Report on Air Canada flight 759's taxiway overflight at SFO [pdf]

#123

Post by joezydeco »

siberianbear wrote: post #103
joezydeco wrote: post #74

Earlier quoted context omitted.

PilotsEyeTV is a really really neat thing. They sell entire box sets of whole flights. It's pretty cool that the European airlines allow this amount of camera work in the cockpit: http://pilotseye.tv/en/flightroutes/ If you really want to see something captivating, watch this clip of a Swiss A340 crew handling an overheating engine in-flight. It's incredibly well done. https://www.youtube.com/watch?v=rEf35NtlBLg

Wow, that Swiss A340 video was amazing. The pilots were just so chill. "Let's have some chocolate for the landing" LOL

Yeah, it kind of makes up for all the Romansh flying back and forth in that cockpit. =)

Re: Abstract of the NTSB Report on Air Canada flight 759's taxiway overflight at SFO [pdf]

#124

Post by gok »

metanoia wrote: post #19
gok wrote: post #4

It's kind of baffling to me that there's a system for detecting collisions with other airplanes in the sky (TCAS) and a system for detecting collisions with the ground (EGPWS) but not system for detecting collisions with other airplanes on the ground. This easily could have killed a thousand people.

SFO has ground radar systems (ASDE-X/ASSC) [1] which allows ground and tower controllers to see potential conflicts on taxiways and runways. Pure speculation, but I don't think that these systems' conflict logic take into account an aircraft trying to land on a taxiway. [1] https://en.wikipedia.org/wiki/Airport_Surface_Surveillance_C...

Yeah the report mentions that the systems for detecting conflicts and mis-alignments don't really talk to each other.

Re: Abstract of the NTSB Report on Air Canada flight 759's taxiway overflight at SFO [pdf]

#125

Post by [deleted] »

tialaramex wrote: post #121
cpitVoxRec wrote: post #118

Earlier quoted context omitted.

I struggle to believe that it took over 30 minutes to get this thing back down after the incident If your inferring that a 30 minute offset was introduced, in order to dump the stale audio buffer, before permitting access to the CVR instrument on the ground, I'd offer the idea that there were 4 other planes on the taxiway, waiting to take off, and that the intervening 30 minutes could be eaten up by letting those pla…

No, I'm _implying_ that I don't believe it took 30 minutes to get down. Based on the abstract I would say you're going to find out it came back down in under 30 minutes, and then "oops" they let the CVR be re-used, overwriting the recording anyway. The text from the linked abstract says: "Cockpit voice recorder (CVR) information was not available for this incident because the data were overwritten before senior Air C…

[deleted]

Re: Abstract of the NTSB Report on Air Canada flight 759's taxiway overflight at SFO [pdf]

#126

Post by cpitVoxRec »

tialaramex wrote: post #121
cpitVoxRec wrote: post #118

Earlier quoted context omitted.

I struggle to believe that it took over 30 minutes to get this thing back down after the incident If your inferring that a 30 minute offset was introduced, in order to dump the stale audio buffer, before permitting access to the CVR instrument on the ground, I'd offer the idea that there were 4 other planes on the taxiway, waiting to take off, and that the intervening 30 minutes could be eaten up by letting those pla…

No, I'm _implying_ that I don't believe it took 30 minutes to get down. Based on the abstract I would say you're going to find out it came back down in under 30 minutes, and then "oops" they let the CVR be re-used, overwriting the recording anyway. The text from the linked abstract says: "Cockpit voice recorder (CVR) information was not available for this incident because the data were overwritten before senior Air C…

Oh, I don't know about these particular ideas you're chasing. There are quite a number of independent, redundant resources that would be very difficult to align forgeries across and present as fraudulent data, worldwide, for weeks, months, and even years after the incident.

It just sounds like a fishing expedition for some kind of cover up that exploits an incredibly narrow gap, covered by a myriad of alternative information sources that are more than capable of sealing up an air tight sequence of events by other means.

Open, consumer information sources like flightaware.com alone had the answer to the questions you're asking, long ago.

The radar history for this event was paywalled here for days after the event:

https://flightaware.com/live/flight/ACA759/history

The open, freebie log only gives like two weeks of charts, but the data you mention was lying around, available for like 8 months, to anyone with premium access to that particular service. And anyway, I'm sure it's just a convenience wrapper to public data that's still floating around to anyone willing to dig.

Here's another service, if you've got $500 bucks, and really would like to know right now:

https://www.flightradar24.com/data/flights/ac759/

And to reiterate, this is only costing money today on account of being late to the party.

Multiple systems surfaced this data to the world in real time, and openly back-logged for months after. I'd bet good money a wide audience fact checked exactly what you've suggested a long time ago (even here: https://news.ycombinator.com/item?id=14741605). But my opinion isn't very important when the information is available in a general sense, to anyone who really wants it, even now, more than a year later. Feel free to be suspicious about these resources being far downstream and non-official consumer products, but if that doesn't suffice, then other (much, much bigger) doubts occlude any potentially satisfactory assessment which won't get solved in a random thread by amateur internet detectives like us.

Re: Abstract of the NTSB Report on Air Canada flight 759's taxiway overflight at SFO [pdf]

#127

Post by MarkMc »

nutcracker46 wrote: post #3

The report identifies good preventive measures. Autotuning the ILS would be handy, as would an aural alert for lateral deviation, perhaps announcing, "Localizer, Localizer." The crew may have caught the closure of 28L and planned better with a review of NOTAMS before top of descent and including them in the approach briefing. When I'm up there, and sleepy, I ask for a coffee and pull out the NOTAMS for one last look…

"Localizer, localizer" seems too obscure - "Landing on taxiway" is much clearer.

It's interesting to listen to the radio chatter for this near-miss [1]. The air traffic controller misses a few chances to notice that something isn't right but when the pilot on the taxiway says in plain English, "Where's this guy going? He's on the taxiway" the problem immidately becomes obvious.

[1] https://youtu.be/ZW-ETmZU0u8

Re: Abstract of the NTSB Report on Air Canada flight 759's taxiway overflight at SFO [pdf]

#128

Post by scrumper »

jackpirate wrote: post #91
scrumper wrote: post #37

Earlier quoted context omitted.

Worth noting that the Canadian regulations are looser than USA in that respect - the Air Canada pilots were in compliance with home regs, but would have been in breach of FAA regs. Other point is that the NTSB isn't generally particularly shy about calling out the need for expensive changes (one example being their recommendation for fuel tank inerting systems after TWA 800). They have no power to mandate their recom…

Why does a plane in US airspace not follow FAA regs?

Well, it does pretty much, just not that bit (14 CFR 117). In this Air Canada case it's governed by 14 CFR part 129, which covers operations by foreign air carriers in the USA.

https://www.gpo.gov/fdsys/pkg/CFR-2011-title14-vol3/xml/CFR-...

EDIT - removed erroneous reference to 14 CFR 121.480-> which applies to cargo ops.

Re: Abstract of the NTSB Report on Air Canada flight 759's taxiway overflight at SFO [pdf]

#129

Post by throwaway5250 »

sokoloff wrote: post #92
captain_perl wrote: post #81

Earlier quoted context omitted.

No, because when there's fog, the strobe gets reflected within the cloud everywhere. This is SFO after all.

In the case of fog or other low clouds though, airplanes are overwhelmingly likely to be following a localizer or GPS/RNAV approach, making this type of incident much less likely.

Hmm. So why not use that technique _all_ of the time?

Re: Abstract of the NTSB Report on Air Canada flight 759's taxiway overflight at SFO [pdf]

#130

Post by sokoloff »

throwaway5250 wrote: post #129
sokoloff wrote: post #92

Earlier quoted context omitted.

In the case of fog or other low clouds though, airplanes are overwhelmingly likely to be following a localizer or GPS/RNAV approach, making this type of incident much less likely.

Hmm. So why not use that technique _all_ of the time?

Well, AC759 should have been doing so, even on the visual approach to 28R. On this particular approach (in contrast to literally every other approach in the FMS's database), a manual tuning step was required and skipped.-[0]

If there were another approach that required manual tuning and it was not a visual approach, the crew would detect they didn't have a localizer/equivalent to follow and would identify the missed step, because that's the only way they could navigate to the airport/runway.

It's a specific combination of visual approach and the only approach that required manual tuning (and not having another aircraft to follow visually) that setup this possible outcome. Then, the crew visually acquires the wrong bit of pavement and there's no safety mechanism inside the airplane remaining unless/until the pilots see that they're lined up wrong or get a go-around call from ATC/another aircrew.

[0] - Quote from the NTSB report: The FMS Bridge visual approach to runway 28R was the only approach in Air Canada’s Airbus A320 database that required manual tuning for a navigational aid, so the manual tuning of the ILS frequency was not a usual procedure for the flight crew.

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