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 before we pull up the approach in the computer, manually set up the radios, and do the briefing.
On final approach, more precise ground based monitoring would be nice to have in case things are fubar in the plane.
!SFO 06/079 SFO OBST RIG (ASN 2017-AWP-3368-NRA) 373740N1222224W (0.5NM NE SFO) 41FT (34FT AGL) FLAGGED AND LGTD 1806201400-1811010100
This is a flagged and lighted obstruction half a mile way that is 34 feet above ground level.
Now put in a full route and takeoff airport and maybe if you have had some stops during the day. The NOTAM seems a bit long. Then if are overseas and have to deal with the BS political notams. Check out greece and turkey notams.
...THE REF (B) TURKISH NOTAM A3009/16 LTAAYNYX (111139
EUECYIYN JUL 2016) HAS NO GROUND, CANNOT PRODUCE ANY INTERNATIONALLY
LEGAL EFFECT WITHIN ATHINAI FIR/ HELLAS UIR AND IS CONSIDERED NULL
AND VOID.
I'm curious how many pilots fully read all NOTAMs, locate them geographically to understand where they are etc etc on every flight.
The recommendations look like important steps, especially the concept of a system that alerts pilots to runway surface non-alignment. I have to wonder, though, does it always take a close call like this (or worse) to bring up such a proposal? Does the NTSB also study otherwise safe flights to identify risks in pilot, tower, or ground crew human factors and make proactive recommendations?
As others pointed out there are fundamental problems with the system and usability of NOTAMs. Its a little absurd that theyre always used to blame the operator (“should have read the NOTAM”) when a flight briefing might have 10s or 100s applicable ones and a VAST number are junk. It reeks of retrospective blame seeking.
That said there is some traction around this. And some interesting alternative takes (https://opsfox.net), which have their own problems.
How difficult is it to see what's happening on the ground at night from a plane? I've never been in a cockpit at night. I'd have to hope that taxiways are marked in some explicit way to make it clear that they're not runways, like with an X or some pattern of lights that's not on runways; or have all runways marked with an obvious pattern that indicates "land here" (so if you don't see that, you know you're not landing on a runway). Don't the runways have their names labeled in lights near the entrances? (Or is that only paint?)
I guess I'm surprised that it took so long for the pilots to see that there were other planes where they were landing.
Is it routine to keep binoculars in a cockpit? Could they have seen what was on the ground sooner if they'd looked through binoculars briefly (after noticing unexpected lights?)
"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.
As a private pilot, small planes going down occasionally are just a fact of life. But this incident scares me. There were four planes lined up on the taxiway the Air Canada narrowly missed. The worst aviation accident ever was a collision of two 747s resulting in 583 deaths: https://en.wikipedia.org/wiki/Tenerife_airport_disaster - this could have doubled that number.
Is it plausible that that AC759 could have taken out all 4 other planes? I don't really have a sense of the distances planes are spaced out on taxiways at major airports.
I've been anticipating the release of this report this since I heard about the incident.
I work on an avionics product that's designed to prevent this exact scenario. We use the aircraft's position along with a database of runways and taxiways to determine if the aircraft is approaching the runway the pilot intends. If we determine the aircraft is landing, we issue a visual and aural alert to the pilot ("TAXIWAY LANDING" or "NOT A RUNWAY").
How do you account for winds and pressure differences, both of which will modify an approach. A plane may look like it is landing short, or to the left/right, when in fact the pilot is anticipating a change in wind as they drop in altitude.
Curious: what inputs feed your system? Presumably at least localizer and GPS, but anything else? What accuracy / confidence interval do you require in order to make a call?
This is what is called a 'cascade of failures' in aviation - and the term is used elsewhere. Multiple failures resulting in a catastrophic failure. In your own life and goings about, it's sometimes interesting to do a failure analysis and you'll often find you experienced a cascade.
It's really unfortunate that the cockpit voice recorder was overwritten. I'm guessing they're using very old technology where storage space is at a premium.
They're still using the flashing X on closed runways - e.g. at SEATAC right now. The lights looked incandescent a couple nights ago while passing the X. So not very bright or visible.
This accident would probably have been one of the worst in history. Multiple passenger planes on the taxiway taken out by a passenger jet.
OMG that is just pure gold! The United guy is SOOOO laconic. Like him speaking up on the open freq saved hundreds of lives and he sounds like he's reading yesterday's corn future prices.
I love hearing ATC radio. I think the guy who did the classic SR71 story about upstaging everyone on some California flyby noted this pretty well - even in the times of near peril pilots and ATC will be the cool-as-steel that keep everyone calm.
I was just about to post that link! VASAviation has a really good youtube channel with ATC radio recordings and high quality visualizations of all kinds of interesting events: https://www.youtube.com/user/victor981994
I'm surprised that remote video cameras aren't used by tower controllers.
The perspective of the control tower makes it difficult to catch issues like this, but a simple video camera aligned with the center-line of each runway would allow controllers to more easily verify that planes are lined up as well as other possible issues like gear down & locked, etc.
> I'm surprised that remote video cameras aren't used by tower controllers.
There are software and hardware/network setups designed to do this now, in fact London City Airport is about to move to a fully virtual control tower, with a bunch of super high res pan/tilt/zoom cameras on a mast instead of an on-site tower.
> I'm surprised that remote video cameras aren't used by tower controllers.
I'm surprised that forward-looking infrared cameras aren't more commonly used in civilian aircraft, especially given the availability of staring arrays with decent resolution/framerate that don't require cooling.
Even without the requisite certification for use as a for-realsies landing aid, it's nevertheless a useful tool to get situational awareness in inclement weather / at night.
I'm not operationally familiar with SFO. But based on experience at other airports, a taxiway at night can be a sea of black at even 100' above the ground. I would probably see airplane navigation lights at some point, but would I bet my life on it? No. So this incident has to be taken seriously.
However, I'm still not clear from this reporting how the crew mistook blue taxiway lighting for white runway lighting. This isn't supposed to be subtle, and I haven't ever experienced it to be subtle.
Edit: OK there is a partial explanation here that appears as though at the time they committed to taxiway C as runway 28R, the visual cue they relied on was airplane lighting looking like it was runway lighting. Airplane taxi and takeoff/landing lights are white, navigational lights are green or red. Strobes usually aren't on while on the ground or at least probably shouldn't be.
It's an interesting dilemma. And fatigue is a significant contributing factor as well.
Human consciousness tries to form a coherent model that integrates current sensory perception with knowledge. During an approach at night, scarce sensory input is interpolated to form a full model by the brain. The report uses the term "expectation bias" for this phenomenon. This drive for coherence runs below consciousness and we only notice when the coherence falls apart: When our sensory input cannot be reconciled anymore with the current model. We blink, shift our head, and our model rebuilds anew.
What happened here is that the pilots were locked into a wrong model: In an environment with very little light there is no visual source to compare taxiway lighting against. If we know from experience that a light is white, our brain will use this to calibrate. Without this ever becoming a conscious thought. Color correction happens automatically for us and we don't feel it. This process can easily lead to nominally weird things like blue lights being percieved as white.
Fatigue and stress would contribute to ward off looming decoherence such as "why are the lights on 28L redder than on 28R?" When under pressure, we go with the strongest signal. And that signal may very well come from our knowledge, not our perception.
Here in Seattle, SeaTac airport has a parallel taxiway (Taxiway Tango) with a long history of being mistaken for a runway. The list of things tried so far to resolve the issue is interesting:
"The cues available to the flight crew to indicate that the airplane was aligned with a taxiway did not overcome the crew’s belief, as a result of expectation bias, that the taxiway was the intended landing runway."
Damn. It didn't matter that the whole world was telling him it was a taxiway because he was so sure it was a runway.
Also that they cite fatigue / circadian low as one of the core causes. I thought they might avoid it because of the potential cost implications for the airline industry.
> 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.
How long are recordings normally kept? I would assume at least a few days for mundane flights (storage is cheap, isn't it?) but any sort of incident similar to this I would assume they keep recordings for much longer, if only for internal purposes.
It's a loop recorder. When that aircraft was certified, only a 30 minute loop was required. If that aircraft was newly certified, it would now require a 2 hour loop.
Speaking with a fair level of ignorance, how hard would it be for some onboard computer to be freaking out that a landing attempt is being made way off course of a known runway?
Going to guess this is one of those things where, yes, we have all the requisite technology, but practical implementation is the hard part.
I get excited seeing stories about aviation on HN because it's something I work on every day. I've written a few comments above but I'm developer on the system you described (and more) being used in aircraft today.
With a GPS and onboard databases of runways and taxiways, we can determine if a pilot is attempting to take off or land on a taxiway. The key is preventing nuisance alerts when the pilot is just flying around and happens to be aligned with a runway. The "11 secret herbs and spices" depend on the aircraft but are usually speed and configuration (ie landing gear) based. Approaches are fairly predictable and we can use that to sequence through a state machine that tells us the pilot intends to land.
Are there any reports from passengers on the taxiway planes? I'd have to imagine an A320 flying 60' over your roof would cause a fairly large disturbance.
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.
TCAS alerts about "conflicts" with other aircraft on take-off and landing all the time. It's just that those are almost always false positives, so they get ignored.
There are many aircraft on the ground at airports. Given the high approach speeds, this is probably a non-trivial problem.
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.
Different problems, no? Trying to pick out an airplane against the ground is different from detecting an object in the air, which doesn't generally reflect radio back, and detecting the ground, which does reflect. The problem you're describing requires you to differentiate between two things that both reflect signals back to you. It's obviously do-able since the military does it all the time for targeting. However, I doubt it's cheap and there might be cheaper ways to do it that don't leverage the two systems you've mentioned.
I think this is really just a case of flying into the ground. It just happened to be in close proximity to other aircraft. There are lots of systems that are available to avoid that (ILS, GPS etc.) which were not used in this instance. And a system for avoiding collisions for taxing aircraft is probably not much use at such high speeds.
Some airports do have a system [0] designed to track taxing aircraft and allow collision risks to be detected.
CVR overwrite is bad news here. The crew knew this was a serious problem when it happened, there's no way they should have allowed the CVR, crucial evidence of exactly what happened, to be overwritten.
Perhaps the full report will have more detail on this, as it stands I have to believe somebody made the decision to overwrite this because they thought it'd be better if it didn't exist. Whether that's the crew, their bosses or other staff, somebody managed to go from "serious incident, preserve evidence" to "maximum ass covering" and that person or persons are an obstacle to effective investigation and thus to safe air travel.
Subject aircraft, C-FKCK, is a 1991 A320, which is only required to have a 30 minute CVR loop. (I don't know which exact CVR it was equipped with, of course.)
By the time the aircraft goes around, is resequenced, completes the second approach, lands, taxis in, and shuts down, much of the initial approach setup conversation may have already been overwritten anyway. I wouldn't jump to the assumption that there was malicious intent in the fact that the CVR was overwritten. (I also wouldn't want the crew to stop the CVR recording only to have a second, more serious incident on the same flight that would then go unrecorded.)
If I understand CVR tech correctly, it's running and constantly overwriting the storage in a loop whenever the plane is powered up. A lot of airplanes are 10, 15, 20 years old. CVR are based on some pretty old late 1980s technology, it's not like a modern flash based storage system with effectively infinite capacity for stereo 44KHz audio (64, 128GB, etc). There's maybe 1 or 2 hours of recording time, max.
They actually do clearly state in this PDF that a degree of fault lies in the crew being compromised by fatigue. Operating for 19 hours straight definitely places an individual in an area where one can be fighting to pay strict attention, even when it really counts.
There's also plenty of communication with Air Traffic Control in the tower, and not a whole lot of gaps to introduce significant mystery, so it's pretty unlikely that there would be anything earth shattering on the cockpit voice recorder.
[+] [-] nutcracker46|7 years ago|reply
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 before we pull up the approach in the computer, manually set up the radios, and do the briefing.
On final approach, more precise ground based monitoring would be nice to have in case things are fubar in the plane.
[+] [-] augustz|7 years ago|reply
!SFO 06/079 SFO OBST RIG (ASN 2017-AWP-3368-NRA) 373740N1222224W (0.5NM NE SFO) 41FT (34FT AGL) FLAGGED AND LGTD 1806201400-1811010100
This is a flagged and lighted obstruction half a mile way that is 34 feet above ground level.
Now put in a full route and takeoff airport and maybe if you have had some stops during the day. The NOTAM seems a bit long. Then if are overseas and have to deal with the BS political notams. Check out greece and turkey notams.
...THE REF (B) TURKISH NOTAM A3009/16 LTAAYNYX (111139 EUECYIYN JUL 2016) HAS NO GROUND, CANNOT PRODUCE ANY INTERNATIONALLY LEGAL EFFECT WITHIN ATHINAI FIR/ HELLAS UIR AND IS CONSIDERED NULL AND VOID.
I'm curious how many pilots fully read all NOTAMs, locate them geographically to understand where they are etc etc on every flight.
[+] [-] mortenjorck|7 years ago|reply
[+] [-] donavanm|7 years ago|reply
That said there is some traction around this. And some interesting alternative takes (https://opsfox.net), which have their own problems.
[+] [-] Pyxl101|7 years ago|reply
I guess I'm surprised that it took so long for the pilots to see that there were other planes where they were landing.
Is it routine to keep binoculars in a cockpit? Could they have seen what was on the ground sooner if they'd looked through binoculars briefly (after noticing unexpected lights?)
[+] [-] MarkMc|7 years ago|reply
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
[+] [-] organman91|7 years ago|reply
[+] [-] oh_sigh|7 years ago|reply
[+] [-] village-idiot|7 years ago|reply
[+] [-] abaillargeon|7 years ago|reply
I work on an avionics product that's designed to prevent this exact scenario. We use the aircraft's position along with a database of runways and taxiways to determine if the aircraft is approaching the runway the pilot intends. If we determine the aircraft is landing, we issue a visual and aural alert to the pilot ("TAXIWAY LANDING" or "NOT A RUNWAY").
[+] [-] sandworm101|7 years ago|reply
[+] [-] outworlder|7 years ago|reply
[+] [-] ryandrake|7 years ago|reply
[+] [-] mmaunder|7 years ago|reply
It's really unfortunate that the cockpit voice recorder was overwritten. I'm guessing they're using very old technology where storage space is at a premium.
They're still using the flashing X on closed runways - e.g. at SEATAC right now. The lights looked incandescent a couple nights ago while passing the X. So not very bright or visible.
This accident would probably have been one of the worst in history. Multiple passenger planes on the taxiway taken out by a passenger jet.
[+] [-] SaberTail|7 years ago|reply
[+] [-] joncrane|7 years ago|reply
[+] [-] SOLAR_FIELDS|7 years ago|reply
[+] [-] 8_hours_ago|7 years ago|reply
[+] [-] tyingq|7 years ago|reply
https://youtu.be/WKf7sfgSjjc
The pilot sounds calmer than the ATC. Former fighter pilot.
[+] [-] aeternus|7 years ago|reply
The perspective of the control tower makes it difficult to catch issues like this, but a simple video camera aligned with the center-line of each runway would allow controllers to more easily verify that planes are lined up as well as other possible issues like gear down & locked, etc.
[+] [-] walrus01|7 years ago|reply
There are software and hardware/network setups designed to do this now, in fact London City Airport is about to move to a fully virtual control tower, with a bunch of super high res pan/tilt/zoom cameras on a mast instead of an on-site tower.
https://www.google.com/search?client=ubuntu&channel=fs&q=lon...
[+] [-] zkms|7 years ago|reply
I'm surprised that forward-looking infrared cameras aren't more commonly used in civilian aircraft, especially given the availability of staring arrays with decent resolution/framerate that don't require cooling.
Even without the requisite certification for use as a for-realsies landing aid, it's nevertheless a useful tool to get situational awareness in inclement weather / at night.
[+] [-] cmurf|7 years ago|reply
However, I'm still not clear from this reporting how the crew mistook blue taxiway lighting for white runway lighting. This isn't supposed to be subtle, and I haven't ever experienced it to be subtle.
Edit: OK there is a partial explanation here that appears as though at the time they committed to taxiway C as runway 28R, the visual cue they relied on was airplane lighting looking like it was runway lighting. Airplane taxi and takeoff/landing lights are white, navigational lights are green or red. Strobes usually aren't on while on the ground or at least probably shouldn't be.
It's an interesting dilemma. And fatigue is a significant contributing factor as well.
[+] [-] lolc|7 years ago|reply
What happened here is that the pilots were locked into a wrong model: In an environment with very little light there is no visual source to compare taxiway lighting against. If we know from experience that a light is white, our brain will use this to calibrate. Without this ever becoming a conscious thought. Color correction happens automatically for us and we don't feel it. This process can easily lead to nominally weird things like blue lights being percieved as white.
Fatigue and stress would contribute to ward off looming decoherence such as "why are the lights on 28L redder than on 28R?" When under pressure, we go with the strongest signal. And that signal may very well come from our knowledge, not our perception.
[+] [-] oasisbob|7 years ago|reply
Here in Seattle, SeaTac airport has a parallel taxiway (Taxiway Tango) with a long history of being mistaken for a runway. The list of things tried so far to resolve the issue is interesting:
https://www.bizjournals.com/seattle/news/2015/12/31/tango-ta...
[+] [-] joezydeco|7 years ago|reply
https://www.youtube.com/watch?v=ENe89j89tBA
What's up with that?
[+] [-] throwaway5250|7 years ago|reply
[+] [-] debt|7 years ago|reply
Damn. It didn't matter that the whole world was telling him it was a taxiway because he was so sure it was a runway.
[+] [-] bahmboo|7 years ago|reply
[+] [-] glup|7 years ago|reply
[+] [-] tetrep|7 years ago|reply
How long are recordings normally kept? I would assume at least a few days for mundane flights (storage is cheap, isn't it?) but any sort of incident similar to this I would assume they keep recordings for much longer, if only for internal purposes.
[+] [-] sokoloff|7 years ago|reply
[+] [-] Havoc|7 years ago|reply
>(storage is cheap, isn't it?)
Not on ancient planes where everything needs a billion certifications from all sorts of regulatory bodies.
[+] [-] Waterluvian|7 years ago|reply
Going to guess this is one of those things where, yes, we have all the requisite technology, but practical implementation is the hard part.
[+] [-] abaillargeon|7 years ago|reply
With a GPS and onboard databases of runways and taxiways, we can determine if a pilot is attempting to take off or land on a taxiway. The key is preventing nuisance alerts when the pilot is just flying around and happens to be aligned with a runway. The "11 secret herbs and spices" depend on the aircraft but are usually speed and configuration (ie landing gear) based. Approaches are fairly predictable and we can use that to sequence through a state machine that tells us the pilot intends to land.
Here's a video of the system on a G1000 (meant for smaller planes) skip to 0:45ish https://www.youtube.com/watch?v=V2bswm0w4cY
[+] [-] captain_perl|7 years ago|reply
Beyond that it gets really hard because visual and circling approaches can be in any heading, as well as large cross-winds.
In this deviation, the pilots literally got lost. Kind of tough to do much about that.
[+] [-] CaliforniaKarl|7 years ago|reply
>The full report will be available on the NTSB website in several weeks.
[+] [-] oh_sigh|7 years ago|reply
[+] [-] gok|7 years ago|reply
[+] [-] outworlder|7 years ago|reply
There are many aircraft on the ground at airports. Given the high approach speeds, this is probably a non-trivial problem.
[+] [-] metanoia|7 years ago|reply
[1] https://en.wikipedia.org/wiki/Airport_Surface_Surveillance_C...
[+] [-] hangonhn|7 years ago|reply
[+] [-] 7952|7 years ago|reply
Some airports do have a system [0] designed to track taxing aircraft and allow collision risks to be detected.
https://en.wikipedia.org/wiki/ASDE-X
[+] [-] tialaramex|7 years ago|reply
Perhaps the full report will have more detail on this, as it stands I have to believe somebody made the decision to overwrite this because they thought it'd be better if it didn't exist. Whether that's the crew, their bosses or other staff, somebody managed to go from "serious incident, preserve evidence" to "maximum ass covering" and that person or persons are an obstacle to effective investigation and thus to safe air travel.
[+] [-] sokoloff|7 years ago|reply
By the time the aircraft goes around, is resequenced, completes the second approach, lands, taxis in, and shuts down, much of the initial approach setup conversation may have already been overwritten anyway. I wouldn't jump to the assumption that there was malicious intent in the fact that the CVR was overwritten. (I also wouldn't want the crew to stop the CVR recording only to have a second, more serious incident on the same flight that would then go unrecorded.)
[+] [-] walrus01|7 years ago|reply
[+] [-] cpitVoxRec|7 years ago|reply
There's also plenty of communication with Air Traffic Control in the tower, and not a whole lot of gaps to introduce significant mystery, so it's pretty unlikely that there would be anything earth shattering on the cockpit voice recorder.