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NTSB Issues Investigative Update on San Francisco Airport Near Miss
- Flammy 9y agoPrevious discussion on this topic: https://news.ycombinator.com/item?id=14741605 https://news.ycombinator.com/item?id=14741605 This literally could have been one of the worst accidents in American aviation history had the pilots of the landing airplane failed to react in time. There were 4 fully loaded and fueled passenger jets directly ahead of them.
- rrmm 9y agoUgly stuff. I'm glad it ended up as a miss. This incident as well as the previous ones shows that pilots need better support in these conditions. Lots of airports are set up with multiple parallel runway configs. It wouldn't be all that difficult to add computer driven confirmations of the runway an aircraft is approaching on. Given the frequency of these incidents as well as the cost of the consequences it seems like a reasonable addition. Such an addition won't end the problem, but will add another safety catch.
- mathgenius 9y ago> but will add another safety catch. The problem with these things is how do they interact: what do you do in the cockpit when several alarms are going off at the same time? Just adding "one more alert" seems easy but... This is actually a deep problem with automation, how do the parts interact. When writing software this is a constant battle, between modularity and connection.
- slavak 9y agoIt's actually even worse than that: In more than one aviation accident multiple alarms and alerts actually served to confuse the pilots as to what's going on, causing them to not perform the action that would have saved the flight. Information overload in the cockpit is a very real thing, particularly in an already task-saturated time like the landing approach. It's entirely unclear that adding yet another alert chime requiring the pilot's attention would help anything.
- rrmm 9y agoYeah I definitely agree with this concern. Rather than an alarm it could be part of the landing checklist. The person not flying would say, "Check approach on <whatever runway cleared>", the person flying would check the display and respond "Confirm approach on <whatever>".
- abaillargeon 9y agoMe too. This is something that already exists today [0]. It can detect when the aircraft is not lined up with a runway and issues a "Taxiway Landing" aural and visual alert. [0] https://buy.garmin.com/en-US/US/p/545578 https://buy.garmin.com/en-US/US/p/545578 , see SurfaceWatch at the bottom.
- phire 9y agoAnd they cut it extremely fine. The final NTSB report will probably calculate this, but I'm guessing if they had waited another second or two before shoving those throttles forwards they would have hit a plane (or three). Whats even more scary, is I get the impression that the pilots only shoved the throttles forwards because the tower told them to abort.
- ssambros 9y agoIf you listen to the recording the pilot suspected something was not right, that's why he asked for confirmation that the runway is clear. Most likely he already anticipated a high probability of a go-around.
- princekolt 9y agoThey teach you in driving school to never overtake in a two-way road unless you are 100% sure you can make it. I'd assume pilots would he held to at least equal standards...
- dsfyu404ed 9y agoDriving school does everything it can to dissuade you from ever overtaking on a 2-lane because driving in a big, slow line is what's acceptable for the lowest common denominator. Driving school treats people like idiots by default. Professional training assumes people have the capacity to evaluate situations and make their own decisions on the appropriate course of action. Comparing training intended for the general public and training for professionals is very much a stretch IMO.
- drfuchs 9y agoNo, they started pulling up just before hearing from the tower; click on the link at the bottom of the referenced page: "The full investigative update and other information about the incident are available online at: https://go.usa.gov/xRPFk https://go.usa.gov/xRPFk " for more detail, including: o At 2356:04 PDT, ACA759 reappeared on the local controller’s ASDE-X/ASSC display as it passed over the first airplane positioned on taxiway C. o About 2.5 seconds after advancing the thrust levers, the minimum altitude recorded on the FDR was 59 ft agl. o At 2356:10 PDT, the local controller directed ACA759 to go around. The airplane had already begun to climb at this point (see figure 4). This means that if they hadn't acted until they heard from the tower, it would have almost certainly been a disaster.
- modeless 9y agoBefore I couldn't imagine how anyone could make this mistake, but now I see it. The pilots were familiar with SFO and knew that there were two runways, but didn't realize the left hand runway lights were turned off, so they had an off-by-one error when choosing the runway.
- mirimir 9y agoThat is quite plausible. They somehow didn't register the "X" on 28R. Edit: Sorry, I meant 28L. Just dyslexic, I guess.
- inferiorhuman 9y agoThere wasn't any.
- deleted 9y ago[deleted]
- CaliforniaKarl 9y ago> Runway 28L was closed to accommodate construction; its approach and runway lights were turned off, and a 20.5-ft-wide lighted flashing X (runway closure marker) was placed at the threshold.
- deleted 9y ago[deleted]
- mosheroperandi 9y agoYou wouldn't be the first person to confuse R for L.
- newman8r 9y agorecently harrison ford screwed up and landed on the taxiway at KSNA in southern california. he didn't even do a go around, just landed on the taxiway - and he gets to keep his certificate apparently http://www.ocregister.com/2017/04/04/harrison-ford-will-keep-pilots-license-after-john-wayne-airport-taxiway-landing/ http://www.ocregister.com/2017/04/04/harrison-ford-will-keep...
- Animats 9y agoThis was a very close call. Initial reports indicated it was like an ordinary go-around. No. "The incident pilots advanced the thrust levers when the airplane was about 85 feet above ground level. Flight data recorder data indicate the airplane was over the taxiway at this time. About 2.5 seconds after advancing the thrust levers, the minimum altitude recorded on the FDR was 59 feet above ground level." They overflew an Airbus A340 on the taxiway, tail height 55 feet.
- mirimir 9y agoWow. A few feet lower, and they might have clipped a tail. I wonder what would have happened.
- mirimir 9y agoMy point, by the way, was that tails are relatively speaking, breakaway structures. So maybe not much would have happened. I've had three accidents where my vehicle was hit from the side by another, moving at ~100 km/h. In two of them, the other vehicle hit crumple zone stuff, and I hardly felt the impact. In the third, there was frame-frame contact, and I experienced extreme angular acceleration. It almost ripped my head off.
- johnm1019 9y agoSomething doesn't add up then, the listed elevation for SFO is 13.1 ft MSL. http://www.airnav.com/airport/KSFO http://www.airnav.com/airport/KSFO UPDATE: tolerances around GL are 20 ft https://www.ecfr.gov/cgi-bin/retrieveECFR?gp=&SID=&r=PART&n=14y1.0.1.3.21#14:1.0.1.3.21.0.363.14.57 https://www.ecfr.gov/cgi-bin/retrieveECFR?gp=&SID=&r=PART&n=...
- bgentry 9y agoI would love to see the video that frame is taken from to watch the arc of the plane as it initiated go-around and missed a collision by just a few feet.
- mosheroperandi 9y agoFrom the current report (https://ntsb.gov/investigations/Pages/DCA17IA148.aspx https://ntsb.gov/investigations/Pages/DCA17IA148.aspx): The NTSB has obtained a security camera video from SFO of the incident approach that will be released along with the other factual information when the public docket for this incident is opened in the next several months.
- rcthompson 9y agoMaybe taxiways parallel to runways shouldn't be a thing.
- URSpider94 9y agoHow do you propose to get to and from the runways?
- 0xFFFE 9y agoVTOL, ducks.
- rurounijones 9y agoI may be putting words in OPs mouth here but I imagine he meant not putting parallel taxiways so close to the main runway. I know that space restrictions make this very tenuous but I must admit that looking at the overhead on https://ntsb.gov/investigations/Pages/DCA17IA148.aspx https://ntsb.gov/investigations/Pages/DCA17IA148.aspx that the taxiway marked C looks a lot more like a runway than the one marked F. (due to the width maybe?)
- tacostakohashi 9y agoThat's been my takeaway from this incident too. Can't the taxiways be not straight, like have a slight zig zag to them, so that they're easily distinguishable from a runway? Not ridiculously zigzagged, but maybe 3 or 4 angles of 15 degrees along the length or something would do it.
- probablybanned 9y agoVASAviation made a video on this with radio traffic from the incident. https://www.youtube.com/watch?v=ZW-ETmZU0u8 https://www.youtube.com/watch?v=ZW-ETmZU0u8 (1:33)
- TrickyRick 9y agoThat video doesn't match the sequence of events in the report (Which makes sense, it was published a few weeks ago). According to the report the remarks from UAL1 come as the airplane is overflying the taxiway.
- viraptor 9y agoI've seen people mentioning this could be a big disaster, but I'm curious exactly what the effects could be. Specifically, ignoring the wheels for the moment, would the hull of the landing plane slide off on contact at all, or would the planes just get squashed? I have no intuition about friction / stiffness of materials at that scale. (I'm also assuming the planes were at least a little bit offset to the side) With the wheels down, they would just tear through the hull of the lower plane, right?
- abritinthebay 9y agoIt wouldn’t have been just the wheels. They’d have flattened onto each other in a big squash that blew fuel everywhere. It would have probably continued due to momentum as a fireball towards the 3 other fully loaded planes. Basically it could have been a 5 fully loaded plane bowling alley of flaming metal at 150mph
- dakrisht 9y agoThis. Sure. But pure speculation. The forward momentum of that airplane could have clipped a tail and taken it off while pulling up and max thrust. He was wayyyy below minimum decision height (called out and set before landing, usually a few hundred feet). OTOH, he could have very well collided with the other Airbus on the taxiway rapidly halting his forward momentum and exploding into a fireball subsequently taking out everything for half a mile ahead. What's alarming her is the distance of the Air Canada jet to the ground, less the tail of the Airbus = this guy was FEET AWAY from clipping that jet.
- TrickyRick 9y agoActually the first plane on the ground was staggered with respect to the others and the final two ones had quite a bit of separation so another, not too unlikely outcome, is that it would have hit UAL1 and then veered of the taxiway, wrecking the ACA flight but nothing else (Save for possible some last-row passengers on UAL1).
- stordoff 9y agoWe're discussing a matter of 10s of feet between the near-collision we saw, clipping the tail of one plane, or hitting the plane behind at landing speed, so I imagine the set of "what could have happened" is rather large. That said, I suspect the following three crashes give _some_ indication of what might have happened: USAir 1493 - 737 collides with a turbo-prop on landing; the smaller plane is essentially crushed by the 737 Asiana 214 - Landing gear and tail clip seawall on approach Tenerife disaster - 747 strikes the side of a second 747 a few seconds after leaving the ground on takeoff; engines, lower fuselage and main landing gear struck the plane. 583 fatalities. https://en.wikipedia.org/wiki/USAir_Flight_1493 https://en.wikipedia.org/wiki/USAir_Flight_1493 / https://en.wikipedia.org/wiki/Asiana_Airlines_Flight_214 https://en.wikipedia.org/wiki/Asiana_Airlines_Flight_214 / https://en.wikipedia.org/wiki/Tenerife_airport_disaster https://en.wikipedia.org/wiki/Tenerife_airport_disaster
- greenhouse_gas 9y agoWhat I don't understand (and I'm being honest here) is that between GPSs, computers, and HUDs, how do these errors still happen? I mean that if your GPS sees you're aiming at the wrong runway, why can't it alert the pilot (and/or tower) that it's going to miss.
- isomorphic 9y agoI don't think GPS is accurate enough for that sort of thing, you'd need ground radar, working with onboard computers that understand which runway you're cleared for, etc. (I'm not a pilot, I'm speculating.) If you read the Guardian article from planetjones' comment: https://www.theguardian.com/business/2017/aug/03/air-canada-near-miss-picture-shows-how-close-planes-came-to-crashing https://www.theguardian.com/business/2017/aug/03/air-canada-... Quoting: The investigators said that as the Air Canada jet approached the taxiway just before midnight after a flight from Toronto, it was so far off course that it did not appear on a radar system used to prevent runway collisions. The next paragraph states they are working on improving that.
- mseebach 9y agoIt's called ILS, Instrument Landing System, and it's been around for literally 80 years. > The first landing of a scheduled U.S. passenger airliner using ILS was on January 26, 1938, when a Pennsylvania Central Airlines Boeing 247D flew from Washington, D.C., to Pittsburgh, Pennsylvania, and landed in a snowstorm using only the Instrument Landing System https://en.wikipedia.org/wiki/Instrument_landing_system https://en.wikipedia.org/wiki/Instrument_landing_system Presumably they must have done a visual approach or something, because their ILS would have been outright incapable of directing them down the taxiway, as it's for obvious reasons not equipped for ILS approaches.
- jbg_ 9y agoILS is separate from the radar system mentioned by parent. ILS uses directional radio signals from each end of the runway to provide a glideslope and lateral guidance, not radar. The signals are transmitted from the ground and used for guidance by the aircraft. No part of ILS could alert ATC to anything since the ground stations are only transmitters.
- planetjones 9y agoInvestigators could not hear what the Air Canada captain and co-pilot said to each other during the aborted landing because their conversation was recorded over when the plane made other flights, starting with a San Francisco-to-Montreal trip the next morning. Recorders are required to capture only the last two hours of a plane’s flying time I wonder what the procedure is in a near Miss like this. It looks like not enough of the 'process' to capture evidence kicked in soon enough. Judging by the photo and distances this looks like it was an imminent disaster, which hadn't been clear to me previously. Source: https://www.theguardian.com/business/2017/aug/03/air-canada-near-miss-picture-shows-how-close-planes-came-to-crashing https://www.theguardian.com/business/2017/aug/03/air-canada-...
- reustle 9y agoOn top of that, storage is cheap. They can probably afford to keep conversations longer than 24 hrs.
- TrickyRick 9y agoStorage is cheap today, it wasn't 30 years ago when these rules were put in place (And probably some of the systems manufactured)
- justinjlynn 9y agoRetrofits to safety equipment are common when new issues are discovered. That said, an enforcement action or a procedure change is probably necessary in this case.
- TrickyRick 9y agoFor sure, and it might get changed now, but it wouldn't surprise me if planes are still flying with age old cockpit voice recorders, simply because the requirements on that front haven't changed. (Bearing in mind this is just an educated guess, I have no idea about whether or not they have changed)
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- TrickyRick 9y agoThe map view seems a bit off to me, UAL1 obviously saw the incoming plane and on the photos it looks to me like there are 4 planes in a straight line, yet UAL1 is oriented in the other direction on the radar.
- mosheroperandi 9y agoI think it's the case as depicted in the first radar image, UAL1 turned 90-ish of degrees right on the exit from the taxi-way, and the other three lined up. It could be the angle of the camera is such that it's an illusion they're all in a straight line. That probably still gives them plenty enough view out the side of cockpit to see that the plane they're expecting is heading behind them and not in front of them where it should be. I think the orientations in the subsequent screens where UAL-1 looks turned around are probably a case of the radar over-extrapolating from its heading from the turn and then not being able to tell its heading while it's parked.
- LittlePeter 9y agoHow about using different colour lights for taxiways and runways. They are already using different colour tarmac lines: yellow vs white.
- alexeckermann 9y ago> Lights for taxiway C were also on and set to default settings that included centerline lights (green) along its length. Default settings also included edge lights (blue) and centerline lights (green) illuminating the transition or stub taxiways from the runway to the taxiway. > Runway and approach lighting for runway 28R were on and set to default settings, which included a 2,400-foot approach lighting system, a precision approach path indicator, touchdown zone lights (white), runway centerline lights (white at the approach end), runway threshold lights (green), and runway edge lights (white at the approach end). Taxiway: centre green along length, blue edge lights. Can have planes on it. Runway: centre white along length and edges (also landing zone), perpendicular green at end thresholds. Should not have planes on it.
- brianshaler 9y agoThe planes on the taxiway have white takeoff/landing lights. It sounds like the second in the queue didn't turn theirs on until just before the incident, but if any of the others had theirs on prior, it could contribute to misidentifying the taxiway. I think it's common to have the lights on while taxiing and turning them off at rest.
- mnw21cam 9y agoYes, they do already.
- garduque 9y agoAm not a pilot, but the difference looks pretty clear to me: https://www.youtube.com/watch?v=MnzNvhQxu90 https://www.youtube.com/watch?v=MnzNvhQxu90
- zkms 9y agoSo the guy keying up and saying "Where is this guy going?" and "He's on the taxiway" might actually have made a difference in the outcome, huh: > The flight crew of the first airplane in queue on taxiway C (UAL1) transmitted statements regarding ACA759, one of which mentioned the alignment of ACA759 with the taxiway while ACA759 was on short final (see figures 2 and 3). > The flight crew of the second airplane in queue on taxiway C switched on their airplane’s landing lights as the incident airplane approached.
- mannykannot 9y agoIt may be doubly fortunate that that multiple pilots and controllers did not attempt to say this at the same time. At Tenerife, both the Pan-Am crew and the tower suspected that the KLM aircraft had started its take-off roll, and both tried to warn its crew at the same time, but the resulting radio interference between the concurrent transmissions made the messages unintelligible. This was discussed in detail here: http://www.salon.com/2002/03/28/heterodyne/ http://www.salon.com/2002/03/28/heterodyne/ The author states that there is a feasible technical solution that, at the time of the article (2002) had not been mandated. Does anyone know if the situation has changed?
- deleted 9y ago[deleted]
- throw2016 9y agoWouldn't this whole problem disappear if runways were designed differently, at the minimum one exclusive for landing and one for takeoff with no chance for planes landing and planes taking off to meet, like 2 parallel hockey sticks. Both runways would be painted and lit up completely differently with large lettering explicitly saying take off and landing.
- sjg007 9y agoLack of space, weather conditions and also a lot more planes to get through the system means they use multiple runways for both takeoff and landing.
- krallja 9y agoNo. The captain was not attempting to land on a runway. He was attempting to land on a taxiway, which is painted and lit up completely differently, and also covered in airplanes.
- phkahler 9y agoI'm think I'm getting it now. Look here at the map: https://www.google.com/maps/@37.6265932,-122.3812022,15z?hl=en https://www.google.com/maps/@37.6265932,-122.3812022,15z?hl=... 28L is longer than 28R. Similar to how 28R (or at least its lighting) is longer than taxiway C. The general geometric appearance of the lighting was probably similar enough to what they were used to that it looked mostly correct. As for the X, it was 20 feet wide and about 1000 feet away from where they were aiming, so it would not be relevant to the incident.
- Doxin 9y agoMaybe I'm looking at this wrong, but 28L is most definitely shorter than 28R. Unless they marked the runways wrong of course but somehow I doubt that.
- phkahler 9y ago>> Maybe I'm looking at this wrong, but 28L is most definitely shorter than 28R. You are looking at it wrong. 280 degrees from north would be approaching from the upper right heading down and to the left on the map. From the pilot point of view 28L would be to the east and extends further out into the bay.
- phkahler 9y agoWell that's just a big oops on my part. It's 19L and 19R I was looking at, not 28L & R