12 ms·

Armchair air crash investigator

230 points by momavujisic 13y ago

bdirgo 13y ago
I heard a reporter on TV reporting that the airplane was doing cartwheels on the runway, and I pictured the semi-truck being flipped over in Batman. And then I thought what the hell could have done that? Fishtailed makes more sense, thanks for the clarification.
- austenallred 13y ago
  There were a lot of reports like these that were complete assumption based on the fact that one witness said the airplane had flipped over. It actually hadn't.
  - JshWright 13y ago
    Just like the comment that Michael Hastings' car crash 'sounded like a bomb' resulted in all sorts of assumptions that the car exploded.
  - stcredzero 13y ago
    I don't think airframes have quite the strength to flip end over end from contact with the ground, even at landing speeds. I can grab this pen rom my desk and throw it on the carpet so it flips vertically end over end. A 777 airframe might do something halfway between that and crumbling as it bounces.
  - dmourati 13y ago
    O RLY? http://www.cnn.com/2013/07/07/us/plane-crash-main/index.html?hpt=hp_t1 http://www.cnn.com/2013/07/07/us/plane-crash-main/index.html...
    - coin 13y ago
      That is not a cartwheel
      - dmourati 13y ago
        Why, because the plane was not 100% vertical on the Z-axis?
        coin 13y ago
        Yes
- WalterBright 13y ago
  With cameras everywhere on the streets, I am baffled that there aren't cameras on the runways. Many, many airplane accidents on runways would be a lot easier to investigate, including, for example, the one where the SST caught fire.
  - timcederman 13y ago
    There are runway cameras.
- momavujisic 13y ago
  CNN just released video footage they have of the actual crash. The plane (from what I see) after crashing does a near 360-degree turn with the right wing high up – in fact you can see that the plane is almost nose down-tail up which almost makes it look like it was cartwheeling. Very surprising revelation, I really did not expect an airframe to remain as intact as it did after going through that.
  - rogerbinns 13y ago
    http://edition.cnn.com/video/?/video/us/2013/07/07/vo-plane-sf-plane-crash-on-cam.courtesy-fred-hayes http://edition.cnn.com/video/?/video/us/2013/07/07/vo-plane-...
  - neurotech1 13y ago
    I looked at the video again and again, and ironically, if the jet had done a 360 on the ground it would have broken into pieces, but this jet did a airborne near-360 after the wingtip dug in and the jet became airborne again for an instant.
Lusake 13y ago
Here is graphical comparison of safe landing and Asiana crash: https://pbs.twimg.com/media/BOhIDCWCUAApHFV.jpg:large https://pbs.twimg.com/media/BOhIDCWCUAApHFV.jpg:large . Also it appears that runway was modified: http://metabunk.org/sk/HL7742_777_Crash%2C_Korean_Asiana_Airlines%2C_San_Francisco_%7C_Metabunk-20130706-142510.jpg http://metabunk.org/sk/HL7742_777_Crash%2C_Korean_Asiana_Air...
- pcl 13y ago
  Interesting. I wonder what the Asiana's descent profile looks like compared to the average and some outliers of other safe 777 landings at SFO. Did you generate that image? If not, what was the source?
  - Lusake 13y ago
    I found picture on twitter, it is generated by FlightAware - live flight tracking (http://www.flightaware.com http://www.flightaware.com)
  - gklitt 13y ago
    I saw another image online, which compared the descent profiles of the past week of landings for the same flight. It showed that the July 6th landing was very close to the normal descent profile, and the July 5th landing was actually the outlier -- it had an unusually shallow glide slope. Unfortunately I can't find the image right now, but perhaps someone else knows where it is and can provide it?
    - vladd 13y ago
      There are some at http://flyingprofessors.net/what-happened-to-asiana-airlines-flight-214-2/ http://flyingprofessors.net/what-happened-to-asiana-airlines...
      - RockyMcNuts 13y ago
        like this link better than the OP which is fairly uninformed speculation ...
ronnier 13y ago
This is an excellent article. Like Air France 447, seems very plausible that pilot error did play some role. This reinforces my respect for the pilot of US Airways Flight 1549, Captain Sullenberger.
jared314 13y ago
Thank you for your armchair analysis, but I will wait for the NTSB's report.
- JshWright 13y ago
  That seems needlessly snarky in response to some thoughts that are very clearly labeled as speculation.
  - jared314 13y ago
    It was snarky, and I expected the down votes. But, I think it needs to be said. Neither I, nor the OP, have enough information to make any conclusions. It is just a lot of observations, rumors, and opinions. I love speculating about everything from government policy to interpersonal relationships. (It helps me validate my mental model of the world.) But, in this case, I know the NTSB currently has a better picture of the situation than anyone on the internet.
    - snom380 13y ago
      Why say it when it's already mentioned several times in the post? I'll wait for the report, in the meantime I'm interested in qualified speculation based on the available data.
- joshbaptiste 13y ago
  indeed, which will take ~2 years
  - neurotech1 13y ago
    They'll make a preliminary, primarily "factual" report within days, or weeks. This will be based on the FDR, Quick Access Recorder, statements by crew, passengers and witnesses to the NTSB investigators. Even though I'm a former pilot, I've not made any posts prior to this one, because I didn't want to speculate.
madiator 13y ago
Sorry to go offtopic here, but the images seem to be used without any credits. The first one was taken by David Eun (https://path.com/p/1lwrZb https://path.com/p/1lwrZb)
- momavujisic 13y ago
  I'm actually working right now to try to put some kind of overlay over the images for credit situations. My blog is still a WIP. Sorry!
  - pedrocr 13y ago
    You say that as if giving credit is enough. If you don't have a license/permission to use the image you're violating copyright and the correct response is to take it down.
    - mjn 13y ago
      Several of them might fall within the bounds of fair-use, such as the one about halfway down showing the debris trail, which is included in the context of a discussion of the debris trail. The large image at the top isn't used in a way that would make for a good fair-use argument, though.
    - nikcub 13y ago
      They all fall under fair use since they were uploaded to social media (so the photographer is no longer the only rights holder and most social media sites assign rights to republish content). That said, it is only fair and nice to credit all sources. The web relies on links and being able to source content back to origins.
- avree 13y ago
  Well, the whole blog design is very gray-area 'theft' of Medium's design.
  - madiator 13y ago
kop316 13y ago
"The final bit of information is interesting. It shows a positive rate of climb – 120 feet per minute to be exact, which for a jet airliner, is very slow. For reference, at takeoff the vertical speed is most often +1500 feet per minute. Another interesting bit of information is the aircraft’s airspeed; 85 kts – for a Boeing 777 that is (and I’m guessing here) probably way below stall speed." That is actually expected. It is called the flare just before touchdown: https://en.wikipedia.org/wiki/Landing_flare https://en.wikipedia.org/wiki/Landing_flare
- lukecampbell 13y ago
  I've never flown a B777 or any heavy aircraft so I can't comment on their typical flares, but in a Cessna 172 the flare doesn't induce a positive rate of climb, it simply slows the vertical descent speed to something manageable for touch down, a positive vertical speed seems counterintuitive to me as a good flare. What I want to know is what his IAS (indicated air-speed) at the decision altitude. Again the only thing I've flown are parachutes and some hours in a C172 and a C182.
  - VLM 13y ago
    It gives a pretty good estimate of the error involved in the descent rate reporting. Probably accurate +/- 200 FPM or so. The airspeed encoder is probably from the same system that displays the pilot instruments, indicated airspeed IAS. I thought it odd that the analysis of conditions didn't think 125 and 98 were ridiculously low airspeeds, but claimed that an approach around 130 knots was a "fast approach". However what little I know about the 777 from the flightsim and real pilot community is that a typical approach is around 150-something slowing to a bit above 130 at flare. I've read some claims from actual heavy pilots that under really light conditions a Vref below 120 is theoretically possible. None of us know the weight and balance calcs so its impossible to determine if the pilots were doing the correct thing, although it is possible to determine they were flying a flight path implying they thought they were very light indeed. Now why? Who knows. Maybe because they were right, they were light. Maybe because they were low-ish on fuel. Maybe they didn't trust their IAS instrument. Maybe their IAS was actually broken and comparing their visual approach with instruments, well, its just a really strong headwind today. Maybe they made a math error. Somebody overcontrolled? He could have found this info by violating the copyright of numerous google-able flight sim forums, and forums with real genuine 777 pilots talking about their experience with the 777. Instead he violates the copyright of a picture which we've all already seen, oh well.
jervisfm 13y ago
It goes without saying that my qualifications in aviation matters are only as an aviation enthusiast and for the full cause of the accident, we'll have to wait for the NTSB report (which has access to vital black box data and cockpit recordings). However, I did give this accident some thought as well given the circumstances of the accident and came the pretty much the same final conclusion as the OP. An airline pilot I once spoke to told me once that all the big jetliners use automated ILS with autopilot to automate the landings. The system is pretty accurate and reliable and can deliver landings as good as a well-trained and experienced pilot can. When I saw the rather steep final approach the aircraft was making, I had suspected that the pilots were doing a manual landing. Now that we have information that the ILS was temporarily inoperational this appears to be what transpired and the pilots manually flew the final approach. The precise reasons for why the manual approach ended up in this accident are still to be determined. One thing that I will point out though is that pilots for modern jetliners do relatively little actual manual flying of the plane. Modern airplanes have advanced FMS (Flight Management System) that allow for automatic flying from lift-off until landing with pilots overseeing the system. Given this lack of manual flying, there is a greater potential for human error when a pilot is required to actually do manual flying.
- cjrp 13y ago
  Pilots will actually very rarely use the autoland functionality (apart from when weather, e.g. low visibility, requires it, and also to ensure that they're current with the procedure). They'll use the autopilot for the initial part of the approach, but then when visual with the runway will often disconnect it in order to fly the actual landing manually (still following the indications on the flight director, which are provided by the localiser/glidescope signals).
  - simpleigh 13y ago
    Relevant link: http://www.freakonomics.com/2011/12/12/cockpit-confidential-the-autopilot-myth/ http://www.freakonomics.com/2011/12/12/cockpit-confidential-... "The touchdown had been a fully manual one, as the vast majority of touchdowns are."
  - 13y ago
rdl 13y ago
NY Daily News is reporting that VASI was down as well (http://www.nydailynews.com/news/national/expert-runway-guidance-systems-sfo-disabled-article-1.1392294 http://www.nydailynews.com/news/national/expert-runway-guida...) Which appears to be due to someone incorrectly reading a post-crash NOTAM which is about the aids being gone due to the crash, so there's no particular reason to think VASI was down before the crash. I really don't think I'd trust SF city government to run an airport, even under FAA regulations. Look at every other city service SF has, and imagine that quality applied to preventing hundred ton soda cans full of people and jet fuel from exploding.
- dave5104 13y ago
  How many of those other services are as highly federally regulated as flying an airplane, though? MUNI may suck, but MUNI doesn't need to answer to the feds.
  - rdl 13y ago
    Rail is federally regulated; it's part of why BART and Caltrain and HSR are so screwed up (passenger rail has to conform to some very very high crash standards to operate on the same network as freight rail, unlike in Europe and Asia -- so instead they built BART as a separate network and used essentially custom gauge, trainsets, etc. for everything.) Admittedly the parts of Muni, BART, etc. which are the most screwed up are not the parts regulated much by the federal government, but at the very least SF is the organization picking the people to do things, and I'm wary of that. (although elected officials are also bad in SF; a Chief Law Enforcement Officer who beats his wife, etc.)
    - deleted 13y ago
      [deleted]
- snom380 13y ago
  I bet those other services aren't subject to frequent inspections by the FAA.
- VLM 13y ago
leoedin 13y ago
The accuracy of something like flighradar24 at low altitudes (where the difference between a landing and a crash is a matter of feet) is not high enough, and the data reporting interval is not small enough, to be used to do more than guess what happened. The article gives 3-4 data points per minute. You can't look at that data and draw any conclusions about the motion of an aircraft. It's fun speculating, but please remember that the data from ADS-B is not designed to reflect the aircraft's motion over the time periods that matter in a crash. We have no idea what delays are present in the system, what delays flightradar's system adds in, and what the accuracy of the system is. It's very important to understand the limitations of any sensor data you analyse. It would be good to mention that in the article. Edit: I notice that there's a little disclaimer at the bottom of the article saying that Flightradar24/flightaware data is "not 100% accurate", which is sort of covering the issue. However, when dealing with data like this it's important to remember that there's all sorts of ways data can be "accurate" or not. The uncertainty of the data itself, the frequency of data captured, the accuracy of the timestamps attached to the data and all sorts of other variables need to be considered when you're trying to understand the picture that sensor data is painting.
- tonylemesmer 13y ago
  I would hope the difference between a landing and a crash is a little more than 'feet' otherwise we'd have a lot more crashes. Maybe the difference between a BAD landing and a crash is only feet :)
  - mikeash 13y ago
    A typical airliner approach is a 3 degree angle touching down at 1000ft past the end of the runway. That means that they pass over the threshold at about 150ft. Let's say there's another 1000ft past that before things get problematic (at SFO it's considerably less, I believe), that means that the airliner passes over the dangerous bit at about 300ft when operating normally, and 300ft lower would cause a crash. This isn't normally a problem, because detecting and ensuring that 300ft difference is not really hard.
    - 13y ago
nostromo 13y ago
Curious as to why autopilot isn't being used to land planes yet. My understanding is that pilots can choose to use it to land, but only do so when visibility is very low. (ex: http://www.youtube.com/watch?v=DOFs-oa-bbc http://www.youtube.com/watch?v=DOFs-oa-bbc)
- cpncrunch 13y ago
  The autopilot requires the ILS to land the plane. If the ILS is inoperative, it can't autoland. However pilots do still land planes to keep their skills honed.
  - vl 13y ago
    Presumably GPS and/or visual recognition system can be used to achieve the same, after all airstrip location is know in advance.
    - yutyut 13y ago
      Presumably, the visual recognition system in this case was a human.
- pbhjpbhj 13y ago
  They mention that the ILS was off for repairs. Isn't that a major negative for doing autopilot landing (if indeed it's still allowed/possible without the external location based information).
  - dakrisht 13y ago
    Correct. You cannot Autoland without the ILS (both glide slope + localizer are required)
- snom380 13y ago
  It's being used when needed. When not needed, pilots use the opportunity to practice landings. It's important to not get over-dependent on automation.
cpncrunch 13y ago
It looks like this was an unstabilized approach right down to the ground. It would be interesting to see what the company SOP is. Any safe airline has a no-fault go-around policy for unstabilized approaches, and you'll actually get in trouble if you continue with an unstabilized approach and you don't go around. From what pilots are saying on the message boards it seems that a lot of Asian airlines have pretty much the opposite policy - you get in trouble if you go around for any reason, and they would prefer you to salvage an unstabilized approach to save money.
- VladRussian2 13y ago
  pretty much looks the same to me - the guy stalled and when he finally, at the last second (actually - well past the last second), decided to go around, he did jerk up the nose and that increased the stall, so they fell. Reminds me about the AirFrance fall in the Atlantic some years ago - that guy was trying to gain altitude by jerking the nose up (i.e. increasing the "angle of attack") instead of "pressing the accelerator pedal".
  - marvin 13y ago
    If this is what really happened, I'll say the same thing I said then - it shocks me that airline pilots with thousands of flight hours can make the most elementary piloting mistake possible. But I've read accident reports before, and it's rarely a good idea to speculate. I won't have an opinion about this until the official report is published.
    - cpncrunch 13y ago
      Pilots are human, and they make mistakes. Good training, having two pilots on the flightdeck and having good SOPs should prevent anything like this ever happening. It looks like training and/or SOPs were severely lacking here. As well as the "don't waste our company money doing a go-around" fuckwitted notion, people are saying that Asian airlines don't like doing visual approaches period. Therefore whenever the pilot is required to do a visual approach, he/she will be severely lacking in the skills to do it.
rogerbinns 13y ago
There is an excellent posting with graphs comparing the Asiana flight to a United 777 that landed 10 minutes before. The graphs compare height, speed and importantly energy. http://flyingprofessors.net/what-happened-to-asiana-airlines-flight-214-2/ http://flyingprofessors.net/what-happened-to-asiana-airlines... As most have hypothesized, it was an unstabilized approach and they should have done a go around (barring unknown technical/mechanical factors).
- VLM 13y ago
  Looking at the graphs the plane was ahead of them by about 5-10 seconds. That usually doesn't turn out too well. Gotta be ahead of the plane, not the plane ahead of you. Usually a noob mistake (on the ground system failure, hard to fix) OR hopefully extensive extenuating circumstances (on the plane system failure, easy to fix).
JonFish85 13y ago
I don't really like when people post these sort of "arm-chair" hypotheses. As much as it's fun to try to figure things out, there is always the danger of people jumping to conclusions based on bad or incomplete data. It reminds me a lot of the reddit people immediately following the Boston Marathon bombings. It's definitely an interesting read, but I don't want to take it for much more than just idle speculation.
- momavujisic 13y ago
  Idle speculation and having a bit of fun trying to play air crash investigator, is exactly what this article is. I hope that I was able to convey that this is about "what I think" happened and not "what happened".
joejohnson 13y ago
Does anyone know if they've released the information about where the people who died/were severely injured were sitting in the plane? I'd love to see a seating chart that shows the safest and least safe seats on a 777.
- hga 13y ago
  It really depends on the type of accident (skim Wikipedia on ones with survivors) ... and after looking at the CNN supplied video https://news.ycombinator.com/item?id=6003232 https://news.ycombinator.com/item?id=6003232 right now I'm thinking "Major miracle" and "If it's ain't Boeing, I ain't going", although I'm sure it's a lot more of the former than the latter.
Wistar 13y ago
Cellphone video shot by a guy, Fred Hayes, watching aircraft land yesterday at SFO shows the tail dragging in the water for quite a distance before striking the seawall. http://statter911.com/2013/07/07/must-see-crash-of-asiana-flight-214-captured-on-video/ http://statter911.com/2013/07/07/must-see-crash-of-asiana-fl... I'm guessing that the pilot was praying for those engines to spool-up faster.
United857 13y ago
To the OP just curious -- are you a licensed pilot? Not to question you since you did say this was just speculation but just wondering. It's pretty well informed.
jussij 13y ago
Here is my one minute as an armchair air crash investigator. In recent times I've read some very strange incidents reports with regard to airline pilots. One plane crashed on landing while coming in to final approach at twice the recommended speed. Another was coming in for final approach some 500 feet below the allowable height and off the designated flight path. These are examples of some very basic flying errors. In years previous pilots had to do many hours in light aircraft, then move on to bigger aircraft and only after decades of flying experience did they make it onto the big jets. But in todays cut price flying environment I suspect most pilots don’t do that much flying and as such they don’t know as much about flying as they should. This one is going to be pilot error.
damian2000 13y ago
Some more relevant news just breaking now ... http://www.nydailynews.com/news/national/asiana-flight-214-pilots-realized-seconds-crash-approach-slow-article-1.1392535 http://www.nydailynews.com/news/national/asiana-flight-214-p...
elnate 13y ago
Is anyone else puking mad at those people carrying their luggage in the photo? I feel like getting off a burning plane should take priority over duty free purchases.

230 points by momavujisic 13y ago

I heard a reporter on TV reporting that the airplane was doing cartwheels on the runway, and I pictured the semi-truck being flipped over in Batman. And then I thought what the hell could have done that? Fishtailed makes more sense, thanks for the clarification.

austenallred 13y ago
There were a lot of reports like these that were complete assumption based on the fact that one witness said the airplane had flipped over. It actually hadn't.
- JshWright 13y ago
  Just like the comment that Michael Hastings' car crash 'sounded like a bomb' resulted in all sorts of assumptions that the car exploded.
- stcredzero 13y ago
  I don't think airframes have quite the strength to flip end over end from contact with the ground, even at landing speeds. I can grab this pen rom my desk and throw it on the carpet so it flips vertically end over end. A 777 airframe might do something halfway between that and crumbling as it bounces.
- dmourati 13y ago
  O RLY? http://www.cnn.com/2013/07/07/us/plane-crash-main/index.html?hpt=hp_t1 http://www.cnn.com/2013/07/07/us/plane-crash-main/index.html...
  - coin 13y ago
    That is not a cartwheel
    - dmourati 13y ago
      Why, because the plane was not 100% vertical on the Z-axis?
      - coin 13y ago
        Yes
WalterBright 13y ago
With cameras everywhere on the streets, I am baffled that there aren't cameras on the runways. Many, many airplane accidents on runways would be a lot easier to investigate, including, for example, the one where the SST caught fire.
- timcederman 13y ago
  There are runway cameras.
momavujisic 13y ago
CNN just released video footage they have of the actual crash. The plane (from what I see) after crashing does a near 360-degree turn with the right wing high up – in fact you can see that the plane is almost nose down-tail up which almost makes it look like it was cartwheeling. Very surprising revelation, I really did not expect an airframe to remain as intact as it did after going through that.
- rogerbinns 13y ago
  http://edition.cnn.com/video/?/video/us/2013/07/07/vo-plane-sf-plane-crash-on-cam.courtesy-fred-hayes http://edition.cnn.com/video/?/video/us/2013/07/07/vo-plane-...
- neurotech1 13y ago
  I looked at the video again and again, and ironically, if the jet had done a 360 on the ground it would have broken into pieces, but this jet did a airborne near-360 after the wingtip dug in and the jet became airborne again for an instant.

Lusake 13y ago

Here is graphical comparison of safe landing and Asiana crash: https://pbs.twimg.com/media/BOhIDCWCUAApHFV.jpg:large https://pbs.twimg.com/media/BOhIDCWCUAApHFV.jpg:large . Also it appears that runway was modified: http://metabunk.org/sk/HL7742_777_Crash%2C_Korean_Asiana_Airlines%2C_San_Francisco_%7C_Metabunk-20130706-142510.jpg http://metabunk.org/sk/HL7742_777_Crash%2C_Korean_Asiana_Air...

pcl 13y ago
Interesting. I wonder what the Asiana's descent profile looks like compared to the average and some outliers of other safe 777 landings at SFO. Did you generate that image? If not, what was the source?
- Lusake 13y ago
  I found picture on twitter, it is generated by FlightAware - live flight tracking (http://www.flightaware.com http://www.flightaware.com)
- gklitt 13y ago
  I saw another image online, which compared the descent profiles of the past week of landings for the same flight. It showed that the July 6th landing was very close to the normal descent profile, and the July 5th landing was actually the outlier -- it had an unusually shallow glide slope. Unfortunately I can't find the image right now, but perhaps someone else knows where it is and can provide it?
  - vladd 13y ago
    There are some at http://flyingprofessors.net/what-happened-to-asiana-airlines-flight-214-2/ http://flyingprofessors.net/what-happened-to-asiana-airlines...
    - RockyMcNuts 13y ago
      like this link better than the OP which is fairly uninformed speculation ...

ronnier 13y ago

This is an excellent article. Like Air France 447, seems very plausible that pilot error did play some role. This reinforces my respect for the pilot of US Airways Flight 1549, Captain Sullenberger.

jared314 13y ago

Thank you for your armchair analysis, but I will wait for the NTSB's report.

JshWright 13y ago
That seems needlessly snarky in response to some thoughts that are very clearly labeled as speculation.
- jared314 13y ago
  It was snarky, and I expected the down votes. But, I think it needs to be said. Neither I, nor the OP, have enough information to make any conclusions. It is just a lot of observations, rumors, and opinions. I love speculating about everything from government policy to interpersonal relationships. (It helps me validate my mental model of the world.) But, in this case, I know the NTSB currently has a better picture of the situation than anyone on the internet.
  - snom380 13y ago
    Why say it when it's already mentioned several times in the post? I'll wait for the report, in the meantime I'm interested in qualified speculation based on the available data.
joshbaptiste 13y ago
indeed, which will take ~2 years
- neurotech1 13y ago
  They'll make a preliminary, primarily "factual" report within days, or weeks. This will be based on the FDR, Quick Access Recorder, statements by crew, passengers and witnesses to the NTSB investigators. Even though I'm a former pilot, I've not made any posts prior to this one, because I didn't want to speculate.

madiator 13y ago

Sorry to go offtopic here, but the images seem to be used without any credits. The first one was taken by David Eun (https://path.com/p/1lwrZb https://path.com/p/1lwrZb)

momavujisic 13y ago
I'm actually working right now to try to put some kind of overlay over the images for credit situations. My blog is still a WIP. Sorry!
- pedrocr 13y ago
  You say that as if giving credit is enough. If you don't have a license/permission to use the image you're violating copyright and the correct response is to take it down.
  - mjn 13y ago
    Several of them might fall within the bounds of fair-use, such as the one about halfway down showing the debris trail, which is included in the context of a discussion of the debris trail. The large image at the top isn't used in a way that would make for a good fair-use argument, though.
  - nikcub 13y ago
    They all fall under fair use since they were uploaded to social media (so the photographer is no longer the only rights holder and most social media sites assign rights to republish content). That said, it is only fair and nice to credit all sources. The web relies on links and being able to source content back to origins.
avree 13y ago
Well, the whole blog design is very gray-area 'theft' of Medium's design.
- madiator 13y ago

kop316 13y ago

"The final bit of information is interesting. It shows a positive rate of climb – 120 feet per minute to be exact, which for a jet airliner, is very slow. For reference, at takeoff the vertical speed is most often +1500 feet per minute. Another interesting bit of information is the aircraft’s airspeed; 85 kts – for a Boeing 777 that is (and I’m guessing here) probably way below stall speed." That is actually expected. It is called the flare just before touchdown: https://en.wikipedia.org/wiki/Landing_flare https://en.wikipedia.org/wiki/Landing_flare

lukecampbell 13y ago
I've never flown a B777 or any heavy aircraft so I can't comment on their typical flares, but in a Cessna 172 the flare doesn't induce a positive rate of climb, it simply slows the vertical descent speed to something manageable for touch down, a positive vertical speed seems counterintuitive to me as a good flare. What I want to know is what his IAS (indicated air-speed) at the decision altitude. Again the only thing I've flown are parachutes and some hours in a C172 and a C182.
- VLM 13y ago
  It gives a pretty good estimate of the error involved in the descent rate reporting. Probably accurate +/- 200 FPM or so. The airspeed encoder is probably from the same system that displays the pilot instruments, indicated airspeed IAS. I thought it odd that the analysis of conditions didn't think 125 and 98 were ridiculously low airspeeds, but claimed that an approach around 130 knots was a "fast approach". However what little I know about the 777 from the flightsim and real pilot community is that a typical approach is around 150-something slowing to a bit above 130 at flare. I've read some claims from actual heavy pilots that under really light conditions a Vref below 120 is theoretically possible. None of us know the weight and balance calcs so its impossible to determine if the pilots were doing the correct thing, although it is possible to determine they were flying a flight path implying they thought they were very light indeed. Now why? Who knows. Maybe because they were right, they were light. Maybe because they were low-ish on fuel. Maybe they didn't trust their IAS instrument. Maybe their IAS was actually broken and comparing their visual approach with instruments, well, its just a really strong headwind today. Maybe they made a math error. Somebody overcontrolled? He could have found this info by violating the copyright of numerous google-able flight sim forums, and forums with real genuine 777 pilots talking about their experience with the 777. Instead he violates the copyright of a picture which we've all already seen, oh well.

jervisfm 13y ago

It goes without saying that my qualifications in aviation matters are only as an aviation enthusiast and for the full cause of the accident, we'll have to wait for the NTSB report (which has access to vital black box data and cockpit recordings). However, I did give this accident some thought as well given the circumstances of the accident and came the pretty much the same final conclusion as the OP. An airline pilot I once spoke to told me once that all the big jetliners use automated ILS with autopilot to automate the landings. The system is pretty accurate and reliable and can deliver landings as good as a well-trained and experienced pilot can. When I saw the rather steep final approach the aircraft was making, I had suspected that the pilots were doing a manual landing. Now that we have information that the ILS was temporarily inoperational this appears to be what transpired and the pilots manually flew the final approach. The precise reasons for why the manual approach ended up in this accident are still to be determined. One thing that I will point out though is that pilots for modern jetliners do relatively little actual manual flying of the plane. Modern airplanes have advanced FMS (Flight Management System) that allow for automatic flying from lift-off until landing with pilots overseeing the system. Given this lack of manual flying, there is a greater potential for human error when a pilot is required to actually do manual flying.

cjrp 13y ago
Pilots will actually very rarely use the autoland functionality (apart from when weather, e.g. low visibility, requires it, and also to ensure that they're current with the procedure). They'll use the autopilot for the initial part of the approach, but then when visual with the runway will often disconnect it in order to fly the actual landing manually (still following the indications on the flight director, which are provided by the localiser/glidescope signals).
- simpleigh 13y ago
  Relevant link: http://www.freakonomics.com/2011/12/12/cockpit-confidential-the-autopilot-myth/ http://www.freakonomics.com/2011/12/12/cockpit-confidential-... "The touchdown had been a fully manual one, as the vast majority of touchdowns are."
- 13y ago

rdl 13y ago

NY Daily News is reporting that VASI was down as well (http://www.nydailynews.com/news/national/expert-runway-guidance-systems-sfo-disabled-article-1.1392294 http://www.nydailynews.com/news/national/expert-runway-guida...) Which appears to be due to someone incorrectly reading a post-crash NOTAM which is about the aids being gone due to the crash, so there's no particular reason to think VASI was down before the crash. I really don't think I'd trust SF city government to run an airport, even under FAA regulations. Look at every other city service SF has, and imagine that quality applied to preventing hundred ton soda cans full of people and jet fuel from exploding.

dave5104 13y ago
How many of those other services are as highly federally regulated as flying an airplane, though? MUNI may suck, but MUNI doesn't need to answer to the feds.
- rdl 13y ago
  Rail is federally regulated; it's part of why BART and Caltrain and HSR are so screwed up (passenger rail has to conform to some very very high crash standards to operate on the same network as freight rail, unlike in Europe and Asia -- so instead they built BART as a separate network and used essentially custom gauge, trainsets, etc. for everything.) Admittedly the parts of Muni, BART, etc. which are the most screwed up are not the parts regulated much by the federal government, but at the very least SF is the organization picking the people to do things, and I'm wary of that. (although elected officials are also bad in SF; a Chief Law Enforcement Officer who beats his wife, etc.)
  - deleted 13y ago
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snom380 13y ago
I bet those other services aren't subject to frequent inspections by the FAA.
VLM 13y ago

leoedin 13y ago

The accuracy of something like flighradar24 at low altitudes (where the difference between a landing and a crash is a matter of feet) is not high enough, and the data reporting interval is not small enough, to be used to do more than guess what happened. The article gives 3-4 data points per minute. You can't look at that data and draw any conclusions about the motion of an aircraft. It's fun speculating, but please remember that the data from ADS-B is not designed to reflect the aircraft's motion over the time periods that matter in a crash. We have no idea what delays are present in the system, what delays flightradar's system adds in, and what the accuracy of the system is. It's very important to understand the limitations of any sensor data you analyse. It would be good to mention that in the article. Edit: I notice that there's a little disclaimer at the bottom of the article saying that Flightradar24/flightaware data is "not 100% accurate", which is sort of covering the issue. However, when dealing with data like this it's important to remember that there's all sorts of ways data can be "accurate" or not. The uncertainty of the data itself, the frequency of data captured, the accuracy of the timestamps attached to the data and all sorts of other variables need to be considered when you're trying to understand the picture that sensor data is painting.

tonylemesmer 13y ago
I would hope the difference between a landing and a crash is a little more than 'feet' otherwise we'd have a lot more crashes. Maybe the difference between a BAD landing and a crash is only feet :)
- mikeash 13y ago
  A typical airliner approach is a 3 degree angle touching down at 1000ft past the end of the runway. That means that they pass over the threshold at about 150ft. Let's say there's another 1000ft past that before things get problematic (at SFO it's considerably less, I believe), that means that the airliner passes over the dangerous bit at about 300ft when operating normally, and 300ft lower would cause a crash. This isn't normally a problem, because detecting and ensuring that 300ft difference is not really hard.
  - 13y ago

nostromo 13y ago

Curious as to why autopilot isn't being used to land planes yet. My understanding is that pilots can choose to use it to land, but only do so when visibility is very low. (ex: http://www.youtube.com/watch?v=DOFs-oa-bbc http://www.youtube.com/watch?v=DOFs-oa-bbc)

cpncrunch 13y ago
The autopilot requires the ILS to land the plane. If the ILS is inoperative, it can't autoland. However pilots do still land planes to keep their skills honed.
- vl 13y ago
  Presumably GPS and/or visual recognition system can be used to achieve the same, after all airstrip location is know in advance.
  - yutyut 13y ago
    Presumably, the visual recognition system in this case was a human.
pbhjpbhj 13y ago
They mention that the ILS was off for repairs. Isn't that a major negative for doing autopilot landing (if indeed it's still allowed/possible without the external location based information).
- dakrisht 13y ago
  Correct. You cannot Autoland without the ILS (both glide slope + localizer are required)
snom380 13y ago
It's being used when needed. When not needed, pilots use the opportunity to practice landings. It's important to not get over-dependent on automation.

cpncrunch 13y ago

It looks like this was an unstabilized approach right down to the ground. It would be interesting to see what the company SOP is. Any safe airline has a no-fault go-around policy for unstabilized approaches, and you'll actually get in trouble if you continue with an unstabilized approach and you don't go around. From what pilots are saying on the message boards it seems that a lot of Asian airlines have pretty much the opposite policy - you get in trouble if you go around for any reason, and they would prefer you to salvage an unstabilized approach to save money.

VladRussian2 13y ago
pretty much looks the same to me - the guy stalled and when he finally, at the last second (actually - well past the last second), decided to go around, he did jerk up the nose and that increased the stall, so they fell. Reminds me about the AirFrance fall in the Atlantic some years ago - that guy was trying to gain altitude by jerking the nose up (i.e. increasing the "angle of attack") instead of "pressing the accelerator pedal".
- marvin 13y ago
  If this is what really happened, I'll say the same thing I said then - it shocks me that airline pilots with thousands of flight hours can make the most elementary piloting mistake possible. But I've read accident reports before, and it's rarely a good idea to speculate. I won't have an opinion about this until the official report is published.
  - cpncrunch 13y ago
    Pilots are human, and they make mistakes. Good training, having two pilots on the flightdeck and having good SOPs should prevent anything like this ever happening. It looks like training and/or SOPs were severely lacking here. As well as the "don't waste our company money doing a go-around" fuckwitted notion, people are saying that Asian airlines don't like doing visual approaches period. Therefore whenever the pilot is required to do a visual approach, he/she will be severely lacking in the skills to do it.

rogerbinns 13y ago

There is an excellent posting with graphs comparing the Asiana flight to a United 777 that landed 10 minutes before. The graphs compare height, speed and importantly energy. http://flyingprofessors.net/what-happened-to-asiana-airlines-flight-214-2/ http://flyingprofessors.net/what-happened-to-asiana-airlines... As most have hypothesized, it was an unstabilized approach and they should have done a go around (barring unknown technical/mechanical factors).

VLM 13y ago
Looking at the graphs the plane was ahead of them by about 5-10 seconds. That usually doesn't turn out too well. Gotta be ahead of the plane, not the plane ahead of you. Usually a noob mistake (on the ground system failure, hard to fix) OR hopefully extensive extenuating circumstances (on the plane system failure, easy to fix).

JonFish85 13y ago

I don't really like when people post these sort of "arm-chair" hypotheses. As much as it's fun to try to figure things out, there is always the danger of people jumping to conclusions based on bad or incomplete data. It reminds me a lot of the reddit people immediately following the Boston Marathon bombings. It's definitely an interesting read, but I don't want to take it for much more than just idle speculation.

momavujisic 13y ago
Idle speculation and having a bit of fun trying to play air crash investigator, is exactly what this article is. I hope that I was able to convey that this is about "what I think" happened and not "what happened".

joejohnson 13y ago

Does anyone know if they've released the information about where the people who died/were severely injured were sitting in the plane? I'd love to see a seating chart that shows the safest and least safe seats on a 777.

hga 13y ago
It really depends on the type of accident (skim Wikipedia on ones with survivors) ... and after looking at the CNN supplied video https://news.ycombinator.com/item?id=6003232 https://news.ycombinator.com/item?id=6003232 right now I'm thinking "Major miracle" and "If it's ain't Boeing, I ain't going", although I'm sure it's a lot more of the former than the latter.

Wistar 13y ago

Cellphone video shot by a guy, Fred Hayes, watching aircraft land yesterday at SFO shows the tail dragging in the water for quite a distance before striking the seawall. http://statter911.com/2013/07/07/must-see-crash-of-asiana-flight-214-captured-on-video/ http://statter911.com/2013/07/07/must-see-crash-of-asiana-fl... I'm guessing that the pilot was praying for those engines to spool-up faster.

United857 13y ago

To the OP just curious -- are you a licensed pilot? Not to question you since you did say this was just speculation but just wondering. It's pretty well informed.

jussij 13y ago

Here is my one minute as an armchair air crash investigator. In recent times I've read some very strange incidents reports with regard to airline pilots. One plane crashed on landing while coming in to final approach at twice the recommended speed. Another was coming in for final approach some 500 feet below the allowable height and off the designated flight path. These are examples of some very basic flying errors. In years previous pilots had to do many hours in light aircraft, then move on to bigger aircraft and only after decades of flying experience did they make it onto the big jets. But in todays cut price flying environment I suspect most pilots don’t do that much flying and as such they don’t know as much about flying as they should. This one is going to be pilot error.

damian2000 13y ago

Some more relevant news just breaking now ... http://www.nydailynews.com/news/national/asiana-flight-214-pilots-realized-seconds-crash-approach-slow-article-1.1392535 http://www.nydailynews.com/news/national/asiana-flight-214-p...

elnate 13y ago

Is anyone else puking mad at those people carrying their luggage in the photo? I feel like getting off a burning plane should take priority over duty free purchases.