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Armchair air crash investigator

momav.me

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Re: Armchair air crash investigator

#31

Post by snom380 »

jared314 wrote: post #21
JshWright wrote: post #9

Earlier quoted context omitted.

That seems needlessly snarky in response to some thoughts that are very clearly labeled as speculation.

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…

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.

Re: Armchair air crash investigator

#32

Post by mjn »

pedrocr wrote: post #28
momavujisic wrote: post #17

Earlier quoted context omitted.

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!

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.

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.

Re: Armchair air crash investigator

#33

Post by dave5104 »

rdl wrote: post #29

NY Daily News is reporting that VASI was down as well ( 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. L…

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.

Re: Armchair air crash investigator

#34

Post by leoedin »

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.

Re: Armchair air crash investigator

#35

Post by WalterBright »

bdirgo wrote: post #2

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.

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.

Re: Armchair air crash investigator

#36

Post by RockyMcNuts »

vladd wrote: post #27
gklitt wrote: post #11

Earlier quoted context omitted.

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?

There are some at http://flyingprofessors.net/what-happened-to-asiana-airlines...

like this link better than the OP which is fairly uninformed speculation ...

Re: Armchair air crash investigator

#37

Post by rdl »

dave5104 wrote: post #33
rdl wrote: post #29

NY Daily News is reporting that VASI was down as well ( 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. L…

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.

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.)

Re: Armchair air crash investigator

#38

Post by tonylemesmer »

leoedin wrote: post #34

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…

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 :)

Re: Armchair air crash investigator

#39

Post by jevinskie »

cjrp wrote: post #24
jervisfm wrote: post #18

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…

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 ar…

Why is this? Can they do a better (in terms of passenger comfort) job landing manually?

Re: Armchair air crash investigator

#40

Post by jevinskie »

cjrp wrote: post #24
jervisfm wrote: post #18

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…

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 ar…

Why is this? Can they do a better (in terms of passenger comfort) job landing manually?
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