
Armchair air crash investigator - momavujisic
http://momav.me/armchair-air-crash-investigator/
======
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.

~~~
tonylemesmer
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
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.

~~~
momavujisic
Just a note about approaches and landings – most, if not all airline ops
usually say that you should be ~50ft when passing above the threshold.

~~~
mikeash
My simplistic analysis ignored the flare, thus why the real-world height would
be lower. Thanks for pointing that out.

------
jervisfm
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
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).

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

~~~
lisper
No, autoland is pretty good. But there are two factors that cause pilots to
land manually most of the time: 1) pilots think they are better at handling
last-minute unexpected contingencies like wind sheer or bird strikes (and they
may well be right about that) and 2) pilots don't want to give the Powers that
Be any additional data to suggest that they aren't actually needed to fly a
plane at all. The fact of the matter is that there are no technological
barriers to making aircraft completely autonomous, but pilots want the world
to remain in denial about this for as long as possible for the sake of their
job security. (FWIW, I'm an instrument-rated private pilot.)

~~~
sneak
> The fact of the matter is that there are no technological barriers to making
> aircraft completely autonomous, but pilots want the world to remain in
> denial about this for as long as possible for the sake of their job
> security.

Two words: anomalous conditions.

As we both know, pilots aren't needed in the vast majority of commercial
flights. The plane is perfectly capable of taking off, navigating, avoiding
collisions, and landing with minimal, mostly unskilled supervision.

We don't need pilots on planes... until something unexpected goes wrong, and
we do.

[https://en.wikipedia.org/wiki/US_Airways_Flight_1549](https://en.wikipedia.org/wiki/US_Airways_Flight_1549)

[https://en.wikipedia.org/wiki/Gimli_Glider](https://en.wikipedia.org/wiki/Gimli_Glider)

[https://en.wikipedia.org/wiki/United_Airlines_Flight_232](https://en.wikipedia.org/wiki/United_Airlines_Flight_232)

~~~
CamperBob2
Devil's-advocate: fine, OK, we still need pilots, for the time being. But do
they actually need to be _on_ the planes?

In the case of two recent crashes (AF447 and this one, assuming pilot error
turns out to be the cause as seems likely), it's safe to say that a computer
would've easily done a better job than the pilots.

Would be interesting to hear Capt. Sullenberger's take on the question.

~~~
snom380
Assuming we could make such a system secure and unhackable as well as
unjammable, why would we want to? To save some money? I would rather pay a
little more to have the pilot sit in the same airplane and have his life on
the line as well.

I just find it fascinating how obsessed people seem with getting rid of
pilots. You don't often hear the same discussion about train or bus drivers,
or doctors for that matter, even though we are just as close to having
automated robotic surgery and expert systems have been around for a long time.

~~~
bergie
_You don 't often hear the same discussion about train or bus drivers_

Plenty of cities are getting rid of their subway drivers at least. And if many
airport shuttle trains around the world are automated as well.

------
Lusake
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_Air...](http://metabunk.org/sk/HL7742_777_Crash%2C_Korean_Asiana_Airlines%2C_San_Francisco_%7C_Metabunk-20130706-142510.jpg)

~~~
pcl
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?

~~~
gklitt
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
There are some at [http://flyingprofessors.net/what-happened-to-asiana-
airlines...](http://flyingprofessors.net/what-happened-to-asiana-airlines-
flight-214-2/)

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

~~~
RockyMcNuts
some video of the crash - kind of looks like it was skimming the waves in
ground effect trying to go around

[http://www.cnn.com/video/?/video/us/2013/07/07/vo-plane-
sf-p...](http://www.cnn.com/video/?/video/us/2013/07/07/vo-plane-sf-plane-
crash-on-cam.courtesy-fred-hayes)

I stand by the parent having some useful data and analysis, and the OP being
totally speculation, and in many respects uninformed.

\- number 1, if you say 'loss of power', makes sense as a possible cause. if
you say 'icing in the FOHE', it's like saying the murder was done with a
yellow pistol. nothing points to that, no icing conditions
(humidity/temperature), and of course not same engine as the previous plane
crash attributed to that

\- number 2, you can't be unaware of an ILS out of op, you wouldn't be cleared
for the ILS approach, you wouldn't be using the ILS on visual approach, you
would be cued there's no signal, you wouldn't hear the outer marker, etc. etc.

\- number 3, auto-throttle, well again, if you say malfunction in power
setting, OK could make sense, if you get as specific as 'confliction with
autopilot/auto throttle' that's a purple pistol. Clearly not on cat3 autoland,
you're basically saying pilot forgot to set throttle in the right
configuration for visual approach and landing.

\- number 4, pilot error/bad approach, can't argue with that. the story is
what's interesting, eg undiagnosed walleye vision, ate the bad fish etc.

~~~
VLM
"\- number 4, pilot error/bad approach, can't argue with that. the story is
what's interesting"

Pilot induced oscillation on a really big scale. Coming in way too hot, slam
down, whoops way over corrected, now coming in too low, whoops ran outta air
and time to correct. Coming in way too hot, now are you better off trying to
salvage or go around and get fired? Different nations airlines have differing
policies on this...

~~~
bajsejohannes
Do you really risk getting fired for a go around? I mean, I can see that
happening if you do it way more than other pilots, but just doing it once?

(For the record, I have no idea how these things works, it's just very
surprising)

~~~
RockyMcNuts
I think you might get a call from a chief pilot for an anomalous approach,
whether you salvage it at last minute or go around. If there's a pattern of
things not going by the book, would guess you get sent for 'retraining' before
you get fired... airline version of big data FTW I guess...

------
rdl
NY Daily News is reporting that VASI was down as well
([http://www.nydailynews.com/news/national/expert-runway-
guida...](http://www.nydailynews.com/news/national/expert-runway-guidance-
systems-sfo-disabled-article-1.1392294)) 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.

~~~
VLM
The short version is there are multiple things on a runway that emit light and
I think they're being confused.

"Which appears to be due to someone incorrectly reading a post-crash NOTAM
which is about the aids being gone due to the crash"

OK first of all VASI has been obsolete since I was a kid in the 90s, its all
PAPI now. (edited to add, in the USA) Much like people still call the AWOS an
ATIS because it does about the same thing. I'm not just picking nits, if you
try researching this, you'll find the VASI has been outta service probably
since the 90s, you want the PAPI. Its all the same anyway, white you're light,
red you're dead. VASI is before my time but I'm told it was the same
arrangement?

If you want NOTAMs you can just go to FAA's pilotweb, this link might work or
you can search. Holy cow SFO has a lot of NOTAMS to read about.

[https://pilotweb.nas.faa.gov/PilotWeb/notamRetrievalByICAOAc...](https://pilotweb.nas.faa.gov/PilotWeb/notamRetrievalByICAOAction.do?method=displayByICAOs&reportType=RAW&formatType=DOMESTIC&retrieveLocId=SFO&actionType=notamRetrievalByICAOs)

!SFO 07/047 SFO RWY 10R/28L CLSD WEF 1307062309

!SFO 07/046 SFO RWY 28L PAPI OTS WEF 1307062219

The PAPI (precision approach whatever indicator or something) was marked out
on the 6th at 2219 and the runways (not all listed above) formally closed at
2309. I think that is after the crash UTC time?

Now according to this NOTAM

!SFO 06/003 SFO RWY 28R ALS OTS WEF 1306011400-1308222359

They've been screwing around with the ALS lights for like 5 weeks now as per
the daily news story. The ALS is mostly to light the place up at night, make
sure you can line up on the correct runway (L or R) and most importantly in
the USA this has the decision bar, if the weather is so poor that you can't
see the decision bar, its too poor to continue the approach. I'm told the
weather was beautiful during the crash, so I don't think the decision bar
being rebuilt or whatever had much if anything to do with the crash.

Something I don't understand about ALS on an airport by an ocean (not exactly
a problem where I live) is how they mount the decision bar and its little
friends. Its going to be quite a distance from the end of the runway and some
runways seem to go right up to the sea, so piers out in the ocean or
something? If they hit the SFO ALS that would imply the plane would be well
offshore under water.

The ALS, aside maybe from some wiring, is probably not any more or less messed
up by the crash than anything else's power wiring. I could imagine a plane
running off the runway into the PAPI and that would be about the end of that
PAPI, or at least it'll have to be aligned.

~~~
rdl
It looks like they mount stuff on CA-92/San Mateo Bridge
([http://www.flysfo.com/web/export/sites/default/download/abou...](http://www.flysfo.com/web/export/sites/default/download/about/news/pressres/fact-
sheet/pdf/PRM_SOIA_version_1.pdf)) and then from there along the approach. The
main issue seems to be the two parallel runways. From when I took photos of
the airfield, there were a lot of lights and other things sticking out of the
bay on the approach path. Decision Bar is supposed to be 1000' off the
threshold so that was probably it.

I'm not a pilot; once I have spare money and time (and enough to fly monthly
to keep current), probably.

It's interesting reading about stuff like the "No Transgression Zone", though.

~~~
VLM
"once I have spare money and time"

I've been telling myself that for decades and never quite had both at the same
time. Often a great excess of one or the other. By the time I finally have
both, I'll probably fail my medical with my luck. I did do ground school + a
bit more on my own, and I've got a couple hours in the air with an instructor.
I do some semi-serious sim flying for fun, mostly the X-Plane. If I ever get
serious I'll already be pretty good at navigation, flight planning, reading
approach plates, E6B use, METAR decoding, NOTAM decoding, etc.

There's a remarkable number of free electronic E6B apps for most phones. And
some paid ones that are marginally better. I find my tablet to be quite
helpful when "flying" although I also use old fashioned mechanical E6B...
Figure $10 for a paper one that'll last "awhile" and $30 for a lifetime metal
one.

The frontier of flight sims right now is no one does NOTAM simulation. Why not
shut down some ground stuff occasionally, just like you can shut down aircraft
systems and screw around with weather? It may be there's a sim out there that
does this that I don't know about.

~~~
rdl
I'm think in the Bay Area it's mostly a question of $10-15k and maybe 100
hours (flight + study time) to get the first license, and there are a decent
number of rental choices.

My dream (well, the realistic one) is to get a CH-801 STOL kit plane with a
diesel engine so I can live in Central Washington and get to I-5 in a
reasonable amount of time, although weather probably prevents that often.
That's only $150k or so, which would be saved in taxes and property cost
differential several times over.

------
madiator
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))

~~~
avree
Well, the whole blog design is very gray-area 'theft' of Medium's design.

~~~
jrockway
I don't know what Medium is, but ... a white page with a title on the top?
This is just as much a 'theft' of the default Apache "It works!" page.

~~~
ricardobeat
Design is about choices. In this case you can point out:

    
    
        1. top-left square logo, dark gray, slab serif, fixed on scroll
        3. bold, large sans-serif title in "off-black"
        4. large serif body text with extended line-height
        5. 100% width image on top
    

Despite the visual simplicity, there are a lot of variables in effect. It's
definitely "inspired" by Medium.

(medium has a few different post layouts, but they share the same spirit:
[https://medium.com/lift-and-drag/5f803f1482e3](https://medium.com/lift-and-
drag/5f803f1482e3) vs [https://medium.com/lift-and-
drag/51691e99279f](https://medium.com/lift-and-drag/51691e99279f))

------
rogerbinns
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...](http://flyingprofessors.net/what-happened-to-asiana-airlines-
flight-214-2/)

As most have hypothesized, it was an unstabilized approach and they should
have done a go around (barring unknown technical/mechanical factors).

~~~
VLM
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).

------
bdirgo
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
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.

~~~
dmourati
O RLY? [http://www.cnn.com/2013/07/07/us/plane-crash-
main/index.html...](http://www.cnn.com/2013/07/07/us/plane-crash-
main/index.html?hpt=hp_t1)

~~~
coin
That is not a cartwheel

~~~
dmourati
Why, because the plane was not 100% vertical on the Z-axis?

~~~
coin
Yes

------
cpncrunch
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
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
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.

~~~
VladRussian2
well, until report is out, we're here to speculate (or to read a good
speculation if we're lucky :). From the Flightaware data the plane had 109kts
at 100feet altitude before the seawall. The stall speed of 777 is about 110kts
(its Vat is ~140, and it is 1.3 of the stall). And the speed was falling as
the next recording is 85kts. While we can only guess about the original cause
- pilot error or hardware, etc... - the stall seems to be there.

~~~
marvin
Are you sure that the Flightaware data is accurate enough? When flying a
glider, I have attempted to make similar judegments from GPS log data when
doing an outlanding, and I'd be similarly careful when using radar data from a
website.

I don't want to be very negative here, but my point is I've made wrong calls
about this when speculating in the past. So currently I'm opposed to doing it
for reasons other than entertainment.

~~~
VladRussian2
> for reasons other than entertainment.

well, i'd be surprised if there are people here for any other reasons :)

the flightaware data correlates very well with what is on video. Personally i
spent a bunch of time on Coyote Pt. so i can mentally correlate the video with
how it looks for other planes/landings at SFO. As we aren't ordained NTSB
officers, we're free to make wrong calls :)

------
ronnier
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.

------
nostromo
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
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
Presumably GPS and/or visual recognition system can be used to achieve the
same, after all airstrip location is know in advance.

~~~
yutyut
Presumably, the visual recognition system in this case was a human.

------
jussij
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.

------
JonFish85
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
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".

------
Wistar
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-
fl...](http://statter911.com/2013/07/07/must-see-crash-of-asiana-
flight-214-captured-on-video/)

I'm guessing that the pilot was praying for those engines to spool-up faster.

------
damian2000
Some more relevant news just breaking now ...
[http://www.nydailynews.com/news/national/asiana-
flight-214-p...](http://www.nydailynews.com/news/national/asiana-
flight-214-pilots-realized-seconds-crash-approach-slow-article-1.1392535)

------
joejohnson
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
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.

------
kop316
"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
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
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.

~~~
momavujisic
About the speed, you're correct – 130 kts for a 777 is not fast, I was
mistaken. In fact the NTSB just said the target approach given by the pilots
was to be 137 kts. I should have chose one of the higher airspeeds given but I
did not want to give a high estimate. I am not familiar with 777 speeds and
should of done some more research in that regard. I did however, write that I
found the sub-100 speeds to be extremely slow, even suggesting that it's most
likely below stall speed – which seems to be correct as the NTSB says the
stick shaker went off some 4 seconds before impact.

~~~
VLM
I read sometimes you can get a Vref under 120, great density altitude, sea
level, winter, no pax cargo and low on fuel, but yeah when the IAS is
reporting 98 you're pretty much screwed under any conditions. Maybe it was
already on the ground at that point, if it wasn't.. it going to be on the
ground real soon...

I would imagine some of the flightsim people I know are flying the approach
under identical conditions right now. Would be interesting to hear at what
point they found it unrecoverable. 98 kts is unrecoverable, but I wonder when
it went unrecoverable. One problem with sims is if you know how its supposed
to turn out, that screws up your actual reaction if you sim it 20 times trying
different things. All you need is a cockpit distraction to totally screw up an
approach. Maybe a false alarm of some type at just the wrong moment.

------
United857
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.

------
elnate
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.

------
jared314
Thank you for your armchair analysis, but I will wait for the NTSB's report.

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

~~~
jared314
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
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.

