Armchair air crash investigator
momav.me
momav.me
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.
This isn't normally a problem, because detecting and ensuring that 300ft difference is not really hard.
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.
"The touchdown had been a fully manual one, as the vast majority of touchdowns are."
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
EDIT: Notice that you had to go back 30 years to find your third example of a human pilot saving the day. And automation technology has improved a lot since then.
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.
On the other hand, if your onboard autopilot is in control of everything, you run the risk of having autopilot bugs causing an accident - indeed, a software issue in the airbus flight protections (which, unlike the autopilot, are always active unless a very severe system failure occurs, and can override the pilot's inputs) has caused an incident that resulted in passenger injuries: http://en.wikipedia.org/wiki/Qantas_Flight_72
While none of this is impossible, it's certain to be expensive, heavy, have its fair share of bugs at the start, and by quite difficult to get past the regulators. Not to mention passengers probably won't be very happy being on an unmanned plane, even if the system really was perfect. So it's easier in the end to just put pilots on the plane.
(Shrug) Sorry, but given the complexity of the rest of the aircraft's systems, none of these engineering tasks sound impossible. 40 years ago we did this stuff on the freakin' Moon.
Although yes, I tend to agree that any move in this direction amounts to fixing something that isn't broken. (In the "freakin' Moon" example, the human pilot still had to handle the tricky part.)
...
> In the "freakin' Moon" example, the human pilot still had to handle the tricky part.
Since you're apparently well aware that the Apollo missions were conducted with manual docking and landing, why bring it up?
Especially given the relative simplicity of "final approach" on the moon, given the lower gravity, zero wind speed, and slower pace, I don't understand what your point is.
[1] Actually, the Eagle did experience a computer malfunction that almost caused an abort to the landing before an engineer said they could ignore it. You want a computer to judge for itself whether it can still safely fulfill its mission while malfunctioning?
For further terror, consult the Apollo 12 lightning strike. When the computer is FUBAR, how do you propose it fix itself?
The whole point is we're not talking about when things go according to plan.
For that matter, how many times has the skycrane been used? What is its safety record? If you go ask the guys at JPL how many times out of 1000 they think it'll work perfectly, what will they say?
Incidentally, not cool moving goalposts.
You win this one, it looks like. GG.
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.
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.
I think I agree with you in general about this, but that's sort of a shitty and unpersuasive way of making that argument.
That wouldn't do anything for patching in pilots for planes in the middle of the pacific, but I wonder how often that would be necessary.
If it's hard for most of us from varying technological backgrounds to say yes than it's going to be almost impossible to convince the more mature passengers.
This is one of the reasons why all planes look the same (they have the same configuration, low wing with engine below wing) even tho Airbus and Boeing keep churning out concepts. Would you get on a plane that looked even slightly funky?
Given that the most common cause of aircraft accidents (by quite some margin) is human error, I'll take my chances with the computer.
As for completely autonomous, do you seriously think we have the technology available today to make an autopilot handle any conceivable situation without a human being present and ready to take over? (non-IR PP here)
And no, automation can't handle "every conceivable situation", but neither can humans. Furthermore, humans screw up more often than autopilots. Pilot error is currently the single biggest contributor to the overall accident rate.
Mind you, I'm not advocating fully autonomous aircraft. I like having a human in the loop, but that's in part because I am the human in the loop. It's far from clear that human pilots are a net win for safety.
In the meantime, the solution to the human factor isn't to eliminate humans, but to improve training (which is already happening after AF447).
I like having human pilots primarily because I'm a programmer and I know how difficult it is to design robust computer systems. There's been one runway overrun and one serious in flight incident with passenger injury due to software design faults. Now try to design a system that makes sense of audio, video and smell in addition to the existing sensors, and not have it fail in some spectacular unforeseen way..
I can only think of a single example of a "creative" response to an in-flight emergency that actually helped, and that was UA232 in 1989.
The way we have solved reliability in autopilots and FBW systems today is to make them as simple as possible and to give them sensible fallback modes (like the Airbus FBW removing stall protection when missing certain inputs), and even then we have had real life accidents because of programming errors or design errors. So if you think pilot automation is mainly a question of politics as you said earlier, I think you are being overly optimistic (which, of couse, is not uncommon in the software industry).
I think a better approach to removing pilots is to see the strengths in both computers and humans and design systems where the advantages of both are maximized.
If you are interested in reading more on software safety, http://sunnyday.mit.edu/ is a good starting point.
Do pilots typically glide unpowered 767s to landings at abandoned military airfields? (A result, incidentally, that could not be reproduced by other crews in simulators; are you sure it's the crews, and not inadequate programming? Still trust the computer?)
Are you willing to bet your life that the computer on a 737 that looked like this[1] could find its way to a safe landing?
As programmers, we should know better.
[1] http://en.wikipedia.org/wiki/File:Aloha_Airlines_Flight_243_...
Yes, ditching an airplane that has lost all of its engines is a standard emergency procedure.
> Prior to 2009, how likely do you think it would have been for someone to have programmed an autopilot with such a capability?
What difference does that make? I'm not saying it's a good idea to take pilots out of the cockpit right now, I'm just saying it's a lot more plausible than most people think. The main limiting factor is politics, not technology.
> Are you willing to bet your life that the computer on a 737 that looked like this[1] could find its way to a safe landing?
Sure, why not? Losing the top of the fuselage looks dramatic, but it probably doesn't change the flight characteristics all that much. Also, very good adaptive control algorithms exist that could almost certainly handle this.
Also, you're cherry-picking your anecdotes. There are plenty of examples of flights that would almost certainly have ended safely but for some stupid mistake the pilot made. Controlled flight into terrain accidents, for example, are much more common than heroic rescues, and they could be entirely eliminated if you took human pilots out of the loop.
See my reply to krisoft. You're changing a specific situation into a general one. You can't just say "ditch the plane if you lose power", you have to anticipate every possible variable that may influence whether that is actually the correct course of action, and the manner in which it is carried out. And you have to do that before it ever happens.
> What difference does that make?
Unanticipated situations are unanticipated situations. We don't have AI. We haven't replicated the ability of a human being to adapt on-the-fly. There is no reason to believe we will in the near future.
> Controlled flight into terrain accidents [...] could be entirely eliminated if you took human pilots out of the loop.
The problem I have with this line of reasoning is that so much more could be done to prevent them even without taking the pilots out of the loop, and yet it's not. That does nothing to give me confidence that the right thing will be done when pilots ARE taken out of the loop.
Edit: What it comes down to is this. All you're ultimately doing is completely and irrevocably substituting the unalterable judgement of somebody in a completely different time, place, and circumstance for the adaptable judgement of the person on the plane. When you do that, what you're really saying is "I refuse to give people in a scenario I didn't think about the chance to survive". I can't accept that.
A plane suddenly loses power in a highly urbanized area. It's very near multiple airports. Prior to 2009, I have no expectation that an autopilot would have been equipped to judge whether it should attempt to land in a heavily-trafficked river. (I further have no expectation that it would have been equipped to notice in the highly plausible scenario of one or more small boats being in the way.)
It's not a question of landing on water, it's a question of making the decision to do so and where.
Humans have the judgement gained by a lifetime of learning. Computers only have what it occurs to us to put into them while we're sitting safe and sound in our little offices pushing little buttons that don't threaten our lives.
The handling of the aircraft is a small part of the job. Autoflight systems have been capable of flying and landing since the 1960s. It is a mature technology although it does need to be monitored by humans as equipment failures do occur. I am confident a system could be developed with sufficient fail safes to remove the requirement for monitoring, and a fully automatically flown aircraft could be built tomorrow although at a higher cost than the current monitored setup.
Even if an unmonitored autoflown aircraft was developed, judgement decisions about the operation of the aircraft still need to be taken, and these are best done by a human. Examples of decisions I make:
1. The best fuel consumption maybe achieved at a higher flight level, but I elect to stay low and burn into contingency because I've heard reports of turbulence at the higher level. I judge that I probably won't need the contingency fuel later based on previous experience of the route and destination. So I give my passengers a smooth ride, which helps repeat custom for the airline.
2. I experience radio crackle whilst in cloud and elect to change my routing as I suspect we are near a developing thunderstorm that may soon become active. I have to balance the extra fuel burn of a non-optimal route versus the risks of being caught in a thunderstorm which could destroy the aircraft.
I'm not an AI expert, but it seems to me these are value judgements that are best made by a human. So the fully autoflown aircraft will still need a human in the loop at some point.
It is possible to remotely site this human, and maybe make efficiency savings by a single human controlling many aircraft but this would require a bulletproof, near realtime datalink. Again, I'm not an expert in the field, but I would suggest this is, if not technically impossible, then a lot more expensive than the cost of employing human pilots. I imagine this datalink would also be of interest to people with ill intent- no fun when you get the airborne equivalent of a rickroll.
TL;DR: A human is required in the loop, not to handle the aircraft but to make decisions. It's cheaper to have them on-board than the cost of a datalink. It's cheaper to have them trained to take manual control than the cost of an autopilot sufficiently fail safe that it can be left unmonitored.
Also it appears that runway was modified: http://metabunk.org/sk/HL7742_777_Crash%2C_Korean_Asiana_Air...
[1] http://www.ana.co.jp/eng/aboutana/corporate/galleryclassi/19...
Unfortunately I can't find the image right now, but perhaps someone else knows where it is and can provide it?
http://www.cnn.com/video/?/video/us/2013/07/07/vo-plane-sf-p...
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.
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...
(For the record, I have no idea how these things works, it's just very surprising)
Icing in the fuel lines may be caused by fluid flowing through an orfice (pressure differential). All that is needed is water in the fuel.
I kind of assumed the FOHE was something that used external air, it wasn't water in the oil or the fuel. you descend through humid and coolish air ie not summer heat, water condenses and freezes as it's sucked through something from the pressure differential, or from actual icing conditions. but I could be wrong.
While that's true, it takes time, and it won't get enough of the water out of the fuel[0]. Also, the aircraft must not be disturbed for the water to settle out. Operation demands for aircraft don't allow that. Even if they did, some water will remain in the fuel.
While the engines are operating, fuel is constantly circulating which disperses any water within the fuel. Airport fuel supplies at major airports are usually tightly controlled, but it's still be possible for water to get in.
>I kind of assumed the FOHE was something that used external air,
The FOHE is a Heat Exchanger, sort of like the radiator in your car, but instead of engine coolant/air the working fluids are Engine Oil/Jet Feul. Both the fuel and oil systems are closed systems, with one exception. As fuel is consumed in flight, the volume of that fuel must be displaced by outside air. Fuel tank to atmospheric pressure must never exceed some low differential pressure. This is one source of moisture ingress that must be dealt with, and can cause water to accumulate in tanks if left unchecked.
>you descend through humid and coolish air ie not summer heat,
Are you aware that the air temperature at altitude 35,000 ft is around -55C?
[0] http://www.petrolplaza.com/technology/articles/MiZlbiYxMDI3N...
edit: Here is a bunch of related photos if you're interested. http://englishrussia.com/2013/06/20/how-aircrafts-are-fueled...
"PPrune[2] also had a guy weighing in saying that when he flew for a Korean carrier he saw guys try to do banana-shaped approaches to get a smoother landing. Wouldn't be the first time the Koreans have pulled something like this."
[1] http://www.reddit.com/r/worldnews/comments/1hrewx/asiana_air...
http://flightaware.com/live/flight/AAR214/history/20130625/0...
http://flightaware.com/live/flight/AAR214/history/20130626/0...
http://flightaware.com/live/flight/AAR214/history/20130706/0...
Nothing like URLs with obvious patterns!
And to get all Tufte of the graphics: Most of this is chart junk. The 3d view only serveres to hide information, and overlaying the paths (in 2d) would actually let us compare more accurately.
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.
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.)
"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...
!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.
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.
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.
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.
As best I can tell from the available photos, the reason the 28L PAPI is out is because the plane took out the three rightmost ones when it slid/bounced across the blast pad area.
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.
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
(medium has a few different post layouts, but they share the same spirit: https://medium.com/lift-and-drag/5f803f1482e3 vs https://medium.com/lift-and-drag/51691e99279f)
The logo and typography seem very similar, even to my untrained eye, though.
As most have hypothesized, it was an unstabilized approach and they should have done a go around (barring unknown technical/mechanical factors).
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.
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.
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.
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.
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 :)
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.
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.
That is actually expected. It is called the flare just before touchdown:
The positive rate of climb to me, indicates that they attempted to climb (go-around) but their low airspeed resulted in a stall.
It's important to remember that this data was pulled off Flightware which is basically aggregated data. and not from an accurate source such as the FDR. So my guess could be totally wrong.
Again the only thing I've flown are parachutes and some hours in a C172 and a C182.
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.
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.
I'd wager that 120fpm climb reading to be due to a measurement error of some kind, not actually something that really happened.
The plane is far outside it's normal operating conditions by this point, it's possible the plane instruments actually experienced a brief moment of 'climb' while the plane was crashing, or it could be equipment malfunction.
However, from what I can tell, the plane never reached that far down the runway. And the gps coordinates have actually snapped to the middle of runway 19L, near where it intercepts 28L, suggesting that flight radar 24 are doing some post-processing to make the planes stick to runways better.
I wouldn't trust that last data-point at all, as it's definitely post-seawall.
The data points are in the neighborhood of 15 seconds apart. There are 4 points labeled 2:25PM, 3 points labeled 2:26PM, and 5 points labeled 2:27PM.
The altitude data is all rounded to the nearest 100ft. Obviously this is coming from transponder data. The mode C transponder carried by an airliner reports pressure altitude back to the interrogating radar at 100ft intervals.
Vertical velocity is all multiples of 60fpm. I have no idea where that would be coming from. As far as I know, vertical velocity is not transmitted by either radar transponders nor the newer ADS-B position broadcasting equipment. Simply taking the derivative of reported altitude wouldn't produce these results, because with 100ft altitude intervals and 15s reporting intervals, that gives you a vertical velocity resolution of only 400fpm.
Let's skip that question for the moment. The raw altitude data does show an increase from 100ft to 200ft at the end. But what conclusion can we draw from this? Essentially nothing. Because the altitude is so quantized, this could in theory indicate anything between a 0ft and 200ft increase in altitude, non-inclusive. Of course, the instruments are not that precise, so in practice the range is even larger. This is especially true given that the instrument was in the middle of a fairly violent plane crash when it gave that last reading. From the video of the crash, it's clear the plane never got very high above the runway. Since the runway is only 13ft above sea level, and the plane didn't crash into the ocean, the amount of climb possible is very much limited. The transponder may well have increased in altitude a bit for this last reading, but if so, the alignment with the reported altitude increase is pretty much just coincidental.
Now back to the vertical velocity. Where did it come from? I can only speculate that they're applying some kind of curve-fitting or smoothing to transform the coarse altitude data into smoother vertical velocity figures. These numbers are therefore even less reliable than the altitude figures, and can probably just be ignored.
Just to briefly support that last bit, there are some obvious numerical anomalies in the vertical velocity figures earlier in the flight. At 9:38AM, the data source briefly switches from "FlightAware Transoceanic" to "Oakland Oceanic" and then back again. The two Oakland data points show an altitude of 37,000ft, while the FlightAware data shows 34,000ft. The vertical velocity for these four points is shown as 2280fpm, 9960fpm, -4320fpm, and -1800fpm. These changes obviously didn't actually happen (otherwise we'd have heard about people being flung about the cabin in mid-flight!) and are just some sort of reporting anomaly. The ridiculous vertical velocity figures (nearly 10,000fpm climb accompanied by a minor increase in horizontal speed!) are obviously just some sort of post-processing going crazy trying to fit the bad altitude data.
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.
Even though I'm a former pilot, I've not made any posts prior to this one, because I didn't want to speculate.