The missed [soccer] match

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Re: The missed [soccer] match

Postby jwocky » Thu Dec 01, 2016 2:57 pm

I listened through it again. Some other little details stuck out, but I don't get the whole picture

about 2:55, 2933 asks for vectors after they got already instructions to head for the VOR? So, if everything aside of low fuel would have been okay, they should have had the VOr in their NAV1 and know aboutish which way to fly, right? So, why asking for vecots again, in a situation, the ATC had just turned around 3020 to land fast to get her out of the way?
And what is that "runway inspection"? See, the airport was open, so it was not a big inspection closing the runway for hours, it was probably just someone looking for how many water was on the runway. Still this information makes no real sense at this time unless the ATC would expect a delay due to it?

at 4:03, the pilot says, he is at 18,000ft and confirms, he sees the other traffic
at 4;19, he says, he is just through 16,000 and calls for vectors again
sooooo, 16 seconds, 2000ft, that makes 7500fpm. Exactly 7500fpm! Now, if a pilot flies the descend for example manually, he would end up with a number somewhere between 7400 and 7600. The chances to hit exactly such an even number by accident are very low, so it appears to me, the decend was controlled by AP. But 7500 is also the maximum descend you can even set in that AP and it is for the steep approach procedure which normally goes along with flaps out and slow. So, he was 0.1nm from VOR Rionegro and less than a minute, he was 8.2 miles out of Medellin. Now, the only Rionegro VOR, I can find is 2.7 miles away ... sooo, this can't be right, and therefore, I can't figure out the speed of the plane. Maybe Israel, who knows the area can throw some light on this. But given how near it all is, the speed of the plane was actually quite low (in FG we would call this the JWocky-slow-as-molassis-approach).
The point, I don't get here, this is totally inconsistent. If I am low on fuel, so low, I run already on fumes, I try to descend steep okay, and I will do so probably manually because that gives me basically access to all the spare capacities of the plane, an AP usually doesn't use. The point is, I would want to go down fast, but without flaps to get for the moment as high speed as I can probably get without ripping the crate to pieces, every knwo gives me some meters more glideway and if I have too much speed, I can always butterfly-butt it. Especially if I am already in a good position to just glide down, as Vincent already saw. So, this is like this pilot had either notreally any deeper familarity with the type of plane he was flying or he didn't expect really to run out, only to land with criminal little fuel in the tanks.

at 4:46 the pilot reports total failure, asks for vectors
Now, that makes sense ans it doesn't. It makes sense to report it, it makes sense to ask for vectors if his ILS was dead due to electrical failure, alright! But when the ATC asks him for his course, he says 360, straight north ... uh ... magnetic 360, and that is NOT straight North there. I can't find the deviation, but I remember from earlier flights in that area, it is quite noticeable. Consequently, the ATC told him to steer 10 degrees. Soooo ... he knew earlier already the course, even if he lost the electrical systems, his course should remain a constant, he was on localizer and this is not FG where he crosses a tile border and suddenly everything is different. All he needed to do was to keep the course from before, now by magnetic compass and glide. Even with his weird descend before, he should have had enough altitude and speed to reach the runway and I kind of assume, if I can do this math and give it a try, a trained pilot should be able to a thousand times. On the other hand ... who knows, Whut da-fuk, Som-tingis wrong?Maybe I just overestimate trained pilots?
So, now, he reports total loss of electrical and no fuel at all. At 4:46. Like, he had maybe fuel till maybe 4:30 or so? So, he was just for a few seconds without fuel and therefore without generators. This plane had a 1900nm flight behind it, that is roughly what 4 hours 20 or 30 minutes, give or take depending on the weather. Over four hours with two running generators, one should assume. So, even if the batteries were old, without maintencan and dragged through a swamp before they put them in to un-mothball the bird, if those batteries would have been that dead, he wouldn't have been able to start the plane to begin with (even not with external power supply because the battery system would have sucked more than the external would be able to supply). I mean, at least the crew would have noticed it. However, there is always one dirty trick more. You can feed a whole system directly from the generators and just switch the batteries out of the circuit. There are a thousand reasons not to do it, but you could get the bird flying. Problem is, if the fuel runs out, you are really without electricity from one moment to the next. So, this would be consistent with what the pilot reports ... only if it was that, he wouldn't have been able to report it because also his radio would have been without juice, but it sounds strong to the last moment. So, curious me, I looked at the schematics. Now, I have only the Bae-146 here, not the later RJ85 and Avro made probably some changes, so it's a bit wobbly but bottom line seems to be, there are several buses and in standard configuration, the avionics, like AP. ILS, AI and so, hang on another one than communications, at least in early BAe-146s. A little weird seems to be, that in normal operation, the avionics bus, bus B is fed by the APU while smaller devices actually hang on a C-bus fed by the generators in the outboard engines. I am not sure how reliable my schematics are, but if, that means, the APU was off, the engine generators were running or still spinning down and thus still producing a little electricity.
Lets think here for a moment very primitive. The last message was at 5;40 at 9000ft. Not sure where the pilot got that information from if all his instruments were dead, most RJ85s were updated to glass cockpits, right? See, this all makes no sense. Even with the generators still spinning down, this message should have been noticeable weaker if he really had no electricity. So, what, if he had juice, he only didn't know? Somewhere a failure in the avionics bus, not generator failure or really no electricity? He was at the end panicking because he expected to run out of fuel, so, when his instruments went off, he reported what he ASSUMED to be the reason and that was what he expected, to run out of fuel.

I also looked at various photos of the crash site, but that makes the details even weirder:

1.) The point of first impact and then the main crash site are both mostly distinct. There is not much debris I can see between them. Like the plane hit that mountain low and then slid upwards.
Image
The two left ones are the main debris site, the right one is the first impact side.
Now, basic physics tells, the nearer your impace angle is to the perpendicular angle of the surface you crash into, the lower the defelction and the higher the force. What we see at the first impact site is the tail (or a part of it), the forward plane slid upwards and left a cut lane in the vegation, basically only leaving small debris along the way.
So, at the moment of impact, the nose was up and not just two degree or so, but significantly. Basically more than the angle of that slope. This indicates, there was at least elevator control to get the nose up that far. So, at this point, there was electricity because the hydraulic pump had to run to move the elevator.

2.) To lose the tail in first impact is the typical tail strike situation. However, if you look at the main debris, the aft and middle of the plane are practically disintegrated.
Image
But from the wings on forward till almost where the ockpit once was, there is a part of the fuselage still intact. Then, the cockpit is missing, but that's maybe the angle of the photo. So, if I identified the parts right, the force was still on the real. Means, the plane had not much turn impuls after the initial tail strike. The speed had to be low. She didn't just fall out of the sky like a stone.

3:) The engines ...
Image
Okay the engine case is gone, but what I don't see here is missing or twisted turbine blades. And the more you look to the outside, the deeper, the dirt is pressed between the blades. The engines on a Jumbolino hang high, okay, but at the time, this one touched dirt, it was spinning. Not so fast to spread it's parts over the vicinity, but fast enough for a cutting effect. If thos blades would have stood still while that engoine started to eat dirt, it would havre meant to overcome resistance which means, the blades would be at least bent backwards. Which is weird because the pilot reported no fuel at 4:46 on the tape and the planes was in the air still at 5:40, almost a minute later. So, at this time, the engines should have been standing still or, while still gliding spinning with the airflow. So, to me, there seems to be a discrepancy because those little ALFs don't need that long to spin down without fuel. They don't have enough mass to keep the moment long.

4.) The direction between first impact and main debris is roughly 290 degrees. So, the last ATC instruction, confirmed by the pilot was a course of 10 degrees. Now, at the time of the impact, the sliding body was of course tunred around and followd basically the direction of the valley. Only, that would have left a curved debris trial and #I see only a straight one. So, maybe someone with better eyes takes a look and maybe see a curve there, but if it is strainght, it means, that the plane was at the time of the impact headed to roughly 290. Which poses the question how did the plane get there and on this course without engine power, without electricity for the hydraulic pumps and without any idea where they were and where they wanted to go?

Sooo, as usually, I will be accused of speculating, but then, it is a way to share thoughts. And also of course, there are like a thousand details we can't see in those pictures and data, we don't have, so in the end, in like two years, we will hear, it was all the pilot's fault.



*** Edited because clumsy me linked a wrong picture ***
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Re: The missed [soccer] match

Postby jwocky » Thu Dec 01, 2016 2:59 pm

I am sorry, I linked the wrong picture. The first one should be
Image
this one ... very sorry
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Re: The missed [soccer] match

Postby SHM » Thu Dec 01, 2016 3:05 pm

Another video. I haven't watched it yet.

https://youtu.be/g-gspJzK6uM
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Re: The missed [soccer] match

Postby D-ECHO » Thu Dec 01, 2016 3:06 pm

Is it only me who can't see the picture?
However, it seems to me, some people think this crash is worse because there was a soccer team in the plane, as if the life of a well-known soccer player was more worth than the life of a "usual" guy (am I correct?) This seems to be a major thing in news I often noticed, that accidents, terroristic activities or else are considered worse if a specific group of people is involved (prominents).

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Re: The missed [soccer] match

Postby KL-666 » Thu Dec 01, 2016 3:40 pm

jwocky wrote:the pilot reports total failure


It can very well be that we should not take such message from a pilot in distress too seriously. It has happened before that pilots reported things like "both engines flamed out", where later investigation found that no such thing was the case. The pilots just panicked in a stall and it felt to them that the engines gave no power.

Now in this case, what in the cockpit is still on when on batteries? If it is only the backup instruments, then the pilot may have mistaken the black screens in front of him as a total failure. This would explain why every other thing that needs electricity was still functioning.

Kind regards, Vincent

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Re: The missed [soccer] match

Postby jwocky » Thu Dec 01, 2016 3:55 pm

@D-ECHO: I really can't speak for journalists, for some of them we are still lacking prove that they are actually human, sooo ... it's kind of a weird subspecies as far as I am involved.
However, I know, in South America, this team had a lot of followers, a lot of fans. So this hits home for a lot of people there. Israel for example is from Rionegro, not fully three miles away from where it happened. So I know, why he is following this closely.
I have just an allergy against unanswered questions. I mean, okay, those guys played a good soccer, I like that, but I am always wondering, how and why things happen. Must be some personal mental thing with me.
But on a general level, prominent people, celebrities, actors, soccer players, singers, take which brand you want, mean a lot for a lot of people. 200 people dead and nobody knows them but their families is terrible - but nobody knows them, nobody has an emotional connection. It is different if your favorite singer dies or an actor whose movies you liked. There is some connection, if also most people would deny it. The human brain has its own little games with that. See, this kind of emotional participation doesn't start only when celebrities die, it starts when they become celebrities. People suddenly want to know more about them. Millions of people read what a Kardashian said in the last interview ... why? By mere fact standards, we have yet to see any of them something that would be worth the time to listen to those interviews, but it is about emotion about connection. Which is in its nature deeply human, be it good or bad. If a plane would go down with 500 people on board and only one of them would be a Kardashian, you know what would happen. You can claim, this is wrong and some would agree, some wouldn't and most people would try to hide it just is that way without even admitting to themselves why. It's just human and honestly, I am too lazy and tired atm the moment to be too judgmental about it (being judgmental is another one of those charming human traits).
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Re: The missed [soccer] match

Postby jwocky » Thu Dec 01, 2016 4:59 pm

@KL-666: That is the thing, well both points are the thing in fact.

1.) The human brain has a specific order of things. When in panic mode (fight or flight reactions), the technical proficiency decreases and the mere quick impression becomes the primary information input. Makes sense because the brain is in a mode in which speed gives usually a better chance of survival than accuracy. Alas, not in planes and cars, this rule applies more if a sabertooth is after you.
So, the order when something happens is
a.) what you expected already (that is what it looks like here)
b.) what you can pick up fast (like in a stall, it feels as if you have no thrust)
c.) only when a.) and b.) lead you nowhere, the technical analysis and always with the risk to go down the first road your brain finds (that would be the story of AF446)

2.) The batteries should have kept primary and secondary instruments alive for 30 minutes. The only things that switch off when the system goes on battery are entertainment, galley and such stuff. So, if he was on battery, he would have had also radio nav and ils and it sounds as if he hadn't. So, maybe, but it's speculation, he had actually no battery failure but a bus failure. Maybe, if he would have switched the instruments to the other bus, he would have landed the bird without too much trouble.
The thing that makes me really frown is the photo of the turbine. I can be wrong, but to me, it looks like it was spinning down only after the first impact. See, the crazy thing is, those little ALFs are quiet and the sound is quite directed. You can hear them when you are behind,b ut even outside of the plane and maybe 20m away, you can already normally talk to someone. Inside at cruise, you really have to concentrate on it to hear them and if people talk in the cabin, you won't. I flew several times in those planes and it was always amazing to me how quiet they were. So, if your instruments show you n1=0, n2=0 and you expect anyway, you are out of fuel, you assume, they are off. Maybe even more if the system is actually still running and has brought your throttle down to the last AP setting, steep descend and low speed in this case. Only there is nothing, showing this to you. As I calculated, the plane was a while earlier in a 7500fpm descend. So, your butt tells you, you are going down, but your brain tells you it is because your engines are not running. You don't realize in this moment the discrepancy because you should have instruments and you don't. So you try to figure out what to do. Takes some seconds, maybe ten, maybe twenty. Then you decide, you need to pull that yoke, stop your descent. You pull and actually, the plane reacts. But you are slow. So all your experience telly you you need more thrust only you think, you can't get it because the engines are off. Only they are not off, you are slow because the flaps are out, you are in a steep descent configuration. You don't even touch the thrust lever, why, you beleive your engines are off.
The last radio message said they were at 9000ft. I can't figure out how high that ridge is, but there are some high ones around Rionegro. So you pull the yoke. The plane goes nose up, but the climb is slow in this configuration and if you pull too hard, your lift goes down due to alpha. Soo, lets do the math:

lets say 30 seconds delay, that makes 3750 feet lower. 9000-3750 is 5250 feet left. Rionegro has an elevation of roughly 7000 feet and the crash site is definitively higher, even the 9000 feet sound overly optimistic there. 5205 is definitively under ground. So, the delay way shorter than 30 seconds. We could probably calculate it if we know the exact elevation of the first impact site. Problem is, the faster his reaction time wa,s the higheris the probability of a merely instinctive reaction and given the impact angle or my guesses about it based on some laws of physics, this plane was very nose up, maybe also already in stall. Like he pulled the yoke as far back as he could. So, the speed forward was low. The wreckage seems to indicate there was no real pitch moment after the initial tail strike. Now, I couldn't find the actual weight of the plane, but MTOW is 93,000lbs or 42,184kg. CG is roughly in the middle of the fuselage, makes aboutish 21,000 kg on each side of the CG. So, to give it an impulse forward of only 1m/s, you would not only need a force of 21,000N at the tail end at a spring factor of 1 (because we talk basically of the factor submitted forward by the "bouncing" of the tail end (and a factor of 1 would be better than a rubber ball). So, to get there, you need the speed vector*weight. Just to make it easy, lets work with a purely horizontal one. Then

b=(a*cos(alpha))/sin(alpha) where alpha is the pitch angle.
but
the real impact impulse that would work on the forward end of the plane would be alpha-i(slope) where i(slope) would be a profile integral over the slope. We can for a mere guestimation use the average angle of the slope. For which I have no data, but it looks damn steep. So, if someone can get the exact elevations of first impact site and main debris site, it would be as first approximation (feet(main debris)-feet(first impact))/distance ...
so, without actual numbers, we can say, the smaller the effective impact angle was, the smaller the vector of the taill impact that actually is submitted to the forward part. Then, the nose hits the ground and would deliver an impulse into the opposite direction. The cell has to withstand all those forces and we know, it did to a point or the main debris wouldn't be so far from the first impact. Sooo, and because it a pain to try equations in this editor, the real impulse was strong enough to break part of the rear off but the submitted vector was not strong enough to pulverize the front end. So, for comparison, we are looking for plane accidents with a similar pattern and known impact speeds at or about an impact angle>ground angle (or in other word, pitch-profile angle of the ground) has to be slightly positive and the pitch has to be big enough for a stall. But it can't be really too much, given the debris.
Or we just guess how steep that slope is ... duh. So, and I have no idea how to get this equation into this editor, for a 30 degree slope and 32 degrees pitch, I end up with a x of aboutish 100-120 knots, probably a little nearer to the 100 knots. So that would be consistent with pulling the yoke too strong, elevator full up.


See, there is another detail, that disturbs me a little. There is no sign of fire. None at all. No blakc spots on the wings, no outward bend, nothing at all. Of course, every journalist says, that is because the plane was out of fuel, the tanks were empty. Sure, that would prevent a bit impact explosion. But empty tanks are not actually empty, they are full of fumes. Fumes ignite easier than actual fuel but they deflagrate also in a second and don'tproduce a lot of kinetic energy when exploding (v-burst is too low for most of them and there is not much burn mass). Still if there was such kind of deflagration, shouldn't be at least something be visible on the wings? Fumes would explode for sure, liquid fuel, maybe not if the effective impact angle is low and there is no spark (and sliding with high wings prevents for example hitting the wing tanks into something hard producing a spark).
See, I don't know what really happened, I am only thinking aloud about the details, I see.
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Re: The missed [soccer] match

Postby IAHM-COL » Thu Dec 01, 2016 6:35 pm

SHM wrote:Another video. I haven't watched it yet.




@Jabberwocky

You posed interesting questions that I myself have at my time.

The video posted by SM above is a very nice analysis of a time slice of the 2 planes declared in Emergency in SKRG. It gives good light on what happend.

Overall. You've got several factors.
1. A plane Viva Colombia A320 travelling SKBO-SKSP. Declares emergency for fuel leakage and deviates by turning looking for SKRG for emergeny landing. The plane reaches Medellin already as declared emergency when the AvroRJ85 by Lamia (CP2933) even reached the approach zone in RNG VOR.

2. The A320 is turning for final approach when the AvroRJ85 arrives the VOR and being instructed to hold VOR due to the emergency aircraft being in final then the pilot requests priority for landing due to low fuel. The plane is at FL210. The ATC informs that the A320 is landing also declared emergency.

A battle against the time began. Now the ATC has 2 planes in fuel problems. One is on landing and the other too high for approach.

I can hear confusion in the pilot of the AvroRJ85. But keeps cool and controls the plane in a last turn towards RNG VOR, after being instructed to descend down from FL210.

Here you point he descend fast. He ought to. At FL210 in RNG he cant face runway. He needs RNG at 12000 to ILS and final. so He is requested to drop elevation and helped with 2 vectors towards RNG. The ATC then gets all other traffic out of the Way and gives all RWY to CP2933.

It seems she sorted it out. The plane ready to final, descending, but then the pilot report "Total Failure". Electrical is out. No GPS. No fuel, engines out.

At that point the ATC has no transponder anymore. All she knows is by secondary radar the position, but she does not have altitude information. The terrain there is bone-chilling and he was coming down to prevent go around due to being too high as it was initially. She asks for altitude. He is at 9000.

Now. He is TOO Low. The plane was with a good heading. The ATC ,she made a quick correction 350 to 010, and gives him distance as 8 miles for threshold. The pilot is in total distress. "Vectors. Senorita. Vectors" are his last words. He had the vectors correct. He had the heading correct. It is too low to clear Cerro Gordo which he crashed too.

He also had zero visibility. His cockpit was surely partly alive. He knew altitude. He could guide the plane (asking vectors). He declared: No electrical. No GPS. The plane probably was very dark, no external lights anymore. The night had dense fog, rain and low visibility -- which contributed to the fact he couldnt see PAPIS or RWY lights at all, even thou they were straight ahead of him 010. As he is falling he knows the treacherous of the high terrain below him. The peaks are around 7-8000 feet high on that final approach area to SKRG.
https://raw.githubusercontent.com/IAHM-COL/gpg-pubkey/master/pubkey.asc

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Re: The missed [soccer] match

Postby IAHM-COL » Thu Dec 01, 2016 6:43 pm

IAHM-COL wrote:As he is falling he knows the treacherous of the high terrain below him. The peaks are around 7-8000 feet high on that final approach area to SKRG.


Image

I probably never told anyone in this forum. But I had always found a bit nerve-wrecking to be a passenger landing SKRG. The reason. You perceive as if the plane is loosing altitude and falling into very sinous montain side. This is south of the airport

A feeling of: Arent we descending a lot too early? fills me up!

The first time you ever see a flat surface, its already the basin where the runway is located. As a passenger it feels quite a lot as if the runway would have emerged from the menacing "los Andes" peaks. The airport is located in a table top close to an small municipality called "Rionegro"

This image does reflect how the airport basin seems carved out of mountain peaks

Image


The airport "Rionegro" (SKRG) is a bit too far-- east of the City where I was born. Medellin. Medellin is a low valley completely surrounded by very fast-climbing peaks reaching between 7 to 9 thousand feet. is like the bottom of a mountains pot. The initial airport Olaya Hererra SKMD was a very treacherous airport, and basically too challenging for Jet engines to operate, so in my City, it was decided to build the aiport on the table top of the peaks east of the City. That's how SKRG came to be developed. One lands, therefore, typically in Rionegro (SKRG) and comes down to Medellin in automobile, which adds 2 additional hours to most arrivals to my city.

This is how an approach to the Olaya SKMD can look like

Image
Image

I think those 2 images speak volume of why SKRG is the main airport to the city of Medellin (as opossed to the "in the city" SKMD), and why SKMD is mostly reserved for regional props.
SKRG in contrast is the second busiest comercial and freight airport of the country.
https://raw.githubusercontent.com/IAHM-COL/gpg-pubkey/master/pubkey.asc

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Re: The missed [soccer] match

Postby SkyBoat » Thu Dec 01, 2016 8:32 pm

I agree that the analysis is very good. @SHM, thank you for finding it and posting it for us! It really does appear that had the A320 not been present, the RJ85 might just have had enough fuel (perhaps running on fumes) to make it to the threshold of the runway and touchdown with all alive. How deeply, deeply, sad.

I did find one thing missing and that is in terms of the operational capacity, what is the recommended (required?) reserve fuel capacity for the RJ85 aircraft on a scheduled or chartered flight? How could you take off, with all the possible variabilities of weather and wind to affect fuel consumption with only 100nm reserve in your tanks? To me that sounds ludicrous, or do I just have a case of United States FAA tunnel vision, and the rest of the world does not necessarily enforce such safety measures?
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