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Jet goes down on its way to Medellin, Colombia

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Jet goes down on its way to Medellin, Colombia

Old 16th Dec 2016, 23:42
  #921 (permalink)  
 
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There are versions of the ATC transcript recording that have been edited and are not reflective of real-time, beware. I have annotated MSL altitude versus UTC time with the transmissions from LMI2933. The information correlates well with the ADS-B reports.

Added to the blog entry
Satcom Guru: LMI2933 LAMIA AVRO RJ85 Medellín Deadstick



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Old 17th Dec 2016, 09:55
  #922 (permalink)  
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Lemme , while I am impressed by your talents , playing home-made accident investigator can be dangerous for other people, especially when you appear " an expert" to the public and journalists that might take your version of events as established facts.
An example here on your beautiful graphs is you separate the aircraft transmissions from those of ATC , inducing to the non-professional the idea that the pilot was in distress requesting assistance ( vectores, vecrores Senorita.." ) and got no responses..

But even if you do include the ATC transmissions , they will be misleading unless you add that a controller can only give vectors if/when he/she actually sees the aircrfat position on radar. This was not the case , as she states she lost him ( whether due terrain or loss of electric on transponder still needs to be established )
Accident analysis it is a bit more complex that just taking You tube videos and Flight radar 24.

Finally ,as you said there are different VHF/ATC transcripts around, and the exact time stamps will be critical to establish the actual sequence of events.

Speculating of what might have happened is what we all do here, nothing wrong with that , but playing amateur incident investigator delivering home made " facts" is playing with fire. .
Before posting things , think of the effect this will have on the surviving people , the air traffic controller on duty and the families of the victims if you get it wrong.
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Old 17th Dec 2016, 11:14
  #923 (permalink)  
 
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@ATC Watcher,

I think what Lemme do here is well within what we can expect, and in fact what we should appreciate on this forum. I think everyone reading here is capapble to understand that Lemme has no access to the complete data and as such his teories and findings might get revised at a later stage. Something he has said and done several times in this case already.

Speaking for my self I, can say that I find what Lemme has said in this topic to be very interesting and enlightening to read all while I am fully aware that the complete picture is by no means available yet.

As to what you say about the ATC transmissions missing in the above post from Lemme, I am sure everyone that have read this topic in only the most superficial way am aware that the ATC transmissions is missing and that his post is only indended to give the approximate timeline for the LaMia transmissions and the aircrafts height at each of those transmissions.

Edit: And, by the way, I am a non-professional, and I am still fully able to understand the non-completeness and potential inaccuracies in Lemmes posting.
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Old 17th Dec 2016, 13:15
  #924 (permalink)  
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SteinarN : I basically do not disagree with what you say , but this thread is not only read by people having a sound understanding of the "unsaid" and " not shown " items. They are used by many , including journos , as a kind of an " expert source" .
The headlines of some newspapers in Columbia were harassing the Controller for not having helped...and pointing fingers at her.. with her full name attached. No need to revive this.

Yes Lemme is doing good posts, but those are only speculative . An example out of many : Lemme , like many others who have posted here, are taking it for a fact that the gear must have been down because the words " gear down" can be heard on the background of one transmission.
But there is no factual info that this was indeed the case. Could have been words on a check list , to which the Capt replied : No keep it up" for instance.
Only the investigation team and/or FDR will tell us if it was indeed down and when. Only then you can start talking about gliding ratio and " blaming" pilots for putting it down so so high...
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Old 17th Dec 2016, 15:04
  #925 (permalink)  
 
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Surely r.o.d in the last stage of the flight indicates gear down, as does speed (indicating landing flap, ie landing configuration). Maybe not "Proof", but no one would imagine full flap without gear down, would they? - warning horn and all?
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Old 17th Dec 2016, 17:14
  #926 (permalink)  
 
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Typical seating arrangement.
Notice the aft facing attendant seats behind the aft bulkhead. This is most likely where Suárez and Tumiri where seated.

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Old 17th Dec 2016, 19:06
  #927 (permalink)  
 
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Melax:

Yeah right !!
Why don't you tell that to the passengers of AVA52 !!
Unlike the current case, they departed with adequate and legal fuel.
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Old 17th Dec 2016, 19:28
  #928 (permalink)  
 
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Yes indeed you're correct, I was however addressing his ludicrous statement, That "if they had an FE they would not run out of fuel"
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Old 17th Dec 2016, 19:56
  #929 (permalink)  
 
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Originally Posted by FE Hoppy View Post
There is no flight engineer on an RJ.
Trust me, if there was they wouldn't have run out of fuel.
May I be so bold to presume what is postulated here is that such a FE would have unstrapped hisself, stood up, reached in his kit bag for one of his meaty adjustable spanners, klocked the captain round the head with it and safely landed the plane at the nearest for a quick sip of fuel. Now before you all start screaming and saying it is not cricket, not the proper thing to do and all that, just remember the good old days when such a suitable object was standard eqpt in the rear cockpit within easy reach of the instructor.
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Old 17th Dec 2016, 20:35
  #930 (permalink)  
 
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Originally Posted by ATC Watcher View Post
SteinarN : ...this thread is not only read by people having a sound understanding of the "unsaid" and " not shown " items. They are used by many , including journos , as a kind of an " expert source" .

Yes Lemme is doing good posts, but those are only speculative ...
Only the investigation team and/or FDR will tell us if it was indeed down and when. Only then you can start talking about gliding ratio and " blaming" pilots for putting it down so so high...
I had responsibility for both flight data recording and communications while at Boeing, continuing most of my career on communications. One area we, as an industry, have been seeking is telemetry for use in both operational quality assurance and for air-safety investigation. Like it or not, the public has little tolerance for the glacial pace of aviation evolution, especially in the area of accident investigation.

Mode S transponders and ADS-B open up an new generation of analysis unrelated to air traffic control or collision avoidance.

Public companies like flightradar24.com have crowd-sourced a very comprehensive set of data and make this available in real-time. Not only can we examine the flight of interest, we can look at all the other flights too. This adds a whole new dimension of insight.

I have personally undertaken a quest to see how far I can get with the ADS-B data as the core of an analysis. I am only operating with position, track heading, ground speed, pressure altitude. There are other parameters available, and I am advocating for them as an enhancement to investigation. Only by working through the analysis am I able to fully appreciate what is missing.

I have looked at other accidents, notably EK521 and the Pence LGA overrun. In those cases, I was able to find the likely sequence of events (failure to add go-around power, landing long) right away.

I am not looking at assessing blame. I am trying to understand what happened. That does required digging deep and wondering about scenarios, and that does reek of speculation.

LMI2933 had significant loss of life, and therefore is much more deserving of analysis - it is the nature of aviation to learn from catastrophe.


I am looking for help to be sure my analysis reflects the technical issues accurately, and so I have decided to join PPRuNe.org and airliners.net bulletin boards.

I find a litany of statements everywhere. Most of it is piece-meal, missing context. Some of it is plain wrong. Some of it is mis-guided. The point of the blog was to give me (and you) a single reference point from which I would aggregate all the info I stumbled upon, and then add considerable analysis based on my personal expertise.

If you tell me something is wrong, I will go hunt it down until it is for-sure, and I will revise the blog. No worries, I don't know everything, and I love to learn new things or think from unexpected perspectives. Running down a wrong path is not a waste, because you learn more about it and that can pay dividends.

I was lead engineer (control laws) for Boeing automatic flight controls, Thrust Management, for 757, 767, 747-400 and am very familiar with airplane systems. If you fly those planes, or 777 or 747-8, you are using thrust management, data link, flight data recording, and satcom systems I once led, or are directly based on developments I played a principal role in.

As supervisor for data link and satcom, I led the ability to for satellite voice and for ACARS/FANS to connect pilot and controller, to which I spend considerable time dealing with human factors and having to invent "comm messages" as a whole new category.

As a manager for terminal-area projects, i was tasked to work with NASA and the FAA to look at ways to reduce accidents in the terminal area, and we as group studied every accident report going back 20 years to search for improvements.

I am very accustomed to looking at a subset of data and applying it to complex systems and to airplane operation. As a (not current) private pilot (SEL, SES) with instrument rating, I have had a chance to try it all myself. But I am no line or experimental captain (plus I am not current anyway), and for this I am looking for help.

Also, I am not that familiar with the RJ85. I have only a subset of the manuals. For sure, love to hear from those with first-hand experience.

Forgive my writing style. I am a systems engineer at heart, so I write everything into positive statements that may come off as too confident or assured. I make mistakes, I get tunnel-vision, I can be over-confident, and I for sure don't know everything. But I love to learn, and I am not afraid to make a mistake.

I appreciate your suggestions. I have seen some people react almost with anger that I dare publish any information. I want to understand what those concerns are so I can address them. In the end, I am really just trying to figure out if we can use ADS-B to make aviation safer.

These observations stem from sparse ADS-B reports, an unauthorized copy of a related RJ85 Flight Crew Operations Manual, Vol 1. plus other references not known to be accurate in comparison to CP2933 airplane combined with best-intentioned judgements and helpful advice from online commentators, may have errors, and are in no way a substitute for the official accident investigation.
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Old 17th Dec 2016, 22:06
  #931 (permalink)  
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Lemme :
Thanks for your detailed list of qualifications. very impressive indeed . I went to visit your web/sire Blog and read some of your Tweets and likewise I was very impressed . You also seem to spend a tremendous amount of time doing this.
The first question that come to my mind is why are you doing this? Is it just a hobby or is it professionally motivated, like selling a technology or a project/ idea ? or just wanting to show what people can do with FR24/ ADS ?

The problem I have is that your presentations are using sentences like , the aircraft did this, the crew did that, ATC replied, etc.. like these were factual .
one example : quote from your blog :
The airplane initially arrived with conceivably enough fuel to complete the approach and landing safely
How do you know ?
But in fact a lot of this is taken unofficial sources like newspaper coverage, so called witnesses , You tube R/T transcripts of unknown origin , posts in forum by unknown " experts" etc..
To be fair, you do mention this in your introduction :
These observations stem from sparse ADS-B reports, an unauthorized copy of a related RJ85 Flight Crew Operations Manual, Vol 1. plus other references not known to be accurate in comparison to CP2933 airplane combined with best-intentioned judgments and helpful advice from online commentators.
But to the uniformed non aviation specialist , the end product on your blog looks very much like a serious accident investigation. And it is not. And there lies my problem . You become yourself another informed source for the uniformed . Kind of he blind leading the blind .

Another and final example to prove my point : as far as I know there is so far no real official statement coming from a bona fide source like the NTSB or the UK AAIB that this accident was due to a fuel exhaustion, and even if it really was the cause (although it looks like it was) , I personally very much doubt that the 4 engines would quit at the exact same time .But i am not an expert in RJ fuel systems . cross feeds and pumps, so I leave this part for those in the know. . Anyway all that can be very easily verified in a sim. And that is where the real accident investigation team comes in , and look at the facts.

Last edited by ATC Watcher; 17th Dec 2016 at 22:16. Reason: typo
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Old 17th Dec 2016, 22:52
  #932 (permalink)  
 
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On all of the various jet aircraft that I have flown, a windmilling engine (ie flamed-out but not mechanically failed) would still drive the relevant hydraulic pump(s) fast enough and therefore maintain adequate pressure in that system.

Having watched thousands of engine start cycles over the years, the Hyd pump coming 'on-line' is invariably one of the first things to occur as the engine rpm builds.

When airborne, I know an engine's windmilling rpm is a function of IAS, but are the RJ85 guys telling us that these guys having flamed-out all 4 engines would have had the indications of a total Hyd failure?

Last edited by H Peacock; 17th Dec 2016 at 23:06.
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Old 18th Dec 2016, 02:45
  #933 (permalink)  
 
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Originally Posted by Small cog View Post
lemme

As to (roll) spoilers, they operate off the Yellow system and will float up with the loss of that system.
I agree I was confused and confusing. From my fallible understanding the airbrake will stow in response to loss of power and may trail slightly open with loss of hydraulic power. The lift spoilers will remain locked down. The roll spoilers use a mechanical actuated hydraulic servo off of yellow.

Could windmilling #2 drive yellow enough to power the roll spoilers - that is the question.

A related issue is mentioned in the rudder discussion, where it is stated that

Hydraulic power is not available to the rudder from engine 2 because the power is absorbed by the standby fuel pumps. When main DC is lost, the standby fuel pumps:
• Automatically run
• Cannot be selected off.


So if yellow can't drive the rudder will it drive the roll spoilers?

This schematic seems to stack the services in order, and if nothing gets past the standby fuel pump to the rudder, it seems the roll spoilers are not going to work. I found no such reference, and appreciate your comment that they will float up a bit in response to bernoulli.



PS - this is a personnel quest along a professional curiosity.
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Old 18th Dec 2016, 10:01
  #934 (permalink)  
 
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I need to complete this analysis before the official release, or my analysis would be tainted. it is a good study even if I get it wrong, because we can figure out what was missing or where it went awry.
If you get 'it' wrong - or partly wrong - how can anything meaningful be drawn from 'it'? How will we know if you got 'it' wrong until the official report is published?
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Old 18th Dec 2016, 10:56
  #935 (permalink)  
 
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I need to complete this analysis before the official release, or my analysis would be tainted.
Your analysis would be tainted by the official investigation?

Given the nature of the internet I suspect it would be other way round, especially as official reports tend to take 12-18 months. The amount of information, correct or not, that you are presenting would become the received version and any divergences from the official report would be seen as a cover up by those who lack the patience to wait for the official release.
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Old 18th Dec 2016, 14:02
  #936 (permalink)  
 
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Too many people inferring what happened from limited, low accuracy information and from unsubstantiated references.
The key to understanding why this accident occurred, which may provide value to future safety, is by considering a range of possibilities (irrespective of any official report), starting from a view that the crew were trying to do a good job.
They did not set out to kill themselves.

The departure fuel load may have been insufficient for the plan, but there was probably an unrecorded plan to make an en-route tech stop to refuel. What aspects could have affected the decisions related to this.
Was the departure fuel as stated, were the indications correct, were there gauge errors or MEL items, or possible fungal fuel contamination which can give erratic fuel indications.

If the en-route refuel option was rejected then what influenced the decision; fuel gauging issues as above or mistaken use of of the fuel planning page on the GNS. Who made the decision, were they aware of the pitfalls of the planning page or gauging inaccuracies.
If the decision was made to press on, then why no change of plan when a preceding aircraft required priority and the crew were requested to hold.

The easy view in hindsight is to blame the crew, but the balancing view is that the crew may have believed that the fuel state was sufficient; if so, why.
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Old 18th Dec 2016, 15:38
  #937 (permalink)  
 
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fungal fuel contamination which can give erratic fuel indications
It can????

The easy view in hindsight is to blame the crew
Who on earth else is involved? Crew ordered the fuel. Crew were happy with it even when questioned. Crew did not divert. Gauges??? This wasn't a minor 100Kg infraction of min flight fuel for God's sake!
I know there is a stubborn resistance here to accepting that pilots can screw up monstrously even when it's plain as daylight but surely this is so clear-cut no one can imagine any outside help was needed in this case?
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Old 18th Dec 2016, 15:49
  #938 (permalink)  
 
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SafetyPee

You really need to wind in the "how do we understand this accident" it might be this it might be that it, wasn't the crews fault some more consultant BS. This was entirely the fault of the man in command!
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Old 18th Dec 2016, 15:55
  #939 (permalink)  
 
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lemme, et al.
Most of the diagrams presented are too simple for this discussion.
Fortunately the aircraft systems were designed to be simple in operation, or as depicted to the crew. Generally you the pilot, had whatever was available / indicated.

If AC1 and AC2 are lost, for whatever reason, then the StBy gen will start automatically; provided it is armed. The crew can override this by manually selecting 'on' or, inappropriately 'off'.
When the StBy generator is running, this section of the green hydraulic system, including hydraulic accumulator, is protected from the rest of the green system.

If the yellow pump fails, then preference is for emergency gear locking and brakes, via the DC pump /accumulator; other services are not available/only available at higher pressures - see engine windmill.
If the green pump has failed then all green services are isolated and unavailable except as for StBy Gen via PTU.

There are a significant number of scenarios for system operation and indication as the engines shut down /fail, but the bottom line is that the crew will have emergency elect instruments, gear free fall and hyd locking, emergency brakes; but probably flapless.

If the gear and flaps were down then more likely this used intermittent pressure from a failing engine or when windmilling at high speed. The engine windmill characteristics involve a relatively fast N1 but slow N2, even to the point of stopping (170kts?).
Hydraulic and elect services require high N2. Normal operations use a flight idle stop.

Flap extension requires elect and hydraulic power. Flap extension takes time, e.g. 0-18, ~ 20 sec.
Without elects, flap position indication is not available, thus crew have to respect airspeed according to the last indication (not selector handle) or the flap position indicated on the wing markings as seen from the cabin (requiring a torch?).
The air brake will 'blow back' towards closed, according to airspeed.

Irrespective of rudder fixed angle or spoiler float, flight control should not be an issue, (some views were that the aircraft was easier to fly without spoilers!). Please avoid the auto systems view 'speed on elevator'; pilots 'fly' an aircraft to achieve an objective, even though the objective may be incorrect.

Some of the calculated speeds appear very slow for what could have been a low or zero flap setting. Thus unless the flaps were selected before all power loss, it would be more consistent speculation to consider stall or near stall conditions.
From deep and failing memory, I recall that the stall warning was available on essential AC and possibly emergency DC.

Other aspects to consider should include resetting/checking the st by altimeter pressure datum, instrument flying accuracy using st by instruments, particularly airspeed ... at night, using emergency lighting.

CAVIAT, any technical inexactitudes above relate to the quest for simplicity; particularly where the simplest view of an accident is often correct.

flynomore; fungus, yes it can, first hand experience of gauging problems, world wide; and corrosion (Columbia!). Also there were reports of possible fuel pump blocking and engines stopping - far east.

Blame implies error or irrational decision and action, for which I prefer more modern views of 'error'.
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Old 18th Dec 2016, 16:56
  #940 (permalink)  
 
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Pilot in Colombia plane tragedy that killed most of Brazilian football team 'was not trained properly' - The Telegraph
https://apple.news/Abrq6ZRpqS3C-WXCoq2yi-A
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