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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 21st Dec 2016, 10:35
  #981 (permalink)  
 
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lemme, your speculation increasingly relies on assumptions of what the crew were thinking; their plan at the time, not ours with hindsight.
For future safety it's good question why did an aircraft with a reasonable chance of achieving some form of landing, ended up on a hill side; particularly when the industry recalls at least two previous events with a successful outcome (Gimli, VIE), involving higher tech aircraft, in a similar technical scenarios, and of the same certification basis.
The degree of success depends on being on/off an airport, the distance vs altitude available, weather, and terrain. The latter two in this event were unfavourable.

A pilot might be more interested in conserving altitude, not descending early to meet some objective, particularly if this is defined by range information which the crew may not be aware of (no DME display). Also, the speculative 3-4D navigation assumed that the crew had accurate altitude information; this required resetting the StBy altimeter scale; the alternative is ILS GS. Is there any evidence that ATC broadcast the airfield datum.

I doubt that the crew would recall the glide ratios for configuration; I would not recall 15:1*, but for other reasons 6:1 is remembered, 1nm/1000 ft (note range requirement). Thus a plan might involve stretching the glide until committed to the final configuration selection.

Emergency navigation information is shown overlaid on the StBy attitude gyro (not IRS) as a two axis cross pointer. Without care this display could be interpreted as a FD command.
With a VOR tuned the lateral axis would provide directions to the ground station; I cannot recall what the vertical axis displays, but if shown and followed as a FD command, then a null reading could result in unmonitored flight into terrain. AFAIR there is no range information.
With an ILS tuned then both axis would be valid, but the aircraft would have to maintain flight at or above the GS. If the display was used as a FD command with the aircraft closing from above or being on the GS, then there would be a point at which the aircraft would be unable to maintain both speed and GS if fully configured (but 15:1 clean or low flap, low wt vs high alt, might be an interesting challenge).


* 20 years on type, including steep approaches.
The 146/RJ aircraft types have never to date, suffered 'deep stall'. The 'straight' wing design has a conventional stall which is forcefully assisted with a stick push for the manual controls
.
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Old 21st Dec 2016, 12:38
  #982 (permalink)  
 
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Safetypee, I think the stby attitude nav display is for ILS only. If ILS is not tuned then the bars move from view. The #1 DBI is available at the emerg power level with a bearing pointer for tracking a VOR or NDB. The possibility of treating the stby ILS bars as a flight director is very real and could easily lead to trouble.
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Old 21st Dec 2016, 13:24
  #983 (permalink)  
 
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Thanks for responding.
@YRP
But A0283 surely any root cause(s), if there are multiple causes for this particular accident, had to be before the departure. … But anything that happened after they pushed the throttles forward on departure is just reaction not cause.
That depends on definitions. Some may find that academic, but aerospace is ‘art and science’ if we like it or not. If you use the word “cause” then you would have to define the difference between root and general causes. Root suggests main or single. If you use the word “cause” at all, then in my perception an accident always is a series of (minor, medium, major,...) causes. A cause would then be something going wrong that is not limited (minor,medium, major,...) by the ‘aerospace system’. There are a lot of ‘limiters’ in the system, examples are redundancy, training, experience, procedures, rules, etcetera. For an accident to happen you need multiple causes with multiple limiters failing along a specific timeline. Based on that, your “reactions” are causes. Also, reaction may not be a conventient word. In some cases accidents happen because people/systems react, but in others because they do no react. So in general you will have multiple causes even after you push the throttles forward. After takeoff the FO might have said “we will not be able to make it” and say “I take control and we return”. The FO might have reacted to the low fuel warnings (if they got them) by a Pan or Mayday... etcetera. In each case there would probably be serious @#$%, but not an accident.

@SteinarN
Regarding the root cause, I would say it is simply that the airline company and the pilot/owner was a "cowboy" totally neglecting any prudent planning and industry standard for flight planning, safety margins, CRM and whatever. So, the root cause goes well before what happened on the departing airport.
If it turns out that the company/pilot was a ‘cowboy’ then big questions would be how did they get in that position, how did they stay in that position (introduce Venezuela), and even why they and their crews survived for such a long time. Which means you also have to look at the multiple causes and limiters in the years before and on the pre-departure side. Indeed well before what happened on the departing airport.

@Finally, accident reports generally talk about cause(s) and contributing factors. In some cases the investigation runs into issues that are neither but should be mentioned. In this case doubts about the quality and consistency of the various AIP maps should be mentioned.
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Old 21st Dec 2016, 14:35
  #984 (permalink)  
 
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Thanks Aerocat, aah the S2 (never had the pleasure).
You are correct, just found my reference. This makes sense with the VOR as bearing information, the ILS as a beam.
The GS display had conventional scaling, and presumably suffered beam 'reversal' at excessively large deviations (as for a 6:1 glide).
Also was the DME powered as part of Nav 1 and displayed on the DBI?

Oh for a list of all those forgotten things ... at least I know that they are forgotten, ... I think.
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Old 21st Dec 2016, 20:01
  #985 (permalink)  
 
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lemme's analysis is some of the only intelligence on this entire thread and I've been enjoying it. If his speculation is a waste of time, then entire thread is certainly a waste of time.

Good stuff lemme, keep it up.
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Old 22nd Dec 2016, 00:12
  #986 (permalink)  
 
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I think the issue with "Lemme's" post, and I am not criticising him for what he has written, but it the professional commercial aviation world it's a pointless exercise.

You are not supposed to in Commercial aviation rely on the fact that you "might" be able to glide in to the runway so you can safe fuel, and extend your endurance.

I believe all this speculation if they could have made it in without fuel, shows that there are many "flight sim" pilots here trying to work out some absurd theories.

Medellin was they final destination, they should have arrived Medellin with "minimum" fuel to an alternate + 30 minutes final reserve. The fact is that they knew already at departure that they did not have this, makes them criminals, and that they did not divert them en-route makes them criminals.

When they started their descent into Medellin, they did NOT have this fuel, at this point when they was aware of this, any PROFESSIONAL pilot would have declared a fuel emergency.

Of course that would have meant they would have had to answer to the Colombian authorities why they left with insufficient fuel, and why they did not divert en-route.

I guess they took a massive gamble, and wanted to avoid a Colombian jail (which they deserved), and instead got the death penalty.

The tragedy is all the innocent people they took with them on their narcissistic final flight.

It's irrelevant if they could have reached the runway from their current position when they ran out of fuel, even speculating about this is just childish.

How do you expect someone who have already committed the most basic errors and ignored the most basic of all regulations, to suddenly have the skill set and mental capacity to glide the aircraft without fuel.

Fact is that he should NEVER have been in that position anyway. This is not a scenario I would expect ever to need to practise, as you should never get yourself into this situation from start anyway.
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Old 22nd Dec 2016, 08:55
  #987 (permalink)  
 
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How do you expect someone who have already committed the most basic errors and ignored the most basic of all regulations, to suddenly have the skill set and mental capacity to glide the aircraft without fuel.
I think the point is that even after all that - knowing that even if all went well they would arrive with dry tanks - nonetheless they seemed unprepared for actually running out of fuel, were apparently caught out by it, and look as if they handled it badly. They appear to have had no Plan B even though it was highly probable that they'd need it.

That's Denial with knobs on. Perhaps the Captain really was a very good handling pilot who, based on his overconfidence, decided his exceptional skills could increase the flight's profitability by overflying the refuelling stop, and then simply refused to believe it when they actually ran dry. [I don't really believe missing the stop was to avoid loss of face. The football team had already changed travel plans just to be able to use this airline. I don't think an additional stop would have been likely to put them off.]

It wouldn't be the first time this sort of thing has happened. Aerosucre could easily turn out to be something similar.

It appears to me that Lemme thinks the final report might not be entirely objective, and wishes to try to establish as disinterested and factual a narrative as he possibly can first, perhaps to hold some feet to the fire. That's understandable. I've read similar sentiments concerning Metrojet and Egyptair, among others, and I daresay some Aerosucre people at this moment might well be wondering how best to cover their backs.
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Old 22nd Dec 2016, 09:24
  #988 (permalink)  
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Iron dick :
It appears to me that Lemme thinks the final report might not be entirely objective, and wishes to try to establish as disinterested and factual a narrative as he possibly can first,
Using FR24 ? and giving on a plate lawyers arguments to fool victims families and try to nail some people? very dangerous game . This is what I was trying to warn lemme about , but he is on a crusade... words won't stop strong believers.

Same for Aerosucre, everyone mentions overweight and start hammering the crew. .But no-one knows for sure , could also be an engine failure past V1 on a very short runway on a hot day...
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Old 22nd Dec 2016, 09:35
  #989 (permalink)  
 
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Same for Aerosucre, everyone mentions overweight and start hammering the crew. .But no-one knows for sure , could also be an engine failure past V1 on a very short runway on a hot day...
It may well have been an engine failure, but surely their limited Mtow should have factored this in. If an engine stops above V1 you'd be expected to continue the takeoff and have the required performance to get airborne before you run out of runway. They clearly didn't achieve that, so if it was just an engine failure I think you can still safely conclude they were indeed too heavy!
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Old 22nd Dec 2016, 09:40
  #990 (permalink)  
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H Peacok : Good point . yes, you are correct .
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Old 22nd Dec 2016, 09:50
  #991 (permalink)  
 
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Part of the issue with Aerosucre is that there is footage of a take-off from the same runway on a different day and they very nearly did the same thing. That would suggest that they were playing with fire and got burnt.
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Old 22nd Dec 2016, 10:13
  #992 (permalink)  
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Trial by You tube !
Well " Comparison is not reason " always hammered my philosophy teacher in high school.
I think we are entering a era where everything is instantly visible on FR24, Live ATC leak, You tube, Twitter etc.. and everyone wants to play judge and jury. Getting closer and closer to public mobbing with no chance to reply.
Then come people like lemme who think he knows and brings this to yet another level. And the someone here ( Iron Dick) even suggesting the reason for doing this is that he thinks the final report will not be objective! but lemme suggestions based on FR24 are?
That worries me . But maybe I am just getting too old for this .
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Old 22nd Dec 2016, 10:19
  #993 (permalink)  
 
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It may well have been an engine failure, but surely their limited Mtow should have factored this in. If an engine stops above V1 you'd be expected to continue the takeoff and have the required performance to get airborne before you run out of runway. They clearly didn't achieve that, so if it was just an engine failure I think you can still safely conclude they were indeed too heavy!
Or its an engine failure and the remaining donks weren´t up to it...
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Old 22nd Dec 2016, 10:28
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Originally Posted by ATC Watcher View Post
AerocatS2A :

Trial by You tube !
Well " Comparison is not reason " always hammered my philosophy teacher in high school.
I think we are entering a era where everything is instantly visible on FR24, Live ATC leak, You tube, Twitter etc.. and everyone wants to play judge and jury. Getting closer and closer to public mobbing with no chance to reply.
Then come people like lemme who think he knows and brings this to yet another level. And the someone here ( Iron Dick) even suggesting the reason for doing this is that he thinks the final report will not be objective! but lemme suggestions based on FR24 are?
That worries me . But maybe I am just getting too old for this .
Well put, I think we need to start a club for us oldies
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Old 22nd Dec 2016, 10:58
  #995 (permalink)  
 
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Iron Dick?

Er...

Not to drift the thread, but:

Trial by You tube !
Well " Comparison is not reason " always hammered my philosophy teacher in high school.
The YouTube stuff is clearly documentary - it wasn't generated by a flight sim - and shows a succession of takeoffs that would brown most peoples' trousers. No matter why Aerosucre were doing that, you'll get away with it until one day you won't.

Then come people like lemme who think he knows and brings this to yet another level. And the someone here ( Iron Dick) even suggesting the reason for doing this is that he thinks the final report will not be objective! but lemme suggestions based on FR24 are?
I think we're all familiar with the 'whitewash'. It appears to me that Lemme thinks (note the language construction) that by using new sources of 'independent' data he can construct a narrative that makes a whitewash less likely, or easier to invalidate, than was possible before the advent of services such as FR24. I don't have the knowledge to judge whether or not he's made a success of it.

That's all.
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Old 22nd Dec 2016, 11:05
  #996 (permalink)  
 
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Originally Posted by ATC Watcher View Post
AerocatS2A :

Trial by You tube !
Well " Comparison is not reason " always hammered my philosophy teacher in high school.
It's a datapoint and a thorough investigation would take it in to account and give it the weight it deserves. For us plebs on the sideline we don't have access to much of the information and so perhaps we give the datapoint too much weight, or maybe we are right on the money.

I think it is normal for an investigative team to ask "what normally happens in this operation?" IF the marginal take-off by the previous Aerosucre flight is what normally happens then it is not very surprising that they eventually crashed.

Likewise we might ask "how does LaMia normally operate their long distance flights?" If it is found that there was a culture of eating into their reserve or not planning for any reserve at all then again, not very surprising that they eventually run out of fuel.

I don't have an opinion on what Lemme is doing. The only thing I thought when I read some of his material is that he has too much time on his hands, but I understand that people develop an interest in things that don't interest me to the same extent.

I would rather see someone put some critical thought into their amateur sleuthing the way Lemme is, rather than the useless dreck that the more ignorant put out.

For what it's worth I think the comments about objectivity are the wrong way around. Lemme wants to investigate as much as he can with publicly available information and doesn't want the official report to bias his own work, in other words, he's not worried about the official report being objective, he's worried about his own objectivity being biased by knowledge of the final report. Basically he doesn't want to know the answer before working it out for himself.

Another poster commented that Lemme's interest is academic, and I think it is exactly that, a very academic interest in accident investigation via publicly available information.
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Old 22nd Dec 2016, 11:56
  #997 (permalink)  
 
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I think we're all familiar with the 'whitewash'. It appears to me that Lemme thinks (note the language construction) that by using new sources of 'independent' data he can construct a narrative that makes a whitewash less likely, or easier to invalidate, than was possible before the advent of services such as FR24. I don't have the knowledge to judge whether or not he's made a success of it.
Sorry, but I strongly disagree with that point of view. Lemme's narrative, based as it is on incomplete data, is more likely to lead to cries of whitewash when the official report comes out, if it contains anything that doesn't agree with his analysis.

That isn't a direct criticism of his work but an observation on the nature of the internet. Nobody wants to wait, people want "facts" now, flawed or otherwise. Lemme's narrative is already being read by some as "the only true story" and so anything that comes later contradicting this received wisdom will be seen as a cover up.

Now where do I pick up my old git t-shirt?
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Old 22nd Dec 2016, 20:15
  #998 (permalink)  
 
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Don`t know how to put one of those thumbs up symbols, so instead I say spot on to alemaobaiano.
The "true story", if it ever comes to light will not be found in the mangled wreckage, the debris lying on the mountainside nor the radio signals and radar traces. And if it did, am certain it will be of Biblical age and proportion. Much like the Mt.Erebus and the Ermenonville Turkish DC10 disasters.

Alemaobaino could you spare one of your old git-t shirts, mines a bit threadbare.
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Old 22nd Dec 2016, 20:21
  #999 (permalink)  
 
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Hey whats all this talk of whitewash? Thats the stuff of Politics, Governments, Enquiries etc, dedicated to finding someone, anyone, on whom to pin the blame. I dont ever recall hearing that said of an ICAO-mandated accident report only dedicated to digging out the facts and causes and coming to meaningful conclusions from which something can be learned. I am expecting Colombia's reports to be the usual high standard.
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Old 22nd Dec 2016, 20:39
  #1000 (permalink)  
 
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Waiting...

Originally Posted by portmanteau View Post
Preliminary report will be published on December 22 says Director of Colombia Civav.
Now.? Looking.. 😳
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