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Mid-air collision over Brasil

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Mid-air collision over Brasil

Old 2nd Oct 2006, 22:04
  #221 (permalink)  
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Senior Dispatcher;

Thanks for the link. They're excellent photos. Wonder where the original ones showing the vertical stab might be...Still wondering if the wreckage is separated by a substantial distance...

Sunfish;

Now that the photos show more of the jungle "ahead of" and "behind" the wings, where is the rest of the fuselage?....
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Old 2nd Oct 2006, 22:04
  #222 (permalink)  
 
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Originally Posted by mini
How is the timebase of data recorders "set"? i.e will it be possible to synchronise events downloaded from the data recorders from both aircraft?
A GMT/UTC is recorded from either the Capt's Clock, ACARS, or an internal clock on the Data Acquisition Unit. However, synchronization will probably be done based on ATC tapes and radio-keying parameters from each aircraft.
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Old 2nd Oct 2006, 22:04
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Grrr

How can two aircraft collide considering all the 'in built' safety contained within two brand new airframes? Add to the equation, within extremely 'quite' airspace compared to Europe and North America?

If this was a freak chain of events culminating in such carnage, those involved were shockingly unlucky.

For whatever reason, TCAS/ACAS has not prevented a mid air collision, why? A question no doubt on the lips of many folk?

A glancing blow over millions of square miles that is just jungle.
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Old 2nd Oct 2006, 22:12
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Originally Posted by Checkers
However, synchronization will probably be done based on ATC tapes and radio-keying parameters from each aircraft.
In this case would it seem likely that the initial contact event itself will provide one clear synchronization point?
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Old 2nd Oct 2006, 22:26
  #225 (permalink)  
 
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My 2p worth

I may not be an ATPL, but I have been a licenced engineer on the 737 and EMB135/145 for a good few years now, and so if I may, I'd like to put forward my theory about all this. Just to see....

I think that the 737 was in a turn to the right, possibly an avoidance turn iaw aviation practice. I think the EMB stab tip struck the l/h wing inboard / #1 engine area, causing substantial damage to it. This led to either structural faliure of the engine pylon, or the engine loads generated allowed it to seperate as designed. The winglet of the EMB tore a hole in the underside of the 737 causing a decompression.

The upset of the 737, combined with the decompression led to loss of control of the aircraft and subsequent overspeed, which is why the gear was lowered by the crew in an attempt to create a bit more drag to slow their descent. The aircraft eventually broke up mid-air and the centre section fell upside down vertically into the jungle.

This would explain the trees around it being intact, ie: no forward speed on it, and also the fact that the wing tank access panels on the l/h wing appear to have suffered more than the opposing side (being blackened from maybe a post crash fire, or possible fire when the wing was damaged?). Obviously it is a distinct possibility that the damage to the leading edge and pylon area of the left wing were caused when it hit the forest, but it may be the case that the #2 engine has departed the aircraft in the designed manner during the uncontrolled descent, ie: the rest of the wing area around the pylon is undamaged, but the area of the #1 looks far worse.

Not putting this out there as the ultimate truth. Just wanted some rational arguments against my theory to help my understanding.
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Old 2nd Oct 2006, 22:45
  #226 (permalink)  
 
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Assuming that the fuselage has been found any initial pictures might be too distressing for immediate publication and nothing is likely to be available until the area has been sanatised.
Also to find anything it is virtually necessary to first fly immediatly over it and then lower a number of chain saw operators.
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Old 2nd Oct 2006, 22:53
  #227 (permalink)  
 
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From Checkers "A GMT/UTC is recorded from either the Capt's Clock, ACARS, or an internal clock on the Data Acquisition Unit. However, synchronization will probably be done based on ATC tapes and radio-keying parameters from each aircraft."

Wouldn't it make sense to have data recorders take their time stamp from the GPS equipment?

PS, I haven't sussed how to do the quote thing...
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Old 2nd Oct 2006, 23:02
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what follows is something quoting an article in a south american newspaper...if true, it makes some sense

also, being granted such a large altitude for enroute is sometimes known as a "bock altitude" clearance. ie: maintain block Fl350-FL390.

read on.

ouch if true:




Rio de Janeiro - A lack of dialogue between two control towers was likely to blame for Brazil's worst ever plane crash last week in which 155 people died, the Brazilian daily O Globo reported Monday.

The mid-air collision between a Boeing 737-800 and a smaller twin- engine plane occurred because both machines flew into a so-called border region in the state of Para which was jointly controlled by two towers, O Globo reported citing an anonymous official in Brazilian air traffic control.

The two control towers did not speak to each other about the planes entering the same airspace and offered similar flight altitudes to their respective planes, thereby causing the crash, according to the report.

The US pilot of the smaller Embraer Legacy plane managed to make an emergency landing at a military landing site in Para.

Rescuers said there was no hope of finding survivors as they began the arduous task of removing bodies from the crash site of the Boeing plane, whose wreckage was discovered early Saturday in a remote, heavily forested area of the Amazon.

Brazilian President Luis Inacio Lula da Silva called for three days of mourning Saturday.

Air traffic control in Manaus allegedly suggested the Boeing maintain a flight altitude of between 35,000 and 39,000 feet, while the tower in Brasilia recommended an altitude of 37,000 feet for the Embraer Legacy flying in the opposite direction.

A full investigation into the cause of the accident would take about three months, given the difficulty of reaching the crash site, the authorities said.

The worst previous aviation accident in Brazil was in June, 1982, when a Boeing-727 of the Vasp airline crashed into a mountain in the north-eastern state of Ceara, killing all 137 people on board.
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Old 2nd Oct 2006, 23:22
  #229 (permalink)  
 
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some news.

-gol 737 cvr and fdr have been found late this afternoon.
-legacy crew are now not allowed to leave brazil and their passports were apprehended
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Old 2nd Oct 2006, 23:42
  #230 (permalink)  
 
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It appears some bodies were found in another section of aircraft 1km away...

http://g1.globo.com/Noticias/Brasil/...1-5598,00.html
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Old 3rd Oct 2006, 01:48
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I heard another airline report my position over Swan Island in the carib just north of Nicaragua one minute from my position time, same altitude, IFR, and asked him his heading and continued knowing he was not on my wing. That was before GPS. I wish we could have those several mile errors now after this incident. The big sky theory doesn't work any more with GPS. I used to suggest to my students to not fly right on the centerline of an airway to avoid conflicts back when I was instructing. That is where everybody else is.
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Old 3rd Oct 2006, 01:50
  #232 (permalink)  
 
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Originally Posted by mini
From Checkers "A GMT/UTC is recorded from either the Capt's Clock, ACARS, or an internal clock on the Data Acquisition Unit. However, synchronization will probably be done based on ATC tapes and radio-keying parameters from each aircraft."

Wouldn't it make sense to have data recorders take their time stamp from the GPS equipment?

PS, I haven't sussed how to do the quote thing...
It depends what recorders you have got hold of and which type they are. In general, there may be a timestamp at the start and then the recorders all seem to run at slightly different rates if they are the older generation, say 1 in 60 difference, so you get 59 to 61 second minutes. You can work out relative speeds and then timestamp with the same ATC transmission. They you have to coordinate all the different ATC clocks etc.

Having got the reference time frames, then you need to work out when each data block was obtained, as the time that it writes to the memory or tape can be different. There could be a significant difference between each vital parameter here.

It can be quite a job just doing this part, without any analysis whatsoever.
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Old 3rd Oct 2006, 01:54
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Mini:
The recorders get their time information from the Captains clock in the NG. The Captains clock time comes from the GPS system.
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Old 3rd Oct 2006, 03:11
  #234 (permalink)  
 
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Joe Sharkey's account in the October 3th NYT....

Riveting, absolutely riveting....

http://www.nytimes.com/2006/10/03/bu...pagewanted=all

Last edited by SeniorDispatcher; 3rd Oct 2006 at 05:41.
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Old 3rd Oct 2006, 03:25
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Further to Senior Dispatcher's post above, the Globo article quotes Brazil's defense minister as informing that 100 bodies were found in the "tail section" of the aircraft 1km away from where the wing centre section fell. No precise definition of "tail section" is given; it could be most of the fuselage including the over-wing part which does not seem to be connected to the wings in the photographs thus far released. 100 out of 153 in the main cabin may seem like a lot but it could also turn out to be a clue to what happened to the Gol aircraft immediately after the collision, e.g. the effect of centrifugal force in a spin.

Woomera, I'll go with RiverCity's interpretation of "living on borrowed time". And it doesn't seem at all unreasonable to ensure the Legacy crew stick around until their role in events is established.

A few personal impressions: one, that Gol's crisis management has been excellent, the airforce are doing a good job of informing and ANAC (Brazil's equivalent to CAB) are too new in the job to be more than a hindrance. Two, that cause is rapidly narrowing down to lack of ATC coordination. I do think all the basics of this accident will be known in well under three months.
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Old 3rd Oct 2006, 05:37
  #236 (permalink)  
 
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Joe Sharkey's account in the October 13th NYT....

Riveting, absolutely riveting....
Obviously, you meant the October 3 NYT... I agree...
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Old 3rd Oct 2006, 05:39
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Lightbulb

Mr.Sharkey's account of events as experienced from his perspective is quite a read indeed. His description of his interaction with the flightcrew and fellow passengers is completely consistent with normal flying interupted by (to them) a completely random and unexpected event. His visit to the cockpit, and recollection of the idicated altitude of 37,000' moments before the collision is interesting. I presume he is well aware of the import of that statement.

On a related note, I was unaware that flight over the Amazon region is still conducted at non RVSM flight levels for direction of flight. Now I know. I tend to agree with some other posters that a "tipping point" has been reached in the matter of the "cowboy antics" theory of this accident. The recovery of the data from both aircraft's data and voice recorders will put the final nail in that coffin and finally put that irresponsible and inflammatory rumor to rest.

Once it has been established just who was cleared to do what by whom, the matter of the TCAS and what, if any warning was or was not provided to either or both crews in time to avoid a collision will become a primary matter of focus. If indeed no warning was recieved by either crew, the angle of the sun probably provided the GOL crew the best opportunity to see the other aircraft, perhaps indicating that a last second avoidance maneuver was attempted, consistent with one of the theories regarding the relative attitudes of the aircraft at the point of collision. Time and investigation will tell.

As to the matter of the main gear position after the Boeing came to rest, Examination of the uplocks themselves will likely indicate whether they simply failed in overload or were released by other means. The CVR may not be easy to listen to for those unfortunate enough to find it their duty. I have heard just one such unedited post-crash CVR audio and would not care to repeat the experience. I tend not believe that the currently available evidence supports that any contact took place between the Legacy wing and the Boeing cockpit. I picture them fighting to the end, however long that took. Whoever listens to that audio will likely be the first to know.

The NTSB has today assembled a team consisting of three NTSB accident investigators, and representatives of the FAA and the Boeing company to assist in the investigation, in accordance with ICAO procedures.

This will certainly be worth following. The spectre of mid-air collision should always be in the minds of aviators. Events like this serve to drive that point home. Whatever happened to cause this accident, I wanna know.

Respects to all the victims of this tragedy,

Westhawk
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Old 3rd Oct 2006, 07:16
  #238 (permalink)  
 
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Beginning to look a bit like either no tcas or RA not complied with...reports the 737 was assigned a block altitude 370-390 emb 370.. adjacent controller handling the emb not aware of this conflict.... uberlingen revisited???
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Old 3rd Oct 2006, 09:27
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From the news:

Recovery teams in Brazil have located both the cockpit-voice and flight-data recorders from the Gol Boeing 737-800 which crashed in the Amazon on 29 September, apparently after a mid-air collision with a corporate jet.

Military personnel have been concentrating on removing the remains of victims from the crash site – near Peixoto de Azevedo in central Brazil – to the air base at Cachimbo.

But the Brazilian ministry of defence, aeronautics command, adds: “The voice recorder and digital data recorder of the Gol Boeing 737 have also been found – these will be sent to the accident inquiry commission to be analysed.”

None of the 155 occupants of the aircraft, operating domestic flight 1907 between Manaus and Brasilia, survived the crash which appears to have followed a mid-air collision with an Embraer Legacy business jet.
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Old 3rd Oct 2006, 10:34
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Ref what if RA Climb is issued when already at max FL.
Although I'm not an avionics engineer but I did occassionally whitnessed TCAS programming (because most or all TCAS processor units are out-of-box devices they need to be programmed after installation to particluar airframe to reflect actual indicators/controllers/transponders/etc config). One of the settings should be entered at programming stage there is AIRCRAFT MAX FL. Normally it would be the max certified FL. As I was told by engineers, this setting is to prevent TCAS to issue RA Climb when aircraft is already at max FL. So I believe this answers the question in general, however TCAS knows nothing about real time FL limitations due to weight or temperature.
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