Talk:Gol Transportes Aéreos Flight 1907/Archive 4

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Issues not answered

Please, there are some fundamental issues not explained in this article, and could be better written in order to a non expert person, like me, understand it.

• It says: "At 16:02, seven minutes after crossing the Brasilia VOR, secondary radar contact was lost with the Embraer, thus stopping the display of the Embraer's reported altitude (Mode C) on the controller's radar screen". Well, Brasilia is the Brazil's capital; it is not in the middle of Amazon and it is a very large city. How ATC lost radar contact when Legacy was over Brazil's capital? This is hard to believe and should be better explained. And then it is said: "At 16:59:50, about three minutes after the collision, Amazonic Center started to receive the Embraer's secondary radar reply, with its correct altitude and last assigned code". This is crazy! In Brasilia they lost radar contact, and then in the middle of Amazon, after the accident, they recover radar contact? I just don't understand.
• NTSB says "The evidence collected during this investigation strongly supports the conclusion that this accident was caused by N600XL and GOL1907 following ATC clearances which directed them to operate in opposite directions on the same airway at the same altitude resulting in a midair collision". How ATC directed them (Legacy) at the same altitude if there was not radar contact? How ATC can direct an aircraft without knowing where it is flying? What I can understand is that ATC lost control of aircraft and not that they "direct them to operate in directions on the same airway at the same altitude". This seems different issues to me. ATC direct them in blind? As far as I can understand, ATC sees two aircrafts approaching in their radar screen and then separate them. If they don't see one of them, how can they separate them? Guessing?

I think that those issues must be better explained here. Only experts can understand this article. Lmc9 (talk) 00:50, 10 December 2009 (UTC)

Note: Lmc9 was confirmed to be a sockpuppet of User:Sdruvss
Crum375 (talk) 23:47, 1 January 2010 (UTC)

Note: I confirm all I wrote. "Now every one who, in the domain of ideas, brings his stone by pointing out an abuse, or setting a mark on some evil that it may be removed--every such man is stigmatized as immoral" (Balzac).XX Sdruvss 16:13, 2 January 2010 (UTC)

Lmc, you are welcome to read the CENIPA and NTSB reports, which are very detailed, and contain answers to all your questions. Regarding your first question, you have to separate primary radar from secondary radar contact. Primary radar is a direct physical echo reflected from a target back to the radar antenna, and is generally less accurate and sensitive than secondary radar. Secondary radar is an indirect "echo" emitted by the aircraft's transponder when it detects an "interrogation" signal emitted from the ground. In the case of the Embraer aircraft, its secondary signal was lost over Brasilia, in all likelihood because the on-board transponder stopped working. CENIPA hypothesizes this was because the Embraer pilots apparently (most likely accidentally) switched off their transponder, and didn't notice this until after the collision. NTSB also believes the Embraer transponder was most likely switched off, but does not provide a definitive hypothesis as to how or why. After the collision, the transponder started emitting its signal again, which made it appear on ATC's radar screen. Distance from the ground radar facility was apparently not a factor. As far as NTSB's conclusion that the two aircraft were sent on a collision course by ATC, you seem to believe that ATC can only direct aircraft when they are visible on radar, but this is often not the case. For example, over oceans and other areas with poor or no radar coverage ATC routinely directs aircraft to fly in specific directions and altitudes without seeing them on radar. This is done by ATC "clearing" blocks of airspace at given locations, times and altitudes for individual aircraft, and it works as long as both ATC and the flight crews do their jobs properly. Nowadays, on-board collision detection and avoidance systems help in reducing collision risk even when one side drops the ball. Crum375 (talk) 01:28, 10 December 2009 (UTC)

Crum375, thank you very much for your explanations, but it seems to me that you are an “expert” reader of those huge reports, and by your high quality comments, you do not even need Wikipedia to understand this accident. It’s impossible to us (me), that just travel by planes understand those technical reports. I think that Wikipedia, as an online encyclopedia, should use a language and explanations that an “average” reader can understand it, something like “Gol flight 1907 collision for dummies”. I think, just an opinion for the guys that write here, that they should read your comments posted here and them complete the article, explaining those issues. But one thing I don’t understand in what you said (don’t think I am too stupid, but I’m not an “aircraft expert”). You said “This is done by ATC "clearing" blocks of airspace at given locations, times and altitudes for individual aircraft”. How ATC clears blocks of airspace for individual aircraft if they don’t see them in radar screen? It is said here it “disappeared completely from the radar screen”. How can they separate them without seeing them in radar screen? How ATC knows where is aircraft? How they know that the aircraft have not crashed? How they know that another aircraft that has just departed is not crossing its way? How they know that an aircraft is not in the wrong way by an instrument failure? I’ve read somewhere that ATC amends aircraft altitude all the time, asking them to climb and descend, due to winds, weather and other aircrafts that crosses their way. How they can amend altitude without knowing where is aircraft? What for radar is used? How ATC can do their work without radar? All these issues are not answered in this article. Thank you again, but I think that this article misses a lot of thinks. We read it and keep not understanding why this tragedy happened. Lmc9 (talk) 11:37, 10 December 2009 (UTC)

Lmc9, WP articles try to focus on the specific topic they are covering, without going into great detail about the generic underlying topics. If we did go into such detail, it would make the article much harder to read for most people who are only interested in the specific article topic. This is why we refer readers of articles to other articles, both on and off WP, for further reading and more in-depth information. In this case, we have links to air traffic control and air traffic controller. If you read these articles, as well as the sources which are linked to them, you'll have a better understanding of the underlying technologies and methods of ATC traffic separation and control. The bulk of your questions seem to be focused on how ATC operates, with and without radar, and are not specific to this article. As I noted above, ATC relies on flight crews (and vice-versa), and aircraft cross the world's oceans and other remote areas every day without radar coverage (although nowadays collision prevention systems are also helpful as backup). Historically, close radar control, as we have today in the busier areas, came into use after many years where aircraft were separated without radar at all, often with very limited radio communication (and with no collision prevention instrumentation), especially enroute. Crum375 (talk) 12:04, 10 December 2009 (UTC)

Thanks Crum375. Now I see that you have a lot of comments here, and it is easy to you to understand all those issues. My comment was just a feedback to people who writes Wikipedia, and it is not mandatory that volunteer people who writes articles here uses an approach that I can understand. This is my problem and not theirs. I can’t understand the radar role in this accident. I’ve ever thought that radar coverture played an important role and this was the debate in the media all this years, but the way is written here, it is not important. I will search in those sources why it is not. Thank you again. Lmc9 (talk) 12:50, 10 December 2009 (UTC)

Lmc9, if your search turns up something that you feel needs to be added to (or changed in) this article, please provide your sources and we can discuss it. Thanks, Crum375 (talk) 13:25, 10 December 2009 (UTC)

Dear Crum375, what I didn’t understand in the article, you explained me here in discussion. Perhaps it could be written in the article: 1) Legacy was out of radar because transponder was turned off and not because there was a “black hole” in Brasilia; 2) It is not necessary radar to control aircrafts as I thought. Aircrafts cross the world's oceans and other remote areas without radar coverage. Lmc9 (talk) 16:39, 10 December 2009 (UTC)

Both CENIPA and NTSB, as stated in the article, agreed on the basic facts, and specifically that seven minutes after it crossed Brasilia, the Embraer's transponder stopped functioning and sending a secondary signal to the ground. The Embraer's primary radar signal continued to show up on the controller's radar screen for twenty four more minutes. These points are addressed in footnotes 12 and 13 in Embraer flight and communication sequence. We cannot put this directly in the article without violating WP:NOR (unless a proper secondary source is found), but as I see it, the lack of radar coverage over the Amazon was not an issue or a contributor in this accident. We do have this indirectly in the article, as neither CENIPA nor NTSB cite lack of radar coverage (or other equipment deficiency) as an important contributor to this accident. Crum375 (talk) 21:15, 10 December 2009 (UTC)

Crum, you said that ATC relies on flight crews (and vice-versa). I don’t want to create a debate around this, here is not the place, but it is not completely true. Nobody relies upon anybody ;-) ATC relies on their radar screen. It is the main instrument that verifies that the crew is following the clearance. It doesn’t matter what crew understood and what someone said before, what matters is if they are following what they want. If they are not following due to misunderstandings, they call the aircraft and repeat instructions or amend the clearance. Without radar, ATC cannot do their job and it becomes a guessing game. Controllers have an eye at radar screen and the other at the flight strip. Ocean crossing is another issue. Herbmartin (talk) 20:03, 10 December 2009 (UTC)

Note: Herbmartin was confirmed to be a sockpuppet of User:Sdruvss
Crum375 (talk) 23:44, 1 January 2010 (UTC)

Note: I confirm all I wrote. "Now every one who, in the domain of ideas, brings his stone by pointing out an abuse, or setting a mark on some evil that it may be removed--every such man is stigmatized as immoral" (Balzac).XX Sdruvss 16:13, 2 January 2010 (UTC)

You say "ocean crossing is another issue", but actually ocean crossing is similar to many routine situations around the world on dry land, where planes are outside radar coverage and are still operating under air traffic control (ATC). In other words, although radar is an important tool, it is not absolutely required for air traffic control, and both ATC personnel and pilots are trained to operate in a radar-less environment. Without radar, controllers do rely on the pilots, and the pilots (on instrument flight plans) always rely on ATC. BTW, even in a radar environment, sometimes the altitude readouts (Mode C), or the secondary signal (Mode A or Mode C), are not received by controllers, in which case they still need to rely on pilots to be at the proper altitude. Crum375 (talk) 20:54, 10 December 2009 (UTC)

You said "similar"...

"Air Traffic Control and Radar"

"Every day tens of thousands of people board airplanes to travel from one place to another. These flights, thousands of which take off and land daily, are among the safest forms of travel. Although airplane crashes are tragic and headline grabbing, the fact is the sky is a very safe place to be. But how, with so many airplanes in the air, does air travel maintain such a good safety record? The answer is, in large part, air traffic control, the complex system of directing planes and telling them how high or low to fly, and when and where to land safely. Air traffic control systems rely heavily on radar. [...] The use of transponders increases the detection range of the radar, eliminates clutter interference from other reflectors, and provides a means of aircraft identification and altitude reporting. In the early 1960s the U.S Federal Aviation Administration (FAA) published a national standard for air traffic control interrogators and transponders. By the end of the decade over 200 ground-based interrogators were in use in the U. S and the FAA made it mandatory to equip aircraft with transponders before they could operate in positive controlled airspace at high altitudes and near major airports". ATC relies on Radar and they on transponders and both are fundamental to ATC do their job. Herbmartin (talk) 22:22, 10 December 2009 (UTC)

There is no doubt that radar is an important tool which greatly contributes to safety and efficiency of air travel. But that does not mean that there are no areas around the world, including some in the most developed countries (e.g. in remote regions, lower altitudes and/or near mountainous areas) where there is no radar coverage, and ATC functions just fine. It's like the automobile: it is very useful for transportation, but there are other ways of getting from A to B. Crum375 (talk) 22:38, 10 December 2009 (UTC)

Thank you, HerbMartin. The link between transponder and radar screen becomes understandable and why ATC guessed that Legacy was following their flight plan. Lmc9 (talk) 11:21, 11 December 2009 (UTC)

Note: Lmc9 and Herbmartin were confirmed to be sockpuppets of User:Sdruvss
Crum375 (talk) 23:50, 1 January 2010 (UTC)

Note: I confirm all I wrote. "Now every one who, in the domain of ideas, brings his stone by pointing out an abuse, or setting a mark on some evil that it may be removed--every such man is stigmatized as immoral" (Balzac). XX Sdruvss 16:13, 2 January 2010 (UTC)

Crum, there are more fundamental issues not explained in this article:

• Any pilot knows that aircrafts don't flight towards northwest at odd levels for long distances. As an aircraft fan, a see at FlightAware that there is not a single aircraft crossing America southeast to northwest stabilized at an odd level. The pilots didn't know it?
• Why the Legacy flight plan have a first small leg at 37,000 feet and then a few minutes latter a planned descent to 36.000 feet and then a few minutes later a climb to 38.000 feet? This article should explain these ups and downs. Is this usual? I don't see something like that at FlightAware.
• Then, why ATC changed this flight plan to a single altitude?
• Why the pilots didn't see that transponder was turned off for almost one hour? As far as I know its status is displayed in the aircraft control panel. What the pilots were doing for almost one hour without watching control panel?

Regards, Lmc9 (talk) 15:04, 12 December 2009 (UTC)

Lmc9, don't expect that Crum is here to explain anything. He only select what should be written, and this is a talk page. Please respect the talk page guidelines. Herbmartin (talk) 16:38, 12 December 2009 (UTC)

Note: Lmc9 and Herbmartin were confirmed to be sockpuppets of User:Sdruvss
Crum375 (talk) 23:50, 1 January 2010 (UTC)

Note: I confirm all I wrote. "Now every one who, in the domain of ideas, brings his stone by pointing out an abuse, or setting a mark on some evil that it may be removed--every such man is stigmatized as immoral" (Balzac). XX Sdruvss 16:13, 2 January 2010 (UTC)

Herbmartin, I don't expect that Crum explain me here. I think that this article is incomprehensible. If all the answers are in CENIPA and NTSB reports, it would be enough to put a link to them. The article could have only one line: read the report moron. It is impossible to me to understand all this huge report and understand it. I'm just suggesting that this article includes what reports and other articles say about these issues. If it is not possible, ok, I will read the entire report. Thanks, anyway. Lmc9 (talk) 16:56, 12 December 2009 (UTC)

Lmc9, for flight above FL290 (approx. 29,000 ft), up to about 10 years ago, and in some parts of the world until more recently, aircraft had to maintain 2,000 ft of vertical separation, cruising at "odd" altitudes only. In recent years, Reduced Vertical Separation Minima were implemented, allowing cruise flight at "even" altitudes for properly certified aircraft and crews. Flying at odd altitudes westbound is unusual, but does happen periodically, due to traffic or weather conditions. ATC has the final say about altitudes and routes, and when they clear a flight for a given altitude, the most recent ATC clearance overrides any previous clearances or plans, unless radio contact is lost, in which case special radio loss rules apply. In this particular case, the Embraer crew used a commercial flight planning service to create and file their flight plan for them, and apparently it was that company which created the "strange" proposed flight altitudes. When the Embraer crew got their IFR clearance from ATC before takeoff, they were apparently (and mistakenly, as it turned out) cleared to climb to FL370, with no mention of any subsequent altitude change (which is typically done by adding the words "then as filed"). This error was further compounded when the Embraer crew communicated with ATC near Brasilia, confirming their altitude at FL370, with no mention of any change in clearance by ATC. Since the accident involves living persons — the Embraer flight crew and ATC — we can't speculate about the reasons for ATC's actions, beyond the general statements made by CENIPA and NTSB in their conclusions. Regarding the Embraer crew not noticing their transponder being off, apparently there was no special blinking annunciator light alerting them to the transponder being off. As I understand it, the transponder function on the Embraer is combined and integrated with many other flight instruments (navigation and communication), without a dedicated permanent display, as in older equipment. This makes the transponder's ON/OFF status harder or less obvious to notice, as mentioned in the CENIPA and NTSB reports. This is also the case with the collision prevention system, which relies on the transponder. Under normal conditions, if the transponder is off or malfunctioning, ATC would notice it and request the flight crew to recycle the transponder or switch to a backup unit, but in this case this did not happen, with tragic results. Crum375 (talk) 17:20, 12 December 2009 (UTC)

Crum, thank you, but I think that your explanations could be integrated in the article. It's not my intent to make here a forum, as Herbmanrtin said. But you didn't answer my questions. 1) As I said, even I, as an airplane fan, know that planes don't cross a continent going northwest in an odd level. I observed at FightAware, thousands of flights, and I didn't observe just one. If it happens periodically, it is once in a life. The question was if crew was aware of this issue. 2) The second question was also not answered; it was why that company created the "strange" proposed flight altitudes, with so many climbs and descents. As I said, I also don't observe just one flight plan at FlightAware with planned climbs and descents. 3) If I understood what you said, ATC didn't change their flight plan, did they just omit the three magical words "then as filed" at departure? 4) Why the transponder's ON/OFF status is harder or less obvious to notice? Why, immediately after collision they noticed that it was OFF and not before? Lmc9 (talk) 22:48, 12 December 2009 (UTC)

Crum, if you allow me, I can help you. 1) Crew awareness - CENIPA says that "(...) according to the interviews, the flight crew showed a lack of attention to the flight plan and was not able to interpret the routes and flight level changes prescribed in item 18 of their ICAO flight plan form". According "to the CVR data, the pilots did not make any comments concerning the flight management, such as, for example, the thirty-degree heading change to the left (from 006º to 336º) at the vertical of BRS VOR [Brasilia]. There were no comments about the joining of the new airway, or the possibility of a flight level change. The left turn was made automatically by the autopilot, and the CVR did not record any supervising action by the crew at that moment". And follows "When, at an interview, the crew was asked about having entered a wrong flight level for the heading they were flying, they said it is not uncommon to receive non-standard levels from the air traffic control [indeed, it is very, very uncommon as you can check by yourself, monitoring flights online]. According to them, they were flying en route, under radar contact, and did not receive any instruction from the control unit whose frequency they were monitoring. They were in accordance with the last instructions received". So, apparently they were not aware. 2) Flight plan - The file plan profile had been produced by the software of an American commercial flight planning service program considering the winds aloft available at the several WIND ALOFT charts for the FL300, FL340 and FL390. This is a long story, but making it short, CENIPA says that the navigation presented to crew was rather "unusual". Nobody is able to explain it, because those charts are valid for 12 hours, and they asked the flight plan a few days before departure. 3) Clearance - Yes, it was an ordinary clearance issued by airport towers, but has omitted "then as filed" or also could be said "limit Brasilia". 4) Transponder status not observed - Since the beginning of the recording of the Legacy CVR, the PIC and SIC were together using a notebook to calculate and obtain data of the landing and takeoff performance relative to Manaus. The crew was learning how to use it in the calculation of the aircraft weight and balance. There was a distraction from the focus of the routines relative to the monitoring of the flight progress, which made the crew direct their attention to the search and analysis of the available data relative to the remaining fuel, as well as the information contained in the software of the notebook, during a long time, possibly longer than the one that was recorded in the CVR. Between 19:00:01.5 UTC and 19:01:44.3 UTC occurs the interruption of the transponder transmission. The pilots confirmed that, at this moment, the SIC was with the laptop and worked on it alone during the two minutes; he neither passed it to the PIC, nor placed it next to the panel. The PIC, who had declared in his last interview not recalling exactly what he had been doing during this period of silence, may have been still focused on their calculation of the fuel for the departure from Manaus (seemingly) to check the current fuel status of the N600XL. The subject of the drawing of the attention of the crew to it was only solved (closing of the notebook), approximately 11 minutes after the transponder had stopped transmitting. There was a distraction from the focus of the routines relative to the monitoring of the flight progress, which made the crew direct their attention to the search and analysis of the available data relative to the remaining fuel, as well as the information contained in the software of the notebook, during a long time, possibly longer than the one that was recorded in the CVR. They didn't observed the instruments, because during this long period of time, they were working with a notebook in the cockpit, which is prohibited by many commercial airlines and even led to FAA revoke the pilots certificates in the recent incident of Northwest Airlines Flight 188. Herbmartin (talk) 01:55, 13 December 2009 (UTC)

Herbmarting, Why NTSB disagrees with these evidences? Lmc9 (talk) 15:24, 13 December 2009 (UTC)

Lmc9, NTSB doesn't disagree with these evidences. They argue that these events are only contributor factors, and not the accident cause. These events didn't change the conduction of the flight; they didn't change the trajectory of the aircraft, and NTSB is totally right. What NTSB says is that "The evidence collected during this investigation strongly supports the conclusion that this accident was caused by N600XL and GOL1907 following ATC clearances which directed them to operate in opposite directions on the same airway at the same altitude resulting in a midair collision". In other words, they can assure that the cause of accident was because the aircrafts collided. This is the cause. This is not in dispute, it is simple logic: ATC directs aircrafts; if they collide, the cause is that ATC made a mistake. As NTSB says, they failed in their mission to separate them. Investigation reports consist of findings (factual) and conclusions to reach a probable cause. Conclusions in aircraft accident investigation are not supported by scientific procedures and are just opinions. As an example, if A causes B and B causes C, NTSB argues that the cause was B and CENIPA argues that cause was A. Herbmartin (talk) 21:26, 13 December 2009 (UTC)

Note: Lmc9 and Herbmartin were confirmed to be sockpuppets of User:Sdruvss
Crum375 (talk) 23:50, 1 January 2010 (UTC)

Note: I confirm all I wrote. "Now every one who, in the domain of ideas, brings his stone by pointing out an abuse, or setting a mark on some evil that it may be removed--every such man is stigmatized as immoral" (Balzac). XX Sdruvss 16:03, 2 January 2010 (UTC)

This article should be better written

These are my comments about this article, and if editors allow me, I would like to edit it.

Gol Transportes Aéreos Flight 1907

This article says:

“The accident was investigated by both the Brazilian Air Force Centro de Investigação e Prevenção de Acidentes Aeronáuticos (CENIPA) and the U.S. National Transportation Safety Board (NTSB), with a final report issued on December 10, 2008. CENIPA concluded that the accident was caused by errors committed both by air traffic controllers and by the Embraer's pilots, while the NTSB determined that all pilots acted properly and were placed on a collision course by a variety of "individual and institutional" air traffic control errors”.[1][2][6][7]

The sentence “NTSB determined that all pilots acted properly” is nonspecific, cannot be verified, and was extracted of its context. Indeed, what NTSB says is that “there was no evidence of regulatory violations”. This does not mean that “pilots acted properly”. NTSB even recognizes some crew mistakes, as for instance, “[...] they did have a long term opportunity to note a nonstandard situation and request clarification or confirmation from ATC. For about 1 hour the significance of the long time period spent at a nonstandard cruise altitude for the flight direction by N600XL was not recognized”, and “Without question, N600XL proceeded for an inordinately long time without two-way communication”.

Therefore, the sentence should be corrected to:

The accident was investigated by both the Brazilian Air Force Centro de Investigação e Prevenção de Acidentes Aeronáuticos (CENIPA) and the U.S. National Transportation Safety Board (NTSB), with a final report issued on December 10, 2008. CENIPA concluded that the accident was caused by many errors committed both by air traffic controllers and by the Embraer's pilots and doesn’t point a single cause. Whereas NTSB argues that none of the errors committed by Embraer’s pilots pointed by CENIPA are evidences of regulatory violations, and they flew the route precisely as cleared and complied with all ATC instructions. NTSB concludes that accident probable cause was that aircrafts were placed on a collision course by a variety of "individual and institutional" air traffic control errors. [1][2][6][7].

Embraer aircraft and crew

The topic omits an important issue and should be amended with:

CENIPA says that Embraer’s crew had little experience of the N600XL, and had never flown together as part of the same crew. The experience of the pilot-in-command in the installed avionics of the Embraer airplane was restricted to the hours spent in the simulator, plus the 5 hours and 35 minutes of flight time prior to the accident. Even though the second-in-command was already certified in a similar Embraer model, with a total of 368 hours flown, the company decided to send him for a complete training program. [1]

Embraer flight and communication sequence

“At 16:02, seven minutes after crossing the Brasilia VOR, secondary radar contact was lost with the Embraer, thus stopping the display of the Embraer's reported altitude (Mode C) on the controller's radar screen.[note 12].”

This sentence leads the reader to understand that there was a radar failure. It is not explained that secondary radar relies on transponder signal. These are the crucial moments, fundamental to accident comprehension. It should be more detailed. I would redact the topic this way:

At 16:02, seven minutes after crossing the Brasilia VOR, secondary radar contact was lost with the Embraer, thus stopping the display of the Embraer's reported altitude (Mode C) on the controller's radar screen. According to the information available, the loss of the Transponder signal indicates that the STANDBY feature of the transponder had probably been selected.

CENIPA says that “the analysis of the CVR showed that the atmosphere in the cockpit was rather relaxed, with the pilots working with a notebook. According to the CVR data, the pilots did not make any comments concerning the flight management, such as, for example, the thirty-degree heading change to the left (from 006º to 336º) at the vertical of BRS VOR. There were no comments about the joining of the new airway, or the possibility of a flight level change. The left turn was made automatically by the autopilot, and the CVR did not record any supervising action by the crew at that moment. The pilots were busy, making use of a laptop in the cockpit, for calculations and for obtaining data relative to the landing at and takeoff from Manaus, in the software provided by Embraer for performance and weight and balance calculations. The change to “STANDBY” occurred at the end of the period of crew silence, when the second-in-command suddenly informed the pilot-in-command, who was probably working with the RMU (Radio Management Unit), that he had finally obtained in his notebook the information which would allow them to depart from Manaus airport on the following day. The Transponder / TCAS system of the Legacy is operated through two Radio Management Units (RMU), both located on the frontal instrument panel in the cockpit.

CENIPA findings show that at 19:38, the primary radar contact was lost, and Embraer aircraft was completely out of radar screen. They say that if the transponder had been transmitting, the secondary radar coverage would have been available to the controllers. From the moment that the Transponder entered standby mode, the altitude information relative to that aircraft was being obtained by 3D primary radar equipment and not from the Transponder mode C any longer. The secondary radars are utilized by the ATC for the provision of vertical separation, and the 3D radar does not have a documentation approved by the ICAO concerning its use for traffic separation. The Brazilian ATC system does not use the 3D radar for the provision of vertical separation. It is used only for air defense purposes. When the mode C was lost, the real altitude field in radar screen started showing variable altitudes at values around 360, although the information in the data block was clearly warning that the information was coming from a 3D radar, requiring immediate actions to be taken by the controller. According to CENIPA the controller failed to act probably caused by a lack of perception or a mistaken perception of the information conveyed by the data block displayed in his radar screen.

NTSB Safety Recommendation

This topic should be amended with the final report findings, that are:

CENIPA argues in final report that it was observed that the pilots dedicated themselves to the investigation of the weight and balance software that had been inserted in the Captain’s laptop, an aspect that distracted them from the prescribed tasks of aircraft monitoring. The N600XL crew remained distracted and work while keeping their heads down for a long time.

Conflicting CENIPA and NTSB conclusions

“[...] whereas the NTSB focuses on the controllers and the ATC system, concluding that both flight crews acted properly [...] [2][6][7][47][48][49]”

The sentence is not verifiable in NTSB report and in any of the references (2,6,7,47,48,49). NTSB’s comments say that “there was no evidence of regulatory violations” which is different. The sentence should be changed to:

“[...] whereas the NTSB focuses on the controllers and the ATC system, concluding that Embraer airplane was placed on a collision course by the air traffic controllers, and that there was no evidence of regulatory violations by the crewmembers. [2][6][7][47][48][49]”

“According to Aviation Week, [...]”. That is a signed article, and then it should be written: “According to Jim Swickard in Aviation Week, [...]”.

“Aviation Week adds that "the Brazilian military operates that country's air traffic control system, conducted the investigation and authored the report.". This sentence inside “Conflicting Conclusions” must be excluded or should be in another place. It induces readers that there is a conspiracy theory of the report produced by CENIPA.
Sdruvss (talk) 18:23, 15 December 2009 (UTC)

Note: Sdruvss was confirmed to be the sockmaster of Herbmartin, Lmc9 and Wiki2wk who have all posted on this talk page. See: Category:Wikipedia sockpuppets of Sdruvss
Crum375 (talk) 02:46, 2 January 2010 (UTC)

Note: I confirm all I wrote. "Now every one who, in the domain of ideas, brings his stone by pointing out an abuse, or setting a mark on some evil that it may be removed--every such man is stigmatized as immoral" (Balzac). XX Sdruvss 16:13, 2 January 2010 (UTC)

This article has been reviewed by the community and was promoted to featured article status. If you'd like to make substantive changes, you should gain consensus on the talk page. At the moment, it seems you are adding your own WP:OR instead of relying on reliable secondary sources. Crum375 (talk) 18:28, 15 December 2009 (UTC)

I'm asking to you turn this article reliable analyzing these comments and editing it, not me. All information provided in my comments are from the same sources as you use. If you don't want, I and community will understand. I didn't expected that you would allow it. Your comment was expected. Regards. Sdruvss (talk) 18:41, 15 December 2009 (UTC)

Wikipedia can be edited by anyone; I have no more right to edit it than anyone else, and you don't need anyone's permission to edit. Having said that, this article has undergone close scrutiny by the community and achieved featured article status. Therefore, if you'd like to make substantive changes, you should gain consensus for them on the talk page. As I noted above, your suggested changes, which interpret and select specific pieces from primary sources, seem like original research to me. Crum375 (talk) 18:53, 15 December 2009 (UTC)

Crum, this is a old comment (not mine) in Portuguese Wikipedia page of Gol flight 1907:

“The English page is very different from Portuguese. It misses data on the flight plan. There is excessive focus on journalist Joe Sharkey (who gave interviews critical of aviation in Brazil), while there is little or zero references to Brazilian news, such as those conducted by Globo and Folha de Sao Paulo. Some times, the article in English seems a bit biased in favor of the occupants and/or crew of the Legacy. On the English page there were attempts to add data on the flight plan and references to facts of the investigation officially communicated to the Brazilian press, but one astute user and critical (Crum375) undid almost all of these items on behalf of the Wikipedia rules. It seems to me that he is someone who does not usually travel by air in Brazil, don't read Brazilian press reports, while reading him one will have an incorrect impression about aviation in Brazil and perhaps on the jet manufactured by Embraer. I suggest that someone who is fluent in English read that article and the discussion (Talk page) and if so cunning as the User Crum375, perform the necessary contributions and adjustments to make it fair and/or complete the article in English”. Regards, Sdruvss (talk) 19:10, 15 December 2009 (UTC)

PS: Everybody can see that there isn't a single sentence that interprets primary source. The sources are the same as yours. Sdruvss (talk) 19:10, 15 December 2009 (UTC)

I read that old comment on pt-wp a long time ago, and it is as wrong now as it was when it was written. If you think that Brazilian sources aren't used in this article, please check the reference list and count. I actually added a special translation feature to Wikipedia's citation templates so the translated titles (in any language) would look nice and consistent. I also translated myself many of the titles from Portuguese. You are welcome to check them, perhaps you can improve on them. As far as "the sources are the same as yours", you are correct. It's the way you use the sources, specifically primary ones, which is the problem. If you take a long, detailed primary source in a contentious case and pick out a selected subset from it, or otherwise interpret or analyze it, you are engaging in original research. This is why we need secondary sources to analyze, summarize and interpret primary sources. Crum375 (talk) 19:40, 15 December 2009 (UTC)

Crum, one of your reliable sources is Richard Pedicini, who wrote your reference NTSB, Cenipa at Odds over Midair Accident Report. Joe Sharkey, describes him as “my correspondent in Sao Paulo” and this is how Globo describes Pedicini “The American Pedicini Richard [...] was on Friday (8) to the headquarters of the Superintendent of the Federal Police of São Paulo, [...], to assist pilots Joe Lepore and Jan Paladino. He attended the Federal Police in a suit, tie and panama hat and a mustache similar to Santos Dumont. "What better time to do a tribute to Santos Dumont?" he suggested. You need Santos Dummont spirit to analyze, summarize and interpret primary source? (NTSB as an organization is not primary source, NTSB team is). Sdruvss (talk) 19:49, 15 December 2009 (UTC)

Here is how Richard Pedicini describes himself. He is apparently a freelance writer, and in our own case his byline is on the AIN reference. When we use a published source, it is normally the publisher which lends credibility to the source, because the publisher does the vetting, and the publisher accepts legal responsibility for the content. A reliable source is often without byline, i.e. anonymous, and it is perfectly acceptable for Wikipedia as long as the publisher is reputable, as is Aviation International News. And Santos Dumont was a great aviator and instructor; his spirit could certainly help analyze primary sources, if the analysis were published by a reliable secondary source. Crum375 (talk) 20:43, 15 December 2009 (UTC)

This is your reliable source? Is NTSB organizationa primary source? And NTSB team of investigators? A primary source that produces a report 2 years after the event and was not present at the event being analyzed? And what are the documents gathered in the investigations? And controllers and pilots? Are news secondary sources? Sdruvss (talk) 02:19, 16 December 2009 (UTC)

The NTSB documents are primary as the NTSB wrote it

Newspapers are secondary sources

WhisperToMe (talk) 05:31, 16 December 2009 (UTC)

WhisperToMe, according to WP policies WP:OR, officially published NTSB reports are clearly secondary source. They are not close to the event; they did not participate of the accident. Original documents, testimonies, declarations from investigation team and other material used by NTSB team to produce their reports are primary sources. Signed news are unreliable secondary sources, and in this case, primary sources are their authors (reporters). They shouldn't be used in any scientific paper or encyclopedia, unless be declared as author's opinion and be relevant to the subject. News not signed, that use secondary sources (as NTSB reports) are tertiary sources. Scientific papers or encyclopedias shouldn't use tertiary sources. News that cites primary sources only should be used in original research by a primary source (researcher) as information or data. The sentences that I want to include, and are censored by Crum, is synthesis of published material that does not advance a position. I do not combine material from multiple sources to reach or imply a conclusion not explicitly stated by any of the sources. By other side, Crum is omitting sentences, combining them from different frameworks, and changing words from NTSB and CENIPA to reach or imply a conclusion not explicitly stated by any of them. As everybody knows, one may write a poem with words gathered in a computer manual. As Crum clearly admitted, he doesn't obey WP policies, he makes his own consensus. He and his sockpuppets (himself is a sockpuppet that gained admin status) are the consensus. I suggest you to read WP policies. Sdruvss (talk) 20:00, 16 December 2009 (UTC)

Crum, you are compromising the small credibility that Wikipedia have. Your strategy is demoralizing yourself. Sharkey becomes discredited when he choose to be supported by Pedicini. Now, you choose to be support by Pedicini. You choose your way. I thought you were smarter. You reveled the true story behind this article. Sdruvss (talk) 23:02, 15 December 2009 (UTC)

Is it my support for Dumont that causes me to lose the last bit of credibility? Crum375 (talk) 23:28, 15 December 2009 (UTC)

Crum, it is much more. At first I thought that you were making fun of me, but no, you are making fun of 154 families that lost their parents, their relatives, their suns and daughters. You are trying to hide them the answers they are searching for. You are censoring information to people who are not able to understand technical reports. You are omitting the most important findings they reveal and distorting their meaning using interpretations of unreliable and partisan sources. You interpret WP policies completely wrong, using them to build a selected distorted version of the facts. You are using WP to achieve unethical and immoral results. I've never imagine to find a person as low as you being a WP administrator. You should be ashamed of yourself and WP should be ashamed of having you as an editor. Sdruvss (talk) 02:07, 16 December 2009 (UTC)

Sdruvss, there is no way to undo the damage and pain to the 154 victims and their families, but if we do a good job with this article, there is a chance we can prevent future disasters to other families, including yours and mine. The best way to do that is to present the information in a neutral way, based on the most reliable sources, following Wikipedia's content and BLP policies. This is what I try to do not just in this article, but in every one of the many accident articles I have worked on, which you are welcome to review. As an interesting and apt (perhaps eerie) note, here is the mission statement from the Cachimbo Air Base website which I posted on this talk page more than 3 years ago (translation mine, feel free to improve):

Seção de Prevenção de Acidentes Aeronáuticos

DEFINIÇÃO
Prevenção de Acidentes Aeronáuticos, de Incidentes Aeronáuticos e Ocorrência de Solo é o conjunto de atividades destinadas a impedir essas ocorrências, evitando assim custos adicionais desnecessários à operação através da preservação dos recursos humanos e materiais. Os elementos que constituem a base e o objeto de toda a atividade de Prevenção de Acidentes Aeronáuticos são definidos no trinômio “homem-meio-máquina”.
PRINCÍPIOS BÁSICOS DO SIPAER
a) “Todo acidente aeronáutico pode e deve ser evitado”;

• All aviation accidents can be prevented

b) “Todo acidente aeronáutico resulta de uma seqüência de eventos, e nunca de uma causa isolada”;

• All aviation accidents result from a chain of events; never from a single isolated cause

c) “Todo acidente aeronáutico tem um precedente”;

• All aviation accidents have a precedent

d) “Prevenção de acidentes aeronáuticos é uma tarefa que requer mobilização geral”;
e) “O propósito da Prevenção de Acidentes Aeronáuticos não é restringir a atividade aérea, mas estimular o seu desenvolvimento com segurança”;
f) “Os Comandantes, Diretores e Chefes são os principais responsáveis pelas medidas de segurança”;
g) “Em prevenção de acidentes aeronáuticos não há segredos nem bandeiras”;

• There are no secrets nor borders (flags) in the prevention of aviation accidents

h) “Acusações e punições agem contra os interesses da Prevenção de Acidentes Aeronáuticos”.

• Accusations and punishments do not serve the interests of preventing aviation accidents
  

(From Cachimbo Air Base website, SPAA)

Crum375 (talk) 02:39, 16 December 2009 (UTC)

Crum, you are doing a very bad job with this article, making large use of partisan unreliable sources, not obeying WP content and BLB policies, intentionally messing up what primary and secondary sources are. Acting this way, covering up important issues in this accident, you collaborate to further disasters that will hurt other families. Since you speak Portuguese, it seems to me that you are one of Pedicini's sockpuppets, and then it would be clear your job here. I have these questions for you:
1. Why do you prohibit me to write in the article that FL370 in UZ6 is unusual (according to NTSB, and thousands of other sources)?
2. Why do you prohibit me to write that according to final report (and thousands of other sources) crew was distracted using a notebook when transponder turned to standby and was used in the cockpit for almost one hour?
3. Why do you prohibit me to write that according to all sources (primary, secondary, tertiary, whichever) turning off transponder makes an aircraft not being identifiable in radar screen? That is what "squawk ident" means.
4. Why do you prohibit me to write in the article that according to NTSB, the crew "acted according to appliable rules" instead of which was written here, that "they acted properly"? Which has a different meaning.
Sdruvss (talk) 20:19, 16 December 2009 (UTC)

Sdruvss, please focus on the article, not on me. You may want to read WP:CIVIL, for example. Now regarding your points, I don't "prohibit" you from writing anything; this is a free and open encyclopedia. But if you write things which violate our content policy, they will be removed or changed, by me or by other editors. Specifically, if you pick and choose pieces from a primary source, like the detailed CENIPA report, you'd be engaging in original research. This is why we must focus on high quality secondary sources, which analyze, interpret and summarize the primary sources for us. This article involves living persons (controllers and Embraer crew), and we must be extra careful not to write anything which may be perceived as critical of their actions, unless it is clearly supported by high quality secondary sources. Crum375 (talk) 21:18, 16 December 2009 (UTC)

Crum, Please, facing WP policies (WP:NOR), justify why NTSB or CENIPA reports are primary source.
PS: I counted 7 times you cite Final Report without other references. Sdruvss (talk) 23:40, 16 December 2009 (UTC)

Citing CENIPA or NTSB (or any primary source) directly for non-contentious issues (e.g. the flight origins and destinations) is fine. The problem is when it is done to promote a contentious point of view. In that case we need to be careful, and rely on secondary sources only. Why are CENIPA and NTSB reports primary sources? Because they are "close to the investigation", because they were written by the people in charge of the investigation, because they include a large amount of raw "findings" or evidence, and because they are equivalent to a scientist investigating a specific phenomenon, collecting a lot of raw evidence and writing a report about it. To emphasize, these are highly reliable sources, but to interpret them properly, esp. the contentious parts, we need high-quality secondary sources. Crum375 (talk) 01:17, 17 December 2009 (UTC)

Dear Crum, I apologyse by my words. As you well said: "of the investigation". The subject of this article is the accident and not the "investigation". NTSB is not close to the accident, they are one step away, they are close to its investigation, what is completely different. As WP says "A secondary source contrasts with a primary source, which is an original source of the information being discussed. They are not an original source of the information of the accident. As you well said "they are equivalent to a scientist investigating a specific phenomenon", and all WP articles are based in reliable scientific research. And as WP says "Secondary sources involve generalization, analysis, synthesis, interpretation, or evaluation of the original information". This is clearly what CENIPA and NTSB do. A primary source has information and provide raw material to be analyzed. Who wants to analyze raw material? Not me, for sure, but CENIPA and NTSB do. With your good explanation about the job of CENIPA and NTSB, we both agree that facing WP policies they are secondary source. But you said "...but to interpret them properly". Who wants to interpret them? Not me. Every time I comment I quote them. I use their phrases, expressions and words. Do we have a consensus that I am not interpreting a primary source, but as a matter of fact, I am citing a reliable secondary source? We need to go deeper in this debate or it is enough? Regards, Sdruvss (talk) 02:01, 17 December 2009 (UTC)

Sdruvss, this article is about the accident, which includes the history of the flight, the accident itself, the investigation, and the aftermath. Specifically, the investigation is an important (perhaps key) part of this article, and the CENIPA and NTSB reports are the primary sources describing that investigation. Again, CENIPA and NTSB are close to the investigation since they are in charge of it, and their reports are full of raw bits of information. To avoid original research, we need high quality secondary sources to help us analyze, interpret and summarize the highlights of those reports, as well as compare them to each other. Crum375 (talk) 02:12, 17 December 2009 (UTC)

Let me add, in case it's not clear to you, that selective quoting from a primary source is part of the "summarizing" process, and when done by a Wikipedian to advance a particular position, would be considered original research. Crum375 (talk) 02:36, 17 December 2009 (UTC)

Dear Crums, following your grounds, you should exclude all direct citations to CENIPA or NTSB without “secondary sources” that support them, turning your article not understandable. I count 7 of them. Are you going to exclude them or do you want that others do it? I would like that you justify your rationale facing WP policies because you didn’t. Your affirmative are not verifiable in WP policies. The subject of the article is not the investigation as you said. The subject is the accident. The investigation is a secondary source about the accident. As WP policies prescribes, and everybody knows, an article in an encyclopedia has just a single subject, just a single “event” to be described. On the contrary, it would be a book. If you think that the investigation is a different subject, you must separate in two articles. If one wants to interpret or analyze the reports from CENIPA or NTSB according to several sources, which I don’t want, one should use another midia and not WP because this would be original research. You should follow WP policies. Do we have a consensus here?

Let me add, in case it's not clear to you, you should justify that a specific selective quoting from a “primary source” intent to advance a particular position. Which position are you talking about? Is there positions? This a neutral point of view article.

Regards. Sdruvss (talk) 11:14, 17 December 2009 (UTC)

Sdruvss, you are again missing the point. We are allowed to use reliable primary sources, such as the CENIPA or NTSB reports, but must do so very carefully, to avoid "advancing a position", which means not to use it to promote or support a particular point of view in a contentious situation. For example, we may use the CENIPA report to support the statement that the Embraer's destination was Manaus, but we can't selectively pick one of the many details it includes, if that could be seen as supporting one side in a dispute or creating a new interpretation. We may also not interpret or analyze parts from primary sources if they are not otherwise covered by high quality secondary sources. You are correct that there are many citations in the article to the CENIPA and NTSB reports; if you find any of them which are contentious, i.e. in dispute, or create a new interpretation, please let me know. Crum375 (talk) 12:57, 17 December 2009 (UTC)

Dear Crum, which of these four following comments you believe is "advancing a position" and why?

1) FL370 + UZ6 to Manaus = NTSB says it is “unusual”;

2) Crew distracted using a notebook for about 1 hour;

3) transponder in standby = aircraft out of radar screen;

4) “acted properly” is different of “acted according to appliable rules”.

Best Regards. Sdruvss (talk) 14:03, 17 December 2009 (UTC)

Sdruvss, all of these are contentious issues, and may not be analyzed or interpreted unless attributed to highly reliable secondary sources. The point, again, is not just the interpretation per se, in each case, but the very fact that it is plucked out of many other details inside the investigative reports (which are primary sources), because just mentioning a contentious issue is effectively promoting it. So if something is important, it will be picked up by a secondary source and if that source is highly reliable, as required in a contentious WP:BLP case, we can then use it. Crum375 (talk) 14:14, 17 December 2009 (UTC)

Dear Crum, I insist that you be specific with your arguments. You must be grounded in some reasoning. We must be rational when we disagree.

1) Why those issues are contentious? They are simple facts not in dispute by anyone. Justify why they are contentious, explaining what is the contentiousness of each one. For instance, why the link between transponder signal and secondary radar is contentious?

2) You are not being coherent. As I said, you have used 7 direct citations to CENIPA/NTSB without other references. It is easy to find then, just search for [1] not combined with other references. Why do you disobey what you deem to be WP policies?

Best Regards, Sdruvss (talk) 21:01, 17 December 2009 (UTC)

Let me add a technical correction to your point 3 above. Although what exactly happened to the Embraer's transponder and why is unknown and open to speculation, what you say is technically incorrect. As mentioned in the article, the first event was that the transponder's "secondary signal", including the aircraft's altitude (Mode C), stopped being received by ATC. This means that ATC's radar screen reverted to displaying a "primary" target (unrelated to Wikipedia's primary source concept), which normally (in civilian radars) does not include an altitude readout. In the case of the Embraer, however, according to CENIPA and NTSB reports, ATC radar kept displaying both the primary target as well as an altitude value, apparently because the radar facility was a military installation. Some military radars (which are intended for air defense) can also display altitude for aircraft along with their position, even if their transponders are off, while civilian radars will only display the position (and speed) for no-transponder aircraft. The altitude display in such cases is of limited accuracy, since it is derived from a calculation based on the target's distance and angle above the horizon. This is mentioned in current footnote 12. Crum375 (talk) 15:28, 17 December 2009 (UTC)

Dear Crum, I'm not going to discuss this issue with anyone, my comments are grounded in technical knowledge, and all I can say is that you are completely wrong and confused. You did not even understand CENIPA report, just as NTSB team in charge of investigation that doesn't have the technical knowledge to understand most of the IT issues involved in the accident. NTSB comments are grounded in the reading of CENIPA report and shallow knowledge of the computer system. But here is not the place to debate it. I'm not even debate IT issues in blogs, forums and WP, because discussion with unskilled people let me bored. I prefer to write scientific papers that are submitted to experts blind review. Here, I just want that germane facts and evidences be not deliberately mislaid, turning this article biased, partisan and incomprehensible to most people.

Best Regards, Sdruvss (talk) 21:01, 17 December 2009 (UTC)

PS: You don't need to go too far to understand transponder, primary radar and secondary radar issues. Just consult wikipedia article Transponder (aviation). Sdruvss (talk) 22:59, 17 December 2009 (UTC)

PS2: I saw that you included links to transponder WP article. So you know how it works, I don't need to explain it. Sdruvss (talk) 23:10, 17 December 2009 (UTC)

Good, so hopefully you now understand why this statement is wrong: "3) transponder in standby = aircraft out of radar screen" Crum375 (talk) 01:09, 18 December 2009 (UTC)

Crum, you are always joking and gambling with words, but life should not be a lottery. In your reference of transponders: “In aviation, aircraft have transponders to assist in identifying them on radar. [...] not all primary radars can estimate the altitude of an aircraft. Secondary radar overcomes these limitations but it depends on a transponder in the aircraft to respond to interrogations from the ground station to make the aircraft more visible and to report the aircraft's altitude”. What “identifying on radar”, and “make the aircraft more visible” means? And I couldn’t find any reference that primary radar are for “military use” as you said. Help me, please. You said that this is a contentious subject. Why? Best regards. Sdruvss (talk) 10:22, 18 December 2009 (UTC)

HowStuffWorks - How Air Traffic Control Works] can help people to understand how ATC works around the world. Even Crum is able to understand: “Once your plane takes off, your pilot activates a transponder device inside the aircraft. The transponder detects incoming radar signals and broadcasts an amplified, encoded radio signal in the direction of the detected radar wave. The transponder signal provides the controller with your aircraft's flight number, altitude, airspeed and destination. A blip representing the airplane appears on the controller's radar screen with this information beside it. The controller can now follow your plane”. But this is a contentious issue, we know it. Sdruvss (talk) 12:17, 18 December 2009 (UTC)

Sdruvss, a secondary signal from an aircraft's onboard transponder helps ATC identify the aircraft (which target on my screen is which aircraft?) and increases the maximum range (distance from radar antenna) at which it can be seen. A modern transponder also includes Mode C, which provides an altitude readout. If there is no secondary signal, for example if the transponder is turned off, in standby, or malfunctioning, there will be a "primary target" visible on the radar screen while the aircraft is "in range", which for high altitudes can be well over 100 miles from the radar antenna (and there are multiple antennas). So aircraft do not automatically become "invisible", or disappear from radar screens if their transponders stop functioning; their display reverts to a primary target, normally an icon displayed on the controller's screen without an associated altitude. Except, in this particular case, because Brasilia ATC was a military facility, it had radar equipment designed for air defense purposes, which kept displaying an altitude value for the Embraer's primary target icon, even after its transponder signal was lost. This altitude value was less accurate and reliable than the Mode C derived altitude, and may have contributed to the controllers' confusion about the Embraer's altitude, and perhaps caused ATC to think that the target was still a secondary target, when in fact it became primary.
You ask why this is contentious? Because living people are involved and there are accusations of negligence and incompetence, with 154 people dead. We therefore must strictly follow our BLP and other content policies, to maintain the highest possible quality and avoid original research. Crum375 (talk) 12:53, 18 December 2009 (UTC)

1. As I said I don’t like to debate technical issues with unskilled people in blogs, forums, WP. But I just can say that you are completely wrong, and you know it well. Without transponder signal, a “target” becomes unassociated (the flight becomes unidentified) in radar screen as soon it leaves the coverage area of a specific set of radar’s antennas. In the moment that Legacy turned transponder to standby, there were 5 antennas covering it. The coverage of the last one was lost at 19:38, causing it to disappear from radar screen (as an associated target). CINDACTA I (what you call Brasilia ATC) - Centro Integrado de Defesa Aérea e Controle de Tráfego Aéreo - was not just designed for air defense purposes, it is the link between the Sistema de Controle do Espaço Aéreo (SISCEAB) e do Comando de Defesa Aeroespacial Brasileiro (COMDABRA). It counts with 17 radars. For defense purposes there is a different team and different set of equipments and facilities. What was said in final report is that many primary radars in the world (it doesn’t matter if civilian or military) has the capacity to estimate altitude, but it is not reliable, and this information is used only in defense purposes in any country and not to separate aircrafts, because enemies aircrafts don’t use transponders as you know. But all over the world, when an aircraft turns off transponder, ATC need informations that are available. One of them is primary radar readout, another is the flight plan.

2. You said that this issue is contentious because living people are involved. This logic does not transform an issue of how a transponder, secondary radar, primary radar works into a contentious issue. You are trying to confound readers, making them believe that there was an ATC radar malfunction or because it is a military operated facility that this circumstances contributed to accident, when neither NTSB say that. NTSB focused in computer system (which, by the way, analysis is completely wrong), and not in primary, secondary radar or military issues. What they said, is that when there is not transponder signal, the computer system shouldn’t display in radar screen the primary radar's readout or flight plan's altitude. Instead, they should display the last clearance issued to the aircraft. This is a very contentious issue, and again here is not the place to dispute it (but they are wrong too).

Regards. Sdruvss (talk) 15:49, 18 December 2009 (UTC)

Sdruvss, it seems that you do agree with me that the issue is contentious, and it involves living people. This means we need to be extra careful in anything we say, and attribute everything to the most reliable secondary sources, wherever possible. Hopefully you also understand now that when an aircraft's transponder is not functioning, it can still be seen on the radar screen and is not "invisible". In the case of the Embraer, it was visible on the screen for 36 minutes after loss of the secondary signal. One contentious issue is why ATC did not ask the Embraer to recycle its transponder, which would be the normal response to a loss of secondary signal. The speculation in this case is that ATC didn't do that because they were confused by the altitude display and were not aware that they had lost the secondary signal. But this is speculation only, and in the case of BLP we need harder evidence or better sources, so we can't delve into this issue at this time. Crum375 (talk) 15:57, 18 December 2009 (UTC)

Crum, I don’t want to debate or even suggest changing anything in the article that is not written in any official document. There are many things in this article that are not verifiable whichever source you choose, and I will further tell, but not now. But the first point I want to correct in the article is: the way it is written, it seems that the ATC lost altitude control of the Legacy because there was a malfunction in its radar infrastructure. So it must be clear in the article that when transponder turned to standby, radar system didn’t have altitude information anymore. This is a fact not in dispute by anyone: it was the lack of transponder signal that made ATC loses control of the actual altitude of Legacy. This is what happened, this is proved by any source, primary, second or tertiary source. When secondary radar doesn’t receive information of transponder, computer system that supports radar screen displays primary radar altitude readout, which is unreliable in any system of the world. This is not in dispute, and this should be clearly written in the article. People that don’t know how ATC works, reading your article understand that there was a black hole in radar system over Brasilia. At 19:02 transponder turned to standby, thereafter radar screen began to display an unreliable altitude coming from primary radar and an indication that secondary radar was not receiving transponder signal. At 19:30 occurs the first lost of aircraft identification, due to the lack of transponder signal, and then, at 19:38 occurs the completely missing of Legacy flight in radar screen. These are not disputed facts by any one. What is in dispute, and I don’t want to enter here in this debate, and it is contentious, is what should be done by ATC or by his computer system, or by crew when facing these events. Regards. Sdruvss (talk) 18:34, 18 December 2009 (UTC)

Sdruvss, I am not aware of any report of any malfunction in the ATC "radar infrastructure." Could you please tell me (please quote) where in the article it currently says or implies that? Thanks, Crum375 (talk) 19:39, 18 December 2009 (UTC)

Crum, I said that the article induces that conclusion.

From "At 16:02, seven minutes after..." until "...in the blind" I would change to:

At 16:02, seven minutes after crossing the Brasilia VOR, Embraer's transponder stopped transmitting causing ATC secondary radar to lose contact with the aircraft. Without current altitude readout from secondary radar, ATC computer system started to display primary radar unreliable altitude readout, and a symbol in the flight label that it was not working with secondary radar. At the same time, radar screen data block started displaying that the Embraer's flight plan foresaw a descent from FL370 to FL360 when passing Brasilia. It's not clear what exactly happened among ATC controllers, but investigations concluded that they were confounded by these data. Evidences gathered in the investigations demonstrated that controllers believed that Embraer was flying at FL360 after passing Brasilia, although Embraer's crew had never received any instructions to change levels.

No attempt was made by either the Embraer or Brasilia Center to contact each other from 15:51 until 16:26 when, 24 minutes after the loss of secondary radar contact, Brasilia Center called the Embraer and received no reply. During investigations, it was verified that the radio frequency provided by ATC to the crew didn't reach the point where aircraft was flying, and a suitable frequency was not commnicated to the crew, as would be expected to.

From 16:02 until 16:30 Embraer's altitude in radar screen changed very much. Starting 16:30 the Embraer's primary radar target, a label which indentify the flight in radar screen, became intermittent, and the identification disappeared completely from the radar screen by 16:38, eight minutes later. The flight became an unidentified target.

Brasilia Center unsuccessfully attempted to effect a handoff of the Embraer to Amazonic Center at 16:53, by calling the Embraer in the blind.[note 14]

I think that notes 12 and 13 are unnecessary and are wrong.

Regards. Sdruvss (talk) 19:12, 19 December 2009 (UTC)

Sdruvss, perhaps you missed my above question, so I'll ask it again. You said that the article says or implies that there was a "malfunction" in the "radar infrastructure". I am not aware of any report which says that. Can you please show me (please quote) where in the current article it says or implies that? Thanks, Crum375 (talk) 20:50, 19 December 2009 (UTC)

Crum, perhaps you missed my above answer: "(...) the way it is written, it seems that the ATC lost altitude control of the Legacy because there was a malfunction in its radar infrastructure". "The way it is written" means omitting fundamental information to understand how accident happened. This article makes large use of selecting subsets of information to advance a particular point of view. For instance, the link between transponder and secondary radar deserves just the small note 13. Do we reach a consensus that I can change the text from "At 16:02, seven minutes after..." until "...in the blind" with the above text? Do you agree with the text above? If you don't, what is wrong? Regards, Sdruvss (talk) 13:18, 20 December 2009 (UTC)

Sdruvss, I am sorry for possibly being dense, but you say "the way it is written, it seems that the ATC lost altitude control of the Legacy because there was a malfunction in its radar infrastructure." (emphasis added) I asked you to please quote specific words which say or imply there was any kind of malfunction with the radar. If you have quoted such words which say or imply there was a malfunction, I can't find them. If you'd like to have a meaningful discussion, we need to progress step by step. If you say the current version says or implies a malfunction, you need to be able to quote the words that say or imply it. Thanks, Crum375 (talk) 13:54, 20 December 2009 (UTC)

Crum, Forget what I said. You are trying to make a word game here, and I am not interested. Please, answer: Do you agree with the text above? What is wrong with it? Sdruvss (talk) 14:07, 20 December 2009 (UTC)

Sdruvss, I am not playing any game. You are criticizing the current version by saying it says or implies there was a malfunction in the radar. I can't find where it says or implies it. I ask you to please quote the specific words which say or imply the radar malfunction. If you don't provide such a quote, I can't understand or address your criticism, and we can't progress unless I understand you. Crum375 (talk) 14:12, 20 December 2009 (UTC)

Crum, I clearly answered that the article turns the link between transponder and secondary radar in a tiny footnote. The way is written it is not clear why radar system stopped receiving altitude readout. It could be any cause for those people who don't read footnotes, even a malfunction. Do you agree with the text above? What is wrong with it? Sdruvss (talk) 14:31, 20 December 2009 (UTC)

I am sorry again, but I am still not following. You said above, "the way it is written, it seems that the ATC lost altitude control of the Legacy because there was a malfunction in its radar infrastructure." (emphasis added) I asked you to please show me where it says that there was a "radar malfunction", and to please quote the specific words which say or imply there was a radar malfunction. Can you please do that? If there is a problem with the wording, we need to fix it, but we first need to understand the problem, and the first step is to quote the words in the current version which you believe say or imply "there was a malfunction in its radar infrastructure." Can you understand that without explaining yourself by presenting an exact quote, we can't proceed? Crum375 (talk) 15:58, 20 December 2009 (UTC)

Crum, as I said, many times, I would like to change this text:

ATC maintained normal two-way radio contact with the Embraer up until 15:51, when the last successful radio exchange with the Embraer was made on VHF frequency 125.05 MHz with Brasilia Center.[note 10] At that point the Embraer was just approaching the Brasilia VOR.[note 11] The Embraer overflew the Brasilia VOR at 15:55, four minutes later, and proceeded northwest-bound along UZ6. At 16:02, seven minutes after crossing the Brasilia VOR, secondary radar contact was lost with the Embraer, thus stopping the display of the Embraer's reported altitude (Mode C) on the controller's radar screen.[note 12]

No attempt was made by either the Embraer or Brasilia Center to contact each other from 15:51 until 16:26 when, 24 minutes after the loss of secondary radar contact,[note 13] Brasilia Center called the Embraer and received no reply.

Brasilia Center then unsuccessfully attempted to contact the Embraer six more times, between 16:30 and 16:34. At 16:30 the Embraer's primary radar target became intermittent, and disappeared completely from the radar screen by 16:38, eight minutes later. Brasilia Center unsuccessfully attempted to effect a handoff of the Embraer to Amazonic Center at 16:53, by calling the Embraer in the blind.[note 14]

To this text:

ATC maintained normal two-way radio contact with the Embraer up until 15:51, when the last successful radio exchange with the Embraer was made on VHF frequency 125.05 MHz with Brasilia Center.[note 10] At that point the Embraer was just approaching the Brasilia VOR.[note 11] The Embraer overflew the Brasilia VOR at 15:55, four minutes later, and proceeded northwest-bound along UZ6.

At 16:02, seven minutes after crossing the Brasilia VOR, Embraer's transponder stopped transmitting causing ATC secondary radar to lose contact with the aircraft. Without current altitude readout from secondary radar, ATC computer system started to display primary radar unreliable altitude readout, and a symbol in the flight label that it was not working with secondary radar. At the same time, radar screen data block started displaying that the Embraer's flight plan foresaw a descent from FL370 to FL360 when passing Brasilia. It's not clear what exactly happened among ATC controllers, but investigations concluded that they were confounded by these data. Evidences gathered in the investigations demonstrated that controllers believed that Embraer was flying at FL360 after passing Brasilia, although Embraer's crew had never received any instructions to change levels.

No attempt was made by either the Embraer or Brasilia Center to contact each other from 15:51 until 16:26 when, 24 minutes after the loss of secondary radar contact, Brasilia Center called the Embraer and received no reply. During investigations, it was verified that the radio frequency provided by ATC to the crew didn't reach the point where aircraft was flying, and a suitable frequency was not commnicated to the crew, as would be expected to.

From 16:02 until 16:30 Embraer's altitude in radar screen changed very much. Starting 16:30 the Embraer's primary radar target, a label which indentify the flight in radar screen, became intermittent, and the identification disappeared completely from the radar screen by 16:38, eight minutes later. The flight became an unidentified target.

Brasilia Center unsuccessfully attempted to effect a handoff of the Embraer to Amazonic Center at 16:53, by calling the Embraer in the blind.[note 14]

Is this clear? Do you agree? Regards. Sdruvss (talk) 16:28, 20 December 2009 (UTC)

Sdruvss, the text you want to change has been reviewed and scrutinized by many people, as part of the promotion of the article to a featured article. This doesn't mean it's perfect, but it also means we need to be extra careful when changing it, so as not to lose the FA status. Specifically, you are asking to make changes, without explaining what's wrong with the current version. For example, you said that the current version says or implies that there was a "radar malfunction," but although I have asked you many times for an exact quote showing where the article says or implies this, you have yet to do so. In summary, this is a featured article, involving living persons and contentious issues. We can't make changes unless, at the very minimum, we understand why the changes are needed. Crum375 (talk) 16:40, 20 December 2009 (UTC)

The reason was explained many times and must be stated here why this article is biased: this article omits intentionally in the body of the text that the current altitude of Embraer was lost in radar system because transponder was turned to standby, turning this information into a footnote. Sdruvss (talk) 17:01, 20 December 2009 (UTC)

Sdruvss, even if the transponder were turned to "standby", which is a contentious speculation (and mentioned in the footnote), it still doesn't mean there was a radar malfunction anywhere. You said the "the way [the article] is written, it seems that the ATC lost altitude control of the Legacy because there was a malfunction in its radar infrastructure." I asked you to quote where in the article it says or implies that radar malfunction, and I am still waiting for that quote. Crum375 (talk) 17:11, 20 December 2009 (UTC)

Crum, I said many times, and you don't read: you didn't explicitly write it. I would have to quote the intire article. I said that you omit the reasons why secondary radar data was lost. As you don't explain it, people reading the article could understand that it was a probable radar malfunction. Why do you refuse to include this little neutral piece of information into the body of the text? It seems that this is a big issue to you, is it? Sdruvss (talk) 17:27, 20 December 2009 (UTC)

Sdruvss, now you say "you didn't explicitly write it", but that still means you think it implies there was a malfunction, and I don't see where we even imply that. The only statement we make is that "secondary radar contact was lost with the Embraer, thus stopping the display of the Embraer's reported altitude (Mode C) on the controller's radar screen." This point is "factual" (i.e. asserted or agreed by all sources), and there is then explanation in the footnote that CENIPA hypothesizes that at this point the Embraer crew switched off the transponder or put it in standby, which the crew denies. No reasonable person reading this would "understand that it was a probable radar malfunction," because we don't say or imply that. All we say is that ATC stopped receiving the transponder's signal, with the footnote for extra detail. The entire "Embraer flight and communication sequence" section is "factual", i.e. a description of events which all reliable sources assert or agree to, with some related details from the CENIPA and NTSB reports in footnotes. If you feel something specific is wrong or needs improvement, feel free to mention it and we can then focus on it, but to take an entire section and replace it wholesale is not a good way to achieve results. Crum375 (talk) 17:48, 20 December 2009 (UTC)

Crum, The problem is that the entire section is full of omissions, and that is why it should be rewritten. This is the point here. It omits that secondary radar has as source of altitude information the transponder signal, It omits that controller was confounded by the lack of current altitude of Embraer. It omits that crew use a notebook in cockpit by almost one hour, and they were using the notebook when transponder was turned off. Those issues are fundamental to understand the accident, are factual and not disputed by anyone.

You systematically refuse to include this neutral factual information playing all sorts of games. You make large use of selectively quoting investigation report and unreliable tertiary sources, blocking other people that want to improve this text. You became the owner of this article and use puppets to create a "community" that supports you. You make this article biased, partisan and unreliable.

But I think it is enough. It is obvious that you won't include these important factual omissions, and will run over all resources you have in your hands to achieve your goal. It has became clear your purpose with this article. Don't mind, there is lot of very interesting material here to write about WP unreliability and manipulation. This article is one more to include in your list of manipulated articles in WP. Congratulations Crum, you are becoming famous, I've read a lot about you in internet, and predictably all are verifiable. Regards Sdruvss (talk) 23:23, 20 December 2009 (UTC)

Note: Sdruvss was confirmed to be the sockmaster of Herbmartin, Lmc9 and Wiki2wk who have all posted on this talk page. See: Category:Wikipedia sockpuppets of Sdruvss
Crum375 (talk) 02:49, 2 January 2010 (UTC)

Note: I confirm all I wrote. "Now every one who, in the domain of ideas, brings his stone by pointing out an abuse, or setting a mark on some evil that it may be removed--every such man is stigmatized as immoral" (Balzac). XX Sdruvss 16:13, 2 January 2010 (UTC)

Sdruvss, I ask you again to please focus on the article, not on me. If you feel there is a specific issue you'd like to address, let me know, and we'll focus on one item at a time. This is a featured article, which has been reviewed and scrutinized by many people before being promoted, and which also involves contentious WP:BLP issues. Therefore, we should not make wholesale modifications to it without thinking carefully about every small change. Thanks, Crum375 (talk) 00:30, 21 December 2009 (UTC)

My contributions:

• "while the NTSB determined that all pilots acted properly".

No one of the references says that "pilots acted properly". Affirmative not verifiable.

• "Former Justice Minister Jose Carlos Dias, who was acting as a lawyer for the Embraer's crew, criticized the charges against them as being "biased" and "discriminatory".

Allegations of the defendants made by their attorney are partisan. This is a subjective perspective.

• "The Embraer's crew asserted in their depositions and subsequent interviews that they were cleared by air traffic control (ATC) to FL370 for the entire trip, all the way to Manaus" and the following sentence.

Selectively quote of a primary source.

• "The Embraer's flight plan consisted of flying at FL370 up to Brasilia,[note 7] on airway UW2, followed by a planned descent at Brasilia to FL360, proceeding outbound from Brasilia northwest-bound along airway UZ6 to the Teres fix,[note 8] an aeronautical waypoint located 282 nm (324 mi, 522 km) northwest of Brasilia, where a climb to FL380 was planned".

This sentence would be clearer if it had included headings of airways:

"The Embraer's flight plan consisted of flying heading 006º at FL370 up to Brasilia,[note 7] on airway UW2, followed by a planned descent at Brasilia to FL360, proceeding outbound from Brasilia northwest-bound along airway UZ6 heading 336º to the Teres fix,[note 8] an aeronautical waypoint located 282 nm (324 mi, 522 km) northwest of Brasilia, where a climb to FL380 was planned".

• "At 16:02, seven minutes after crossing the Brasilia VOR, secondary radar contact was lost with the Embraer, thus stopping the display of the Embraer's reported altitude (Mode C) on the controller's radar screen.[note 12]"

Sequence of events omitted. It would be better if written: "At 16:02 Embraer transponder stopped transmitting causing secondary radar to lost contact with the aircraft, thus stopping the display of the Embraer's reported altitude (Mode C) on the controller's radar screen.[note 12]".

I hope they help. Regards Sdruvss (talk) 20:42, 22 December 2009 (UTC)

Note: Sdruvss was confirmed to be the sockmaster of Herbmartin, Lmc9 and Wiki2wk who have all posted on this talk page. See: Category:Wikipedia sockpuppets of Sdruvss
Crum375 (talk) 02:38, 2 January 2010 (UTC)

Note: I confirm all I wrote. "Now every one who, in the domain of ideas, brings his stone by pointing out an abuse, or setting a mark on some evil that it may be removed--every such man is stigmatized as immoral" (Balzac). XX Sdruvss 16:13, 2 January 2010 (UTC)