Mid-air collision over Brasil
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News mid-air Brazil
Some further news and technical explanations regarding the Braziian mid-air that occured on September 29, 2006:
http://www.ifatca.org/press/251106.pdf
http://www.ifatca.org/press/251106.pdf
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Some further news and technical explanations regarding the Braziian mid-air that occured on September 29, 2006:
http://www.ifatca.org/press/251106.pdf
http://www.ifatca.org/press/251106.pdf
The Controller also says that a blind point exists in the area of the accident that is known by them.
Source in portuguese:
http://g1.globo.com/Noticias/Brasil/...98-295,00.html
Last edited by caos; 27th Nov 2006 at 14:34.
One big hole in the cheese
From the IFACTA statement:
Having spent a few decades in software design, my first rule has always been to involve the end users (those at the coalface end). More typically software systems are mandated from on high and the end users get training in how to work around the imperfections rather having the system properly designed in the first place.
I suspect some engineering type (licensed only to drive cars) thought it would be a dandy idea to change cleared levels according to the filed flight plan to save the coalface folks a few keystrokes.
Programmers aspire to make the world a better place by coming up with bright ideas to make the users' lives easier. To complete the job, they have to run said bright ideas by the users to get rid of the bad ones.
In the case of the Legacy coming from Sao Paulo, in the south of Brazil, and proceeding north to Manaus, there was a need to change from an odd level (FL 370) to an even level, being FL 360. When passing over Brasilia VOR (farol de navegação) the software of CINDATCA-1 did automatically change the second altitude indication to 360 (from 370) on the aircraft label shown on the radar screen. However, the flight was still flying at FL 370 and was not cleared down by ATC to FL 360 as shown on the label. Information we have gathered tells us that this “discrepancy” happens several times a day and is a “common scenario” for ACC Brasilia. Of course the situation is not that dramatic when all runs well and according to the book. In these cases when scanning the radar screen, controllers will notice the discrepancy (sometime later), issue a proper descent clearance and so correct the situation.
I suspect some engineering type (licensed only to drive cars) thought it would be a dandy idea to change cleared levels according to the filed flight plan to save the coalface folks a few keystrokes.
Programmers aspire to make the world a better place by coming up with bright ideas to make the users' lives easier. To complete the job, they have to run said bright ideas by the users to get rid of the bad ones.
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I keep hearing from friends ATCOs about the issues they face on a daily basis, and little to nothing is done to remediate the situation.
Is this due to the military legacy in the ATC business worldwide? Once upon a time (?), the lower ranks in front of the screens were commanded to do their job, and keep their mouth shut. Could it be that now ANSPs could finally put their military legacy behind their back and invest in their people with more qualification and motivation, and hopefully the possibility to give constructive feedback to the equipment vendor?
Ciao, Luca
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The IFATCA apparently has some "inside" information that has not previously been released from official sources. This information tracks with my earlier posts...and those of others... that 600XL was never cleared to any level other than 370, the altitude at which the collision occurred.
The question then for the crew of that aircraft is "should they have descended to a different level(360) on their own volition"" after passing BRS. The answer to that question appears to be founded solely in the lost communications regulations. While not having information as to whether Brazil has an exception to ICAO(differences), the ICAO requirement is quite clear. After the aircraft becomes aware that it is in a lost comm situation it must squawk 7600 while maintaining previously cleared course and altitude for 7 minutes and then maintain flight planned parameters. The seven minute window starts with the selection of code 7600(and is obviously intended to give ATC time to make necessary adjustments to other aircraft given the impending change, in altitude, for example, by the NORDO aircraft). In this case, the data indicates 600XL attempted several calls to ATC and after a few calls heard a transmission from ATC directed to it which was partially unreadable. It then attemted several more transmissions to clarify frequency change instructions which apparently were not heard by ATC. The collision occurred 3 minutes later. Whether the timing of the ATC call was serendipitous or in response to hearing the call from 600XL is not clear. It is also not clear whether the 600XL crew had come to the definitive conclusion that a lost comm situation existed but even if it had at this point 3 minutes prior to impact, the rules would have had it maintain 370 until a time well past the actual time of impact.
While the IFATCA statement and comments delineate the possibility of long standing ATC problems with equipment implementations and communications coverage and, further that the controller on duty may have been improperly briefed(believing that flight was at 360) when coming on duty, ATC procedures should have caught the fact that the last confirmed altitude (370)of 600XL verbally occurred just prior to crossing BRS (why wasn't flight instructed to maintain 360 after crossing BRS which was to occur literally in a few minutes ?) with mode C/S altitude reporting being available and showing 370 for some 40 miles after passing BRS. The apparent display of a calculated level of 360 not withstanding, should not the Gol flight have been advised of opposite direction traffic at 360 unconfirmed and NORDO..... if not given a separation vector or climb instructions?
As to equipment failures or poor man/machine interfaces or inadvertent improper operation of equipmnent(none have been eliminated as contributing factors), the ICAO Rules and ATC procedures are(should be) designed to be fail-safe and provide proper alerts/actions to prevent such occurrences.
Also, there has been no mention of the communications with the Gol flight during this period. Had they been on same frequency as 600XL would not they have heard its calls to ATC which (with good phraseology and use) may have included level /position information in its transmissions? Since it is likely that they were not, should there be a procedure/practice in remote areas with possibly less than adequate communications which would assure that aircraft approaching each other at a closure rate of M1.7 would be monitoring the approaching sector frequency if a common frequency is not in use (so that the a/c crews would be aware of other traffic)?
The question then for the crew of that aircraft is "should they have descended to a different level(360) on their own volition"" after passing BRS. The answer to that question appears to be founded solely in the lost communications regulations. While not having information as to whether Brazil has an exception to ICAO(differences), the ICAO requirement is quite clear. After the aircraft becomes aware that it is in a lost comm situation it must squawk 7600 while maintaining previously cleared course and altitude for 7 minutes and then maintain flight planned parameters. The seven minute window starts with the selection of code 7600(and is obviously intended to give ATC time to make necessary adjustments to other aircraft given the impending change, in altitude, for example, by the NORDO aircraft). In this case, the data indicates 600XL attempted several calls to ATC and after a few calls heard a transmission from ATC directed to it which was partially unreadable. It then attemted several more transmissions to clarify frequency change instructions which apparently were not heard by ATC. The collision occurred 3 minutes later. Whether the timing of the ATC call was serendipitous or in response to hearing the call from 600XL is not clear. It is also not clear whether the 600XL crew had come to the definitive conclusion that a lost comm situation existed but even if it had at this point 3 minutes prior to impact, the rules would have had it maintain 370 until a time well past the actual time of impact.
While the IFATCA statement and comments delineate the possibility of long standing ATC problems with equipment implementations and communications coverage and, further that the controller on duty may have been improperly briefed(believing that flight was at 360) when coming on duty, ATC procedures should have caught the fact that the last confirmed altitude (370)of 600XL verbally occurred just prior to crossing BRS (why wasn't flight instructed to maintain 360 after crossing BRS which was to occur literally in a few minutes ?) with mode C/S altitude reporting being available and showing 370 for some 40 miles after passing BRS. The apparent display of a calculated level of 360 not withstanding, should not the Gol flight have been advised of opposite direction traffic at 360 unconfirmed and NORDO..... if not given a separation vector or climb instructions?
As to equipment failures or poor man/machine interfaces or inadvertent improper operation of equipmnent(none have been eliminated as contributing factors), the ICAO Rules and ATC procedures are(should be) designed to be fail-safe and provide proper alerts/actions to prevent such occurrences.
Also, there has been no mention of the communications with the Gol flight during this period. Had they been on same frequency as 600XL would not they have heard its calls to ATC which (with good phraseology and use) may have included level /position information in its transmissions? Since it is likely that they were not, should there be a procedure/practice in remote areas with possibly less than adequate communications which would assure that aircraft approaching each other at a closure rate of M1.7 would be monitoring the approaching sector frequency if a common frequency is not in use (so that the a/c crews would be aware of other traffic)?
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Legacy N600XL X Boeing 737 GOL1907 Collision in Brazil
Events sequence for EMB-145 Legacy N600XL and Boeing 737-800 GOL Flight 1907 Crashed in Brazil on September 29th, 2006 at 16:56:54 GMT-3.
Flight Plan presented to ACC - BR ( Brasilia Area Control Center ) via SBSJ - Sao Jose dos Campos AIS room.
Legacy's crew received Flight Plan CLEARANCE from ACC-BR via Sao Jose dos Campos TWR Air Traffic Controller.
That's the Legacy FPL route detailed:
N0452 F370 DCT PCL UW2 BRS/N0456 F360 UZ6 TERES/N0449 F380 UZ6 MAN DCT
Legacy's pilots received CLEARANCE to CLIMB UP and Maintain FL 370 to Manaus as CLEARED by ACC-BR.
Official Preliminary Investigation Report:
Take Off time: 17:51 (GMT-3) on September 29th, 2006
Legacy N600XL TOC ( Top of Climb ) 37.000 feet: 18:33 (GMT-3)
I am very intrigued with 42 minutes to climb up to 37.000 feet.
Compulsories Fixes along Airway UW 2 :
BCO VOR( 23º 24.4’S, 46º 26.1’W )
BGC VOR( 22º 57.’S, 46º 34.2’W )
PCL NDB ( 21º 50.15’S, 46º 33.94’W )
Track 006º from PCL NDB (415 ) to BRS VOR ( 115.90 )
KERBO INT ( 21º 06.2’S, 46º 44.2’W)
ARX VOR (19º 41.3’S, 47º 03.6’W )
VALDI INT ( 18º 03.8’S, 47º 28.5’W )
Last VHF Contact with ACC-BR 18:51 (GMT-3) before BRS VOR
( 15º 52.4’S, 48º 01.3’W )
At least for twice after leveled off Legacy plane on Flight Level 370 Legacy's pilots had Communications with ACC-BR before they have lost radio contact with ACC-BR.
At 18:51 (GMT-3) Legacy's pilots called Brasilia Center and received these instructions from Brasilia Area Control Center’s Air Traffic Contoller:
Controller - N600 squalk identification, maintaining flight level 370, under radar surveillance.
Legacy - Roger. ( that was the last radio contact ).
The plane overflown BRS VOR at 18:55 ( GMT - 3 ) and it should step DOWN to Flight Level 360 as filed.
Next Compulsory Fix to be flown it should be TERES ( 12º 28.54’S, 51º 28.09’W ), distance 282 NM from BRS VOR on airway UZ 6 centerline, Track 334º. The next TERES Compulsory Fix where Legacy's pilots should CLIMB UP to Flight Level 380 as filed in original Flight Plan, but overruled by LAST Brasilia ACC-BR Controller AUTHORIZATION ( "Maintaining Flight Level 370") on last radio contact.
Legacy aircraft had lost communications with Brasilia Area Controle Center after 18:51 (GMT-3).
Captain Joseph Lepore and co-pilot Jan Paladino affirmed they tried for many times ( listed time in Preliminary Investigation Report present 12 times calls to be exactly ) to make VHF radio contact with Brasilia Area Control Center without success. They have claimed never turned down VHF radio volume and, they did not desengage the Autopilot for any reason after take off, and they felt insulted by some newspaper accusing them by turned off the TRANSPONDER .
The distance, on airway UZ 6, from Compulsory Fix TERES to Brasilia Area Control Center boundary is 157 NM ( NABOL Compulsory Fix ), heading 334 degrees. The next boundary is Manaus Area Control Center.
The distance from MAN VOR to Brasilia Area Control Center boundary ( NABOL Compulsory Fix ) is 610 NM.
Airway UZ 6 from Manaus VOR to Brasilia VOR has 1049 NM.
The collision took place on a point 29 NM after NABOL Compulsory Fix, within Manaus Area Control Center, near Air Force Base - SBCC - RESTRICTED area, at 19:56:54 ( GMT - 3 ).
This area is RESTRICTED to overflight from 18.000 feet until UNLIMETED airspace.
Airspace from BRS VOR to MAN VOR is RVSM area ( Reduced Vertical Separation Minimum ).
The question is:
Why ever didn't Manaus ACC Controller and/or Brasilia ACC Controller put Boeing 737-800 GOL1907 under RADAR VECTORING to keep the plane from COLLISION?
Boeing 737-800 GOL1907 Departure from SBEG was at 18:35 ( GMT - 3 ).
It reached FL 370 at 18:58 GMT-3.
After Legacy plane has overflown BRS VOR at 18:55 ( GMT - 3), Brasilia ACC Air Traffic Controller had 61 minutes and 54 seconds to coordinate with Manaus ACC Air Traffic Controller to ALERT and DIVERT Boeing 737 Flight GOL1907 to a CROSS-TRACK route parallel 10 or 20 miles to airway UZ 6 centerline.
Official Preliminary Investigation Report has many conflicting informations:
Preliminary Investigation Report informs a Collision Point at 10º 44’S, 053º 31’ W, but this point will be plotted to the RIGHT of airway UZ 6 centerline.
Investigator has said Boeing 737-800 GOL 1907 was maintaining Track 155º ( that is in accordance with airway UZ 6 centerline ) and AFTER Collision Point the aircraft ( Boeing GOL 1907 ) took Head 130º and fallen onto the ground 3.3 NM from Collision Point.
That’s meaning LEFT turn.
Investigator has said Collision Point was plotted "approximately 20 Kilometers = 10,7 NM from NABOL Compulsory Fix" within Manaus Area Control Center – Amazonic Center.
Leagacy’ speed was 460 Knots Ground Speed according Radar Data Tag on Flight Level 370 since TOC = Top of Climb, so we can easily calculate the TERES, NABOL and Collision Point right time.
BRS VOR overflight at 18:55 GMT-3.
Distance BRS VOR to TERES Compulsory Fix 282 NM.
Distance TERES to NABOL Compulsory Fix 157 NM ( ACC-BR boundary ).
Collision Point at 19:56:54 GMT-3.
We have calculated 3.9 minutes ( 3 minutes and 54 seconds ) from NABOL to Collision Point and a distance 29 NM on airway UZ 6 centerline.
Correct geographic coordinates for Collision Point are 10º 12’ 5.42" S, 53º 33’ 17.05" W.
There are something cloudy in this Preliminary Investigation Report.
Flight Plan presented to ACC - BR ( Brasilia Area Control Center ) via SBSJ - Sao Jose dos Campos AIS room.
Legacy's crew received Flight Plan CLEARANCE from ACC-BR via Sao Jose dos Campos TWR Air Traffic Controller.
That's the Legacy FPL route detailed:
N0452 F370 DCT PCL UW2 BRS/N0456 F360 UZ6 TERES/N0449 F380 UZ6 MAN DCT
Legacy's pilots received CLEARANCE to CLIMB UP and Maintain FL 370 to Manaus as CLEARED by ACC-BR.
Official Preliminary Investigation Report:
Take Off time: 17:51 (GMT-3) on September 29th, 2006
Legacy N600XL TOC ( Top of Climb ) 37.000 feet: 18:33 (GMT-3)
I am very intrigued with 42 minutes to climb up to 37.000 feet.
Compulsories Fixes along Airway UW 2 :
BCO VOR( 23º 24.4’S, 46º 26.1’W )
BGC VOR( 22º 57.’S, 46º 34.2’W )
PCL NDB ( 21º 50.15’S, 46º 33.94’W )
Track 006º from PCL NDB (415 ) to BRS VOR ( 115.90 )
KERBO INT ( 21º 06.2’S, 46º 44.2’W)
ARX VOR (19º 41.3’S, 47º 03.6’W )
VALDI INT ( 18º 03.8’S, 47º 28.5’W )
Last VHF Contact with ACC-BR 18:51 (GMT-3) before BRS VOR
( 15º 52.4’S, 48º 01.3’W )
At least for twice after leveled off Legacy plane on Flight Level 370 Legacy's pilots had Communications with ACC-BR before they have lost radio contact with ACC-BR.
At 18:51 (GMT-3) Legacy's pilots called Brasilia Center and received these instructions from Brasilia Area Control Center’s Air Traffic Contoller:
Controller - N600 squalk identification, maintaining flight level 370, under radar surveillance.
Legacy - Roger. ( that was the last radio contact ).
The plane overflown BRS VOR at 18:55 ( GMT - 3 ) and it should step DOWN to Flight Level 360 as filed.
Next Compulsory Fix to be flown it should be TERES ( 12º 28.54’S, 51º 28.09’W ), distance 282 NM from BRS VOR on airway UZ 6 centerline, Track 334º. The next TERES Compulsory Fix where Legacy's pilots should CLIMB UP to Flight Level 380 as filed in original Flight Plan, but overruled by LAST Brasilia ACC-BR Controller AUTHORIZATION ( "Maintaining Flight Level 370") on last radio contact.
Legacy aircraft had lost communications with Brasilia Area Controle Center after 18:51 (GMT-3).
Captain Joseph Lepore and co-pilot Jan Paladino affirmed they tried for many times ( listed time in Preliminary Investigation Report present 12 times calls to be exactly ) to make VHF radio contact with Brasilia Area Control Center without success. They have claimed never turned down VHF radio volume and, they did not desengage the Autopilot for any reason after take off, and they felt insulted by some newspaper accusing them by turned off the TRANSPONDER .
The distance, on airway UZ 6, from Compulsory Fix TERES to Brasilia Area Control Center boundary is 157 NM ( NABOL Compulsory Fix ), heading 334 degrees. The next boundary is Manaus Area Control Center.
The distance from MAN VOR to Brasilia Area Control Center boundary ( NABOL Compulsory Fix ) is 610 NM.
Airway UZ 6 from Manaus VOR to Brasilia VOR has 1049 NM.
The collision took place on a point 29 NM after NABOL Compulsory Fix, within Manaus Area Control Center, near Air Force Base - SBCC - RESTRICTED area, at 19:56:54 ( GMT - 3 ).
This area is RESTRICTED to overflight from 18.000 feet until UNLIMETED airspace.
Airspace from BRS VOR to MAN VOR is RVSM area ( Reduced Vertical Separation Minimum ).
The question is:
Why ever didn't Manaus ACC Controller and/or Brasilia ACC Controller put Boeing 737-800 GOL1907 under RADAR VECTORING to keep the plane from COLLISION?
Boeing 737-800 GOL1907 Departure from SBEG was at 18:35 ( GMT - 3 ).
It reached FL 370 at 18:58 GMT-3.
After Legacy plane has overflown BRS VOR at 18:55 ( GMT - 3), Brasilia ACC Air Traffic Controller had 61 minutes and 54 seconds to coordinate with Manaus ACC Air Traffic Controller to ALERT and DIVERT Boeing 737 Flight GOL1907 to a CROSS-TRACK route parallel 10 or 20 miles to airway UZ 6 centerline.
Official Preliminary Investigation Report has many conflicting informations:
Preliminary Investigation Report informs a Collision Point at 10º 44’S, 053º 31’ W, but this point will be plotted to the RIGHT of airway UZ 6 centerline.
Investigator has said Boeing 737-800 GOL 1907 was maintaining Track 155º ( that is in accordance with airway UZ 6 centerline ) and AFTER Collision Point the aircraft ( Boeing GOL 1907 ) took Head 130º and fallen onto the ground 3.3 NM from Collision Point.
That’s meaning LEFT turn.
Investigator has said Collision Point was plotted "approximately 20 Kilometers = 10,7 NM from NABOL Compulsory Fix" within Manaus Area Control Center – Amazonic Center.
Leagacy’ speed was 460 Knots Ground Speed according Radar Data Tag on Flight Level 370 since TOC = Top of Climb, so we can easily calculate the TERES, NABOL and Collision Point right time.
BRS VOR overflight at 18:55 GMT-3.
Distance BRS VOR to TERES Compulsory Fix 282 NM.
Distance TERES to NABOL Compulsory Fix 157 NM ( ACC-BR boundary ).
Collision Point at 19:56:54 GMT-3.
We have calculated 3.9 minutes ( 3 minutes and 54 seconds ) from NABOL to Collision Point and a distance 29 NM on airway UZ 6 centerline.
Correct geographic coordinates for Collision Point are 10º 12’ 5.42" S, 53º 33’ 17.05" W.
There are something cloudy in this Preliminary Investigation Report.
Last edited by georgecrock; 4th Jun 2007 at 09:41.
foxtrot xray
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georgecrock
Not sure where all this data comes from.. You need to identify source.
A quick read notes several problems/errors which may in part be due to linguistic short-comings or translation.
No comment until source of this information is known.
A quick read notes several problems/errors which may in part be due to linguistic short-comings or translation.
No comment until source of this information is known.
Pegase Driver
Georgecrock : joined the forum today and no info on your profile and already asking questions.
Lawyer by any chance ?
As A310driver said, no coments unless we know the source of your information.
But if you go through the 45 pages of this thread you might have by now a pretty good idea of what happenned, or more accurately , what did not happen.
Lawyer by any chance ?
As A310driver said, no coments unless we know the source of your information.
But if you go through the 45 pages of this thread you might have by now a pretty good idea of what happenned, or more accurately , what did not happen.
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I don't think there is anything new in there, all said before and speculative. http://www.pprune.org/forums/showpos...&postcount=757
TAS is not Ground Speed and cannot be taken to calculate a position in the range of a few inches (=seconds) :lol:.
When taken from the powerpoint presentation the coordinates had the usual layman's decimal point/degree error, i.e. they should be 10.44S 53.31W, which equals something like 10°26'S 53°18.6' and is almost exactly on the centerline.
Nothing cloudy.
Lawyer greetings.
10º 44’S, 053º 31’ W
10º 12’ 5.42" S, 53º 33’ 17.05" W
10º 12’ 5.42" S, 53º 33’ 17.05" W
When taken from the powerpoint presentation the coordinates had the usual layman's decimal point/degree error, i.e. they should be 10.44S 53.31W, which equals something like 10°26'S 53°18.6' and is almost exactly on the centerline.
Nothing cloudy.
Lawyer greetings.
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TCAS Tidbits
Greetings, all. I just joined, after slogging through all the posts in this thread. Some of what follows goes back to posts in the first days after the tragic accident, and may no longer be especially pertinent.
TCAS Climb Inhibit: TCAS is strapped (in the aircraft wiring or other method) to know the max altitude which the plane can achieve 1500'/min. rate of climb, for 30 seconds. TCAS assumes needing only 700' of climb or descent to avoid collision. JonDC9, your DC-9 has no limitation below its service ceiling. On the Other Hand, a 747-200 with more than 27 degrees flaps down is inhibited from a climb command. That should be covered in ground school.
The pair of 747s that were almost guided into a collision over Asia about ten years ago was caused by a KAL 747-200 that had been retrofitted with Allied Signal or Honeywell TCAS (they were separate then), and the installers wrongly used Gillham code for altitude input. The AD requiring TCAS specifically stated the most accurate source of altitude be used, which would be the DADC in the 747. There is no monitoring of Gillham code, so a broken wire or miswire results in altitude reporting error with no monitor. Even the synchro air data in the DC-9 autopilot has monitored output.
There are a number of causes for a transponder to stop squawking, if indeed that's what happened. There is a suppressor line that ties the transponders, TCAS R/T and both DME together on a party line. When any of the units transmits, its suppressor signal shuts off the other receivers. Unless someone has addressed that recently, a failure in any of the units will cause the TCAS and active transponder to go quiet. This could have happened in either plane.
Early on, suppressor cables sometimes had intermittent open connections, and a transponder would reply to its own TCAS, creating a red target right over own airplane, and lots of spurious TCAS Advisories. It was a nuisance, to say the least.
GB
TCAS Climb Inhibit: TCAS is strapped (in the aircraft wiring or other method) to know the max altitude which the plane can achieve 1500'/min. rate of climb, for 30 seconds. TCAS assumes needing only 700' of climb or descent to avoid collision. JonDC9, your DC-9 has no limitation below its service ceiling. On the Other Hand, a 747-200 with more than 27 degrees flaps down is inhibited from a climb command. That should be covered in ground school.
The pair of 747s that were almost guided into a collision over Asia about ten years ago was caused by a KAL 747-200 that had been retrofitted with Allied Signal or Honeywell TCAS (they were separate then), and the installers wrongly used Gillham code for altitude input. The AD requiring TCAS specifically stated the most accurate source of altitude be used, which would be the DADC in the 747. There is no monitoring of Gillham code, so a broken wire or miswire results in altitude reporting error with no monitor. Even the synchro air data in the DC-9 autopilot has monitored output.
There are a number of causes for a transponder to stop squawking, if indeed that's what happened. There is a suppressor line that ties the transponders, TCAS R/T and both DME together on a party line. When any of the units transmits, its suppressor signal shuts off the other receivers. Unless someone has addressed that recently, a failure in any of the units will cause the TCAS and active transponder to go quiet. This could have happened in either plane.
Early on, suppressor cables sometimes had intermittent open connections, and a transponder would reply to its own TCAS, creating a red target right over own airplane, and lots of spurious TCAS Advisories. It was a nuisance, to say the least.
GB
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A Little Abstract
Graybeard said
Can you elaborate upon this please Graybeard?
TCAS R/T: means the TCAS verbal directives?
Both DME? Where does DME come into it?
There are a number of causes for a transponder to stop squawking, if indeed that's what happened. There is a suppressor line that ties the transponders, TCAS R/T and both DME together on a party line. When any of the units transmits, its suppressor signal shuts off the other receivers.
TCAS R/T: means the TCAS verbal directives?
Both DME? Where does DME come into it?
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I know most pilots would rather stick to purely technical comments, but there is a demand for information about how things are done in Brazil. So, I am back to the educational posts...
The civil public prosecutors are conducting a criminal investigation precisely to determine everyone's roles.
Since the air traffic controllers are military, they have residence in Brazil and they are not allowed to leave the country without permission. That's why the prosecution did not ask for their passports' seizure.
Brazilian constitution prohibits discrimination against foreigners and the pilots have full access to the Justice. Unfortunately, the US does not grant the same rights to foreigners anymore, not only in case of terrorism, but also in case of illegal immigration.
The civil public prosecutors are conducting a criminal investigation precisely to determine everyone's roles.
Brazilian constitution prohibits discrimination against foreigners and the pilots have full access to the Justice. Unfortunately, the US does not grant the same rights to foreigners anymore, not only in case of terrorism, but also in case of illegal immigration.
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Abbr. and Explanation
Next time you're doing a preflight, take note of the DME and transponder antennas. In most cases they are identical. That's because they operate on similar frequencies in the 1.0 GHz range. The suppressor line connects the two transponders, the TCAS unit, and the two DME transceivers all onto a single line. The line sits near 0 volts. When any of the 5 units transmits, it raises the suppressor line to above 18 volts, commanding the other units to shut off their receivers during that brief portion of time, to avoid interference one with another.
If one of the units fails, and keeps the suppressor line high, the other units will be deafened, so to speak, while not causing any failure indication on the flight deck. The DMEs will show loss of signal, however. This is a rare failure, but possible.
If the suppressor line is disconnected at one or more places, there will be interference between units. Only a few DME frequencies will cause interference with the transponder and TCAS, on their 1030 MHz and 1090 MHz frequencies. A suppressor line disconnect between the active transponder and the TCAS will cause the TCAS to see own transponder and go crazy. That failure has been hidden in later TCAS units, but the interference is still there, and performance will be degraded.
The likelihood of an open line is probably significant in brand new airplanes. I've had to troubleshoot MD-80s where the phased TCAS installation was incomplete before bankruptcy, and when the plane was put back in service, the suppressor cable was overlooked.
What does R/T mean to you, Radio Transmissions?
If you're further interested, somewhere there is a list of DME frequencies paired with VOR frequencies. Any decent DME installation or overhaul manual should have it. If there's no other explanation for the apparent transponder failure on the Legacy, this would be worth exploring.
GB
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Ciao, Luca
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IFord says:
The best advice for a foreign pilot involved in an accident in a country where juridical investigation takes precedence over the technical one would be to get out as fast as possible (if feasible).
The best advice for a foreign pilot involved in an accident in a country where juridical investigation takes precedence over the technical one would be to get out as fast as possible (if feasible).
Prematurely quick departure from the scene (and country) of an accident tends to support presumptions of guilt in connection with the events. This is a great simplifier for folks nearer to the cause who would like to 'delegate' as much blame as possible to the foreigners. In many legal systems, 'flight from justice' is a serious crime in its own right, so it is a reliable way to become a criminal - without much hope of mounting any successful defence , even when not guilty of any other offence.
Pegase Driver
Thanks a lot JJ Cruz for your continuous legal information. I find this extremely interesting.
As I do know very little about legal processes, let me ask a blunt question to our US lawyers friends in this Forum :
If a couple of Forgein pilots ( does not matter which nationality here) were taking delivery of a Business jet in the Continental US and got involved in a collision where 150+ US citizens would have died, would those 2 forgeiners be allowed by the US Judicial System to leave the US freely ?
This is not provocation, just a request for genuine information, that perhaps could help cool down some posts here.
As I do know very little about legal processes, let me ask a blunt question to our US lawyers friends in this Forum :
If a couple of Forgein pilots ( does not matter which nationality here) were taking delivery of a Business jet in the Continental US and got involved in a collision where 150+ US citizens would have died, would those 2 forgeiners be allowed by the US Judicial System to leave the US freely ?
This is not provocation, just a request for genuine information, that perhaps could help cool down some posts here.
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Thanks a lot JJ Cruz for your continuous legal information. I find this extremely interesting.
As I do know very little about legal processes, let me ask a blunt question to our US lawyers friends in this Forum :
If a couple of Forgein pilots ( does not matter which nationality here) were taking delivery of a Business jet in the Continental US and got involved in a collision where 150+ US citizens would have died, would those 2 forgeiners be allowed by the US Judicial System to leave the US freely ?
This is not provocation, just a request for genuine information, that perhaps could help cool down some posts here.
As I do know very little about legal processes, let me ask a blunt question to our US lawyers friends in this Forum :
If a couple of Forgein pilots ( does not matter which nationality here) were taking delivery of a Business jet in the Continental US and got involved in a collision where 150+ US citizens would have died, would those 2 forgeiners be allowed by the US Judicial System to leave the US freely ?
This is not provocation, just a request for genuine information, that perhaps could help cool down some posts here.
"If the shoe were on the other foot, you could bet we'd keep them here until we were finished with the investigation," said Sylvia Royce, former chief of the Justice Department's international prisoner transfer program.
Royce said the Brazilian government is acting within reason, compared with American standards for detention. "Every country wants to hold on to people they think are involved in a crime," Royce said. "
Source: here
Btw, I'm not a lawyer.
Ecce Homo! Loquitur...
You better believe, we have 3 British bankers who were extradited from the UK and can't get permission to leave the USA. And it could be a couple of years before the case comes to court.
And not only wasn't anyone killed, they didn't even commit a crime under UK law.
And not only wasn't anyone killed, they didn't even commit a crime under UK law.
The Analog Kid
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Of course the pilots should be released on the undertaking they'll return if required but I think we can do without the naive indignation.
Cheers,
Rich.