gli77 wrote:modern aircraft I have worked on the second transponder automatically comes on when the first fails.
What happens if it is manually shut off?
Gol's B737 down over Amazon
Moderators: lilfssister, North Shore, sky's the limit, sepia, Sulako, I WAS Birddog
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invertedattitude
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Then go back to my first post and yours. My first point was that the crew had to knowingly disable both transponders. It will be a bad day for pilots and more work for avionics engineers. One more thing that will be fully automated and one step closer to reducing crew requirements.
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invertedattitude
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Well from the avionics suites I have experience with one transponder is on and the other remains in standby. If #1 fails then #2 automatically becomes active. For TCAS it does not matter what codes are being squawked.
Again I may be incorrect with regard to the Legacy but I suspect it would follow the same logic as other aircraft in its class.
My first point was that if in fact the transponders were not operating then the crew would have had to deactivate both. Which I think is the point that has people puzzled as to why they would do this. Since the reports seem to indicate that the Transponder suddenly came to life after they hit then someone is in trouble, as it is not a matter of a switch being in the wrong place, it is most likely a matter of two circuit breakers being pulled. But from my experience a nuissance condition being reset could explain it.
It will be interesting to see what the explanation is on this and its affects.
Again I may be incorrect with regard to the Legacy but I suspect it would follow the same logic as other aircraft in its class.
My first point was that if in fact the transponders were not operating then the crew would have had to deactivate both. Which I think is the point that has people puzzled as to why they would do this. Since the reports seem to indicate that the Transponder suddenly came to life after they hit then someone is in trouble, as it is not a matter of a switch being in the wrong place, it is most likely a matter of two circuit breakers being pulled. But from my experience a nuissance condition being reset could explain it.
It will be interesting to see what the explanation is on this and its affects.
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Lost in Saigon
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DOW JONES NEWSWIRES
November 2, 2006 9:59 a.m.
RIO DE JANEIRO (AP)--The flight recorder transcript from the executive jet involved in Brazil's worst air disaster shows that the jet's American pilots were told by Brazilian air traffic control to fly at the same altitude as a Boeing 737 before the planes collided over the Amazon rainforest, the Folha de S. Paulo newspaper reported Thursday.
According to Folha, the flight recorder shows American pilot Joseph Lepore receiving instructions from the tower in Sao Jose dos Campos to fly northwest at 37,000 feet (11,277 meters) "until Eduardo Gomes," the airport in Manaus. That altitude contradicted the pilots' filed flight plan and as an odd-numbered altitude should be reserved for southbound flights.
Folha did not reveal how it had obtained the transcript, which the air force has not yet released to federal police investigating the Sept. 29 crash. All 154 people on board the Gol airline's 737 were killed. The badly damaged executive jet managed to land safely, and the American pilots have been ordered to stay in Brazil during the investigation.
November 2, 2006 9:59 a.m.
RIO DE JANEIRO (AP)--The flight recorder transcript from the executive jet involved in Brazil's worst air disaster shows that the jet's American pilots were told by Brazilian air traffic control to fly at the same altitude as a Boeing 737 before the planes collided over the Amazon rainforest, the Folha de S. Paulo newspaper reported Thursday.
According to Folha, the flight recorder shows American pilot Joseph Lepore receiving instructions from the tower in Sao Jose dos Campos to fly northwest at 37,000 feet (11,277 meters) "until Eduardo Gomes," the airport in Manaus. That altitude contradicted the pilots' filed flight plan and as an odd-numbered altitude should be reserved for southbound flights.
Folha did not reveal how it had obtained the transcript, which the air force has not yet released to federal police investigating the Sept. 29 crash. All 154 people on board the Gol airline's 737 were killed. The badly damaged executive jet managed to land safely, and the American pilots have been ordered to stay in Brazil during the investigation.
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Lost in Saigon
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It is becoming quite clear that the Legacy pilots did nothing wrong.
They WERE cleared to FL370. They were expecting a climb or descent over Brasillia as they changed to a northwesterly course.
All the facts aren't available yet but.........
Bad luck, bad transponder, bad ATC radio, (maybe even bad ATC radar) caused a loss of radio AND transponder contact with ATC. There wasn't enough time for the Legacy pilots to recognize the radio failure and then follow any radio failure procedures.
At that point it is up to ATC to separate any other aircraft in the area.
Why didn't they?
They WERE cleared to FL370. They were expecting a climb or descent over Brasillia as they changed to a northwesterly course.
All the facts aren't available yet but.........
Bad luck, bad transponder, bad ATC radio, (maybe even bad ATC radar) caused a loss of radio AND transponder contact with ATC. There wasn't enough time for the Legacy pilots to recognize the radio failure and then follow any radio failure procedures.
At that point it is up to ATC to separate any other aircraft in the area.
Why didn't they?
Read this today........
Flight Recorder Is Said to Back American Pilots in Brazil Crash
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By THE ASSOCIATED PRESS
Published: November 3, 2006
RIO DE JANEIRO, Nov. 2 (AP) — The flight recorder transcript from the executive jet involved in Brazil’s worst air disaster shows that its American pilots were told by air traffic control to fly at the same altitude as a Boeing 737 before the planes apparently collided over the Amazon rain forest, a newspaper reported Thursday.
One of the pilots, Joseph Lepore, 42, of Bay Shore, N.Y., was told by the tower in São José dos Campos to maintain an altitude of 37,000 feet as he flew the jet on Sept. 29 beyond Brasília, the capital, on a northwest path to Manaus, the newspaper Folha de S. Paulo quoted the transcript as saying.
That altitude contradicted the pilots’ filed flight plan as well as established norms, which reserve odd-numbered altitudes for southbound flights.
The lawyer representing the pilots, Roberto A. Torricella Jr., who is based in Miami, said last Friday that his clients were at their assigned altitude, despite a flight plan that specified a different altitude.
The Defense Ministry was not immediately able to confirm the report in the newspaper on Thursday, said a spokeswoman, Flavia de Oliveira. She said it would not have more information until air force officials return Monday from Canada, where black boxes from both planes were sent for analysis.
Folha, Brazil’s largest-circulation daily, did not say how it obtained the transcript. The air force, which oversees Brazil’s air traffic controllers, has not released it to the Brazilian federal police or to National Transportation Safety Board investigators.
After it apparently clipped the Embraer Legacy 600 executive jet, the larger plane, Gol Airlines Flight 1907, a Boeing 737, crashed into the Amazon jungle. All 154 people on board the larger plane were killed.
The Legacy’s pilots — employees of ExcelAire Service Inc. of Ronkonkoma, N.Y. — were flying the Brazilian-made jet on its maiden voyage back to New York, and managed to land the badly damaged jet safely. They have been ordered to stay in Brazil during the investigation. The second pilot is Jan Paladino, 34, of Westhampton, N.Y.
Mr. Torricella said Thursday that the Folha report supported the pilots’ testimony to investigators.
“As we’ve maintained from the beginning, the pilots were cleared to Manaus for flight at three-seven-zero at the time of departure, and we’re confident that anyone that is able to hear the tower tapes or see a transcript of the instructions issued by the São José tower will hear the exact same thing,” he said.
The tower instructions may have been the first of a series of problems that led to the crash. As the Legacy approached Brasília, the plane lost radio contact with the control tower. The Legacy’s transponder, which signals the plane’s location to the tower and other airplanes, also stopped working.
Just what caused the failures remains unclear, but from that point on, both the pilots and the air traffic controllers lacked critical information. Controllers had no way of knowing the smaller plane’s altitude.
Brazilian officials have insisted the Legacy should have returned to its original flight plan after losing contact with the control tower.
That plan would have mostly kept the smaller jet at 36,000 feet after Brasília, and out of the path of the 737, which was flying at its customary altitude of 37,000 feet.
Instead, both planes remained on a collision course.
But aviation experts say orders from air traffic controllers always take precedence over flight plans.
http://www.nytimes.com/2006/11/03/world ... nd&emc=rss
Flight Recorder Is Said to Back American Pilots in Brazil Crash
Sign In to E-Mail This Print Reprints Save
By THE ASSOCIATED PRESS
Published: November 3, 2006
RIO DE JANEIRO, Nov. 2 (AP) — The flight recorder transcript from the executive jet involved in Brazil’s worst air disaster shows that its American pilots were told by air traffic control to fly at the same altitude as a Boeing 737 before the planes apparently collided over the Amazon rain forest, a newspaper reported Thursday.
One of the pilots, Joseph Lepore, 42, of Bay Shore, N.Y., was told by the tower in São José dos Campos to maintain an altitude of 37,000 feet as he flew the jet on Sept. 29 beyond Brasília, the capital, on a northwest path to Manaus, the newspaper Folha de S. Paulo quoted the transcript as saying.
That altitude contradicted the pilots’ filed flight plan as well as established norms, which reserve odd-numbered altitudes for southbound flights.
The lawyer representing the pilots, Roberto A. Torricella Jr., who is based in Miami, said last Friday that his clients were at their assigned altitude, despite a flight plan that specified a different altitude.
The Defense Ministry was not immediately able to confirm the report in the newspaper on Thursday, said a spokeswoman, Flavia de Oliveira. She said it would not have more information until air force officials return Monday from Canada, where black boxes from both planes were sent for analysis.
Folha, Brazil’s largest-circulation daily, did not say how it obtained the transcript. The air force, which oversees Brazil’s air traffic controllers, has not released it to the Brazilian federal police or to National Transportation Safety Board investigators.
After it apparently clipped the Embraer Legacy 600 executive jet, the larger plane, Gol Airlines Flight 1907, a Boeing 737, crashed into the Amazon jungle. All 154 people on board the larger plane were killed.
The Legacy’s pilots — employees of ExcelAire Service Inc. of Ronkonkoma, N.Y. — were flying the Brazilian-made jet on its maiden voyage back to New York, and managed to land the badly damaged jet safely. They have been ordered to stay in Brazil during the investigation. The second pilot is Jan Paladino, 34, of Westhampton, N.Y.
Mr. Torricella said Thursday that the Folha report supported the pilots’ testimony to investigators.
“As we’ve maintained from the beginning, the pilots were cleared to Manaus for flight at three-seven-zero at the time of departure, and we’re confident that anyone that is able to hear the tower tapes or see a transcript of the instructions issued by the São José tower will hear the exact same thing,” he said.
The tower instructions may have been the first of a series of problems that led to the crash. As the Legacy approached Brasília, the plane lost radio contact with the control tower. The Legacy’s transponder, which signals the plane’s location to the tower and other airplanes, also stopped working.
Just what caused the failures remains unclear, but from that point on, both the pilots and the air traffic controllers lacked critical information. Controllers had no way of knowing the smaller plane’s altitude.
Brazilian officials have insisted the Legacy should have returned to its original flight plan after losing contact with the control tower.
That plan would have mostly kept the smaller jet at 36,000 feet after Brasília, and out of the path of the 737, which was flying at its customary altitude of 37,000 feet.
Instead, both planes remained on a collision course.
But aviation experts say orders from air traffic controllers always take precedence over flight plans.
http://www.nytimes.com/2006/11/03/world ... nd&emc=rss
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invertedattitude
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- Joined: Tue Jul 06, 2004 1:12 pm
What bothers me more about this, is not the fact they lost contact with the LEgacy, and it was at an incorrect altitude in conflict, it is the fact once discovered, they didn't move the 737 from it's altitude, or hell if they didn't know the Legacys altitude at all, the turn the Gol flight, put them on a parrallel offset or something... scary stuff.
Thanks for those that post the articles. It seems though that the information given has become more sketchy than when the crash happened. Coming from a technical angle it seems that some very major questions as to TCAS warnings and XPRD #1 & #2 status are passed over and now focus is on ATC putting both planes at 37 000 ft.
Even if ATC put both planes at 37 000 ft and they lost communication with the Legacy for both VHF and XPDR, what about the Legacy TCAS warnings?? There seems to be a lot missing from this picture.
Even if ATC put both planes at 37 000 ft and they lost communication with the Legacy for both VHF and XPDR, what about the Legacy TCAS warnings?? There seems to be a lot missing from this picture.
I have been reading a bit about this accident and I am confused a bit. The Legacy was at his cleared altitude, abeit the inappropriate for direction of flight altitude. That has been confirmed. Brazillian officials were very very quick to blame the American pilots as being soley responsible for the accident.
My question to avionics types is this. If the airborne transponder simply repeats radio energy recieved from the ground radar, what happens to the airborne transponder if it is not being interogated by ground radar? Will it respond to TCAS only? I think it will. I don't know. What about the TCAS on the 737? It takes two to have a mid air. If the transponder of the Legacy failed, the TCAS should show the 737 to the Legacy crew. If the Legacy transponders were operating, why could the 737 not "see" them? According to an Aero News article, ATC lost radar contact for about an hour. That sure appears to me to allow time to do something , either move the 737 or the Legacy. Like Cat says, maybe Brazillian officialdom got in the way. "Not My Responsibility""Not My Job".
My question to avionics types is this. If the airborne transponder simply repeats radio energy recieved from the ground radar, what happens to the airborne transponder if it is not being interogated by ground radar? Will it respond to TCAS only? I think it will. I don't know. What about the TCAS on the 737? It takes two to have a mid air. If the transponder of the Legacy failed, the TCAS should show the 737 to the Legacy crew. If the Legacy transponders were operating, why could the 737 not "see" them? According to an Aero News article, ATC lost radar contact for about an hour. That sure appears to me to allow time to do something , either move the 737 or the Legacy. Like Cat says, maybe Brazillian officialdom got in the way. "Not My Responsibility""Not My Job".
The average pilot, despite the somewhat swaggering exterior, is very much capable of such feelings as love, affection, intimacy and caring.
These feelings just don't involve anyone else.
These feelings just don't involve anyone else.
This story keeps getting stranger and stranger.
Now a Brazillian newspaper says the Legacy was at the cleared altitude and the pilots should be found blameless for the accident.
But what I am having a problem with is how did 2 TCAS units fail to alert 4 pilots of an impending collision so I asked an avionics tech today and found out that if the GROUND (Brazillian military) radar failed, the transponders would not reply because they were not interigated, which also means the TCAS would be rendered mute. ATC is having labour problems and the military has refused to release the ATC tapes that the newspaper claims will exonerate the American pilots.
Strange case.
Now a Brazillian newspaper says the Legacy was at the cleared altitude and the pilots should be found blameless for the accident.
But what I am having a problem with is how did 2 TCAS units fail to alert 4 pilots of an impending collision so I asked an avionics tech today and found out that if the GROUND (Brazillian military) radar failed, the transponders would not reply because they were not interigated, which also means the TCAS would be rendered mute. ATC is having labour problems and the military has refused to release the ATC tapes that the newspaper claims will exonerate the American pilots.
Strange case.
The average pilot, despite the somewhat swaggering exterior, is very much capable of such feelings as love, affection, intimacy and caring.
These feelings just don't involve anyone else.
These feelings just don't involve anyone else.
oldtimer I am not sure I understood your comment correctly, but that means the TCAS is useless in over the Atlantic, if it needs ground radar interrogation. Is that what you mean? If so, that is not correct.oldtimer wrote:...so I asked an avionics tech today and found out that if the GROUND (Brazillian military) radar failed, the transponders would not reply because they were not interigated, which also means the TCAS would be rendered mute.
If the Legacy's txponder had failed, or was on stand-by, then the Legacy's TCAS was not operating, which also means the GOL 737 TCAS would not produce an alert because it can't 'see' the Legacy.
What is the difference between a good pilot and a good ATC? A good pilot thinks he's good, an ATC knows he is...
cpl_atc wrote:It is a *very* big sky, but somehow aluminium seems to become magnetic when airborne.
Oldtimer,
If the ground station was not functioning it will not have an affect on the aircraft equipment. It means that the ground crew would not be able to see anyone. TCAS is a stand alone system. I found it helpful to think of the TCAS processor as the ground based interogator.
However TCAS does require at least a Mode A transponder on the threat airplane to see it, and the TCAS is able to generate a TA from the range and bearing info. If the threat aircraft has Mode A & C then the TCAS will know the threat aircraft bearing, range and altitude and will generate a TA and vertical RA. If both aircraft have mode S and TCAS II then you get the TCAS to TCAS coordination.
I would like to know what happened to both ATC transponders on the Legacy aircraft. Does anyone know on the Legacy if the ADU information is transmitted to the TCAS processor via the xpdr or is it direct?
If the ground station was not functioning it will not have an affect on the aircraft equipment. It means that the ground crew would not be able to see anyone. TCAS is a stand alone system. I found it helpful to think of the TCAS processor as the ground based interogator.
However TCAS does require at least a Mode A transponder on the threat airplane to see it, and the TCAS is able to generate a TA from the range and bearing info. If the threat aircraft has Mode A & C then the TCAS will know the threat aircraft bearing, range and altitude and will generate a TA and vertical RA. If both aircraft have mode S and TCAS II then you get the TCAS to TCAS coordination.
I would like to know what happened to both ATC transponders on the Legacy aircraft. Does anyone know on the Legacy if the ADU information is transmitted to the TCAS processor via the xpdr or is it direct?
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sprucemonkey
- Rank 8
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- Joined: Thu Feb 19, 2004 10:31 pm
Hungry already..............
NEW YORK - Families of the victims of Brazil's worst air disaster sued the operator and maker of a business jet that clipped the commercial airliner in midair, saying the collision caused the crash that killed all 154 people aboard.
The families listed ExcelAire Service Inc. of Ronkonkoma, N.Y. and Honeywell International Inc. as defendants in the lawsuit filed Monday in U.S. District Court in Brooklyn.
The lawsuit, which seeks unspecified damages, argues that the Sept. 29 crash occurred because the ExcelAire pilots were flying at an incorrect altitude and the aircraft's transponder was not functioning. The transponder, which transmits the plane's altitude and identification information and operates its automatic anti-collision system, is manufactured by Honeywell, the lawsuit said.
After the two planes collided, Gol Airlines Flight 1907 plunged into the Amazon rainforest.
Although the crash damaged the wing and tail of the smaller jet, the American pilots managed to land safely and all seven on board survived.
A spokeswoman for ExcelAire, Lisa Henrickson, said in an e-mail that the company was aware of the lawsuit and was preparing a reply.
Honeywell spokesman Bill Reavis said Monday afternoon in a statement that the Morristown, N.J., company hadn't seen the lawsuit and couldn't comment on the specific allegations.
Early speculation in Brazil pointed to errors by the U.S. pilots, but the Folha de Sao Paulo newspaper, citing a flight recorder transcript it obtained, said air traffic controllers were recorded putting them on a collision course with the bigger jet.
Since the accident, the two American pilots have been held in Brazil pending the results of an investigation.
This is long winded but I hope it helps to clarify some things.
There seems to be a lot of confusion about TCAS and Transponders here so I will try to clarify a bit.
The setup on an aircraft with two transponders is not like a small twin’s whereby the transponder is right in front of you and you dial in the code right on the transponder itself. On a large aircraft, you control the transponder via a control panel. The actual transponders are in the electronics compartment. Each one looks at the control panel’s settings to transmit the correct code and to see which one of them should be transmitting. It is much like the tuner on your TV. It just tells the guts what they should be doing.
They also don’t transmit at the same time, and on any aircraft I have ever flown, they don’t fail automatically to the second transponder, they just fail. ATC then calls you to say they lost your target and you switch to the second one.
The transponder in question has an AD, because of a bug which puts the transponder in standby mode all by itself.
Airworthiness Directive
Federal Register Information
Header Information
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2006-24639; Directorate Identifier 2005-NM-171-AD;
Amendment 39-14761; AD 2006-19-04]
RIN 2120-AA64
Airworthiness Directives; Honeywell RCZ-833J/K, -851J/K, and - 854J Communication (COM) Units, Equipped with XS-852E/F Mode S Transponders; and Honeywell XS-856A/B and -857A Mode S Transponders;
SUMMARY: The FAA is adopting a new airworthiness directive (AD) for certain Honeywell COM units and transponders, installed on but not limited to certain transport category airplanes. … This AD results from the transponder erroneously going into standby mode if the flight crew takes longer than five seconds when using the rotary knob of the radio management unit to change the ATC code. We are issuing this AD to prevent the transponder of the COM unit from going into standby mode, which could increase the workload on the flight crew and result in improper functioning of the traffic alert and collision avoidance system.
Applicability
(c) This AD applies to the Honeywell parts identified in paragraphs (c)(1) and (c)(2) of this AD, approved under Technical Standard Order TSO-C112, installed on but not limited to…
…EMBRAER Model EMB-135BJ, -135ER, -135KE, -135KL, and - 135LR airplanes; EMBRAER Model EMB-145, -145ER, -145MR, -145LR, - 145XR, -145MP, and -145EP airplanes
The entire AD can be read at http://www.airweb.faa.gov/Regulatory_an ... enDocument
This would explain why radar contact was lost and more importantly, why radar contact was re-established when the crew dialed in 7700. (They would take less than 5 seconds to dial 7700)
There is radar coverage over that area and it is the definition of "the middle of nowhere". Even so, they popped up on radar when they squawked 7700. They couldn’t find a usable frequency because they had lost situational awareness and didn’t know where they were. All the frequencies for a given sector are published on the Jepp. enroute charts for that area. They couldn’t find a useable airport by themselves as well ( they needed help from a passing cargo flight) even though where they landed is asphalt 8547 X 145 and has VOR and NDB approaches. It is a non English non sched. public airport as it is only used for medivacing indians out of the bush.
If their transponder went to standby, their TCAS would be inop according to the AD, as it would not be radiating nor processing any signal . The Legacy would therefore be invisible to the 737’s TCAS.
Contrary to popular belief, jet pilots are not scanning for traffic while in cruise flight. No-one is supposed to be there so why the hell look?
As to what happened: The initial clearance to maintain FL370 was correct as the airway was one way until Brasilia.
Either ATC just clean forgot about the flight after Brasilia, or the pilots upon hearing “Radar Contact, maintain FL370” turned down the volume of their radios too far because that sector has a lot of traffic/ chatter. (I fly it every week). That is WAY more common than people like to admit.
Brasilia center doesn’t normally change codes, but if they had given a new code to the Legacy and then lost radar contact, the Legacy should still be on frequency. (5 seconds)
My gut feeling is that they turned down the radios to play with the new toys in the aircraft and while messing with the transponder managed to trip it to standby. There were multiple calls to the aircraft registered on tape.
This in no way excuses ATC from not moving the 737. That was a blatant error.
As to what happened to the 737.
A friend of mine is part of the investigation and had access to the Flight Data Recorders and was on site.
The 737 was hit in the wing and started an immediate roll. It reached 6 G’s in the roll. The engines separated from their pylons. The main gear was ejected from the gear wells as the uplocks only withstand 4 G’s I am told. Catastrophic failure of the fuselage occurred below 10,000 feet. The aircraft remains are in a small area for a midair as everything went nearly vertical after the collision.
Time to impact from 37,000 feet was 2 minutes and 55 seconds.
He sent me pictures from the crash site, believe me you don’t want to see them. Bodies were found more than a meter under ground.
The crew of the Legacy were held because everyone, myself included, thought that they had been playing with their new toy and were relying on the Big Sky Theory to keep them out of trouble. As the airspace is all RVSM, that seemed at the time like criminal negligence causing death. In 1997 a flight for the company I flew for screwed up badly at LAX. There was not an accident but the crew were under house arrest (hotel) in LA for over 2 weeks, so it is not a third world thing.
We will just have to wait and see.
PS Do not believe anything that the papers publish here about the accident. I have NEVER seen so much drivel about aviation in my life as to what has been published here.
There seems to be a lot of confusion about TCAS and Transponders here so I will try to clarify a bit.
The setup on an aircraft with two transponders is not like a small twin’s whereby the transponder is right in front of you and you dial in the code right on the transponder itself. On a large aircraft, you control the transponder via a control panel. The actual transponders are in the electronics compartment. Each one looks at the control panel’s settings to transmit the correct code and to see which one of them should be transmitting. It is much like the tuner on your TV. It just tells the guts what they should be doing.
They also don’t transmit at the same time, and on any aircraft I have ever flown, they don’t fail automatically to the second transponder, they just fail. ATC then calls you to say they lost your target and you switch to the second one.
The transponder in question has an AD, because of a bug which puts the transponder in standby mode all by itself.
Airworthiness Directive
Federal Register Information
Header Information
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2006-24639; Directorate Identifier 2005-NM-171-AD;
Amendment 39-14761; AD 2006-19-04]
RIN 2120-AA64
Airworthiness Directives; Honeywell RCZ-833J/K, -851J/K, and - 854J Communication (COM) Units, Equipped with XS-852E/F Mode S Transponders; and Honeywell XS-856A/B and -857A Mode S Transponders;
SUMMARY: The FAA is adopting a new airworthiness directive (AD) for certain Honeywell COM units and transponders, installed on but not limited to certain transport category airplanes. … This AD results from the transponder erroneously going into standby mode if the flight crew takes longer than five seconds when using the rotary knob of the radio management unit to change the ATC code. We are issuing this AD to prevent the transponder of the COM unit from going into standby mode, which could increase the workload on the flight crew and result in improper functioning of the traffic alert and collision avoidance system.
Applicability
(c) This AD applies to the Honeywell parts identified in paragraphs (c)(1) and (c)(2) of this AD, approved under Technical Standard Order TSO-C112, installed on but not limited to…
…EMBRAER Model EMB-135BJ, -135ER, -135KE, -135KL, and - 135LR airplanes; EMBRAER Model EMB-145, -145ER, -145MR, -145LR, - 145XR, -145MP, and -145EP airplanes
The entire AD can be read at http://www.airweb.faa.gov/Regulatory_an ... enDocument
This would explain why radar contact was lost and more importantly, why radar contact was re-established when the crew dialed in 7700. (They would take less than 5 seconds to dial 7700)
There is radar coverage over that area and it is the definition of "the middle of nowhere". Even so, they popped up on radar when they squawked 7700. They couldn’t find a usable frequency because they had lost situational awareness and didn’t know where they were. All the frequencies for a given sector are published on the Jepp. enroute charts for that area. They couldn’t find a useable airport by themselves as well ( they needed help from a passing cargo flight) even though where they landed is asphalt 8547 X 145 and has VOR and NDB approaches. It is a non English non sched. public airport as it is only used for medivacing indians out of the bush.
If their transponder went to standby, their TCAS would be inop according to the AD, as it would not be radiating nor processing any signal . The Legacy would therefore be invisible to the 737’s TCAS.
Contrary to popular belief, jet pilots are not scanning for traffic while in cruise flight. No-one is supposed to be there so why the hell look?
As to what happened: The initial clearance to maintain FL370 was correct as the airway was one way until Brasilia.
Either ATC just clean forgot about the flight after Brasilia, or the pilots upon hearing “Radar Contact, maintain FL370” turned down the volume of their radios too far because that sector has a lot of traffic/ chatter. (I fly it every week). That is WAY more common than people like to admit.
Brasilia center doesn’t normally change codes, but if they had given a new code to the Legacy and then lost radar contact, the Legacy should still be on frequency. (5 seconds)
My gut feeling is that they turned down the radios to play with the new toys in the aircraft and while messing with the transponder managed to trip it to standby. There were multiple calls to the aircraft registered on tape.
This in no way excuses ATC from not moving the 737. That was a blatant error.
As to what happened to the 737.
A friend of mine is part of the investigation and had access to the Flight Data Recorders and was on site.
The 737 was hit in the wing and started an immediate roll. It reached 6 G’s in the roll. The engines separated from their pylons. The main gear was ejected from the gear wells as the uplocks only withstand 4 G’s I am told. Catastrophic failure of the fuselage occurred below 10,000 feet. The aircraft remains are in a small area for a midair as everything went nearly vertical after the collision.
Time to impact from 37,000 feet was 2 minutes and 55 seconds.
He sent me pictures from the crash site, believe me you don’t want to see them. Bodies were found more than a meter under ground.
The crew of the Legacy were held because everyone, myself included, thought that they had been playing with their new toy and were relying on the Big Sky Theory to keep them out of trouble. As the airspace is all RVSM, that seemed at the time like criminal negligence causing death. In 1997 a flight for the company I flew for screwed up badly at LAX. There was not an accident but the crew were under house arrest (hotel) in LA for over 2 weeks, so it is not a third world thing.
We will just have to wait and see.
PS Do not believe anything that the papers publish here about the accident. I have NEVER seen so much drivel about aviation in my life as to what has been published here.
Last edited by TTJJ on Thu Nov 09, 2006 1:32 pm, edited 1 time in total.
Great post TTJJ. I was unaware of the AD for the honeywell xpdr and the setup on the Legacy.
I do diagree with one of your points, but not in the application to this accident. You listed that if the xpdr is inop then the TCAS is inop. This is not always the case. It would depend if altitude information is routed via the xpdr or direct to the TCAS. If it goes via the xpdr and the xpdr fails then yes the TCAS does not know where it is so it can not determine range, bearing, altitiude of intruder aircraft.
TCAS is actually two systems, surveillance and collision avoidance. There are TCAS installations where surveillance is possible without a XPDR.
I also find it strange that the Legacy does not automatically switch to the #2 xpdr once #1 has reported failed and WofW. Perhaps that will be a new mod across the board as a result.
Once again thanks for the information.
I do diagree with one of your points, but not in the application to this accident. You listed that if the xpdr is inop then the TCAS is inop. This is not always the case. It would depend if altitude information is routed via the xpdr or direct to the TCAS. If it goes via the xpdr and the xpdr fails then yes the TCAS does not know where it is so it can not determine range, bearing, altitiude of intruder aircraft.
TCAS is actually two systems, surveillance and collision avoidance. There are TCAS installations where surveillance is possible without a XPDR.
I also find it strange that the Legacy does not automatically switch to the #2 xpdr once #1 has reported failed and WofW. Perhaps that will be a new mod across the board as a result.
Once again thanks for the information.
[quote="TTJJ"] In 1997 a flight for the company I flew for screwed up badly at LAX. There was not an accident but the crew were under house arrest (hotel) in LA for over 2 weeks, so it is not a third world thing.
[/quote]
More details please. I find this very difficult to believe.
[/quote]
More details please. I find this very difficult to believe.
Gli77
I don't know if the Legacy's transponder switches automatically to #2 when #1 fails. I said that I had never flown an aircraft that did.
You are correct about some aircraft having a working TCAS even when the transponder is in standby. The MD-11 is like that. The AD however does state that the TCAS might go west if the transponder is in standby.
Pelmet;
I was incorrect in implying/stating that the crew was confined to the hotel. They had to stay in the USA/LAX area during the investigation.
It was on or about April 17, 1997.
They were returning from Korea and they had been vectored onto a tight downwind,in VMC, which made the base leg too short. The controller was busy on the radio and they were turned to intercept final late, almost on the localizer. It takes time to turn a heavy aircraft.
They blew through the localizer and a KLM 747 got a RA on his TCAS to descend. The KLM, who was on final for a parallel runway, saw the MD-11 descended and turned INTO the MD-11. The MD-11 saw the KLM turn into him and thought " If I turn inbound to the runway (a right turn) I will lose the 747 from sight." So he continued straight ahead, on base, crossing the approach paths of 3 runways, before turning to the center of the field and starting a missed approach. As did the KLM 747 but in the opposite direction. I know this because I was in LA the day it happened and I talked to our pilot over beer at the hotel.
The controller was transferred to ground control duties and nothing happened to the pilots. The FAA found that our pilot, while he should have turned inbound by himself, did the right thing in avoiding the 747 by keeping it in sight at all times. The 747 should not have turned. He should descended straight ahead. Both aircraft were at about 2500 AGL at the time.
The press went nuts.
Our guy never flew to the USA again. Poor guy, it was the last leg of his last training flight before being considered apt by the training department.
I don't know if the Legacy's transponder switches automatically to #2 when #1 fails. I said that I had never flown an aircraft that did.
You are correct about some aircraft having a working TCAS even when the transponder is in standby. The MD-11 is like that. The AD however does state that the TCAS might go west if the transponder is in standby.
Pelmet;
I was incorrect in implying/stating that the crew was confined to the hotel. They had to stay in the USA/LAX area during the investigation.
It was on or about April 17, 1997.
They were returning from Korea and they had been vectored onto a tight downwind,in VMC, which made the base leg too short. The controller was busy on the radio and they were turned to intercept final late, almost on the localizer. It takes time to turn a heavy aircraft.
They blew through the localizer and a KLM 747 got a RA on his TCAS to descend. The KLM, who was on final for a parallel runway, saw the MD-11 descended and turned INTO the MD-11. The MD-11 saw the KLM turn into him and thought " If I turn inbound to the runway (a right turn) I will lose the 747 from sight." So he continued straight ahead, on base, crossing the approach paths of 3 runways, before turning to the center of the field and starting a missed approach. As did the KLM 747 but in the opposite direction. I know this because I was in LA the day it happened and I talked to our pilot over beer at the hotel.
The controller was transferred to ground control duties and nothing happened to the pilots. The FAA found that our pilot, while he should have turned inbound by himself, did the right thing in avoiding the 747 by keeping it in sight at all times. The 747 should not have turned. He should descended straight ahead. Both aircraft were at about 2500 AGL at the time.
The press went nuts.
Our guy never flew to the USA again. Poor guy, it was the last leg of his last training flight before being considered apt by the training department.
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Lost in Saigon
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From PPRUNE.ORG
http://www.pprune.org/forums/forumdispl ... forumid=13
The Brasilia newspaper Correio Brasiliense said today that an airforce source close to the investigation and who has seen/heard the FDR and CVR data, confirmed that the Legacy’s FDR indicates the transponder “jammed” (literal translation from the Portuguese word “travou” which can cover several other meanings including “went to standby”) shortly after overflying Brasilia and that this “impeded all radio transmission or reception” (see note below).
The FDR also confirms the flight was stable at FL370 and not, as Cindacta primary radar recordings showed, varying between FL 320 and FL 420.
The Legacy’s CVR recorded five attempts to contact Cindacta 1 by radio and that they were tuned to the correct Brasilia frequency. At the same time Cindacta were attempting to contact the Legacy, first requesting it to switch the transponder on and, when primary radar began showing the altitude variations, to follow its flight plan - equally without success. Shortly before the collision Cindacta asked on an open frequency that any other aircraft in the vicinity contact the Legacy. There was no reply until after the collision, when the Legacy switched to emergency frequency and both radio and transponder resumed functioning.
http://www.pprune.org/forums/forumdispl ... forumid=13
The Brasilia newspaper Correio Brasiliense said today that an airforce source close to the investigation and who has seen/heard the FDR and CVR data, confirmed that the Legacy’s FDR indicates the transponder “jammed” (literal translation from the Portuguese word “travou” which can cover several other meanings including “went to standby”) shortly after overflying Brasilia and that this “impeded all radio transmission or reception” (see note below).
The FDR also confirms the flight was stable at FL370 and not, as Cindacta primary radar recordings showed, varying between FL 320 and FL 420.
The Legacy’s CVR recorded five attempts to contact Cindacta 1 by radio and that they were tuned to the correct Brasilia frequency. At the same time Cindacta were attempting to contact the Legacy, first requesting it to switch the transponder on and, when primary radar began showing the altitude variations, to follow its flight plan - equally without success. Shortly before the collision Cindacta asked on an open frequency that any other aircraft in the vicinity contact the Legacy. There was no reply until after the collision, when the Legacy switched to emergency frequency and both radio and transponder resumed functioning.
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Alex YCV
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Update on this... the pilots of the Legacy are apparently being charged...
http://www.cnn.com/2006/WORLD/americas/ ... index.html
http://www.cnn.com/2006/WORLD/americas/ ... index.html
This is a my sig... I hope you like it.
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sprucemonkey
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TTJJ, excellent post. Thanks.
Gli77, I'm also curious about the TCAS setup. Can you confirm that as installed on the Legacy, the TCAS will not function if one xponder fails (and that it wouldn't necessarily default to the other xponder)? I (perhaps naively) assumed the TCAS system was independant of an aircraft's own transponder system, at least in terms of detecting other traffic.
Gli77, I'm also curious about the TCAS setup. Can you confirm that as installed on the Legacy, the TCAS will not function if one xponder fails (and that it wouldn't necessarily default to the other xponder)? I (perhaps naively) assumed the TCAS system was independant of an aircraft's own transponder system, at least in terms of detecting other traffic.
That's about three minutes of hell I hope nobody ever has to experience. Wow, I have trouble sitting through a 30 second commercial.TTJJ wrote:
Time to impact from 37,000 feet was 2 minutes and 55 seconds.
Aviation- the hardest way possible to make an easy living!
"You can bomb the world to pieces, but you can't bomb it into peace!" Michael Franti- Spearhead
"Trust everyone, but cut the cards". My Grandma.
"You can bomb the world to pieces, but you can't bomb it into peace!" Michael Franti- Spearhead
"Trust everyone, but cut the cards". My Grandma.
