Mid-air collision over Brasil

[Rippa]

Originally Posted by onetrack

The critical factors in this case .. are that there was a change of level, coinciding with a change of ATC unit. Although the flightplan will show a change of level, the crew will not do this, until cleared by ATC.
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Onetrack,

If I am not mistaken, the Legacy was supposed to clear FL370 to 360 over BRS VOR. As an airline pilot in Brazil for the past 6 years, I have never had a communication problem in that area (200NM radius from BRS VOR). However, I have had some trouble with the ATC when flying outbound from BRS to MAO or BEL, when aprox 200NM from Brasilia...In fact I had this problem today, when flying inbound from BEL TO BSB (delay on getting first comm contact, and poor audio return from Brasilia....3/3). But communications work very well when you are "near" Brasilia. Agree that ATC has responsibility on this matter (A class airspace). Disregard the news on the paper...it is clear that the media is trying to drive public opinion against the Legacy pilots, giving unfounded info. The problem is that the majority of population takes this kind of news as a fact. If the ATC had any responsibility on this accident, believe me, they will have their "share of guilt" on the final report...this already happened once, with a Lufthansa in Rio de Janeiro.

Regards

PS: Regarding airspace: This area is a SIVAM area, that means that the radars are not on the ground, but built in airforce airplanes that keep flying 24-7 (Brasilian airforce uses EMB Legacy airplanes on this...ironic). This kind of equipment (onboard radar) is used to intercept unknown traffic, and I am not sure, but do not doubt, of the capability of getting altitude info even with the xpndr off. ATC in that area is Military ONLY.

[Scurvy.D.Dog]

.. now we are back on track (so to speak)
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.. some of the reasonable questions and opinions in the last few postings (such as those from Austrian Simon) are why most of us bother with these discussions .. it is to ‘understand’ an share relevant hypothesis and factual information such as the ICAO quote from PPRuNe Radar, to heighten awareness and avoid similar error scenarios from occurring in the future (such as the incorrect assumptions regarding comm Loss and flight progression thereafter) … NOT APORTION INDIVIDUAL BLAME!
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.. that said .. it is clear there are some .. well … lets call them potential anomalies to this accident sequence that will only really be clarified by thorough investigation. RVSM, TXPDR/TCAS, ATC procedures etc will likely all be in there and so they should be!! .. in the meantime it is important to look at the what if’s even if they in the end have no relevance to this accident .. everyone reading will be thinking of the ‘what if’s’ not matter what they are .. that must be a positive thing for air safety generally!
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My issue is with some of our contributions is that we MUST not accuse individuals without factual basis, rather ask the questions of how and why the events occurred!
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. I get very hot under the collar when ‘individuals’ (be they pilots or air traffic controllers) are besmirched without basis for doing so!
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Clearly, as with all these types of events, the system defences broke! … individuals may or may not have played roles in that!
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.. my point again is that most always the errors are inadvertent and unintentional and it is neither fair nor reasonable to blame individuals when on any given day, given the same set of fault tree components .. ANY INDIVIDUAL could fall into the same holes!!
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.. aside from anything else that might come out of this horrific accident … ICAO mandating of track offsets outside SID/STAR/terminal areas MUST be defined and promulgated globally A.S.A.P! … any argument about tolerances applied on lateral crossing points is mute compared to the safety enhancement gained!!
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Rippa .. that is most interesting regarding the airborne radar .. I will be very interested to see what is said in the wash-up re that system and its operating rules!!

[jondc9]

<my point again is that most always the errors are inadvertent and unintentiona>


or due to a lack of resources or trying to fix a problem and later causing a problem...

consider the transponder AD...going to standby after 5 seconds etc...obviously well intentioned so as not to trigger a 7700 alarm etc...but better the transponder be on with the wrong code than off with the code improperly set...

at least TCAS would work with the wrong code.


AS with the COMAIR thread, swiss cheese lining up...just one thing...if you want more slices of swiss cheese with the same amount of milk, you have to have more holes...

[Rippa]

Originally Posted by Hokie Nation

So much easier to blame US citizens than your own banana republic military buffoons.

Hokie,

As an experienced pilot that I believe you are, you should know that the media news, when the topic is avaition, cannot be considerated at all ! Lots of BS going on at this time. I havent seen anyone blaming US citizens IN A OFFICIAL DOCUMENT YET !!!! So lets give the investigators (the team includes US citizens) some time and stick to a more grown up discution.

Regards

[alemaobaiano]

and buy some new equipment

Hokie, I would guess that Brazil has a more modern ATC infrastructure than many countries, quite possibly including the USA. Their radar systems have been provided by Thomson CSF, Raytheon and Lockheed Martin and the oldest of these dates from 1994. Most systems have been delivered and installed since 2001. They don't need to buy new equipment, they already have it.

[ZOA ATC]

I read with interest the posts about RVSM being discontinued due to in-flight transponder failure. The US does not discontinue RVSM due to transponder failure. I'm curious about ICAO. Is is country specific? I've searched the online ICAO resources and cannot find a concrete answer on in-flight failures.

Thank you

[piombo]

The NYT reports that the Legacy transponder is not included in the AD and that is confirmed by Honeywell themselves.
Now...?

[jondc9]

I think there may be some confusion about RVSM and loss of transponder...I indicated that I thought RVSM should be discontinued , but meant it in the sense that it should be discontinued in general and not neccessarily in this one case due to xpndr failure. I was quite happy with 2000' spacing at higher altitude, but do not want to see the thread get too off course.

As to the honeywell bit about xpndr AD...

I think that there will be plenty of blame to go around, though for the life of me, not too much on the GOL crew.

While looking out the window is still a way not to hit someone else, it cannot really work that well at a 1000mph closing speed. A first you see a spot smaller than a bug on your windshield, then you shudder in delayed fear when you realize its a plane.

Seperation is ATC business

Visual scanning for other planes is a pilot's job, both sides here.


if there was any monkey business with transponder/ etc...we will have to wait and see...but anyone who doesn't think monkey business doesn't happen hasn't been around that much.

j

[PPRuNe Radar]

I read with interest the posts about RVSM being discontinued due to in-flight transponder failure. The US does not discontinue RVSM due to transponder failure. I'm curious about ICAO. Is is country specific? I've searched the online ICAO resources and cannot find a concrete answer on in-flight failures.

It will depend on what is in the ICAO Regional Supplementary for the airspace involved. Most have adopted the European procedures, but I can't confirm if that is also the case for Brasil. Some States in Europe allow continued RVSM flight without a transponder, some don't. I'd imagine it is a similar story in other ICAO regions.

European MELs for RVSM flight are in JAA TGL 6, with further clarification on the Eurocontrol RVSM FAQ page.

8.1 Equipment for RVSM Operations

The minimum equipment fit is:

8.1.1 Two independent altitude measurement systems.
8.1.2 One secondary surveillance radar transponder with an altitude reporting system that can be connected to the altitude measurement system in use for altitude keeping.
8.1.3 An altitude alerting system.
8.1.4 An automatic altitude control system.

Source: TGL6

The ICAO RVSM requirements do not preclude ATC clearance into European RVSM airspace for RVSM-approved aircraft and non-RVSM approved State aircraft that experience Mode C transponder failure (or if the Mode C readout is misreading by more than 200 feet) prior to intended entry into RVSM airspace.

However, the specific requirement for the carriage and operation of transponders is a "State" responsibility, in accordance with �Annex 11 to the Convention on International Civil Aviation�, Chapter 2, paragraph 2.25, which reads as follows:

"States shall establish requirements for carriage and operation of pressure-altitude reporting transponders within defined portions of airspace".

Please refer to relevant National Aeronautical Information Publications (AIPs) for information on transponder requirements.

Source: Eurocontrol

[Johnbr]

Hi everybody,
Being busy these last few days,I came to this forum in the hopes of learning of something new on this accident,which I think,we all in this trade should be doing.Many of us are genuinely concerned about the facts and more important,the lessons to be learned form this and a bit of speculation is in order,I guess.But,nonetheless,I read a few posts here,that really sadden me.Let's see....
The "Banana Republic"airline was operating a brand new 737/800(they have a fleet of 60+ 737's NG,of which they've ordered 100+)in his correct FL/Airway.
The "Äll Mighty" american pilots were flying a "Banana Republic"made brand new EMB145 corporate version Legacy,of which I've seen plenty in "Äll Mighty"places like MIA,JFK,CDG,LHR,you name it....
They were both operating in radar covered area equipped with state-of-the-art radar provided by "All Mighty"makers such as Raytheon,Thomson and Lockheed-Martin , and recently installed.
These are facts.
The 738,was at Fl370 as for his Flight plan,operating a scheduled flight when it was hit by the Legacy,who should be at FL360.Fact!
What remains to be uncovered is:Why was the Legacy at FL370?????
Comm fail? We do have procedures to cover that,published by ICAO,to which Brasil complies with,as have been posted here in this very same forum before...
Transponder fail?? Who knows,the thing went back on,right after the MAC,right?
Maybe someone got too distracted showing off the knew toy to a reporter who shouldn't be at the cockpit,and missed the calls from ATC,or did not realize the seriousness of the situation,or did not see,at the nav chart that he was supposed to change level....Who knows...
Maybe someone got too worried with a blip with no sqwak in his/her screen and lost SA,thus preventing him/her from taking precautionary measures to avoid this MAC.Who knows....
One thing's for sure:The "Banana Republic"Capt on the 738 is out of this "blame game"as someone put it before..
Anyway,I do not believe that this whole thing it's going to come down as a blame game,at all.Brasil has a very good record in aviation safety(not perfect though,like every other "All Mighty"countrys in the world) and I'm pretty confident that the people from NTSB,Boeing,Anac and Brazil's Air Force are all eager to find the answers for all the questions every one of us are waiting for.The whole world is watching!
P.S. I'm not,in any way,trying to get back at anybody with the "Banana Republic"stuff...Just trying to add some sense to the discussion.

[ATC Watcher]

Originally Posted by Hokie Nation

I know that he was trying to communicate with anyone on many differnet freqs, including Guard The CVR has this on tape, and no, there was not seven attempts on the CVR from Cindacta-1 (Brasilia), that is innacurate. Both of us are type rated on the Legacy, and the NORDO procedure is to STAY at your last assigned altitude...370...and squawk 7600. The Legacy has a rotary transponder and the AD applies to this transponder unfortunately.

Hokie Nation , your post indicates that you have either seen the CVR transcript of the Legacy or talked to someone who had.

If the Legacy pilot had tried to call on guard, surely that has been noted and recorded by others, as every ATC unit monitor and records 121,5 .

If the 7 attempts from Brasilia are not on the Legacy CVR, it would indicate they were not on the same frequency , the most common ,and by far, reason for the Comm failures. But normal procedure is to revert to previous Frequency, but if not immediately dedected, by that time you might be out of range .

The NORDO procedures you refer to are the FAA AIM procedures, (i.e in IFR conditions, the pilot is expected to follow the last instructions given by ATC ) which are only valid inside the USA and differ significantly from the ICAO ones .( see the excellent post of PPRuNe Radar on this )
If Brazil follows ICAO rules, the latter will apply unfortunately.That could be one of the discussion points. But if your friend is an ex AA ( as reported elsewhere ) he surely would know the diffrence .

The AD should not normally apply to the Legacy transponder , as this is a brand new unit and Honeywell has fixed the problem already some time ago.
Unless of course the avionic fitted on the aircrfat were not new.

On the other hand if indeed the investigation finds out that the transponder went AGAIN into stand by mode uncommanded, and this is on a brand new unit, then Honeywell, and owners of many 145's are going to loose a lot of money.

As to ATC, I am waiting to read the Telephone coordination transcripts between ACC Brasilia and Manaus to make a judgement, as I believe, here lies one of the main causes of the collision. (regardless of the transponder/ comm failure or not issue )

I will not comment on the " Banana republics" words, other to say that for a first post, you could perhaps be a bit more polite and respecful of other cultures when talking to other professionals.

[Rippa]

Originally Posted by Scurvy.D.Dog

.. .
Rippa .. that is most interesting regarding the airborne radar .. :

Just to illustrate

http://www.airliners.net/open.file/0905637/M/

http://www.airliners.net/open.file/0905601/M/

Regards

[barit1]

Originally Posted by Johnbr

...
These are facts.
The 738,was at Fl370 as for his Flight plan,operating a scheduled flight when it was hit by the Legacy,who should be at FL360.Fact!
What remains to be uncovered is:Why was the Legacy at FL370?????...
...Just trying to add some sense to the discussion.

The further fact is that the Legacy had lost contact with ATC, and had become a known hazard at an unknown altitude to ATC. ATC didn't know, and we do not yet know the reason for the lost contact, but per ICAO, ATC should have required an altitude change, and perhaps a track offset, for the Gol 737 to provide positive (or at least a statistically safe) separation.

For all the allegedly knowledgable quotes from the Embraer CVR, ATC tapes, etc. no one seems to know when or if ATC revised its clearance to the 737.
That seems to be the open issue now.

[fepate]

Originally Posted by PPRuNe Radar

From ICAO Annex 2:
b) in airspace where radar is used in the provision of air traffic control, maintain the last assigned speed and level, or minimum flight altitude if higher, for a period of 7 minutes following:
1) the time the last assigned level or minimum flight altitude is reached; or
2) the time the transponder is set to Code 7600; or
3) the aircraft’s failure to report its position over a compulsory reporting point;
whichever is later, and thereafter adjust level and speed in accordance with the filed flight plan;

I don't understand how this works. How would ATC and the airplane crew start their 7 minute clocks simultaneously? Especially if the transponder doesn't work.
Hypothetically, if the crew realized they had radio communications failure, squawked 7600 and then, 7 minutes later, changed to their flight planned altitude, wouldn't that be extremely dangerous if ATC didn't receive the transponder and didn't realize there was a radio problem?
Its ambiguous the other way as well. What altitude is ATC to think the plane is flying if they realize that there is communications failure but they don't know whether the crew knows this or not?

[gen3]

Was Legacy at fault in 737 crash?

As reported on flightglobal's website... today.

[vapilot2004]

Radar and Altitude Data

Military radar surveillance systems, whether ground-based or airborne can easily determine the altitude of a target without mode C data or with no transponder signal at all.

Typical is a 3D system where 2 antennas handle the azimuth and bearing detection individually. The bearing/distance antenna axis is horizontal and the azimuth antenna axis is vertical.

The newest digital 3D systems can detect a target's azimuth position by ramping the pulse frequencies and correlating small changes in the returning beam angle which can then be used to compute altitude. Only one antenna rotating in the horizontal plane is needed.

[fepate]

Originally Posted by vapilot2004

Military radar surveillance systems, whether ground-based or airborne can easily determine the altitude of a target without mode C data or with no transponder signal at all.
Typical is a 3D system where 2 antennas handle the azimuth and bearing detection individually. The bearing/distance antenna axis is horizontal and the azimuth antenna axis is vertical.
The newest digital 3D systems can detect a target's azimuth position by ramping the pulse frequencies and correlating small changes in the returning beam angle which can then be used to compute altitude. Only one antenna rotating in the horizontal plane is needed.

Fine. But can you deduce pressure altitude to within 300 feet with such a system?

[Carnage Matey!]

Originally Posted by fepate

Fine. But can you deduce pressure altitude to within 300 feet with such a system?

Probably not, what with it being an airborne radar system measuring relative altitude. But if you know the actual altitude of the airborne platform and the local pressure conditions based on recorded met data it doesn't take a genius to do some sums. Either way its fairly irrelevant as the 737s CVR will have recorded its altitude which was obviously the same as the Legacys.

[Johnbr]

Barit1:

I guess you've seen the maybes I've writen in that post...I really don't know,man...Few facts we have so far led me to those big maybes...I do think (speculating obviously)that someone screwd up big time here...MAYBE,just a BIG maybe,both the Legacy and ATC are in the chain of events that led to this catastrphic episode.That Legacy should not be at 370....BRS is a compulsory report point...There's level change indicated in the Jeppesen enroute chart,very clearly marked there...Thats right overhead Brasília center headquartes...no comm failure there...Transponder not working,then all of a sudden working again????Very odd to say the least...ATC MAYBE losing precious time trying to figure out what the hell was wrong with that Legacy,and not taking apropriate action...Again...WHO THE HELL KNOWS??? Let's wait and see...As I pointed out before:THE WHOLE WORLD IS WATCHING,don't you think?

[Johnbr]

BTW,I'd like to apologise to everybody if my previous post(the one with the Oh Mightys) if It felt offensive...No intention ...I was just a bit upset with what I felt as a lack of respect for the 155 "Banana Republic" lives lost...Sorry again..