Mid-air collision over Brasil

[Pom Pax]

Crash site?

A photo of what would appear to be part of the fin and in the wider view perhaps some other parts would to me suggest a debris field.
Explosive decompression has been mentioned, the Lockerbie debris trail was about 70 miles long.
Reports of seeing "aircraft" flying at low altitude, larger pieces of debris viewed at a distance could give the impression of "flying" still having forward momentum.

[Bokomoko]

Originally Posted by AeroBoero

Unfortunately these sorts of procedures are not uncommon between the pilots here. Switching of the transponder and going to a different altitude or level than the one assigned is not uncommon.

I've never heard it before with airplanes flying on upper levels and under radar control, and sorry mate, but based on your statement all Brazilian pilots are a bunch of irresponsible and stimulate that kind of procedure...

There was a Brazilian pilot inside the Legacy.

When an aircraft has any problem with its transponder Brazilian ATC controllers immediately request a check and if it remains on primary mode they usually inform to all essential traffic including its altitude and direction. Ok, Brazil has many problems including poor English communication but so far its reputation in terms of aviation safety is still one of the best of the world.

[Scurvy.D.Dog]

.... I doubt that will be the bulk of the hull ... maybe the vertical stab??
.
.. if what has been posted re TXPDR use is true ... well not much need be said really!
.
... TXPDR's should not have an OFF switch ... and only an ability to go from mode C to A if instructed by ATC due encoder error!
.
... **** oh dear

[cesar]

Both crew and pax on Legacy were Americans.

It´s in the Brazilian press, O Globo newspaper - link below, that both crew (Pilot Joe Lopore and co-pilot Jan palldino) and pax (Henry Yendle, Ralph Michielli, New York Times reporter Joe Sharkey, David Rimmer and Daniel Bachmann) on the Legacy were American.
After being intervied by Brazilian military in the air force base where the jet landed, they were ferried in an Embraer jet to the city of Cuiaba in order to be heard by the police. "O Globo" also reports that all seven only left the plane in Cuiaba about half an hour later, after another Legacy aircraft (carrying the American Vice-consul and an Embraer attorney) landed there.

The link (in Portuguese):

http://oglobo.globo.com/pais/mat/200.../285915657.asp

[misd-agin]

According to a CAB specialist the American Legacy pilot said, during the post-accident debrief, that he'd decided to climb from FL370 to FL390 to gain speed and range, without informing ATC, and that he'd switched off the transponder (for reasons unknown). That would have impeded the 737's TCAS from reacting to the Legacy's presence and delayed ATC's warning that a collision was imminent since, with the transponder off there would be a lag for radar to correctly track the Legacy.

********************************************************

Not a lawyer but if this is true I wouldn't be surprised if they're charged with murder/manslaughter/etc.

[satpak77]

Originally Posted by 6000PIC

...And if that`s the case , he`s had his last flight.

something like that would probably cause the wheels to get into motion for local prosecution of criminal negligence, etc

[Dr. Red]

Originally Posted by jondc9

I recall when TCAS first came out I asked: what if you get a TCAS RA that says climb and you are already at your max altitude?
a good answer was never forthcoming

Try this ACAS II Bulletin which seems to answer your question. Refer to events 5 & 6 (pg. 3). The conclusion is... "DO NOT react contrary to an RA [but] if there is some doubt of the ability to respond to a “Climb” RA, at least remain level, do not descend."

I'm sure we can all think of scenarios where this is not the ideal answer, but it seems the 'least bad' choice, all else being equal. Hope this is of some help.

[Loose rivets]

The sad fact is that, since time immemorial, crews have been shoving up, down and sideways to effect some personal advantage. Almost always, the holes don't line up.

[etrang]

Unfortunately these sorts of procedures are not uncommon between the pilots here. Switching of the transponder and going to a different altitude or level than the one assigned is not uncommon.

Can anyone explain what possible reasons a pilot might have for switching off a transponder on a civilian plane?

[Right Way Up]

Misd-agin,
If and this is a big if, this scenario is true, I only think manslaughter charges can be brought as murder requires intent.
I have been told that this sort of thing happens alot across Africa especially during a certain season.

[Scurvy.D.Dog]

etrang .... Tactical Military .. only when absolutely necessary though! .... and IMHO
should only occur if the Mil Aircraft has functioning Air to Air Radar!
.
.. other than that .... cannot think of any other 'legitimate' reason to turn it OFF ... on the surface, squat switches or air switch does the job!
.
.. as I said previously, if the Alt encoder is inaccurate, ATC 'should' be instructing crews to select mode A only (no altitude)! ... at least they (ATC) will still see their radar return and can notify other traffic around them as appropriate! .... we do not verify levels (in radar CTA/R) on each flight for the fun of it!

[HEATHROW DIRECTOR]

<<he'd switched off the transponder (for reasons unknown). That would have impeded the 737's TCAS from reacting to the Legacy's presence and delayed ATC's warning that a collision was imminent since, with the transponder off there would be a lag for radar to correctly track the Legacy.>>

There would be no "lag" that would of consequence if a return was visible. There are two types of radar but I do not know if Brazil ATC has both - Primary radar shows a response whether or not the a/c has a transponder and secondary shows coded returns from a/c transponders - usually displayed as a label beside the radar target of the aircraft. The display to the controller in each case is updated very frequently - certainly frequently enough for ATC to safely handle extremely busy terminal areas. If the ATC radar does not display primary returns then an a/c with no transponder will not be seen, ie if the pilot switches off his transponder the radar information is lost completely, although a trace of the a/c track could remain for a minute or so. In a positive control situation, if an aircraft disappears from radar for no reason then ATC will attempt to find out why.

As for pilots switching off transponders and changing their flight levels without ATC clearance... such utter irresponsiblity beggars belief.

[Capt Pit Bull]

Jondc9

A few answers for you:

A couple of pages back you asked why sometimes you can see traffic but it isn't displayed.

Its certainly possible that there may not be line of sight to antenna, although less likely now that an upper antenna is required as well as a lower. Much more likely is "Interference Limiting Mode" where in, as part of the overall design strategy of reducing the ammount of ssr transmissions (to decongest the frequencies), TCAS does not continuously interrogate all intruders. Unless the aircraft is in full time tracking, it is not displayed. TCAS may, for distant traffic, or medium range traffic that is closing slowly, and even for fairly nearby traffic that the range is opening on, decrease the interrogation rate. Interference limiting mode is invoked when the TCAS reckons the ssr freqs are becoming congested, so typically in higher traffic densities. If you've ever seen more than 1 blip disappear at once, thats probably interference mode kicking in. [reference - manufacturers bulletin - TCAS: Common causes for traffic disapearance]

I recall when TCAS first came out I asked: what if you get a TCAS RA that says climb and you are already at your max altitude?

a good answer was never forthcoming

pull up into a massive stall/upset?

I ought to be surprised that a good answer was never forthcoming, but sadly I'm not. It seems that a sizeable part of the community feel "TCAS - if you get an RA, follow it" meets the necessary knowledge level and neatly ticks the box in the training requirement.

Firstly, TCAS has inbuilt performance based inhibitions. Based on possibly several inputs, increase climbs and climb RAs can be inhibited.

However, these inhibitions are not comprehensive and ultimately the Pilot has an overriding requirement to protect the aircraft. The answer to your question is the same as to any other RA that presents Hazard: Get as close as you can to the RA, and whatever you do don't manoeuvre opposite. Even if you can only get another couple of hundred feet, its worth doing. Bear in mind RAs only nudge you a few hundred feet from your original flight path (unless the other guy manoeuvres towards you). We are not in the realms of zoom climbing thousands of feet.

As Dr Red quotes in fact.

etrang,

Can anyone explain what possible reasons a pilot might have for switching off a transponder?

Apart from when being naughty of course. Still seem to be a few folk around that turn to standby when changing code, not sure if that practice has been stamped out yet. The other reason will be as per anything else electrical - if it, or some other box nearby, has got smoke pouring out of it.


I hasten to add that non of the above is intended to be comment on this accident, but rather answering TCAS related questions that have been raised.

pb

[M609]

As for pilots switching off transponders and changing their flight levels without ATC clearance... such utter irresponsiblity beggars belief.

If correct, lock him up, and throw away the key!

[woodpecker]

A few years back, during a very smooth Atlantic crossing, someone (never did find out his callsign) on the chat frequency was asking for ride reports at 36000' having just passed 30W. All the responses were "smooth ride" all the way across. One American pilot, who it would seem had worked out that he was two minutes ahead of this traffic and at 37000' on the same track suggested perhaps he was sitting in his wake turbulence (remember vortices descend at about 500'/min).
The chap thanked him for the information and suggested he had tried cruising 500' higher and it was much better. The frequency was then bombarded by others wanting to know who he was and why he was not adhering to is cleared cruising height! He decided not to offer the information.
I hope the American pilot in front of him, who was one of many asking for his callsign, took it further.

[BEagle]

"The supposed reason being that if you are not quick enough changing the code, the box automatically goes to standby."

Huh? No understand. I thought the problem was that if you are interrupted during squawk change, you may display an incorrect squawk. How does 'the box' know when it should 'automatically go to standby'?

We've had 'active' and 'stby' VHF NAVCOMs with changeover buttons for years - why don't many transponders do this?

In an aircraft I'm involved with, the centralised system has a transponder page. The new squawk is entered with the rotary knob and then transferred to the active window by pressing the line select key. None of this 'going to standby' business! And it is not possible to switch off the transponders either!

I cannot believe that any professional pilot would deliberately switch the transponder off and lie about his real flight level......

[dudduddud]

Anyone care to guess why he would have done that? Language barriers? Does Brazillian ATC regularly deny foreign a/c more optimum cruise levels? Might the plane not have been properly equipped for flight at those levels?

[rlsbutler]

According to the maker’s blurb, the Embraer Legacy 600 with full fuel should have made Sao Paulo – Long Island with one intermediate stop anywhere between Manaus and Puerto Rico. With 7 passengers and crew, they should have offloaded some fuel and so narrowed that choice of staging airfields. If as Broomstick Flyer reports (#70) they intended to land at Manaus, they would have had no practical reason to squeeze range and speed performance by climbing illegitimately. But they would almost certainly have had to make another stop - Fort Lauderdale for instance as BF also suggests. By climbing beyond Manaus they might have made the ferry’s three stages into two. Any sign that they refiled after take off – to land at Caracas for instance ?

Notwithstanding BF, I suggest again that, once the captain in such a situation goes over to the wild side, he would get what he is looking for more effectively by cruise climb than by a step change of altitude. How he covers his tracks is another matter.

[brain fade]

Jon Dc9

Re RA at max alt. If it says climb- you climb. Absolutely. That is sop in my company and I am an Embraer pilot.

because.......

Max cert FL in the -145 is 370 at least in our company but I know the a/c can be ferried safely at up to FL410 in order to gain range etc. It's not illegal as it's a non-revenue flight. Therefore a bit of a pull-up even at maxalt is a bit of a non event.

If the -145 pilot needed or wanted a higher FL he only needed to ask. So I see no reason for him to turn off the squawk. After all if the reason for no climb was because the higer FL was occupied by the 737, he'd hardly want to go up there, would he?

[QDMQDMQDM]

I am not a commercial pilot, but if these two aircraft were on an airway on reciprocal headings isn't this accident an argument for an SOP of cruising on an offset track, say by 1NM? Even, extraordinarily, over the Amazon basin.

QDM