Mid-air collision over Brasil

[Scurvy.D.Dog]

.. in principle I am not opposed to offsets, as long as everyone uses the same offset i.e. Right of track .5nm etc (1nm nominal displacement opposite direction)!
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…. In reality it is all dependent on navigational accuracy of any two conflict pairs which in the end might be no lateral displacement at all!
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.. what does concern me though is aircrews relying on the chances of MAC being reduced and thus a relaxation of vigilance and/or adherence!
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Which is the greater ill? …. I’ll leave that to the mathematicians!
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H D touched on something that is niggling me..
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.. notwithstanding the early reports of ‘lost from radar’ (which could mean the B738 failed to appear within radar coverage at the expected time which may have been some time after the MAC) can anyone confirm if there is reliable SSR and/or PRIM coverage at FL300 +.. at the point of conflict?
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.. if yes (and again, if what has been reported as surviving crew testimony is accurate):-
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- presumably something would have been said by ATC when the SSR was lost!?, or
- the aircrew notified ATC TXPDR U/S??, or
- it was switched off shortly before the MAC?!?!
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.. if no:-
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.. would that lack of radar have been known to the Brazilian Embraer Pilot?
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... someone earlier mentioned Comm's issues in this area ..... here's is a hypothetical:-
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…. If the Embraer had been assigned FL350 (due conflicting traffic) … reached that level and reported .. got no response from ATC (ATC may not have received the level report) …. How long before the crew would follow no radio procedures and proceed to their planned level??? … I wonder what the planned level was???
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… quite frankly, I find it unbelievable that a level change (even in remote areas) would be initiated without ATC knowledge or approval ... particularly without the TXPDR for TCAS!
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General comments (hopefully unrelated):-
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900+ KTS Closing speed ….. christ .. a large aircraft would look like bug **** on the window right up until it was way to late to do anything … and that’s assuming it was even seen before the bang!
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Please Folks … if you lose ATC comm's ...use the ATC freq and 121.5 ... make a general broadcast before changing levels/track!
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.......don’t gamble ‘other’ peoples lives by taking a punt on the ‘Big Sky Theory’ …. !!

[Capt Pit Bull]

Blackcap,

Thanks for the info. And without in any way wishing to shoot the messanger, I'm horrified.

I don't understand the design philosophy in the first case. A transponder head that Turns Off the active squawk because you get interupted changing it? Thats almost incredible. I can't see any rationale for that. Make the standby code blank, make it flash, I'd even at a push accept the box reverting to conspicuity, but standby? <boggles>

So there is now an SOP whereby, during an emergency descent, the need to set 7700 is making the aircraft invisible to ATC and other aircrafts TCAS, and incidentally also disabling the aircrafts own TCAS. Thats insane, even if its only for a few seconds.

I don't suppose you could offer the manufacturer and model of the control head?

pb

[Flight Safety]

Another Possibility

Since these were both brand new aircraft (200 hours for one, and ferry delivery for the other), I thought of another possibility.

Many years ago now, I knew of a concept in electronics known as "infant mortality". The idea was that brand new electronics experience a higher failure rate than equipment that is still new, but has been in service for several weeks or months. Similarly, sometimes new owners of brand new (just delivered) autos sometimes have to sort out problems before the autos perform correctly.

In the airline business, do you guys experience similar issues where you sometimes have to sort out a brand new just delivered aircraft? I'm not talking about sorting out a brand new model just introduced, but rather sorting out a brand new line aircraft of an existing model, where the existing model has basically been sorted out.

Could any brand new aircraft issues, have contributed in any way to this accident?

[forget]

Capt Pit Bull,
Honeywell. See AD at;
http://www.airweb.faa.gov/Regulatory...pandSection=-3
In summary;
This AD results from the transponder erroneously going into standby mode if the flightcrew takes longer than five seconds when using the rotary knob of the radio management unit to change the air traffic control 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 flightcrew and result in improper functioning of the traffic alert and collision avoidance system.

[Gregm001]

Originally Posted by Flight Safety

Since these were both brand new aircraft (200 hours for one, and ferry delivery for the other), I thought of another possibility.

Many years ago now, I knew of a concept in electronics known as "infant mortality". The idea was that brand new electronics experience a higher failure rate than equipment that is still new, but has been in service for several weeks or months.

I was of the belief that most manufacturers will burn in equipment, which will take it past this phase. Also the life cycle is sometimes described as being like a U curve, with very high failure rates at the beginning of the lifecycle and also very high hfailure rates at the end of the lifecycle.

[Capt Pit Bull]

Forget,

Thanks for that.

Well, at least its good to know that its not intended to work that way.

Though the AD requires crew to check its functioning correctly after a 4096 change. As I read it the AD does not require a change to SBY whilst making a 4096 change.

pb

[Scurvy.D.Dog]

F S … early on in the piece I pondered that possibility also!
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… it may well be relevant if the Embraer pilots turned the TXPDR off due fault (perceived or real)?!
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.. either way, if it was U/S/OFF (for whatever reason), the poor sods at the sharp end of the B738 (and ATC) would have been blissfully unaware of the impending disaster!
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… It is probably safe to assume (tech logs will verify in any case) that with 200 hours on the B738, any ‘infant’ issues with avionics including TCAS would have been found and rectified (including checks prior to delivery to GOL)!
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.. I would assume similar for the Embraer (how many hours do they do before delivery??)
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.. a side question if I may to Boeing brains:- .. the new ‘short field performance’ mods to the B738
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.… do they have any performance variance (compared to a standard B738) when the wing is in clean config i.e. stall margins in the higher flight levels??

[G4G5]

My question would be,

If the pilots admited to placing the transponder in STBY, what happens to them now? Under Brizillian law can they be charged for a criminal act?

[WindSheer]

Thoughts and wishes to all the families involved....

Given the a/c types involved in this incident, it should not have happened!
Sadly it has happened, and will happen again...!

[aimscabinet]

Offset

Originally Posted by 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.

Originally Posted by QDMQDMQDM

QDM

In fact, in some parts of the world (Africa, NAT, India, Bangladesh), ICAO recommends the use of the offset track. What we do is to set one or two miles (usually one) right of track on the FMC and voilΰ ... you have a decent lateral separation from the opposite traffic.

[fox niner]

Please, someone...Tell me it isn't true that the ferry-flight guys turned off their transponder AND climbed to another flight level...someone??

I - can - not - be - lieve - it!!

unheard of, ever!

That is the same as driving a car on the wrong side of the road with your headlights off, at night!

[CaptainSandL]

Scurvy,

The mods for the SFP include the following:

• Flight spoilers to be capable of 60 degree deflection on touchdown by addition of increased stroke actuators. This compares to the current 33/38 degrees and will reduce stopping distances by improving braking capability.
• Slats to be sealed for take-off to flap position 15 (compared to the current 10) to allow the wing to generate more lift at lower rotation angles.
• Two-position tailskid that extends an extra 127mm (5ins) for landing protection. This allows greater angles of attack to be safely flown thereby reducing Vref and hence landing distance.
• Main gear camber (splay) reduced by 1 degree to increase uniformity of braking across all MLG tyres.
• Reduction of engine idle-thrust delay time from 5s to 2s to shorten landing roll.
• FMC & FCC software revisions.

There may be others that I don’t know about but I would doubt that they would be significant. My point is that none of the above should have any effect on stall margins on a clean wing.

S&L

[aimscabinet]

Legacy level

My question to you is unrelated to the TCAS thing:

So, you have flown in that area? What sort of flight levels would you guys fly from Sao Paulo? It appears that you would be flying Northwestbound, thus EVEN levels, is that right?
I read a few guys talking about the fact that the legacy would be flying at some odd level. Could you elaborate on that?

God bless them all


Many thanks

[forget]

All we have so far is - "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)".

None of this makes any sense. Neither the act - or the (seemingly immediate) admission. If a guy is capable of making himself deliberately TCAS invisible in order to stretch a few miles extra range then he's more than capable of lying to cover his tracks when found out.

............without informing ATC, and that he'd switched off the transponder (for reasons unknown)".

I smell mucho rats here.

[Scurvy.D.Dog]

CaptainSandL ... thanks cobba
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... back to the other
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.. Embraer FL370 to FL390 ... yet the B738 was at FL360 .... have I missed something in the translation???
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.. was FL390 to high to early (heavy) ... would it mush down through FL360 after an 'upset'???

[jondc9]

one more thing about TCAS:

In the three types of planes I flew with TCAS,the transponder had to be selected to TCAS position (TA or RA) thus turning on the tranponder & TCAS

should the legacy pilot have turned the transponder off or to stby the legacy pilot would have turned off his TCAS unit denying himself a TCAS warning while cloaking his plane to other TCAS units & ground secondary radar.

unfamiliar with Legacy

thoughts?

[Zero"G"]

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.

By all means incorrect information and absurd statement.I flew 32 years in major Airline in Brazil and never even heard such a thing.
Airline Pilots and training in any Airline in Brazil,will dump you to the lions,even if you think about it.
Who the hell do you think you are to make a statement like that?
The name says it all...aero bueiro..piper cub like plane..He has no clues to what he is talking about.Just a imature individual afirming something he has no idea how the training and operations of any airlines work.

Shame on you!

[misd-agin]

Originally Posted by forget

All we have so far is - "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)".

None of this makes any sense. Neither the act - or the (seemingly immediate) admission. If a guy is capable of making himself deliberately TCAS invisible in order to stretch a few miles extra range then he's more than capable of lying to cover his tracks when found out.

............without informing ATC, and that he'd switched off the transponder (for reasons unknown)".

I smell mucho rats here.

Thats' why I put "if true" in my post. So far it's just that one report. News report today has a quote "we were at FL370..."(paraphrased). Full investigation to follow...

It doesn't make sense. But unfortunately non-sensical stuff does occur.

[misd-agin]

Originally Posted by 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).

Contrails don't descend much, if at all.

I've had to offset slightly to avoid turbulence from contrails. Offset out of the contrail and the ride improved immediately.

[misd-agin]

Originally Posted by 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?

High altitude flight makes a/c weight very critical, especially at higher AOA(slow, G's, turning). Speed can literally mean life (Pinnacle ferry flight crash).

"Therefore a pull-up even at maxalt is a bit of a non event." Caution is advised if you're at, or close to the max altitude the a/c can be flown at for that weight, regardless of what it's certified to.

Every year several(many?) flights have altitude/speed issues caused by flying to high for a given weight or too slow for the altitude and/or weight.