British Airways flight seconds away from mid-air disaster (Not!)

[delta-delta-papa]

Hundreds of passengers watched in horror as their British Airways jumbo narrowly avoided a collision with another airliner over France.

The Johannesburg-bound flight from Heathrow was suddenly forced to climb to avoid an Argentinian passenger jet.
Aviation insiders said the planes had allegedly been put on to the same flight path by French air traffic controllers.

http://www.dailymail.co.uk/pages/live/articles/news/news.html?in_article_id=492128&in_page_id=1770&ICO=NEWS&ICL=TOPART

[747-436]

Another quality piece from the Daily Mail!!! They are saying insiders said it was hushed up?!?! Yes it may not have been public but I am sure it was published in the internal safety briefs.

Chances are this happend in the dark. When approaching Heathrow at 0630 in the morning when it is dark the other aircraft approaching look a lot closer than they are when you are sitting down the back in economy as their lights are shining right at you as you turn onto finals and they are lining up behind.

[Mungo Man]

Ah well if it's in the Daily Mail it bound to be true, word for word and every little detail!!!!!!!!!!!!!

Ok, so which bits are not true? Sounds like a pretty straight forward TCAS RA to me. No reports of panic or mayhem.

[RexBanner]

If you read the Daily Mail article at the beginning of the piece it says the Aerolineas Argentinas a/c was a 747 then at the end, an Airbus A340. Tells you all you need to know about the standard of journalism here.

[west atc]

"A long-haul aircraft such as a Boeing 747 would typically fly at around 37,000ft. Aircraft usually have to be five miles apart horizontally and with a 1,000ft difference in altitude to reduce the risk of a mid-air smash."

Didn't realise we had to have both 5 miles and a thousand feet. Better stand myself down!

[Wizofoz]

I highly doubt the BA aircraft "turned right" as we all know that's not a TCAS procedure.

It's not the procedure for an RA, however "When two aircraft are on a collision course, both shall alter heading to the right" is still enshrined in legislation.

As a happy result from an RA involves BOTH aircraft following their TCAS (And the DHL smash and JAL near miss both show this does not always happen) I would seriously consider a lateral manouvre if I believed it would aid in seperation. (Indeed, many manuals procedure for a TA invoke considering a lateral manouevre)

[antic81]

Hi there,

If it was a BA 747-400 in French airspace enroute to Johannesburg would it not be closer to FL330 as it would need to burn of a few thousand Kgs of fuel before climbing to a higher level?
And it would have been an evening flight, normal departure time is either 7pm or 9pm local (or there abouts)


I wonder if anyone on board even realised anything out of the ordinary had happened?

Cheers Ant

[apaddyinuk]

The captain probably just came down after the dinner service to stretch his legs...perfectly normal!!!

[Del Prado]

TCAS is really inaccurate in azimuth and must not be used for lateral guidance. If you have the traffic visual then a turn to the right might work.

[fortuna76]

Ohh man here we go again.....

This seems to be a two week returning item from the Daily Mail:

Seconds away from disaster :yuk:, it was very close runnings :yuk:, passengers saw the plane coming :ugh:

Really this is all a waste of our time. It is obvious the 'journalist' is making it up as he/she goes. Not the RA but certainly the rest of the stuff. I personally love the phrase about a 'BA eye witnesses', which seems very unlike to me at 33000 feet unless it was superwoman flying by.....

[Old King Coal]

The following sections cut / pasted from a Boeing QRH (Quick Reference Handbook) wherein I've highlighted some sections in red for added emphasis...

ACTION IN THE EVENT OF A RESOLUTION ADVISORY (RA)
Accomplish recall procedure without delay. NEVER MANOEUVRE IN THE OPPOSITE SENSE because TCAS could be co-ordinating manoeuvres with other aircraft. It should be stressed that excessive pitch rates should not be made unless the approaching aircraft is seen and the situation requires such a response.

RA manoeuvres require only small pitch attitude changes that should be accomplished smoothly and without delay. Properly executed, the RA manoeuvre is mild and does not require large or abrupt control movements. Remember that the passengers and cabin crew may not all be seated during the manoeuvre and shouldn't be subjected to other than moderate accelerations ('g' forces).

Pilot Response :
General: Follow the instructions in the QRH. Do not turn. Note the specific instructions for a Climb RA in a landing configuration. Although RA manoeuvres require only small pitch attitude changes they must be accomplished smoothly and without delay.

Traffic Advisory (TA): The Handling Pilot should adjust the EHSI MAP range or the TCAS IVSI range so that the conflict is clearly visible. Look for traffic using the display as an aid. Call out any conflicting traffic. Do not manoeuvre unless visual contact confirms that separation is not adequate. An intruder is identified as one whose flight path brings it to within 20 to 48 seconds of closest point of approach.

Resolution Advisory (RA): Disconnect the autopilot and authothrust, ignore existing Flight Director pitch demands and respond to the RA by referring to the IVSI or the EHSI as appropriate. Maintain the pre-existing IAS.

TCAS IVSIs presentation:- The “safe” vertical speed band is indicated in green. An initial RA assumed that the PF will respond within 5 seconds using a smooth manoeuvre to enter and maintain the green arc. If a subsequent corrective RA is given, the assumed manoeuvre time is 2.5 seconds.

TCAS EHSI presentation:- The aircraft/s pitch must be adjusted to fly the aeroplane symbol just out of the red region on the EADI. There is no green “safe” area.

One suspects that understanding the simple concepts contained within the instructions above are wayyyy beyond the comprehension of a Daily Mail journo! :rolleyes:

[Mercenary Pilot]

Sometimes I worry about what I read on here!

TCAS doesn't give any azimuth indications only Climb or Descend with possible instructions to increase/decrease vertical speeds, but being ATC you would know that of course.:hmm:

Insiders said it had been "hushed up"Ohhh it must be a conspiracy! Maybe the men in black will invade the CAA to take away the ASR and then use the flashy pen things on the SRG who gather data on near collisions. :rolleyes:

I tried using the Daily Mail as loo paper but it chafes....guess it really is good for nothing!

[Callsign Kilo]

Love this bit

'A BA eye-witness told colleagues...'

Standard Jurno get out clause for "I'm going to make something up here, I have no factual evidence of it ever happening and I haven't spoken to anyone concerned; however to make sound like it has any substance at all I will use the company name and pretend that I was informed by an employee..."

Believe it is covered in Chapter 6, Section 15 of the 'Jurno's Guide to writing Bull****'

[Del Prado]

Wow, this place isn't as friendly as it used to be!

TCAS does display traffic around you though doesn't it? I was trying to get across that these are only diplayed in 12 'sectors' of 30 degrees so it is quite possible that traffic showing on your display at half past 11 could easily be half past 12 and a turn to the right would be a bad thing.

I do know even if you are visual you should still follow the RA but it must be very tempting to make a turn to avoid. Hence the "turn to the right might work" quote.

It's a shame this forum has turned into the place it has. I've learnt so much from it in the past but now it seems posters would much rather flame others than give them the benefit of the doubt.

[Micky]

Hi there,
Last months safety information from my company was about TCAS and RA's, so I would like to ad a couple of facts to the things which were stated there.
1. Never turn, even if your visual with "the" traffic, because who tells you that the traffic you are looking at is the Traffic the RA is for.
2. Acting incorrect or even opposite towards an RA leads to a situation were the the distance between the conflicting traffics is sometimes even less then if none of them had reacted at all.:ooh:

Blue Sky's everyone...

Micky

[Rainboe]

It's a shame this forum has turned into the place it has. I've learnt so much from it in the past but now it seems posters would much rather flame others than give them the benefit of the doubt.
The reason flaming goes on is frustration that so many totally uninformed people like MS Sim flyers and others invade these technical sections and start giving opinions! People forget these technical sections are for aviation professionals only. If they stick their heads in here with idiocy, who can help flaming them?

[Mercenary Pilot]

Yeah a turn to the right might work or it could bury your wingtip into the wing-root of the other aircraft OR maybe even cause a CFIT (admittedly, that is unlikely @33000' but possible at lower altitudes), best just to follow the correct procedure and live. We all remember what happened last time an RA was ignored don't we?!

TCAS III may be able to give headings when developed but until then its climbs and descents only.

[JEM60]

Hi, Rainbow. As an avid MS flyer myself and ex PPL, I can only agree with your post about ignorant people posting on this forum. As a retired person, I find it a HUGE source of interest and learning, but would not dream of posting something I patently knew nothing about. MS has it's own forums, without pretend pilots being on this one. Be like me, MS guys, read, learn, but DONT intervene!!!!

[Capt Pit Bull]

The reason some aircraft preclude turning as part of an RA is because of performance. The RA climb performance might be more marginal in some circumstances if the aircraft isn't turning.
But apart from that, in general terms, there is no inherent reason why you shouldn't be turning just as long as you aren't doing so based on looking at your traffic display.
Still plenty of scope for non TCAS encounters, either by MEL or interaction with non equipped aircraft, so turning for collision avoidance should not be automatically labelled 'never do this'.
pb

p.s.

We all remember what happened last time an RA was ignored don't we?!

Well, we know what happened when a manoeuvre opposite the RA was flown, but that's something different.

[747-436]

Could ATC have instructed the right turn for avoidance before the TCAS RA came??

[Caudillo]

I'm normally one to complain about pilots' hysteria following a press report but this one takes the biscuit.

#1. As was mentioned earlier, following this brush with death the captain allegedly wiped the sweat from his brow and sallied off to calm the passengers? Unlikely I'd say, you might be thinking - locked cockpit, we can't do that - but no, in fact it's because of point #2..

#2. Which is that it was the captain that outmanoeuvred the pesky Argie jet. Now as we all well know, it's usually the pilot who does something. Given that a 747 (in addition to anything else that brings passengers moments from death in the sky) is a single pilot aircraft, who would've been minding the controls whilst our hero went down the back? Perhaps it could've been the CSD in the right seat that performed the RA?

#3. I have been a passenger on a Rome-Buenos Aires flight. I recall it heading south-west, in the general direction of South America. I'd be asking questions as to what the Aerolineas was doing around Marseilles. More than likely it was a conspiracy involving Argentina and France to bring down a British jet.

This paper really isn't fit to polish ones arse with. I'd send it back where it came from. ;)

[moggiee]

Insiders said it had been "hushed up"
It's the Mail, they hate BA and so you can expect this sort of crap to appear if they get a chance.

[Wizofoz]

in the event of an RA I don't think you have time to assess if the area you're turning into is clear, consider it as an option then carry it out.

IF the RA is the first you know of the intruder. You may well have been alerted by ATC, seen him as proximate traffic and had a TA and visual identification before it gets to RA time. Indeed, the procedure for following an RA is to follow it's vertical guidence only. My point is that we seem to now to be of a mindset that TCAS RA is the only avoidence tool we have.

As to "ässess if the area you're turning to is clear", well, the one thing you know is that which you're flying into isn't!

TCAS doesn't give any azimuth indications

BOLLOCKS!

It doesn't give you azimuth ADVISORIES and is not accurate laterally, but it gives you a very good idea about which direction to look!

Are we really saying that, knowing a conflict is about to happen, we sit and wait for the RA and pray the Russian in the other aircraft does the right thing, or do we try and not let it get that far?

[F4F]

What strikes me most is the title of said article:
British Airways flight seconds away from mid-air disaster

May I ask, what about the other flight.... was it not as well seconds away from mid-air disaster?

Yeah well, the other one was not a British flight with British citizens on board, so is probably classified as quantité négligable... a journalistic form of nationalism, politically correct today... not so :ouch:

Rainboe, thanks :ok:


live 2 fly 2 live

[Cyclone733]

Love the article, 4 comments. 3 along the lines of 'heads should roll, we nearly died', one 'TCAS is there to protect and it works' wonder which of the 4 doesn't appear in the sample of comments.:ugh:

[Wizofoz]

because the procedures say you don't.


Topslide,

As I pointed out, the regulations MANDATE a turn if you are on a reciprocal heading at the same altitude!

The procedures FOR AN RA say not to turn, but no procedure UP TO THAT POINT prohibits an avoidence turn.

it concerns me that I might be unlucky enough to be flying above/below you when you respond to an RA and decide it appropriate to throw in a turn for good measure. God forbid I ever am.


I concerns me that YOU would watch a set of lights get bigger in your windscreen, determine it was at the same height as you by your TCAS target, think "Oh how jollÿ" when you get a TA, and then do something ONLY when you recieve an RA!

You can't possibly be a professional pilot.

777 Captain. You?

[Eric T Cartman]

re Micky's post :
"Never turn, even if your visual with "the" traffic, because who tells you that the traffic you are looking at is the Traffic the RA is for?"

Many, many years ago, an Aer Lingus inbound Manch told Preston Airways he had the BEA aircraft opposite direction in sight and asked for descent maintaining VMC which was given. The BEA skipper said "Aer Lingus , how do you know the BEA aircraft you can see is me?". Quick as a flash, the Aer Lingus skipper said " BEA, how do you know the Aer Lingus that just descended through your level was me ?" :)
Get the idea ? :E

[Monarch Man]

As I pointed out, the regulations MANDATE a turn if you are on a reciprocal heading at the same altitude!

The procedures FOR AN RA say not to turn, but no procedure UP TO THAT POINT prohibits an avoidence turn.


Wiz, EVERYONE else have been talking about RA's, we aren't talking about visual avoidance for fecks sake:ugh:
You can bang on all you like about giving way to right, most of the rest of us trust the equipment, and the procedures inherent with that.

[forget]

Could've saved a tree or two.

Hundreds of passengers were left completely unaware that safe separation between their Johannesburg bound 747 and an Argentinian passenger jet was maintained following, it is believed, a minor error by air traffic controllers.

As the aircraft approached one another the BA 747's automated collision avoidance system was triggered, prompting the pilot to initiate a climb. The system triggers an audible alarm with instruction to climb or descend.

Once the aircraft were clear of one another the captain went into the cabin to stretch his legs.

[Tyke]

With respect to turning visually 'away' from another aircraft, perhaps you would consider the following? The aircraft is on the left, heading in a left - right direction. We turn right to avoid it 'visually'. However, all our manouvre achieves is to maintain a constant bearing with the other aircraft - it really does become a 'target'. I think I will stick with the 'up-down' procedure as taught and which is SOP.

[Turn It Off]

I agree with all the stick to the RA comments.

You see the conflicting traffic and decide to turn right to avoid, what about the aircraft in your 5 o'clock on the same heading and level as you?

WIPEOUT!

Please Please follow TCAS RAs

[Del Prado]

Monarch Man, to be fair, Wizofoz brought up TA's way back in post 7. He was speculating on why the BA aircraft may have turned.

I can't help thinking these threads would progress far more if posters would read others comments and try not to jump down each others throats or assume they're talking to sim pilots rather than aviation professionals.

[Wizofoz]

And you would quite happily, under IFR radar control, in all likelyhood in RVSM airspace make a turn off your airway (presumably during a TA and before an RA is triggered) as you believed you were going to have a collision?

Topslide,

RVSM is reduced VERTICAL seperation- yet you bang on about the dangers of a LATERAL manouevre, whislt saying that relying on a VERTICAL manoeuver (the bit of seperation we've recently reduced) is OK?

The DHL pilots followed their TCAS. One of the JAL pilots did. The 738 pilots in Brazil no doubt had your faith in the equipement. That's around two hundred dead and another 350 on bonus days.

If it gets down to an RA you follow the SOP procedure. But you should be doing what ever it takes to not get to that point.

How's about pointing it out to ATC long before it becomes a TA.

GRAND idea. If they can co-ordinate seperation, jobs done. If they can't in a timely manner, YOU need to do something.

WTF are you talking about? If you are genuinely a 777 captain then you have obviously got the wrong end of the stick of this discussion, because that sounds to me like something a PPL would say.


It's been a question in the Air Law exam for all four of the ATPLs I hold...

[Del Prado]

Of course, if there is absolutely no other option and you are about to collide your natural reaction would cause you to make an avoiding manouvre, but how would you EVER get in that situation?


can you think of any examples where this has happened?

[Wizofoz]

Topslide,
Firstly, your saftey quote is in regards to actions DURING AN RA. I have said several times that, if you get an RA you follow SOPs which includes not turning.

What if you're in IMC.

What if you're not? You know damn well we spend 95% of our time in clear air. (Actually, I'm in the Middle East so make that 99.5%!)

Do you just turn because of a TCAS contact?

No, you use it as a guide to make visual contact and confirm the targets relative height to you. If the TCAS says it's at your altitude and you visually confirm it has a constant relative bearing and is getting bigger, it WILL hit you. At this stage I would, time permitting, attempt to co-ordinate with ATC. If that wasn't happening in a timely manner, I would consider a turn, and I defy you to name an airway anywhere in the world where a 1/4 mile deviation would bring you into conflict with other traffic.

It would seem in the above senerio that you would simply wait for the RA. Fine, but consider these points-

1)TCAS only gives RAs on TXP mode C targets, yet many light aircraft around the world, including Europe, only have mode A.
I use to be based in Liverpool and got almost daily TAs from mode A aircraft. The only way to deal with this was to try and aquire the aircraft visually and manoeuvre to aviod if necessary. What would you do? Concentrate on the PFD and wait for the RA that would never come?

2) RAs are only effective if BOTH pilots react to them, yet many pilots from many parts of the world won't. Russia and mainland China are still teaching their pilots to give precedence to ATC over TCAS,and, whilst taught correctly, many cultures have a cultural resistence to go against instructions from ATC.

Like I said, if it gets to an RA, strict adherence to SOPs is your best chance of avoidance. But it is a last ditch effort when every thing else has failed, and if you have let chances to avoid it getting that far go, one of the failures is yours.

Oh, and as long as we are quoting things, B777 QRH Traffic Avoidance Maneuver:-

Traffic Advisory:-

PNF- Look for traffic using Traffic Display as a guide.Call out any conflicting traffic

PF- If traffic is sighted, maneuver as required.

But you know that, right?

[Greek God]

I think Del Prado got it right with how confronational people are now -perhaps its because of how institutionalised we have all become. SOPs are there to be followed and with good reason; however, most are written for single event situations ie the system works & both crews carry out their instructions in a timely manner. What if they don't or the system is not working correctlty? The term airmanship seems to have become lost but it is synonomous with Situational Awareness. I would desperately hope that a crew would be aware of traffic around them during most of their flight regime. (difficult admittedly with GA traffic - Sanford for example) There is the lead up to the RA, the actual RA and what is done about it at what stage. IMC - no brainer but mostly we will be VMC and will be searching for a visual way before the RA happens, ideally steps would taken early to minimise any conflict but if it develops into an RA, and I have actioned the instructions, and have aquired the visual, then if visually the situation warrants I may well break the collision with a turn, and I am not talking about a 160degree turn to conflict with the guy at my 5 oclock x miles behind! All that is required is 5 or 10 degrees - to break the collision and ONLY if required. TCAS is not infallible technically or operationally and as always we are the last slice of cheese - the guy you are going to hit is the one remaining static in your field of view, make him move one way or the other and you won't connect. Furthermore any turn would not be in any defined direction - it would be as the collision required and please don't tell me that a SMALL turn will fly me straight into someone else - We are not flying in close formation here and these are not violent aerobatic reactions. As always when the event is over resume course and level assigned. We all have many tools in our box - when only one is avaliable use it, if others are there be prepared to use them as well if required.

Fly safe the sky is not as big as it once was.
and PS Don't believe the press

[anotherthing]

Topslide6

far be it from me wanting this thread to go further down the pan, but may I suggest you read del prados post properly and his amplifying one?

He is saying that pilots should not initiate turns based on TCAS because the information given in the azimuth plain are very inaccurate. This inaccuracy is the same reason I would politely tell you to do your own job if you pointed out to me that based on TCAS azimuth info, you thought you might have traffic to affect you in the near future... from your post number 38 on this thread - I quote How's about pointing it out to ATC long before it becomes a TA. You know what the solid white diamond means right?


You would be forever nagging me in the London TMA due to the multitude of tracks :ugh:. If you think your A/C is in danger pipe up - otherwise leave the ATC to ATCOs and don't try to interperet a piece of equipment for use it is not designed!

[bubbers44]

RA's only give vertical guidance and we are required to adhere to them. If the conflicting AC can be seen and a turn would increase separation why on earth would you not do so? If you had no TCAS and just saw the situation you would use both vertical and lateral means to minimize the possibility of a midair. Common sense should always prevail over standard procedure.

[Caudillo]

Common sense should always prevail over standard procedure

Amen to that. It should be an SOP.

[PENKO]

This will blow your mind:

What if you get an RA in a turn?:ugh:

[Turn It Off]

Not sure if this has been mentioned yet or not, but, ATC have been told that they are not to issue a turn if a pilot reports a TCAS RA as it may have an impact on the effectiveness of the wing.

Surely, a turn whether instructed by ATC or at the Pilots discretion the effectiveness of the wing is still questionable. Maybe another reason jut to stick to the RA?

TIO

[NigelOnDraft]

Our Airbus manuals nowhere state "Do Not Turn". They do emphasise not to Mvre based on the TA, but to use the TA to visually acquire the traffic. What's the point of visually acquiring it if you are not allowed to avoid it :{

In the event before/after a TA I visually acquired a threat, and time/RT traffic etc. prevented a timely ATC co-ordinated, separation I would consider a turn as required - after all, assessing/achieving visual lateral separation is relatively easy.

If an RA results, then you have to follow the vertical guidance, of course. If it became perf limiting (unlikely) then any AoB would have to be rolled off.
We need to keep an element of commonsense here... TCAS is a great aid, but we still have eyes and ailerons ;)

NoD

Edit for spelling

[Phil Space]

Let's get this in context.
Lots of trucks/coaches rolling up the motorway/freeway with tired drivers/low fuel.
Time to take a break.
However what we are looking at here is lots of red eye flights arriving at the same time and the same place with marginal fuel. OK for the crew but better for the bean counters.

How many people would want to board a long haul where they knew there was marginal fuel?

[BenThere]

Once you've satisfied the RA vertical command, and you've either spotted the intruder visually or ascertained it's azimuth trend on the display, I don't see anything wrong with an avoidance turn.

For one thing, it will likely clear the conflict sooner so that you can resume your assigned altitude and track more quickly. In the unlikely event your manouver creates a new RA-generating conflict, the TCAS can provide resolution for multiple targets, and you'll have to comply with the second RA.

See and avoid remains basic. While the RA must be complied with first, and cannot be ignored, it is not the only tool you have.

[anotherthing]

Ben There -

whats to say, for instance in a busy TMA, that the traffic you think you have spotted and decide to initiate a turn to avoid is
a) the traffic that is generating the RA
or that you will not be
b) causing another RA because you are turning towards traffic that would otherwise not have been a factor?

There is a nice example on record (that happened in UK airspace) of an incident where a pilot thinking he knew better, because of his interpretation of the inherently innacurate azimuth information on TCAS, decided that he was going to be in conflict with an aircraft. The pilot initiated his own turn, without telling ATC, to position his aircraft to cross behind the 'intruder'. He then had an airprox.

The controller had set the 2 aircraft on headings which would have acheived about 12 miles separation, and then went on to concentrate on more pressing matters. He did not see the aircraft make its 'unauthorised' turn and the first he knew about it was when the pilot called an RA descent.

The controller, as is the way, was immediately suspended, subsequently cleared after investigation.

ATCOs are instructed not to pass turn instructions on receipt of an RA call from a pilot - even though they are far more aware of other traffic that may affect the aircraft in question... unless a pilot sees a clear indication of an imminent collision, he/she should restrict themself to a climb/descent. if it's really that close, then your probably too late anyways, or reacting milliseconds after the the a/c has passed the CPA.

The time you are supposed to visually acquire the intruder is on receipt on a TA, and thats when you should be preparing yourself to initiate a manoeuvre to comply with any subsequent RA... during which you should surely be watching the instruments to in sure you keep in the green zone to give yourself the best chance to ge the most separation, not looking out the window relying on reflexes which, at the closure rates involved, will be lagging behind the facts anyway!


In the unlikely event your manouver creates a new RA-generating conflict,....

not so unlikely - there is another incident, again in UK airspace, whereby multiple - more than just 2 or 3 - RA's were triggered because of the density of traffic around an aircraft that was complying with the original RA... we still have the R/T and radar replays in the training department of our unit (along with other incidents to be used as training aids).

[Fropilot]

Until TCAS/ACARS III becomes a reality the recommended TCAS maneuver for a RA is for vertical separation only. Or am I missing something.

[NigelOnDraft]

Last couple of posts...

Lateral Mvre during an RA I think is unworkable... From my Sim training, and for real, during an RA the priority must be to follow it 100% - that takes some drills, 2 crew co-operation in aircraft handling and ATC calls.

My comments above were directed at the posts seemingly implying you cannot look out of the window and avoid - but sit there dumbly awaiting the RA :{ TCAS might be great, but is not infallible.

Whilst TCAS is great vertically (where visual judgement is weak), eyeball lateral separation is relatively easy, and TCAS not involved in. Anyone who thinks a single turn of say 30degrees for 15 seconds will see them hit another aircraft or mountain is living at rather a high stress level :ugh:

NoD

[parabellum]

I have read the entire thread but am unclear if these aircraft were on reciprocal or converging tracks?

I did get quite a fright once in Eastern Europe and then became a very willing proponent of the 'one mile right offset', not possible when on radar vectors, climbing, descending etc. but otherwise not a bad idea.

[BenThere]

Good points, anotherthing.

I concede you would never know to a certainty that the aircraft you were visually avoiding is the one triggering the RA in a high density environment. You can't either be sure to a certainty that the other aircraft is complying with his RA against you.

Let me be clear that I don't advocate not complying with the RA vertical command first and foremost to any other action. Once you do, though, unless you are IMC, a set of eyeballs, assuming a two-place aircraft, should be back outside looking once RA compliance is assured.

Your point about turning into other traffic is valid, too. But I'm not suggesting a sustained course alteration but a turning maneuver of short duration; one just adequate to quell the conflict, which I wouldn't think would displace course by more than a mile at most, and would not, I hope, be likely to cause loss of traffic separation if course is then quickly resumed.

I've only had a few RAs, the last one on approach to Newark 22L last year while being line checked. The trigger was a fast climbing bizjet out of Teterboro whose rate of climb on departure broke into the RA equation even though he leveled off 1,000' below as cleared. Never saw him, but I was definitely looking for him once the VSI was in the green. The check airman didn't seem to mind.

I didn't know for sure the other guy was going to level off. But I damn sure would have turned if I'd spotted him coming at me.

[clicker]

I have read the entire thread but am unclear if these aircraft were on reciprocal or converging tracks?

That's a bit thats confusing me because if the flight turned one would have to hope the crew had a visual on the other aircraft but then the idiot reporter states the SLF in the rear of the aircraft saw the other aircraft approaching.

[Del Prado]

Topslide6,

This thread appears to be going in circles, yet as far as i'm concerned there isn't even an argument.



So why the last paragraph?

For me, what comes out of this thread are there are some pilots who want to interpret this scenario as never, ever turn during a TCAS event as per SOPs. There are others being a bit more pragmatic and saying while they would always follow SOPs and never, in theory, turn during an RA, they are willing to concede that TCAS will not save you 100% of the time and visual aquisition of the traffic, if possible may allow a back up plan.
I don't think it comes down to a lck of trust in ATC though standards around the world are obviously very different.

NoD's example of 30 degrees off track for 15 seconds wouldn't erode other separation by more than a half a mile. (I've seen several pilots avoid weather by more without asking first.)
And I'm not advocating that for every TA in the LTMA but I have to wonder if a visual aquisiton and turn might just save another incident like Brasil or Lake Constance.

Still what do I know, you don't believe I'm really air traffic :E

[p7lot]

Wizz makes a good point about the difference in preference given to TCAS alerts.
The main reason the DHL disaster came about was that westerners tend to obey alerts whereas Russian pilots for example tend to be trained to obey ATC commands......thereby creating another conflict.

The whole point of separation is worthless if we are not all on the same Datum.

[Capt Pit Bull]

Topslide,

Quote:
But apart from that, in general terms, there is no inherent reason why you shouldn't be turning just as long as you aren't doing so based on looking at your traffic display.

I must admit, along with others I am sure, some of what I read on here concerns me somewhat.

IF you are a genuine pilot, it concerns me that I might be unlucky enough to be flying above/below you when you respond to an RA and decide it appropriate to throw in a turn for good measure. God forbid I ever am.

Oh, and by the way, there is an inherent reason why you should not turn...

because the procedures say you don't.

How hard is that to understand?!




Well, I'm going to have to rise to that one.

Project pilot during the implementation of TCAS at a substantial UK airline as a matter of fact. I spent months studying the system and looking at historical incidents from the FAA TCAS transition Program, as well as undergoing training with avionics manufacturers, and liasing with the ATC operational training guys so that our trainees would appreciate what was going on at the other end of the radio.

What you've done is selectively quote me, and ignore the caveat in the preceding part of my post.

You keep banging on about the fact that 'the procedure' says don't turn. It may or may not, depending on the manufacturer and the operator. If it does say 'don't turn' the major factor there is likely to be performance. (Because contrary to perceived opinion, TCAS RA inhibition based on performance is pretty rough and ready, you may well not be able to achieve the RA, and turning in those circumstances isn't going to help. But you don't want to know that do you, after all, I can't possibly be a professional pilot, and can't possibly be better informed than you.)

The bottom line is this:

You have an arsenal of tools at your disposal to avoid hitting another aircraft (6 in fact). None of them are flawless. A truly professional pilot would strive to identify the relative merits of the different methods, so that he or she would appreciate the driving force behind a set of SOPs, rather than just blindly following them in a 'one size fits all' manner.

A turn for collision avoidance has a number of strengths, as well as weaknesses (some of which you have alluded too). I don't suggest that its a flawless method. I certainly don't think people should be throwing in turns willy nilly just because they think its a good idea. But I'm concerned that you seem to insist that no one else must ever consider it, just because your type at your airline has a procedure.

And I reitereate, for the avoidance of any doubt, turns must never be initiated based on the traffic display.

We're falling into the beancounters trap here folks. They don't want to spend money training you to appreciate the systems you work with. They just want to give you a single sentence SOP and would have you believe that all situations can be solved by it. God forbid you might have to exhibit some professional judgement.



Wizo

2) RAs are only effective if BOTH pilots react to them,

Not so. Most RAs are quite adequate to achieve safe separation by themselves, whether the other aircraft manouevres or not. (The only substantial exception to this is where RA inhibitions are present, and both aircraft are inhibited in the same sense.) All that is required is that the other aircraft does not manouevre in the opposite direction. If you look at the alerting times, the flight path changes, and the target separation, either aircraft can generate a vertical miss in most scenarios.

None of which detracts from the virtue of the rest of your post, that I wholeheartedly agree with.

pb

[Capt Pit Bull]

Topslide,

You posted while I was typing. Having read your last post I don't think we're that far apart.

pb

[Wizofoz]

Hi CPB,

Thanks very much for the input. Very much as I understand things.

The quote from me was meant to cover the very senerio you mention, one aircraft following the RA, whilst the other climbs or descends in contravention of it, possibly to follow an ATC command. Just this happened in both the DHL crash and the JAL near-miss.

The other one people seem not willing to touch is the case of mode A only. In this case you won't GET an RA. You can hit the other aircraft and will not have recieved anything more than a TA. As for "Letting ATC do its job", THEY won't have an Altitude read-out either. Thus, with an ATC on duty and an Airliner with two professtional pilots on board, seperation relies on the first-solo guy in his 152 not busting his cleared altitude.

Topslide,

I'm sorry this debate descended into name calling, but, as you can see many "Actual Professtional Pilots" have similar ideas to me (and some disagree, whilst backing their arguments with logical, respectful comments). Do you " Hope I never have to fly" with all of them?

[Capt Pit Bull]

Another poitn worthy of throwing in here is that I think some of the TCAS learning points have got a bit muddled.

There is a very valid point that the aircraft you can see may not be the one that you are getting the RA about. There was a wonderful (from a training reinforcement point of view - I'm sure the blokes shat themselves) incident back in the early days. (Bear in mind the SOPs of the day permited an RA to be disregarded based on a visual spot.)

In a nutshell: The crew had two RAs in quick succession against two different aircraft. They saw the first target as they got the RA against the second one (still unseen). They assessed the second RA as being unnecessary but elected to fly it anyway, and then had aircraft 2 flash directly overhead (i.e.no horizontal miss, TCAS generated vertical miss).

The point is, don't let a visual spot throw you off making the RA vertical manoeuvre.

Misuses of the traffic display, with folks generating their own turns based on it - sometimes way in advance of an RA, and sometimes even turning safe separation into an RA - have a colourful past.

I would argue that if you can see something at constant relative bearing and its getting bigger, then it doesn't matter if its the traffic causing the RA or not; its a collision risk.

Lets also throw in Anotherthings observation:

ATCOs are instructed not to pass turn instructions on receipt of an RA call from a pilot

Yes (though it wasn't always that way). But even so, you'd probably be giving avoiding action up until getting a 'tcas descent (or whatever)' call.

Lets throw in an example. Vectoring in towards a regional airfield, a grobbly day with a fair bit of low level cloud. Lets say 20 miles out, in level flight. Controller suddenly says something like "Callsign! Avoiding action! Turn right heading 090 - pop up traffic from low level". As you thumb the a/p disconnect and start your turn, your TCAS gets about halfway through saying 'Traffic' and then says "Maintain vertical speed - maintain" with a red sector above your current vertical speed (i.e. saying don't climb). What do you do? Surely we'd all maintain the current altitude and fly the turn. Wouldn't we?

pb

[FinalVectors]

Must say I am little scared after reading this thread.

Too many pilots think they allmost have "a radar" in their aircraft these days.
TCAS is a great last option tool...but really also give us ATCO's a LOT of grey hairs too because it's used/misused like a radar by many pilots.

TCAS is not a radar, for sure it shows you about which direction to look for traffic...HOWEVER...it doNOT show you which direction the traffic is moving!!
SO..turning in a RA situation...or even worse..turning to avoid a RA...is not the smart thing to do.

Give you an example...(out of memory from a incident I did read about some time ago).
Pilot see a target on his TCAS approaching him at same level from his 10 o'clock, for the pilot it looks like the traffic is heading direct for him. So with his smart thinking he turns right without telling ATC...to avoid any TCAS RA...result was...yes you guessed correct, a near miss and RA:ugh:

What the pilot ofcourse couldnt't see on his TCAS was that the target was crossing in front of him with 5nm minimum sep. from left to right about 90degrees on his flightpath. So if he had stayed on course he would had seen the target approach him..then do a arcing movement around him from left to right..and leave behind at his 4 o'clock.

TCAS is NOT the same as RADAR, it do only show direction to target, not which way he is flying...so until TCAS has been improved and works both vertically and horisontally...PLEASE..do not turn according to TCAS RA only!!!

Thanks

FinalVectors
ATCO

[malcolmf]

The crew concerned had a turn instruction from ATC followed closely by the RA which explains why they were turning at the time.

[poldek77]

Probably some of us haven't seen this:

http://www.eurocontrol.int/msa/gallery/content/public/documents/ACAS_Bulletin_6_Mar-05.pdf

[Sven Sixtoo]

Now I'm not an airline pilot, and my aircraft doesn't have TCAS - I wish it did, but that's the defence budget for you.
But to me, all that those examples from Eurocontrol demonstrate is that the aircrew did not understand the sole condition for a collision, which is that the target is closing on a constant bearing. This is, incidentally, why see-and-avoid is a poor answer in VMC. The target that's going to hit you is stationary in your field of view (if its in your field of view at all), and evolution has equipped us with a visual system that responds best to movement (it picks up the twitching grass as the sabre-toothed tiger crawls up on you). Change any part of the dynamics and the collision is avoided. For well-thought-out reasons, TCAS uses the vertical as the avoidance dynamic. But on any contact, if the bearing is changing towards the 12 o'clock, the target will pass ahead, and if the bearing is changing towards the 6 o'clock, the target will pass behind.
Sorry if I'm teaching granny to suck eggs.
Sven