TCAS RA in VMC. Follow the RA or Not?
Thread Starter
TCAS RA in VMC. Follow the RA or Not?
I ask this question after watching the ITVV A330 video. They get an RA whilst level at 5000ft. They are visual with the traffic and do not follow the descend RA.
Is that normal? I know an A320 captain who says he would have followed the RA because it could have been for another aircraft that the crew were not visual with. (He hasn't seen the film, he only has my description of events).
Anyone have any thoughts. I would have thought the SOP's give a procedure to be followed in the event of an RA. If the procedure is to follow the RA, should the FO who was PNF said something or taken control?
Is that normal? I know an A320 captain who says he would have followed the RA because it could have been for another aircraft that the crew were not visual with. (He hasn't seen the film, he only has my description of events).
Anyone have any thoughts. I would have thought the SOP's give a procedure to be followed in the event of an RA. If the procedure is to follow the RA, should the FO who was PNF said something or taken control?
Join Date: Dec 2003
Location: SSE of smoki
Posts: 223
Likes: 0
Received 0 Likes
on
0 Posts
Always follow the RA, safety of the aircraft depends on it. There are times when the TCAS will not give you avoiding action, low level for one, and single engine with TA selected the other. You may deviate from an ATC clearance to comply with an RA but let ATC know as soon as practicable. Rgds.
Join Date: Feb 2005
Location: UNITED KINGDOM
Posts: 53
Likes: 0
Received 0 Likes
on
0 Posts
You follow the RA without question.
TCAS doesn't paint an exact picture of where traffic is, just a guide, the traffic you see may not be the traffic generating the RA.
Don't be lulled into a false sense of security because you can see something out of the window that corresponds with TCAS traffic, that will KILL YOU.
ALWAYS FOLLOW THE RA DON'T EVEN THINK ABOUT DOING ANYTHING ELSE.
TCAS doesn't paint an exact picture of where traffic is, just a guide, the traffic you see may not be the traffic generating the RA.
Don't be lulled into a false sense of security because you can see something out of the window that corresponds with TCAS traffic, that will KILL YOU.
ALWAYS FOLLOW THE RA DON'T EVEN THINK ABOUT DOING ANYTHING ELSE.
Join Date: Aug 1999
Location: England
Posts: 1,050
Likes: 0
Received 0 Likes
on
0 Posts
It depends a bit on the vintage of the film you are looking at.
Ultimately, an RA is an advisory. Since manufacturers and regulatory authorities recognise that TCAS can not be aware of every possible circumstance, ultimate authority regarding following an RA has to devolve to the commander on the spot.
It is certainly possible to envisage circumstances where following an RA might actually be more hazardous that not doing so. However, simply feeling that the RA is not necessary does not qualify as such a circumstance.
Many operators do have procedures that allow an RA to be disregarded in the event of visual contact and no confliction, however opinions have hardened against such procedures.
I agree with your A320 acquaintance. In fact, there was an incident in the USA several years ago which was a good learning point (for those that paid attention!). Very paraphrased, it went like this.
- Aircraft has 2 RAs in quick succession against 2 different aircraft.
- First RA is followed, intruder misses by a fair horizontal distance anyway. Crew get visual with first intruder as it passes abeam them.
- Crew get second RA, against a (thus far) unspotted second intruder. They consider the RA to be not needed as they assume it is related to the aircraft they can see passing clear. However, they wisely elect to follow it anyway.
- They do spot second intruder as it intersects with them horizontally, missing purely by TCAS generated vertical seperation.
- Crew become paid up members of the 'TCAS is a good thing' society!
CPB
Ultimately, an RA is an advisory. Since manufacturers and regulatory authorities recognise that TCAS can not be aware of every possible circumstance, ultimate authority regarding following an RA has to devolve to the commander on the spot.
It is certainly possible to envisage circumstances where following an RA might actually be more hazardous that not doing so. However, simply feeling that the RA is not necessary does not qualify as such a circumstance.
Many operators do have procedures that allow an RA to be disregarded in the event of visual contact and no confliction, however opinions have hardened against such procedures.
I agree with your A320 acquaintance. In fact, there was an incident in the USA several years ago which was a good learning point (for those that paid attention!). Very paraphrased, it went like this.
- Aircraft has 2 RAs in quick succession against 2 different aircraft.
- First RA is followed, intruder misses by a fair horizontal distance anyway. Crew get visual with first intruder as it passes abeam them.
- Crew get second RA, against a (thus far) unspotted second intruder. They consider the RA to be not needed as they assume it is related to the aircraft they can see passing clear. However, they wisely elect to follow it anyway.
- They do spot second intruder as it intersects with them horizontally, missing purely by TCAS generated vertical seperation.
- Crew become paid up members of the 'TCAS is a good thing' society!
CPB
Thread Starter
The film was recorded in January 2000, onboard an Airtours A330-200, flying from Manchester to Orlando Sandford. The sector safe was 2800’ and they were at 5000'.
It seems that the general consensus is that the RA should have been followed, regardless of what the pilots could see.
The captain chose not to follow the RA, is it likely that Airtours procedures allowed that in January 2000?
My real purpose in asking this question is to find out what the first officer should have done about it. The 320 captain that I know says if he were the FO he would have taken control and followed the RA. Obviously that could cause some friction down line. In the Airtours case the first officer had just completed his CCQ course and he was on his first trip to North America with the chief training captain. That would obviously make it even harder for the FO to take control if he felt they should have descended. With the timescales involved in a TCAS RA there is no time to discuss this matter so taking control would appear to be the only option if the FO was not happy.
I'm not trying to have a go at anyone concerned, I'm just trying to work out what I would do if I find myself in the same situation.
I’d also be interested to know if any FO’s have actual experience of taking control when the captain was PF.
Thanks
SW
It seems that the general consensus is that the RA should have been followed, regardless of what the pilots could see.
The captain chose not to follow the RA, is it likely that Airtours procedures allowed that in January 2000?
My real purpose in asking this question is to find out what the first officer should have done about it. The 320 captain that I know says if he were the FO he would have taken control and followed the RA. Obviously that could cause some friction down line. In the Airtours case the first officer had just completed his CCQ course and he was on his first trip to North America with the chief training captain. That would obviously make it even harder for the FO to take control if he felt they should have descended. With the timescales involved in a TCAS RA there is no time to discuss this matter so taking control would appear to be the only option if the FO was not happy.
I'm not trying to have a go at anyone concerned, I'm just trying to work out what I would do if I find myself in the same situation.
I’d also be interested to know if any FO’s have actual experience of taking control when the captain was PF.
Thanks
SW
Couldonlyaffordafiver
Join Date: Dec 2000
Location: The Twilight Zone near 30W
Posts: 1,934
Likes: 0
Received 0 Likes
on
0 Posts
Just 'cos you don't follow the RA, doesn't mean the other bloke won't either. Could cause all sorts of problems. Always follow a TCAS RA unless it's blatantly obvious that it's wrong. The DHL accident mentioned above involved one of the aircraft obeying ATC rather than the RA.
Regulations and ops manuals have been changed as a result.
Regulations and ops manuals have been changed as a result.
Join Date: May 2002
Location: Who can say?
Posts: 1,700
Likes: 0
Received 0 Likes
on
0 Posts
I concur entirely with those who say Follow the TCAS every time.
Don't think about it.
Don't try to evaulate whether or not you think it's valid.
Don't think you can see the traffic.
Don't obey ATC instructions if contrary to TCAS.
If you're PNF and the PF doesn't want to obey TCAS, take control IMMEDIATELY.
The alternative? Turn to the page in the QRH that begins "Our Father, who art in heaven..." or "Bismillah Al Rahman Al Rahim" (or your local equivalent) and prepare to meet him.
It's that simple.
Don't think about it.
Don't try to evaulate whether or not you think it's valid.
Don't think you can see the traffic.
Don't obey ATC instructions if contrary to TCAS.
If you're PNF and the PF doesn't want to obey TCAS, take control IMMEDIATELY.
The alternative? Turn to the page in the QRH that begins "Our Father, who art in heaven..." or "Bismillah Al Rahman Al Rahim" (or your local equivalent) and prepare to meet him.
It's that simple.
We were on a long final approach to 28R at SFO, about 2,000' over the bay on a clear day. My first time into SFO. A Jetstream turboprop was passing us on the closely-spaced parallel, 28L (less than seven hundred feet)! This was not recommended. The TCAS said descend! I was not about to push the 757 towards the water, and the Captain said, "don't go down".........In THAT situation, parallel to the traffic which we both clearly saw, that was the only exception to the rule-in all other situations, follow the TCAS commands!
After the collision in southwestern Germany, the Russian father of one victim went to the HOUSE of one of the Swiss Air Traffic controllers and killed him, in his own yard.
After the collision in southwestern Germany, the Russian father of one victim went to the HOUSE of one of the Swiss Air Traffic controllers and killed him, in his own yard.
Join Date: Oct 2001
Location: Washington
Posts: 6
Likes: 0
Received 0 Likes
on
0 Posts
Quite scary the amount of misinformation about RAs. So to clarify guys here is the story.
Previous to the DHL/Sibair midair collision, ICAO defined the response to a RA as 'should' be followed. Grammatically the word 'should' is NOT a command and therefore many states and individual operators technically allowed crews to ignore an RA if they percieved a 'better' solution. However the DHL/Sibair accident showed the vulnerability of this procedure. Namely that there are 3, count them 3, parties involved. The 2 aircraft and the ATC controller, and unless all 3 act in in the same manner, then disaster is possible. (In the DHL/Sibair incident the Sibair was told by ATC to descend just prior to the RA and they continued to do so despite the RA because they viewed the ATC controller as a 'superior', and in Russian culture it is common to act in accordance with a superior's instruction above all else!)
Therefore after the crash investigation had highlighted this procedural failure, ICAO changed the wording for an RA to, 'SHALL' follow RAs, in 2004. 'Shall' is a command word and therefore now there is no 'judgement' involved in whether you decide to follow an RA or not. You simply have no choice, and you unilaterily have too.
Yes, I know there are still arguments against this blanket command, (A TCAS alert in a LHR hold in 2004 had a domino effect on several aircraft, illustrated its short comings) and RA stands for Resolution 'Advisory'. Advisory not being a command word, but many bodies are trying to change this to 'Resolution Action'. Still, at present it is preceeded with 'Shall' which is the key command action.
With regard to incidents of non compliance to RA's, these were previous to these grammatical changes when it wasn't a 100% command function.
Anyone, still thinking that they can ignore any RA, has to be 100% sure that not compliance is the safest action! But how as an individual can you know this when you do not know catagorically who is the other parties involved (the other aircraft is not always the closest or the one insight) and what they are doing!!! Its not just your license at risk, its all the lives behind you! Only TCAS has the complete picture.
Hope this clarifies the situation!
Previous to the DHL/Sibair midair collision, ICAO defined the response to a RA as 'should' be followed. Grammatically the word 'should' is NOT a command and therefore many states and individual operators technically allowed crews to ignore an RA if they percieved a 'better' solution. However the DHL/Sibair accident showed the vulnerability of this procedure. Namely that there are 3, count them 3, parties involved. The 2 aircraft and the ATC controller, and unless all 3 act in in the same manner, then disaster is possible. (In the DHL/Sibair incident the Sibair was told by ATC to descend just prior to the RA and they continued to do so despite the RA because they viewed the ATC controller as a 'superior', and in Russian culture it is common to act in accordance with a superior's instruction above all else!)
Therefore after the crash investigation had highlighted this procedural failure, ICAO changed the wording for an RA to, 'SHALL' follow RAs, in 2004. 'Shall' is a command word and therefore now there is no 'judgement' involved in whether you decide to follow an RA or not. You simply have no choice, and you unilaterily have too.
Yes, I know there are still arguments against this blanket command, (A TCAS alert in a LHR hold in 2004 had a domino effect on several aircraft, illustrated its short comings) and RA stands for Resolution 'Advisory'. Advisory not being a command word, but many bodies are trying to change this to 'Resolution Action'. Still, at present it is preceeded with 'Shall' which is the key command action.
With regard to incidents of non compliance to RA's, these were previous to these grammatical changes when it wasn't a 100% command function.
Anyone, still thinking that they can ignore any RA, has to be 100% sure that not compliance is the safest action! But how as an individual can you know this when you do not know catagorically who is the other parties involved (the other aircraft is not always the closest or the one insight) and what they are doing!!! Its not just your license at risk, its all the lives behind you! Only TCAS has the complete picture.
Hope this clarifies the situation!
The Original Party Animal
Join Date: Dec 2000
Location: Around the corner
Posts: 375
Likes: 0
Received 0 Likes
on
0 Posts
ICAO should have changed "should" to "shall" already after the Japan incident in January 2001, as recommended by the japanese investigation authorities.
They didn't, and one and a half years later the crash over Ueberlingen happened.
This is a first rate scandal and they get away with it!
Remember: TCAS is a last resort tool and has to be used as such!
They didn't, and one and a half years later the crash over Ueberlingen happened.
This is a first rate scandal and they get away with it!
Remember: TCAS is a last resort tool and has to be used as such!
Join Date: Nov 2000
Location: Planet Claire
Age: 63
Posts: 587
Likes: 0
Received 0 Likes
on
0 Posts
I'm always wary of these 'always do THIS' or 'the crew SHALL' do etc, type instructions. That DHL crew, for example followed the TCAS and where are they now?
For sure the DHL midair removed all doubt from my mind, and no doubt many others, about what to do when TCAS & ATC instructions conflict. It's as well to remember tho, that TCAS is not infallible. As someone else pointed out it issues 'advisories' not ultimately commands. Wasn't there a near miss when the TCAS missread it's own altimeter and gave an RA which damn near CAUSED a collision? Also, although the Sibair crew were at fault in that awful midair, without the presence of the TCAS there would have been no accident. Once these TCAS climbs/descents get going who knows whats going to happen next!
All I'd say is yes, always always follow the TCAS and get the manoevre under way, but keep looking out the window too!
For sure the DHL midair removed all doubt from my mind, and no doubt many others, about what to do when TCAS & ATC instructions conflict. It's as well to remember tho, that TCAS is not infallible. As someone else pointed out it issues 'advisories' not ultimately commands. Wasn't there a near miss when the TCAS missread it's own altimeter and gave an RA which damn near CAUSED a collision? Also, although the Sibair crew were at fault in that awful midair, without the presence of the TCAS there would have been no accident. Once these TCAS climbs/descents get going who knows whats going to happen next!
All I'd say is yes, always always follow the TCAS and get the manoevre under way, but keep looking out the window too!
Join Date: Jun 2001
Location: Surrounded by aluminum, and the great outdoors
Posts: 3,780
Likes: 0
Received 0 Likes
on
0 Posts
TCAS only works if everybody complies with RA..otherwise it's deadly especially when flying CONTRARY to an RA..(the loss of my two colleagues proves this)..legislation should have been in place prior to equipping the aircraft with these devices..as usual the politicos are mucking about, and another disaster is in the waiting
Join Date: Oct 2001
Location: Washington
Posts: 6
Likes: 0
Received 0 Likes
on
0 Posts
TCAS as a system requires full compliance by all for it to be effective!
Yes its hard, especially for pilots who in general have a 'control' persona, to put their faith in a machine. But, lets keep it in context. There were many mid air collisions prior to TCAS, it is also a fundamental part of other systems and procedures, such as RVSM and FANS and therefore it is not really a option to remove it. It has undoubtedly saved more lives.
What is needed is for everyone to respond to TCAS in the same manner. This is why lives were lost in the DHL/Sibair collision.
So;
1) if you get an RA on an approach, respond to it even by a descending. The other aircraft will be climbing and the sooner you BOTH do it the sooner the conflict will clear, and the system is safeguarded by RAs being automatically disconnected below 700' radio height, to remove unwanted 'approach' proximaty alerts. I would be immensely surprised if you haven't been given a similar scenario in a sim check!
2) EGPWS terrain warnings etc have precedence over RA's, so you won't have a CFIT
3) RA's have precedence over ATC. Remember or familise yourself with your RT. 'Callsign, Climbing/Descending due TCAS' this removes ATC from the loop until, 'Callsign, clear of conflict'
4) Operate correctly, and not just for TCAS. Equipment is only as good and correct as the information given to it, by us. So always confirm you have the correct altimeter settings, and climb or descend less than 1000' per minute in the last 1000 feet of your climb and descent profiles (Very few of the pilots in my company regulary do this) to eliminate unwanted TCAS alerts.
To summaries, correct operation and compliance with TCAS by ALL is the safest and most effective system.
With regard the authorities, In there defense (and I am not one of them) the original terminology was written with the intent that it was a 'command'. However it was interpreted differently and this is what was tightened up after DHL/Sibair. In fact the Japan incident had already started to raise concerns, unfortunately nothing happens over night, which is what happened here, and unfortunately DHL/Sibair occurred before changes could be implemented.
Yes its hard, especially for pilots who in general have a 'control' persona, to put their faith in a machine. But, lets keep it in context. There were many mid air collisions prior to TCAS, it is also a fundamental part of other systems and procedures, such as RVSM and FANS and therefore it is not really a option to remove it. It has undoubtedly saved more lives.
What is needed is for everyone to respond to TCAS in the same manner. This is why lives were lost in the DHL/Sibair collision.
So;
1) if you get an RA on an approach, respond to it even by a descending. The other aircraft will be climbing and the sooner you BOTH do it the sooner the conflict will clear, and the system is safeguarded by RAs being automatically disconnected below 700' radio height, to remove unwanted 'approach' proximaty alerts. I would be immensely surprised if you haven't been given a similar scenario in a sim check!
2) EGPWS terrain warnings etc have precedence over RA's, so you won't have a CFIT
3) RA's have precedence over ATC. Remember or familise yourself with your RT. 'Callsign, Climbing/Descending due TCAS' this removes ATC from the loop until, 'Callsign, clear of conflict'
4) Operate correctly, and not just for TCAS. Equipment is only as good and correct as the information given to it, by us. So always confirm you have the correct altimeter settings, and climb or descend less than 1000' per minute in the last 1000 feet of your climb and descent profiles (Very few of the pilots in my company regulary do this) to eliminate unwanted TCAS alerts.
To summaries, correct operation and compliance with TCAS by ALL is the safest and most effective system.
With regard the authorities, In there defense (and I am not one of them) the original terminology was written with the intent that it was a 'command'. However it was interpreted differently and this is what was tightened up after DHL/Sibair. In fact the Japan incident had already started to raise concerns, unfortunately nothing happens over night, which is what happened here, and unfortunately DHL/Sibair occurred before changes could be implemented.
The Original Party Animal
Join Date: Dec 2000
Location: Around the corner
Posts: 375
Likes: 0
Received 0 Likes
on
0 Posts
unfortunately nothing happens over night
4 pilots and 79 passengers got killed, an ATCO became a victim subsequently,
7 employees of Skyguide are currently being questioned by the examining magistrate and they potentially face trial.
And ICAO is getting away with it!!
Join Date: Jun 2001
Location: In da north country
Age: 62
Posts: 452
Likes: 0
Received 0 Likes
on
0 Posts
I think TCAS is the best thing to hit aviation in the last 20 years.
I believe in it more than anything.
However, a few years ago, I was in a beloved Tri-star and we were climbing like a homesick angel only to get a traffic advisory from ATC saying there was another beloved Tri-star at 11,000 FT and we were climbing to 10,000FT. shortly there after we got our RA, but had the other guy in sight , so elected to do nothing more than reduce our rate of climb instead of push it over and go down. We just had an excessive closure rate, and the TCAS picked this up! It is a very rare circumstance where i would ignore an RA! Believe in it unless you have a positive ID on the traffic!
I believe in it more than anything.
However, a few years ago, I was in a beloved Tri-star and we were climbing like a homesick angel only to get a traffic advisory from ATC saying there was another beloved Tri-star at 11,000 FT and we were climbing to 10,000FT. shortly there after we got our RA, but had the other guy in sight , so elected to do nothing more than reduce our rate of climb instead of push it over and go down. We just had an excessive closure rate, and the TCAS picked this up! It is a very rare circumstance where i would ignore an RA! Believe in it unless you have a positive ID on the traffic!
Join Date: Oct 2001
Location: Washington
Posts: 6
Likes: 0
Received 0 Likes
on
0 Posts
Spuds McKenzie, with all due respect, I do believe the DHL/Sibair was extremely unfortunate, because nothing does change overnight in the real world. I wish it did, I wish we had a magic ball and could see which of the hundreds of incidents would have an imminient reoccurrances and which incidents were actually caused by the first prime suspect and which corrective actions don't have any unfavourable consequences themselves! I'm not condoling this delay, just putting a real world slant on the situation. There are hundreds of incidents similar to this. AeroPeru 757 off Lima in 1996 could of been avoided if the Birginair recommendations were implemented sooner, not to mention the ADs that leave aircaft flying for years with faulty equipment, eg: MPET lining, found to be a major contributing factor of the Swissair MD11 fire, is still in many aircraft worldwide, as the AD gives until 2005 for its replacement to be installed, and many airlines have asked for extensions. I could go on and on.
Yes we can and should lobby the powers to be to accomplish these tasks in a quicker fashion, but we know that this costs and these costs are pushed down the ladder to the passenger, which the airlines hate! But in the real world we can accomplish a safer enviroment by us ALL operating in a 100% correct manner, especially when it comes to TCAS.
One common misconception with TCAS is that it only gives you 1 RA aircraft at a single time. It does not, you can have and it can display more than one RA at the same time (think of all those formation military fast jets out there). Therefore to say we didn't follow the RA because we had visual contact with the RA, is wrong because the second RA will collide with you 1 second later and you will never see it, possibly even not on TCAS if you are preoccupied with scanning the horizon for the first RA!
So my point still stands. As pilots what we can do is our jobs 100% correctly. Repond to all RAs! We don't have an option anymore, there are no exceptions and if we all act the same then the system will work. Its that simple!
Correction, to my previous post, RA functions are not given below 900 feet on the approach.
Yes we can and should lobby the powers to be to accomplish these tasks in a quicker fashion, but we know that this costs and these costs are pushed down the ladder to the passenger, which the airlines hate! But in the real world we can accomplish a safer enviroment by us ALL operating in a 100% correct manner, especially when it comes to TCAS.
One common misconception with TCAS is that it only gives you 1 RA aircraft at a single time. It does not, you can have and it can display more than one RA at the same time (think of all those formation military fast jets out there). Therefore to say we didn't follow the RA because we had visual contact with the RA, is wrong because the second RA will collide with you 1 second later and you will never see it, possibly even not on TCAS if you are preoccupied with scanning the horizon for the first RA!
So my point still stands. As pilots what we can do is our jobs 100% correctly. Repond to all RAs! We don't have an option anymore, there are no exceptions and if we all act the same then the system will work. Its that simple!
Correction, to my previous post, RA functions are not given below 900 feet on the approach.
Join Date: May 2002
Location: Who can say?
Posts: 1,700
Likes: 0
Received 0 Likes
on
0 Posts
Willit Run - no, no, no, no, no.
Just because you can see traffic does NOT mean that that is the traffic you are being RA'd about. The representation on the screen is NOT a spatial representation, and nothing like all traffic is shown on it. And just because you can see one aircraft out there does not mean there are not more. Do not bet your life, that of the rest of your crew and the lives of all your passengers on an assumption.
FOLLOW THE TCAS EVERY TIME.
If you had excess closure rate, you were climbing far too fast too close to your level-off altitude. Can anyone else detect at least two elements of an accident chain here?
Just because you can see traffic does NOT mean that that is the traffic you are being RA'd about. The representation on the screen is NOT a spatial representation, and nothing like all traffic is shown on it. And just because you can see one aircraft out there does not mean there are not more. Do not bet your life, that of the rest of your crew and the lives of all your passengers on an assumption.
FOLLOW THE TCAS EVERY TIME.
If you had excess closure rate, you were climbing far too fast too close to your level-off altitude. Can anyone else detect at least two elements of an accident chain here?